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12<div class="ARTICLE">
13<div class="TITLEPAGE">
14<h1 class="TITLE"><a name="AEN2" id="AEN2">NCURSES Programming
15HOWTO</a></h1>
16<h3 class="AUTHOR"><a name="AEN4" id="AEN4">Pradeep Padala</a></h3>
17<div class="AFFILIATION">
18<div class="ADDRESS">
19<p class="ADDRESS"><code class="EMAIL">&lt;<a href=
20"mailto:ppadala@gmail.com">ppadala@gmail.com</a>&gt;</code></p>
21</div>
22</div>
23<p class="PUBDATE">v1.9, 2005-06-20<br></p>
24<div class="REVHISTORY">
25<table width="100%" border="0">
26<tr>
27<th align="left" valign="top" colspan="3"><b>Revision
28History</b></th>
29</tr>
30<tr>
31<td align="left">Revision 1.9</td>
32<td align="left">2005-06-20</td>
33<td align="left">Revised by: ppadala</td>
34</tr>
35<tr>
36<td align="left" colspan="3">The license has been changed to the
37MIT-style license used by NCURSES. Note that the programs are also
38re-licensed under this.</td>
39</tr>
40<tr>
41<td align="left">Revision 1.8</td>
42<td align="left">2005-06-17</td>
43<td align="left">Revised by: ppadala</td>
44</tr>
45<tr>
46<td align="left" colspan="3">Lots of updates. Added references and
47perl examples. Changes to examples. Many grammatical and stylistic
48changes to the content. Changes to NCURSES history.</td>
49</tr>
50<tr>
51<td align="left">Revision 1.7.1</td>
52<td align="left">2002-06-25</td>
53<td align="left">Revised by: ppadala</td>
54</tr>
55<tr>
56<td align="left" colspan="3">Added a README file for building and
57instructions for building from source.</td>
58</tr>
59<tr>
60<td align="left">Revision 1.7</td>
61<td align="left">2002-06-25</td>
62<td align="left">Revised by: ppadala</td>
63</tr>
64<tr>
65<td align="left" colspan="3">Added "Other formats" section and made
66a lot of fancy changes to the programs. Inlining of programs is
67gone.</td>
68</tr>
69<tr>
70<td align="left">Revision 1.6.1</td>
71<td align="left">2002-02-24</td>
72<td align="left">Revised by: ppadala</td>
73</tr>
74<tr>
75<td align="left" colspan="3">Removed the old Changelog section,
76cleaned the makefiles</td>
77</tr>
78<tr>
79<td align="left">Revision 1.6</td>
80<td align="left">2002-02-16</td>
81<td align="left">Revised by: ppadala</td>
82</tr>
83<tr>
84<td align="left" colspan="3">Corrected a lot of spelling mistakes,
85added ACS variables section</td>
86</tr>
87<tr>
88<td align="left">Revision 1.5</td>
89<td align="left">2002-01-05</td>
90<td align="left">Revised by: ppadala</td>
91</tr>
92<tr>
93<td align="left" colspan="3">Changed structure to present proper
94TOC</td>
95</tr>
96<tr>
97<td align="left">Revision 1.3.1</td>
98<td align="left">2001-07-26</td>
99<td align="left">Revised by: ppadala</td>
100</tr>
101<tr>
102<td align="left" colspan="3">Corrected maintainers paragraph,
103Corrected stable release number</td>
104</tr>
105<tr>
106<td align="left">Revision 1.3</td>
107<td align="left">2001-07-24</td>
108<td align="left">Revised by: ppadala</td>
109</tr>
110<tr>
111<td align="left" colspan="3">Added copyright notices to main
112document (LDP license) and programs (GPL), Corrected
113printw_example.</td>
114</tr>
115<tr>
116<td align="left">Revision 1.2</td>
117<td align="left">2001-06-05</td>
118<td align="left">Revised by: ppadala</td>
119</tr>
120<tr>
121<td align="left" colspan="3">Incorporated ravi's changes. Mainly to
122introduction, menu, form, justforfun sections</td>
123</tr>
124<tr>
125<td align="left">Revision 1.1</td>
126<td align="left">2001-05-22</td>
127<td align="left">Revised by: ppadala</td>
128</tr>
129<tr>
130<td align="left" colspan="3">Added "a word about window" section,
131Added scanw_example.</td>
132</tr>
133</table>
134</div>
135<div>
136<div class="ABSTRACT"><a name="AEN67" id="AEN67"></a>
137<p><em>This document is intended to be an "All in One" guide for
138programming with ncurses and its sister libraries. We graduate from
139a simple "Hello World" program to more complex form manipulation.
140No prior experience in ncurses is assumed. Send comments to
141<a href="mailto:ppadala@gmail.com" target="_top">this
142address</a></em></p>
143</div>
144</div>
145<hr></div>
146<div class="TOC">
147<dl>
148<dt><b>Table of Contents</b></dt>
149<dt>1. <a href="#INTRO">Introduction</a></dt>
150<dd>
151<dl>
152<dt>1.1. <a href="#WHATIS">What is NCURSES?</a></dt>
153<dt>1.2. <a href="#WHATCANWEDO">What we can do with
154NCURSES</a></dt>
155<dt>1.3. <a href="#WHERETOGETIT">Where to get it</a></dt>
156<dt>1.4. <a href="#PURPOSE">Purpose/Scope of the document</a></dt>
157<dt>1.5. <a href="#ABOUTPROGRAMS">About the Programs</a></dt>
158<dt>1.6. <a href="#OTHERFORMATS">Other Formats of the
159document</a></dt>
160<dt>1.7. <a href="#CREDITS">Credits</a></dt>
161<dt>1.8. <a href="#WISHLIST">Wish List</a></dt>
162<dt>1.9. <a href="#COPYRIGHT">Copyright</a></dt>
163</dl>
164</dd>
165<dt>2. <a href="#HELLOWORLD">Hello World !!!</a></dt>
166<dd>
167<dl>
168<dt>2.1. <a href="#COMPILECURSES">Compiling With the NCURSES
169Library</a></dt>
170<dt>2.2. <a href="#DISSECTION">Dissection</a></dt>
171</dl>
172</dd>
173<dt>3. <a href="#GORY">The Gory Details</a></dt>
174<dt>4. <a href="#INIT">Initialization</a></dt>
175<dd>
176<dl>
177<dt>4.1. <a href="#ABOUTINIT">Initialization functions</a></dt>
178<dt>4.2. <a href="#RAWCBREAK">raw() and cbreak()</a></dt>
179<dt>4.3. <a href="#ECHONOECHO">echo() and noecho()</a></dt>
180<dt>4.4. <a href="#KEYPAD">keypad()</a></dt>
181<dt>4.5. <a href="#HALFDELAY">halfdelay()</a></dt>
182<dt>4.6. <a href="#MISCINIT">Miscellaneous Initialization
183functions</a></dt>
184<dt>4.7. <a href="#INITEX">An Example</a></dt>
185</dl>
186</dd>
187<dt>5. <a href="#AWORDWINDOWS">A Word about Windows</a></dt>
188<dt>6. <a href="#PRINTW">Output functions</a></dt>
189<dd>
190<dl>
191<dt>6.1. <a href="#ADDCHCLASS">addch() class of functions</a></dt>
192<dt>6.2. <a href="#AEN298">mvaddch(), waddch() and
193mvwaddch()</a></dt>
194<dt>6.3. <a href="#PRINTWCLASS">printw() class of
195functions</a></dt>
196<dt>6.4. <a href="#ADDSTRCLASS">addstr() class of
197functions</a></dt>
198<dt>6.5. <a href="#ACAUTION">A word of caution</a></dt>
199</dl>
200</dd>
201<dt>7. <a href="#SCANW">Input functions</a></dt>
202<dd>
203<dl>
204<dt>7.1. <a href="#GETCHCLASS">getch() class of functions</a></dt>
205<dt>7.2. <a href="#SCANWCLASS">scanw() class of functions</a></dt>
206<dt>7.3. <a href="#GETSTRCLASS">getstr() class of
207functions</a></dt>
208<dt>7.4. <a href="#GETSTREX">Some examples</a></dt>
209</dl>
210</dd>
211<dt>8. <a href="#ATTRIB">Attributes</a></dt>
212<dd>
213<dl>
214<dt>8.1. <a href="#ATTRIBDETAILS">The details</a></dt>
215<dt>8.2. <a href="#ATTRONVSATTRSET">attron() vs attrset()</a></dt>
216<dt>8.3. <a href="#ATTR_GET">attr_get()</a></dt>
217<dt>8.4. <a href="#ATTR_FUNCS">attr_ functions</a></dt>
218<dt>8.5. <a href="#WATTRFUNCS">wattr functions</a></dt>
219<dt>8.6. <a href="#CHGAT">chgat() functions</a></dt>
220</dl>
221</dd>
222<dt>9. <a href="#WINDOWS">Windows</a></dt>
223<dd>
224<dl>
225<dt>9.1. <a href="#WINDOWBASICS">The basics</a></dt>
226<dt>9.2. <a href="#LETBEWINDOW">Let there be a Window !!!</a></dt>
227<dt>9.3. <a href="#BORDEREXEXPL">Explanation</a></dt>
228<dt>9.4. <a href="#OTHERSTUFF">The other stuff in the
229example</a></dt>
230<dt>9.5. <a href="#OTHERBORDERFUNCS">Other Border
231functions</a></dt>
232</dl>
233</dd>
234<dt>10. <a href="#COLOR">Colors</a></dt>
235<dd>
236<dl>
237<dt>10.1. <a href="#COLORBASICS">The basics</a></dt>
238<dt>10.2. <a href="#CHANGECOLORDEFS">Changing Color
239Definitions</a></dt>
240<dt>10.3. <a href="#COLORCONTENT">Color Content</a></dt>
241</dl>
242</dd>
243<dt>11. <a href="#KEYS">Interfacing with the key board</a></dt>
244<dd>
245<dl>
246<dt>11.1. <a href="#KEYSBASICS">The Basics</a></dt>
247<dt>11.2. <a href="#SIMPLEKEYEX">A Simple Key Usage
248example</a></dt>
249</dl>
250</dd>
251<dt>12. <a href="#MOUSE">Interfacing with the mouse</a></dt>
252<dd>
253<dl>
254<dt>12.1. <a href="#MOUSEBASICS">The Basics</a></dt>
255<dt>12.2. <a href="#GETTINGEVENTS">Getting the events</a></dt>
256<dt>12.3. <a href="#MOUSETOGETHER">Putting it all Together</a></dt>
257<dt>12.4. <a href="#MISCMOUSEFUNCS">Miscellaneous
258Functions</a></dt>
259</dl>
260</dd>
261<dt>13. <a href="#SCREEN">Screen Manipulation</a></dt>
262<dd>
263<dl>
264<dt>13.1. <a href="#GETYX">getyx() functions</a></dt>
265<dt>13.2. <a href="#SCREENDUMP">Screen Dumping</a></dt>
266<dt>13.3. <a href="#WINDOWDUMP">Window Dumping</a></dt>
267</dl>
268</dd>
269<dt>14. <a href="#MISC">Miscellaneous features</a></dt>
270<dd>
271<dl>
272<dt>14.1. <a href="#CURSSET">curs_set()</a></dt>
273<dt>14.2. <a href="#TEMPLEAVE">Temporarily Leaving Curses
274mode</a></dt>
275<dt>14.3. <a href="#ACSVARS">ACS_ variables</a></dt>
276</dl>
277</dd>
278<dt>15. <a href="#OTHERLIB">Other libraries</a></dt>
279<dt>16. <a href="#PANELS">Panel Library</a></dt>
280<dd>
281<dl>
282<dt>16.1. <a href="#PANELBASICS">The Basics</a></dt>
283<dt>16.2. <a href="#COMPILEPANELS">Compiling With the Panels
284Library</a></dt>
285<dt>16.3. <a href="#PANELBROWSING">Panel Window Browsing</a></dt>
286<dt>16.4. <a href="#USERPTRUSING">Using User Pointers</a></dt>
287<dt>16.5. <a href="#PANELMOVERESIZE">Moving and Resizing
288Panels</a></dt>
289<dt>16.6. <a href="#PANELSHOWHIDE">Hiding and Showing
290Panels</a></dt>
291<dt>16.7. <a href="#PANELABOVE">panel_above() and panel_below()
292Functions</a></dt>
293</dl>
294</dd>
295<dt>17. <a href="#MENUS">Menus Library</a></dt>
296<dd>
297<dl>
298<dt>17.1. <a href="#MENUBASICS">The Basics</a></dt>
299<dt>17.2. <a href="#COMPILEMENUS">Compiling With the Menu
300Library</a></dt>
301<dt>17.3. <a href="#MENUDRIVER">Menu Driver: The work horse of the
302menu system</a></dt>
303<dt>17.4. <a href="#MENUWINDOWS">Menu Windows</a></dt>
304<dt>17.5. <a href="#SCROLLMENUS">Scrolling Menus</a></dt>
305<dt>17.6. <a href="#MULTICOLUMN">Multi Columnar Menus</a></dt>
306<dt>17.7. <a href="#MULTIVALUEMENUS">Multi Valued Menus</a></dt>
307<dt>17.8. <a href="#MENUOPT">Menu Options</a></dt>
308<dt>17.9. <a href="#MENUUSERPTR">The useful User Pointer</a></dt>
309</dl>
310</dd>
311<dt>18. <a href="#FORMS">Forms Library</a></dt>
312<dd>
313<dl>
314<dt>18.1. <a href="#FORMBASICS">The Basics</a></dt>
315<dt>18.2. <a href="#COMPILEFORMS">Compiling With the Forms
316Library</a></dt>
317<dt>18.3. <a href="#PLAYFIELDS">Playing with Fields</a></dt>
318<dt>18.4. <a href="#FORMWINDOWS">Form Windows</a></dt>
319<dt>18.5. <a href="#FILEDVALIDATE">Field Validation</a></dt>
320<dt>18.6. <a href="#FORMDRIVER">Form Driver: The work horse of the
321forms system</a></dt>
322</dl>
323</dd>
324<dt>19. <a href="#TOOLS">Tools and Widget Libraries</a></dt>
325<dd>
326<dl>
327<dt>19.1. <a href="#CDK">CDK (Curses Development Kit)</a></dt>
328<dt>19.2. <a href="#DIALOG">The dialog</a></dt>
329<dt>19.3. <a href="#PERLCURSES">Perl Curses Modules CURSES::FORM
330and CURSES::WIDGETS</a></dt>
331</dl>
332</dd>
333<dt>20. <a href="#JUSTFORFUN">Just For Fun !!!</a></dt>
334<dd>
335<dl>
336<dt>20.1. <a href="#GAMEOFLIFE">The Game of Life</a></dt>
337<dt>20.2. <a href="#MAGIC">Magic Square</a></dt>
338<dt>20.3. <a href="#HANOI">Towers of Hanoi</a></dt>
339<dt>20.4. <a href="#QUEENS">Queens Puzzle</a></dt>
340<dt>20.5. <a href="#SHUFFLE">Shuffle</a></dt>
341<dt>20.6. <a href="#TT">Typing Tutor</a></dt>
342</dl>
343</dd>
344<dt>21. <a href="#REF">References</a></dt>
345</dl>
346</div>
347<div class="SECT1">
348<h2 class="SECT1"><a name="INTRO" id="INTRO">1.
349Introduction</a></h2>
350<p>In the olden days of teletype terminals, terminals were away
351from computers and were connected to them through serial cables.
352The terminals could be configured by sending a series of bytes. All
353the capabilities (such as moving the cursor to a new location,
354erasing part of the screen, scrolling the screen, changing modes
355etc.) of terminals could be accessed through these series of bytes.
356These control seeuqnces are usually called escape sequences,
357because they start with an escape(0x1B) character. Even today, with
358proper emulation, we can send escape sequences to the emulator and
359achieve the same effect on a terminal window.</p>
360<p>Suppose you wanted to print a line in color. Try typing this on
361your console.</p>
362<table border="0" bgcolor="#E0E0E0" width="100%">
363<tr>
364<td>
365<pre class="PROGRAMLISTING">
366<font color="#000000">echo "^[[0;31;40mIn Color"</font>
367</pre></td>
368</tr>
369</table>
370<p>The first character is an escape character, which looks like two
371characters ^ and [. To be able to print it, you have to press
372CTRL+V and then the ESC key. All the others are normal printable
373characters. You should be able to see the string "In Color" in red.
374It stays that way and to revert back to the original mode type
375this.</p>
376<table border="0" bgcolor="#E0E0E0" width="100%">
377<tr>
378<td>
379<pre class="PROGRAMLISTING">
380<font color="#000000">echo "^[[0;37;40m"</font>
381</pre></td>
382</tr>
383</table>
384<p>Now, what do these magic characters mean? Difficult to
385comprehend? They might even be different for different terminals.
386So the designers of UNIX invented a mechanism named <var class=
387"LITERAL">termcap</var>. It is a file that lists all the
388capabilities of a particular terminal, along with the escape
389sequences needed to achieve a particular effect. In the later
390years, this was replaced by <var class="LITERAL">terminfo</var>.
391Without delving too much into details, this mechanism allows
392application programs to query the terminfo database and obtain the
393control characters to be sent to a terminal or terminal
394emulator.</p>
395<div class="SECT2">
396<hr>
397<h3 class="SECT2"><a name="WHATIS" id="WHATIS">1.1. What is
398NCURSES?</a></h3>
399<p>You might be wondering, what the import of all this technical
400gibberish is. In the above scenario, every application program is
401supposed to query the terminfo and perform the necessary stuff
402(sending control characters etc.). It soon became difficult to
403manage this complexity and this gave birth to 'CURSES'. Curses is a
404pun on the name "cursor optimization". The Curses library forms a
405wrapper over working with raw terminal codes, and provides highly
406flexible and efficient API (Application Programming Interface). It
407provides functions to move the cursor, create windows, produce
408colors, play with mouse etc. The application programs need not
409worry about the underlying terminal capabilities.</p>
410<p>So what is NCURSES? NCURSES is a clone of the original System V
411Release 4.0 (SVr4) curses. It is a freely distributable library,
412fully compatible with older version of curses. In short, it is a
413library of functions that manages an application's display on
414character-cell terminals. In the remainder of the document, the
415terms curses and ncurses are used interchangeably.</p>
416<p>A detailed history of NCURSES can be found in the NEWS file from
417the source distribution. The current package is maintained by
418<a href="mailto:dickey@his.com" target="_top">Thomas Dickey</a>.
419You can contact the maintainers at <a href=
420"mailto:bug-ncurses@gnu.org" target=
421"_top">bug-ncurses@gnu.org</a>.</p>
422</div>
423<div class="SECT2">
424<hr>
425<h3 class="SECT2"><a name="WHATCANWEDO" id="WHATCANWEDO">1.2. What
426we can do with NCURSES</a></h3>
427<p>NCURSES not only creates a wrapper over terminal capabilities,
428but also gives a robust framework to create nice looking UI (User
429Interface)s in text mode. It provides functions to create windows
430etc. Its sister libraries panel, menu and form provide an extension
431to the basic curses library. These libraries usually come along
432with curses. One can create applications that contain multiple
433windows, menus, panels and forms. Windows can be managed
434independently, can provide 'scrollability' and even can be
435hidden.</p>
436<p>Menus provide the user with an easy command selection option.
437Forms allow the creation of easy-to-use data entry and display
438windows. Panels extend the capabilities of ncurses to deal with
439overlapping and stacked windows.</p>
440<p>These are just some of the basic things we can do with ncurses.
441As we move along, We will see all the capabilities of these
442libraries.</p>
443</div>
444<div class="SECT2">
445<hr>
446<h3 class="SECT2"><a name="WHERETOGETIT" id="WHERETOGETIT">1.3.
447Where to get it</a></h3>
448<p>All right, now that you know what you can do with ncurses, you
449must be rearing to get started. NCURSES is usually shipped with
450your installation. In case you don't have the library or want to
451compile it on your own, read on.</p>
452<p><em>Compiling the package</em></p>
453<p>NCURSES can be obtained from <a href=
454"ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz" target=
455"_top">ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz</a> or any
456of the ftp sites mentioned in <a href=
457"http://www.gnu.org/order/ftp.html" target=
458"_top">http://www.gnu.org/order/ftp.html</a>.</p>
459<p>Read the README and INSTALL files for details on to how to
460install it. It usually involves the following operations.</p>
461<table border="0" bgcolor="#E0E0E0" width="100%">
462<tr>
463<td>
464<pre class="PROGRAMLISTING">
465<font color=
466"#000000"> tar zxvf ncurses&lt;version&gt;.tar.gz # unzip and untar the archive
1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
2<HTML
3><HEAD
4><TITLE
5> NCURSES Programming HOWTO </TITLE
6><META
7NAME="GENERATOR"
8CONTENT="Modular DocBook HTML Stylesheet Version 1.79"></HEAD
9><BODY
10CLASS="ARTICLE"
11BGCOLOR="#FFFFFF"
12TEXT="#000000"
13LINK="#0000FF"
14VLINK="#840084"
15ALINK="#0000FF"
16><DIV
17CLASS="ARTICLE"
18><DIV
19CLASS="TITLEPAGE"
20><H1
21CLASS="TITLE"
22><A
23NAME="AEN2"
24>NCURSES Programming HOWTO</A
25></H1
26><H3
27CLASS="AUTHOR"
28><A
29NAME="AEN4"
30> Pradeep Padala </A
31></H3
32><DIV
33CLASS="AFFILIATION"
34><DIV
35CLASS="ADDRESS"
36><P
37CLASS="ADDRESS"
38><CODE
39CLASS="EMAIL"
40>&#60;<A
41HREF="mailto:ppadala@gmail.com"
42>ppadala@gmail.com</A
43>&#62;</CODE
44></P
45></DIV
46></DIV
47><P
48CLASS="PUBDATE"
49>v1.9, 2005-06-20<BR></P
50><DIV
51CLASS="REVHISTORY"
52><TABLE
53WIDTH="100%"
54BORDER="0"
55><TR
56><TH
57ALIGN="LEFT"
58VALIGN="TOP"
59COLSPAN="3"
60><B
61>Revision History</B
62></TH
63></TR
64><TR
65><TD
66ALIGN="LEFT"
67>Revision 1.9</TD
68><TD
69ALIGN="LEFT"
70>2005-06-20</TD
71><TD
72ALIGN="LEFT"
73>Revised by: ppadala</TD
74></TR
75><TR
76><TD
77ALIGN="LEFT"
78COLSPAN="3"
79>The license has been changed to the MIT-style license used
80 by NCURSES. Note that the programs are also re-licensed under this.</TD
81></TR
82><TR
83><TD
84ALIGN="LEFT"
85>Revision 1.8</TD
86><TD
87ALIGN="LEFT"
88>2005-06-17</TD
89><TD
90ALIGN="LEFT"
91>Revised by: ppadala</TD
92></TR
93><TR
94><TD
95ALIGN="LEFT"
96COLSPAN="3"
97>Lots of updates. Added references and perl examples.
98 Changes to examples. Many grammatical and stylistic changes to the
99 content. Changes to NCURSES history.</TD
100></TR
101><TR
102><TD
103ALIGN="LEFT"
104>Revision 1.7.1</TD
105><TD
106ALIGN="LEFT"
107>2002-06-25</TD
108><TD
109ALIGN="LEFT"
110>Revised by: ppadala</TD
111></TR
112><TR
113><TD
114ALIGN="LEFT"
115COLSPAN="3"
116>Added a README file for building and instructions
117 for building from source.</TD
118></TR
119><TR
120><TD
121ALIGN="LEFT"
122>Revision 1.7</TD
123><TD
124ALIGN="LEFT"
125>2002-06-25</TD
126><TD
127ALIGN="LEFT"
128>Revised by: ppadala</TD
129></TR
130><TR
131><TD
132ALIGN="LEFT"
133COLSPAN="3"
134>Added "Other formats" section and made a lot of fancy
135 changes to the programs. Inlining of programs is gone.</TD
136></TR
137><TR
138><TD
139ALIGN="LEFT"
140>Revision 1.6.1</TD
141><TD
142ALIGN="LEFT"
143>2002-02-24</TD
144><TD
145ALIGN="LEFT"
146>Revised by: ppadala</TD
147></TR
148><TR
149><TD
150ALIGN="LEFT"
151COLSPAN="3"
152>Removed the old Changelog section, cleaned the makefiles</TD
153></TR
154><TR
155><TD
156ALIGN="LEFT"
157>Revision 1.6</TD
158><TD
159ALIGN="LEFT"
160>2002-02-16</TD
161><TD
162ALIGN="LEFT"
163>Revised by: ppadala</TD
164></TR
165><TR
166><TD
167ALIGN="LEFT"
168COLSPAN="3"
169>Corrected a lot of spelling mistakes, added ACS variables
170 section</TD
171></TR
172><TR
173><TD
174ALIGN="LEFT"
175>Revision 1.5</TD
176><TD
177ALIGN="LEFT"
178>2002-01-05</TD
179><TD
180ALIGN="LEFT"
181>Revised by: ppadala</TD
182></TR
183><TR
184><TD
185ALIGN="LEFT"
186COLSPAN="3"
187>Changed structure to present proper TOC</TD
188></TR
189><TR
190><TD
191ALIGN="LEFT"
192>Revision 1.3.1</TD
193><TD
194ALIGN="LEFT"
195>2001-07-26</TD
196><TD
197ALIGN="LEFT"
198>Revised by: ppadala</TD
199></TR
200><TR
201><TD
202ALIGN="LEFT"
203COLSPAN="3"
204>Corrected maintainers paragraph, Corrected stable release number</TD
205></TR
206><TR
207><TD
208ALIGN="LEFT"
209>Revision 1.3</TD
210><TD
211ALIGN="LEFT"
212>2001-07-24</TD
213><TD
214ALIGN="LEFT"
215>Revised by: ppadala</TD
216></TR
217><TR
218><TD
219ALIGN="LEFT"
220COLSPAN="3"
221>Added copyright notices to main document (LDP license)
222 and programs (GPL), Corrected
223 printw_example.</TD
224></TR
225><TR
226><TD
227ALIGN="LEFT"
228>Revision 1.2</TD
229><TD
230ALIGN="LEFT"
231>2001-06-05</TD
232><TD
233ALIGN="LEFT"
234>Revised by: ppadala</TD
235></TR
236><TR
237><TD
238ALIGN="LEFT"
239COLSPAN="3"
240>Incorporated ravi's changes. Mainly to introduction, menu,
241 form, justforfun sections</TD
242></TR
243><TR
244><TD
245ALIGN="LEFT"
246>Revision 1.1</TD
247><TD
248ALIGN="LEFT"
249>2001-05-22</TD
250><TD
251ALIGN="LEFT"
252>Revised by: ppadala</TD
253></TR
254><TR
255><TD
256ALIGN="LEFT"
257COLSPAN="3"
258>Added "a word about window" section, Added scanw_example.</TD
259></TR
260></TABLE
261></DIV
262><DIV
263><DIV
264CLASS="ABSTRACT"
265><P
266></P
267><A
268NAME="AEN67"
269></A
270><P
271> <SPAN
272CLASS="emphasis"
273><I
274CLASS="EMPHASIS"
275>This document is intended to be an "All in One" guide for programming with
276ncurses and its sister libraries. We graduate from a simple "Hello World"
277program to more complex form manipulation. No prior experience in ncurses is
278assumed. Send comments to <A
279HREF="mailto:ppadala@gmail.com"
280TARGET="_top"
281>this address</A
282>
283 </I
284></SPAN
285>
286 </P
287><P
288></P
289></DIV
290></DIV
291><HR></DIV
292><DIV
293CLASS="TOC"
294><DL
295><DT
296><B
297>Table of Contents</B
298></DT
299><DT
300>1. <A
301HREF="#INTRO"
302>Introduction</A
303></DT
304><DD
305><DL
306><DT
307>1.1. <A
308HREF="#WHATIS"
309>What is NCURSES?</A
310></DT
311><DT
312>1.2. <A
313HREF="#WHATCANWEDO"
314>What we can do with NCURSES</A
315></DT
316><DT
317>1.3. <A
318HREF="#WHERETOGETIT"
319>Where to get it</A
320></DT
321><DT
322>1.4. <A
323HREF="#PURPOSE"
324>Purpose/Scope of the document</A
325></DT
326><DT
327>1.5. <A
328HREF="#ABOUTPROGRAMS"
329>About the Programs</A
330></DT
331><DT
332>1.6. <A
333HREF="#OTHERFORMATS"
334>Other Formats of the document</A
335></DT
336><DD
337><DL
338><DT
339>1.6.1. <A
340HREF="#LISTFORMATS"
341>Readily available formats from tldp.org</A
342></DT
343><DT
344>1.6.2. <A
345HREF="#BUILDSOURCE"
346>Building from source</A
347></DT
348></DL
349></DD
350><DT
351>1.7. <A
352HREF="#CREDITS"
353>Credits</A
354></DT
355><DT
356>1.8. <A
357HREF="#WISHLIST"
358>Wish List</A
359></DT
360><DT
361>1.9. <A
362HREF="#COPYRIGHT"
363>Copyright</A
364></DT
365></DL
366></DD
367><DT
368>2. <A
369HREF="#HELLOWORLD"
370>Hello World !!!</A
371></DT
372><DD
373><DL
374><DT
375>2.1. <A
376HREF="#COMPILECURSES"
377>Compiling With the NCURSES Library</A
378></DT
379><DT
380>2.2. <A
381HREF="#DISSECTION"
382>Dissection</A
383></DT
384><DD
385><DL
386><DT
387>2.2.1. <A
388HREF="#ABOUT-INITSCR"
389>About initscr()</A
390></DT
391><DT
392>2.2.2. <A
393HREF="#MYST-REFRESH"
394>The mysterious refresh()</A
395></DT
396><DT
397>2.2.3. <A
398HREF="#ABOUT-ENDWIN"
399>About endwin()</A
400></DT
401></DL
402></DD
403></DL
404></DD
405><DT
406>3. <A
407HREF="#GORY"
408>The Gory Details</A
409></DT
410><DT
411>4. <A
412HREF="#INIT"
413>Initialization</A
414></DT
415><DD
416><DL
417><DT
418>4.1. <A
419HREF="#ABOUTINIT"
420>Initialization functions</A
421></DT
422><DT
423>4.2. <A
424HREF="#RAWCBREAK"
425>raw() and cbreak()</A
426></DT
427><DT
428>4.3. <A
429HREF="#ECHONOECHO"
430>echo() and noecho()</A
431></DT
432><DT
433>4.4. <A
434HREF="#KEYPAD"
435>keypad()</A
436></DT
437><DT
438>4.5. <A
439HREF="#HALFDELAY"
440>halfdelay()</A
441></DT
442><DT
443>4.6. <A
444HREF="#MISCINIT"
445>Miscellaneous Initialization functions</A
446></DT
447><DT
448>4.7. <A
449HREF="#INITEX"
450>An Example</A
451></DT
452></DL
453></DD
454><DT
455>5. <A
456HREF="#AWORDWINDOWS"
457>A Word about Windows</A
458></DT
459><DT
460>6. <A
461HREF="#PRINTW"
462>Output functions</A
463></DT
464><DD
465><DL
466><DT
467>6.1. <A
468HREF="#ADDCHCLASS"
469>addch() class of functions</A
470></DT
471><DT
472>6.2. <A
473HREF="#AEN298"
474>mvaddch(), waddch() and mvwaddch()</A
475></DT
476><DT
477>6.3. <A
478HREF="#PRINTWCLASS"
479>printw() class of functions</A
480></DT
481><DD
482><DL
483><DT
484>6.3.1. <A
485HREF="#PRINTWMVPRINTW"
486>printw() and mvprintw</A
487></DT
488><DT
489>6.3.2. <A
490HREF="#WPRINTWMVWPRINTW"
491>wprintw() and mvwprintw</A
492></DT
493><DT
494>6.3.3. <A
495HREF="#VWPRINTW"
496>vwprintw()</A
497></DT
498><DT
499>6.3.4. <A
500HREF="#SIMPLEPRINTWEX"
501>A Simple printw example</A
502></DT
503></DL
504></DD
505><DT
506>6.4. <A
507HREF="#ADDSTRCLASS"
508>addstr() class of functions</A
509></DT
510><DT
511>6.5. <A
512HREF="#ACAUTION"
513>A word of caution</A
514></DT
515></DL
516></DD
517><DT
518>7. <A
519HREF="#SCANW"
520>Input functions</A
521></DT
522><DD
523><DL
524><DT
525>7.1. <A
526HREF="#GETCHCLASS"
527>getch() class of functions</A
528></DT
529><DT
530>7.2. <A
531HREF="#SCANWCLASS"
532>scanw() class of functions</A
533></DT
534><DD
535><DL
536><DT
537>7.2.1. <A
538HREF="#SCANWMVSCANW"
539>scanw() and mvscanw</A
540></DT
541><DT
542>7.2.2. <A
543HREF="#WSCANWMVWSCANW"
544>wscanw() and mvwscanw()</A
545></DT
546><DT
547>7.2.3. <A
548HREF="#VWSCANW"
549>vwscanw()</A
550></DT
551></DL
552></DD
553><DT
554>7.3. <A
555HREF="#GETSTRCLASS"
556>getstr() class of functions</A
557></DT
558><DT
559>7.4. <A
560HREF="#GETSTREX"
561>Some examples</A
562></DT
563></DL
564></DD
565><DT
566>8. <A
567HREF="#ATTRIB"
568>Attributes</A
569></DT
570><DD
571><DL
572><DT
573>8.1. <A
574HREF="#ATTRIBDETAILS"
575>The details</A
576></DT
577><DT
578>8.2. <A
579HREF="#ATTRONVSATTRSET"
580>attron() vs attrset()</A
581></DT
582><DT
583>8.3. <A
584HREF="#ATTR_GET"
585>attr_get()</A
586></DT
587><DT
588>8.4. <A
589HREF="#ATTR_FUNCS"
590>attr_ functions</A
591></DT
592><DT
593>8.5. <A
594HREF="#WATTRFUNCS"
595>wattr functions</A
596></DT
597><DT
598>8.6. <A
599HREF="#CHGAT"
600>chgat() functions</A
601></DT
602></DL
603></DD
604><DT
605>9. <A
606HREF="#WINDOWS"
607>Windows</A
608></DT
609><DD
610><DL
611><DT
612>9.1. <A
613HREF="#WINDOWBASICS"
614>The basics</A
615></DT
616><DT
617>9.2. <A
618HREF="#LETBEWINDOW"
619>Let there be a Window !!!</A
620></DT
621><DT
622>9.3. <A
623HREF="#BORDEREXEXPL"
624>Explanation</A
625></DT
626><DT
627>9.4. <A
628HREF="#OTHERSTUFF"
629>The other stuff in the example</A
630></DT
631><DT
632>9.5. <A
633HREF="#OTHERBORDERFUNCS"
634>Other Border functions</A
635></DT
636></DL
637></DD
638><DT
639>10. <A
640HREF="#COLOR"
641>Colors</A
642></DT
643><DD
644><DL
645><DT
646>10.1. <A
647HREF="#COLORBASICS"
648>The basics</A
649></DT
650><DT
651>10.2. <A
652HREF="#CHANGECOLORDEFS"
653>Changing Color Definitions</A
654></DT
655><DT
656>10.3. <A
657HREF="#COLORCONTENT"
658>Color Content</A
659></DT
660></DL
661></DD
662><DT
663>11. <A
664HREF="#KEYS"
665>Interfacing with the key board</A
666></DT
667><DD
668><DL
669><DT
670>11.1. <A
671HREF="#KEYSBASICS"
672>The Basics</A
673></DT
674><DT
675>11.2. <A
676HREF="#SIMPLEKEYEX"
677>A Simple Key Usage example</A
678></DT
679></DL
680></DD
681><DT
682>12. <A
683HREF="#MOUSE"
684>Interfacing with the mouse</A
685></DT
686><DD
687><DL
688><DT
689>12.1. <A
690HREF="#MOUSEBASICS"
691>The Basics</A
692></DT
693><DT
694>12.2. <A
695HREF="#GETTINGEVENTS"
696>Getting the events</A
697></DT
698><DT
699>12.3. <A
700HREF="#MOUSETOGETHER"
701>Putting it all Together</A
702></DT
703><DT
704>12.4. <A
705HREF="#MISCMOUSEFUNCS"
706>Miscellaneous Functions</A
707></DT
708></DL
709></DD
710><DT
711>13. <A
712HREF="#SCREEN"
713>Screen Manipulation</A
714></DT
715><DD
716><DL
717><DT
718>13.1. <A
719HREF="#GETYX"
720>getyx() functions</A
721></DT
722><DT
723>13.2. <A
724HREF="#SCREENDUMP"
725>Screen Dumping</A
726></DT
727><DT
728>13.3. <A
729HREF="#WINDOWDUMP"
730>Window Dumping</A
731></DT
732></DL
733></DD
734><DT
735>14. <A
736HREF="#MISC"
737>Miscellaneous features</A
738></DT
739><DD
740><DL
741><DT
742>14.1. <A
743HREF="#CURSSET"
744>curs_set()</A
745></DT
746><DT
747>14.2. <A
748HREF="#TEMPLEAVE"
749>Temporarily Leaving Curses mode</A
750></DT
751><DT
752>14.3. <A
753HREF="#ACSVARS"
754>ACS_ variables</A
755></DT
756></DL
757></DD
758><DT
759>15. <A
760HREF="#OTHERLIB"
761>Other libraries</A
762></DT
763><DT
764>16. <A
765HREF="#PANELS"
766>Panel Library</A
767></DT
768><DD
769><DL
770><DT
771>16.1. <A
772HREF="#PANELBASICS"
773>The Basics</A
774></DT
775><DT
776>16.2. <A
777HREF="#COMPILEPANELS"
778>Compiling With the Panels Library</A
779></DT
780><DT
781>16.3. <A
782HREF="#PANELBROWSING"
783>Panel Window Browsing</A
784></DT
785><DT
786>16.4. <A
787HREF="#USERPTRUSING"
788>Using User Pointers</A
789></DT
790><DT
791>16.5. <A
792HREF="#PANELMOVERESIZE"
793>Moving and Resizing Panels</A
794></DT
795><DT
796>16.6. <A
797HREF="#PANELSHOWHIDE"
798>Hiding and Showing Panels</A
799></DT
800><DT
801>16.7. <A
802HREF="#PANELABOVE"
803>panel_above() and panel_below() Functions</A
804></DT
805></DL
806></DD
807><DT
808>17. <A
809HREF="#MENUS"
810>Menus Library</A
811></DT
812><DD
813><DL
814><DT
815>17.1. <A
816HREF="#MENUBASICS"
817>The Basics</A
818></DT
819><DT
820>17.2. <A
821HREF="#COMPILEMENUS"
822>Compiling With the Menu Library</A
823></DT
824><DT
825>17.3. <A
826HREF="#MENUDRIVER"
827>Menu Driver: The work horse of the menu system</A
828></DT
829><DT
830>17.4. <A
831HREF="#MENUWINDOWS"
832>Menu Windows</A
833></DT
834><DT
835>17.5. <A
836HREF="#SCROLLMENUS"
837>Scrolling Menus</A
838></DT
839><DT
840>17.6. <A
841HREF="#MULTICOLUMN"
842>Multi Columnar Menus</A
843></DT
844><DT
845>17.7. <A
846HREF="#MULTIVALUEMENUS"
847>Multi Valued Menus</A
848></DT
849><DT
850>17.8. <A
851HREF="#MENUOPT"
852>Menu Options</A
853></DT
854><DT
855>17.9. <A
856HREF="#MENUUSERPTR"
857>The useful User Pointer</A
858></DT
859></DL
860></DD
861><DT
862>18. <A
863HREF="#FORMS"
864>Forms Library</A
865></DT
866><DD
867><DL
868><DT
869>18.1. <A
870HREF="#FORMBASICS"
871>The Basics</A
872></DT
873><DT
874>18.2. <A
875HREF="#COMPILEFORMS"
876>Compiling With the Forms Library</A
877></DT
878><DT
879>18.3. <A
880HREF="#PLAYFIELDS"
881>Playing with Fields</A
882></DT
883><DD
884><DL
885><DT
886>18.3.1. <A
887HREF="#FETCHINFO"
888>Fetching Size and Location of Field</A
889></DT
890><DT
891>18.3.2. <A
892HREF="#MOVEFIELD"
893>Moving the field</A
894></DT
895><DT
896>18.3.3. <A
897HREF="#JUSTIFYFIELD"
898>Field Justification</A
899></DT
900><DT
901>18.3.4. <A
902HREF="#FIELDDISPATTRIB"
903>Field Display Attributes</A
904></DT
905><DT
906>18.3.5. <A
907HREF="#FIELDOPTIONBITS"
908>Field Option Bits</A
909></DT
910><DT
911>18.3.6. <A
912HREF="#FIELDSTATUS"
913>Field Status</A
914></DT
915><DT
916>18.3.7. <A
917HREF="#FIELDUSERPTR"
918>Field User Pointer</A
919></DT
920><DT
921>18.3.8. <A
922HREF="#VARIABLESIZEFIELDS"
923>Variable-Sized Fields</A
924></DT
925></DL
926></DD
927><DT
928>18.4. <A
929HREF="#FORMWINDOWS"
930>Form Windows</A
931></DT
932><DT
933>18.5. <A
934HREF="#FILEDVALIDATE"
935>Field Validation</A
936></DT
937><DT
938>18.6. <A
939HREF="#FORMDRIVER"
940>Form Driver: The work horse of the forms system</A
941></DT
942><DD
943><DL
944><DT
945>18.6.1. <A
946HREF="#PAGENAVREQ"
947>Page Navigation Requests</A
948></DT
949><DT
950>18.6.2. <A
951HREF="#INTERFIELDNAVREQ"
952>Inter-Field Navigation Requests</A
953></DT
954><DT
955>18.6.3. <A
956HREF="#INTRAFIELDNAVREQ"
957>Intra-Field Navigation Requests</A
958></DT
959><DT
960>18.6.4. <A
961HREF="#SCROLLREQ"
962>Scrolling Requests</A
963></DT
964><DT
965>18.6.5. <A
966HREF="#EDITREQ"
967>Editing Requests</A
968></DT
969><DT
970>18.6.6. <A
971HREF="#ORDERREQ"
972>Order Requests</A
973></DT
974><DT
975>18.6.7. <A
976HREF="#APPLICCOMMANDS"
977>Application Commands</A
978></DT
979></DL
980></DD
981></DL
982></DD
983><DT
984>19. <A
985HREF="#TOOLS"
986>Tools and Widget Libraries</A
987></DT
988><DD
989><DL
990><DT
991>19.1. <A
992HREF="#CDK"
993>CDK (Curses Development Kit)</A
994></DT
995><DD
996><DL
997><DT
998>19.1.1. <A
999HREF="#WIDGETLIST"
1000>Widget List</A
1001></DT
1002><DT
1003>19.1.2. <A
1004HREF="#CDKATTRACT"
1005>Some Attractive Features</A
1006></DT
1007><DT
1008>19.1.3. <A
1009HREF="#CDKCONCLUSION"
1010>Conclusion</A
1011></DT
1012></DL
1013></DD
1014><DT
1015>19.2. <A
1016HREF="#DIALOG"
1017>The dialog</A
1018></DT
1019><DT
1020>19.3. <A
1021HREF="#PERLCURSES"
1022>Perl Curses Modules CURSES::FORM and CURSES::WIDGETS</A
1023></DT
1024></DL
1025></DD
1026><DT
1027>20. <A
1028HREF="#JUSTFORFUN"
1029>Just For Fun !!!</A
1030></DT
1031><DD
1032><DL
1033><DT
1034>20.1. <A
1035HREF="#GAMEOFLIFE"
1036>The Game of Life</A
1037></DT
1038><DT
1039>20.2. <A
1040HREF="#MAGIC"
1041>Magic Square</A
1042></DT
1043><DT
1044>20.3. <A
1045HREF="#HANOI"
1046>Towers of Hanoi</A
1047></DT
1048><DT
1049>20.4. <A
1050HREF="#QUEENS"
1051>Queens Puzzle</A
1052></DT
1053><DT
1054>20.5. <A
1055HREF="#SHUFFLE"
1056>Shuffle</A
1057></DT
1058><DT
1059>20.6. <A
1060HREF="#TT"
1061>Typing Tutor</A
1062></DT
1063></DL
1064></DD
1065><DT
1066>21. <A
1067HREF="#REF"
1068>References</A
1069></DT
1070></DL
1071></DIV
1072><DIV
1073CLASS="SECT1"
1074><H2
1075CLASS="SECT1"
1076><A
1077NAME="INTRO"
1078>1. Introduction</A
1079></H2
1080><P
1081>In the olden days of teletype terminals, terminals were away from computers and
1082were connected to them through serial cables. The terminals could be configured
1083by sending a series of bytes. All the capabilities (such as
1084moving the cursor to a new location, erasing part of the screen, scrolling the
1085screen, changing modes etc.) of terminals could be accessed through these
1086series of bytes. These control seeuqnces are usually called escape sequences,
1087because they start
1088with an escape(0x1B) character. Even today, with proper emulation, we can send
1089escape sequences to the emulator and achieve the same effect on a terminal
1090window.</P
1091><P
1092>Suppose you wanted to print a line in color. Try typing this on your console.</P
1093><PRE
1094CLASS="PROGRAMLISTING"
1095>echo "^[[0;31;40mIn Color"</PRE
1096><P
1097>The first character is an escape character, which looks like two characters ^
1098and [. To be able to print it, you have to press CTRL+V and then the ESC key.
1099All the others are normal printable characters. You should be able to see the
1100string "In Color" in red. It stays that way and to revert back to the original
1101mode type this.</P
1102><PRE
1103CLASS="PROGRAMLISTING"
1104>echo "^[[0;37;40m"</PRE
1105><P
1106>Now, what do these magic characters mean? Difficult to comprehend? They might
1107even be different for different terminals. So the designers of UNIX invented a
1108mechanism named <TT
1109CLASS="LITERAL"
1110>termcap</TT
1111>. It is a file that
1112lists all the capabilities of a particular terminal, along with the escape
1113sequences needed to achieve a particular effect. In the later years, this was
1114replaced by <TT
1115CLASS="LITERAL"
1116>terminfo</TT
1117>. Without delving too
1118much into details, this mechanism allows application
1119programs to query the terminfo database and obtain the control characters to be
1120sent to a terminal or terminal emulator.</P
1121><DIV
1122CLASS="SECT2"
1123><HR><H3
1124CLASS="SECT2"
1125><A
1126NAME="WHATIS"
1127>1.1. What is NCURSES?</A
1128></H3
1129><P
1130>
1131You might be wondering, what the import of all this technical gibberish is. In
1132the above scenario, every application program is supposed to query the terminfo
1133and perform the necessary stuff (sending control characters etc.). It soon became
1134difficult to manage this complexity and this gave birth to 'CURSES'. Curses is
1135a pun on the name "cursor optimization". The Curses library forms a wrapper
1136over working with raw terminal codes, and provides highly flexible and
1137efficient API (Application Programming Interface). It provides functions to
1138move the cursor, create windows, produce colors, play with mouse etc. The
1139application programs need not worry about the underlying terminal capabilities.</P
1140><P
1141>So what is NCURSES? NCURSES is a clone of the original System V Release 4.0
1142(SVr4) curses. It is a freely distributable library, fully compatible with
1143older version of curses. In short, it is a library of functions that manages
1144an application's display on character-cell terminals. In the remainder of the
1145document, the terms curses and ncurses are used interchangeably. </P
1146><P
1147>A detailed history of NCURSES can be found in the NEWS file from the source
1148distribution. The current package is maintained by
1149<A
1150HREF="mailto:dickey@his.com"
1151TARGET="_top"
1152>Thomas Dickey</A
1153>.
1154You can contact the maintainers at <A
1155HREF="mailto:bug-ncurses@gnu.org"
1156TARGET="_top"
1157>bug-ncurses@gnu.org</A
1158>.</P
1159></DIV
1160><DIV
1161CLASS="SECT2"
1162><HR><H3
1163CLASS="SECT2"
1164><A
1165NAME="WHATCANWEDO"
1166>1.2. What we can do with NCURSES</A
1167></H3
1168><P
1169>NCURSES not only creates a wrapper over terminal capabilities, but also gives a
1170robust framework to create nice looking UI (User Interface)s in text mode. It
1171provides functions to create windows etc. Its sister libraries panel, menu and
1172form provide an extension to the basic curses library. These libraries usually
1173come along with curses. One can create applications that contain multiple
1174windows, menus, panels and forms. Windows can be managed independently, can
1175provide 'scrollability' and even can be hidden.</P
1176><P
1177>
1178Menus provide the user with an easy command selection option. Forms allow the
1179creation of easy-to-use data entry and display windows. Panels extend the
1180capabilities of ncurses to deal with overlapping and stacked windows.</P
1181><P
1182>These are just some of the basic things we can do with ncurses. As we move
1183along, We will see all the capabilities of these libraries. </P
1184></DIV
1185><DIV
1186CLASS="SECT2"
1187><HR><H3
1188CLASS="SECT2"
1189><A
1190NAME="WHERETOGETIT"
1191>1.3. Where to get it</A
1192></H3
1193><P
1194>All right, now that you know what you can do with ncurses, you must be rearing
1195to get started. NCURSES is usually shipped with your installation. In case
1196you don't have the library or want to compile it on your own, read on.</P
1197><P
1198><SPAN
1199CLASS="emphasis"
1200><I
1201CLASS="EMPHASIS"
1202>Compiling the package</I
1203></SPAN
1204> </P
1205><P
1206>NCURSES can be obtained from <A
1207HREF="ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz"
1208TARGET="_top"
1209>ftp://ftp.gnu.org/pub/gnu/ncurses/ncurses.tar.gz</A
1210> or any of the ftp
1211sites mentioned in <A
1212HREF="http://www.gnu.org/order/ftp.html"
1213TARGET="_top"
1214>http://www.gnu.org/order/ftp.html</A
1215>. </P
1216><P
1217>Read the README and INSTALL files for details on to how to install it. It
1218usually involves the following operations.</P
1219><PRE
1220CLASS="PROGRAMLISTING"
1221> tar zxvf ncurses&lt;version&gt;.tar.gz # unzip and untar the archive
467 cd ncurses&lt;version&gt; # cd to the directory
468 ./configure # configure the build according to your
469 # environment
470 make # make it
471 su root # become root
1222 cd ncurses&lt;version&gt; # cd to the directory
1223 ./configure # configure the build according to your
1224 # environment
1225 make # make it
1226 su root # become root
472 make install # install it</font>
473</pre></td>
474</tr>
475</table>
476<p><em>Using the RPM</em></p>
477<p>NCURSES RPM can be found and downloaded from <a href=
478"http://rpmfind.net" target="_top">http://rpmfind.net</a> . The RPM
479can be installed with the following command after becoming
480root.</p>
481<table border="0" bgcolor="#E0E0E0" width="100%">
482<tr>
483<td>
484<pre class="PROGRAMLISTING">
485<font color="#000000"> rpm -i &lt;downloaded rpm&gt;</font>
486</pre></td>
487</tr>
488</table>
489</div>
490<div class="SECT2">
491<hr>
492<h3 class="SECT2"><a name="PURPOSE" id="PURPOSE">1.4. Purpose/Scope
493of the document</a></h3>
494<p>This document is intended to be a "All in One" guide for
495programming with ncurses and its sister libraries. We graduate from
496a simple "Hello World" program to more complex form manipulation.
497No prior experience in ncurses is assumed. The writing is informal,
498but a lot of detail is provided for each of the examples.</p>
499</div>
500<div class="SECT2">
501<hr>
502<h3 class="SECT2"><a name="ABOUTPROGRAMS" id="ABOUTPROGRAMS">1.5.
503About the Programs</a></h3>
504<p>All the programs in the document are available in zipped form
505<a href=
506"http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs.tar.gz"
507target="_top">here</a>. Unzip and untar it. The directory structure
508looks like this.</p>
509<table border="0" bgcolor="#E0E0E0" width="100%">
510<tr>
511<td>
512<pre class="PROGRAMLISTING">
513<font color="#000000">ncurses
1227 make install # install it</PRE
1228><P
1229><SPAN
1230CLASS="emphasis"
1231><I
1232CLASS="EMPHASIS"
1233>Using the RPM </I
1234></SPAN
1235></P
1236><P
1237>NCURSES RPM can be found and downloaded from <A
1238HREF="http://rpmfind.net"
1239TARGET="_top"
1240>http://rpmfind.net </A
1241>. The RPM can be installed with the following
1242command after becoming root.</P
1243><PRE
1244CLASS="PROGRAMLISTING"
1245> rpm -i &lt;downloaded rpm&gt;</PRE
1246></DIV
1247><DIV
1248CLASS="SECT2"
1249><HR><H3
1250CLASS="SECT2"
1251><A
1252NAME="PURPOSE"
1253>1.4. Purpose/Scope of the document</A
1254></H3
1255><P
1256>This document is intended to be a "All in One" guide for programming with
1257ncurses and its sister libraries. We graduate from a simple "Hello World"
1258program to more complex form manipulation. No prior experience in ncurses is
1259assumed. The writing is informal, but a lot of detail is provided for
1260each of the examples.</P
1261></DIV
1262><DIV
1263CLASS="SECT2"
1264><HR><H3
1265CLASS="SECT2"
1266><A
1267NAME="ABOUTPROGRAMS"
1268>1.5. About the Programs</A
1269></H3
1270><P
1271>All the programs in the document are available in zipped form
1272<A
1273HREF="http://www.tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs.tar.gz"
1274TARGET="_top"
1275>here</A
1276>. Unzip and untar it. The directory structure looks like this.</P
1277><PRE
1278CLASS="PROGRAMLISTING"
1279>ncurses
514 |
515 |----&gt; JustForFun -- just for fun programs
516 |----&gt; basics -- basic programs
517 |----&gt; demo -- output files go into this directory after make
518 | |
519 | |----&gt; exe -- exe files of all example programs
520 |----&gt; forms -- programs related to form library
521 |----&gt; menus -- programs related to menus library
522 |----&gt; panels -- programs related to panels library
523 |----&gt; perl -- perl equivalents of the examples (contributed
524 | by Anuradha Ratnaweera)
525 |----&gt; Makefile -- the top level Makefile
526 |----&gt; README -- the top level README file. contains instructions
1280 |
1281 |----&gt; JustForFun -- just for fun programs
1282 |----&gt; basics -- basic programs
1283 |----&gt; demo -- output files go into this directory after make
1284 | |
1285 | |----&gt; exe -- exe files of all example programs
1286 |----&gt; forms -- programs related to form library
1287 |----&gt; menus -- programs related to menus library
1288 |----&gt; panels -- programs related to panels library
1289 |----&gt; perl -- perl equivalents of the examples (contributed
1290 | by Anuradha Ratnaweera)
1291 |----&gt; Makefile -- the top level Makefile
1292 |----&gt; README -- the top level README file. contains instructions
527 |----&gt; COPYING -- copyright notice</font>
528</pre></td>
529</tr>
530</table>
531<p>The individual directories contain the following files.</p>
532<table border="0" bgcolor="#E0E0E0" width="100%">
533<tr>
534<td>
535<pre class="PROGRAMLISTING">
536<font color="#000000">Description of files in each directory
1293 |----&gt; COPYING -- copyright notice</PRE
1294><P
1295>The individual directories contain the following files.</P
1296><PRE
1297CLASS="PROGRAMLISTING"
1298>Description of files in each directory
537--------------------------------------
538JustForFun
539 |
540 |----&gt; hanoi.c -- The Towers of Hanoi Solver
541 |----&gt; life.c -- The Game of Life demo
542 |----&gt; magic.c -- An Odd Order Magic Square builder
543 |----&gt; queens.c -- The famous N-Queens Solver
544 |----&gt; shuffle.c -- A fun game, if you have time to kill

--- 42 unchanged lines hidden (view full) ---

587 |
588 |----&gt; panel_browse.c -- Panel browsing through tab. Usage of user
589 | -- pointer
590 |----&gt; panel_hide.c -- Hiding and Un hiding of panels
591 |----&gt; panel_resize.c -- Moving and resizing of panels
592 |----&gt; panel_simple.c -- A simple panel example
593
594 perl
1299--------------------------------------
1300JustForFun
1301 |
1302 |----&gt; hanoi.c -- The Towers of Hanoi Solver
1303 |----&gt; life.c -- The Game of Life demo
1304 |----&gt; magic.c -- An Odd Order Magic Square builder
1305 |----&gt; queens.c -- The famous N-Queens Solver
1306 |----&gt; shuffle.c -- A fun game, if you have time to kill

--- 42 unchanged lines hidden (view full) ---

1349 |
1350 |----&gt; panel_browse.c -- Panel browsing through tab. Usage of user
1351 | -- pointer
1352 |----&gt; panel_hide.c -- Hiding and Un hiding of panels
1353 |----&gt; panel_resize.c -- Moving and resizing of panels
1354 |----&gt; panel_simple.c -- A simple panel example
1355
1356 perl
595 |----&gt; 01-10.pl -- Perl equivalents of first ten example programs</font>
596</pre></td>
597</tr>
598</table>
599<p>There is a top level Makefile included in the main directory. It
600builds all the files and puts the ready-to-use exes in demo/exe
601directory. You can also do selective make by going into the
602corresponding directory. Each directory contains a README file
603explaining the purpose of each c file in the directory.</p>
604<p>For every example, I have included path name for the file
605relative to the examples directory.</p>
606<p>If you prefer browsing individual programs, point your browser
607to <a href=
608"http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/"
609target=
610"_top">http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/</a></p>
611<p>All the programs are released under the same license that is
612used by ncurses (MIT-style). This gives you the ability to do
613pretty much anything other than claiming them as yours. Feel free
614to use them in your programs as appropriate.</p>
615</div>
616<div class="SECT2">
617<hr>
618<h3 class="SECT2"><a name="OTHERFORMATS" id="OTHERFORMATS">1.6.
619Other Formats of the document</a></h3>
620<p>This howto is also availabe in various other formats on the
621tldp.org site. Here are the links to other formats of this
622document.</p>
623<div class="SECT3">
624<hr>
625<h4 class="SECT3"><a name="LISTFORMATS" id="LISTFORMATS">1.6.1.
626Readily available formats from tldp.org</a></h4>
627<ul>
628<li>
629<p><a href=
630"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/pdf/NCURSES-Programming-HOWTO.pdf"
631target="_top">Acrobat PDF Format</a></p>
632</li>
633<li>
634<p><a href=
635"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/ps/NCURSES-Programming-HOWTO.ps.gz"
636target="_top">PostScript Format</a></p>
637</li>
638<li>
639<p><a href=
640"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html/NCURSES-Programming-HOWTO-html.tar.gz"
641target="_top">In Multiple HTML pages</a></p>
642</li>
643<li>
644<p><a href=
645"http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/NCURSES-Programming-HOWTO.html"
646target="_top">In One big HTML format</a></p>
647</li>
648</ul>
649</div>
650<div class="SECT3">
651<hr>
652<h4 class="SECT3"><a name="BUILDSOURCE" id="BUILDSOURCE">1.6.2.
653Building from source</a></h4>
654<p>If above links are broken or if you want to experiment with sgml
655read on.</p>
656<table border="0" bgcolor="#E0E0E0" width="100%">
657<tr>
658<td>
659<pre class="PROGRAMLISTING">
660<font color=
661"#000000">&#13; Get both the source and the tar,gzipped programs, available at
1357 |----&gt; 01-10.pl -- Perl equivalents of first ten example programs</PRE
1358><P
1359>There is a top level Makefile included in the main directory. It builds all the
1360files and puts the ready-to-use exes in demo/exe directory. You can also
1361do selective make by going into the corresponding directory. Each directory
1362contains a README file explaining the purpose of each c file in the directory.</P
1363><P
1364>For every example, I have included path name for the file relative to the
1365examples directory. </P
1366><P
1367> If you prefer browsing individual programs, point your browser to
1368<A
1369HREF="http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/"
1370TARGET="_top"
1371>http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/ncurses_programs/</A
1372></P
1373><P
1374>All the programs are released under the same license that is used by ncurses
1375(MIT-style). This gives you the ability to do pretty much anything other than
1376claiming them as yours. Feel free to use them in your programs as appropriate.</P
1377></DIV
1378><DIV
1379CLASS="SECT2"
1380><HR><H3
1381CLASS="SECT2"
1382><A
1383NAME="OTHERFORMATS"
1384>1.6. Other Formats of the document</A
1385></H3
1386><P
1387>This howto is also availabe in various other formats on the tldp.org site.
1388Here are the links to other formats of this document.</P
1389><DIV
1390CLASS="SECT3"
1391><HR><H4
1392CLASS="SECT3"
1393><A
1394NAME="LISTFORMATS"
1395>1.6.1. Readily available formats from tldp.org</A
1396></H4
1397><P
1398></P
1399><UL
1400><LI
1401><P
1402><A
1403HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/pdf/NCURSES-Programming-HOWTO.pdf"
1404TARGET="_top"
1405>Acrobat PDF Format</A
1406></P
1407></LI
1408><LI
1409><P
1410><A
1411HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/ps/NCURSES-Programming-HOWTO.ps.gz"
1412TARGET="_top"
1413>PostScript Format</A
1414></P
1415></LI
1416><LI
1417><P
1418><A
1419HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html/NCURSES-Programming-HOWTO-html.tar.gz"
1420TARGET="_top"
1421>In Multiple HTML pages</A
1422></P
1423></LI
1424><LI
1425><P
1426><A
1427HREF="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/NCURSES-Programming-HOWTO.html"
1428TARGET="_top"
1429>In One big HTML format</A
1430></P
1431></LI
1432></UL
1433></DIV
1434><DIV
1435CLASS="SECT3"
1436><HR><H4
1437CLASS="SECT3"
1438><A
1439NAME="BUILDSOURCE"
1440>1.6.2. Building from source</A
1441></H4
1442><P
1443>If above links are broken or if you want to experiment with sgml read on.
1444<PRE
1445CLASS="PROGRAMLISTING"
1446>&#13; Get both the source and the tar,gzipped programs, available at
662 http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
663 NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml
664 http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
665 NCURSES-HOWTO/ncurses_programs.tar.gz
666
667 Unzip ncurses_programs.tar.gz with
668 tar zxvf ncurses_programs.tar.gz
669

--- 4 unchanged lines hidden (view full) ---

674 to get pdf, first create a single html file of the HOWTO with
675 jade -t sgml -i html -d &lt;path to docbook html stylesheet&gt; -V nochunks
676 NCURSES-Programming-HOWTO.sgml &gt; NCURSES-ONE-BIG-FILE.html
677 then use htmldoc to get pdf file with
678 htmldoc --size universal -t pdf --firstpage p1 -f &lt;output file name.pdf&gt;
679 NCURSES-ONE-BIG-FILE.html
680 for ps, you would use
681 htmldoc --size universal -t ps --firstpage p1 -f &lt;output file name.ps&gt;
1447 http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
1448 NCURSES-HOWTO/NCURSES-Programming-HOWTO.sgml
1449 http://cvsview.tldp.org/index.cgi/LDP/howto/docbook/
1450 NCURSES-HOWTO/ncurses_programs.tar.gz
1451
1452 Unzip ncurses_programs.tar.gz with
1453 tar zxvf ncurses_programs.tar.gz
1454

--- 4 unchanged lines hidden (view full) ---

1459 to get pdf, first create a single html file of the HOWTO with
1460 jade -t sgml -i html -d &lt;path to docbook html stylesheet&gt; -V nochunks
1461 NCURSES-Programming-HOWTO.sgml &gt; NCURSES-ONE-BIG-FILE.html
1462 then use htmldoc to get pdf file with
1463 htmldoc --size universal -t pdf --firstpage p1 -f &lt;output file name.pdf&gt;
1464 NCURSES-ONE-BIG-FILE.html
1465 for ps, you would use
1466 htmldoc --size universal -t ps --firstpage p1 -f &lt;output file name.ps&gt;
682 NCURSES-ONE-BIG-FILE.html</font>
683</pre></td>
684</tr>
685</table>
686<p>See <a href="http://www.tldp.org/LDP/LDP-Author-Guide/" target=
687"_top">LDP Author guide</a> for more details. If all else failes,
688mail me at <a href="ppadala@gmail.com" target=
689"_top">ppadala@gmail.com</a></p>
690</div>
691</div>
692<div class="SECT2">
693<hr>
694<h3 class="SECT2"><a name="CREDITS" id="CREDITS">1.7.
695Credits</a></h3>
696<p>I thank <a href="mailto:sharath_1@usa.net" target=
697"_top">Sharath</a> and Emre Akbas for helping me with few sections.
698The introduction was initially written by sharath. I rewrote it
699with few excerpts taken from his initial work. Emre helped in
700writing printw and scanw sections.</p>
701<p>Perl equivalents of the example programs are contributed by
702<a href="mailto:Aratnaweera@virtusa.com" target="_top">Anuradha
703Ratnaweera</a>.</p>
704<p>Then comes <a href="mailto:parimi@ece.arizona.edu" target=
705"_top">Ravi Parimi</a>, my dearest friend, who has been on this
706project before even one line was written. He constantly bombarded
707me with suggestions and patiently reviewed the whole text. He also
708checked each program on Linux and Solaris.</p>
709</div>
710<div class="SECT2">
711<hr>
712<h3 class="SECT2"><a name="WISHLIST" id="WISHLIST">1.8. Wish
713List</a></h3>
714<p>This is the wish list, in the order of priority. If you have a
715wish or you want to work on completing the wish, mail <a href=
716"mailto:ppadala@gmail.com" target="_top">me</a>.</p>
717<ul>
718<li>
719<p>Add examples to last parts of forms section.</p>
720</li>
721<li>
722<p>Prepare a Demo showing all the programs and allow the user to
723browse through description of each program. Let the user compile
724and see the program in action. A dialog based interface is
725preferred.</p>
726</li>
727<li>
728<p>Add debug info. _tracef, _tracemouse stuff.</p>
729</li>
730<li>
731<p>Accessing termcap, terminfo using functions provided by ncurses
732package.</p>
733</li>
734<li>
735<p>Working on two terminals simultaneously.</p>
736</li>
737<li>
738<p>Add more stuff to miscellaneous section.</p>
739</li>
740</ul>
741</div>
742<div class="SECT2">
743<hr>
744<h3 class="SECT2"><a name="COPYRIGHT" id="COPYRIGHT">1.9.
745Copyright</a></h3>
746<p>Copyright &copy; 2001 by Pradeep Padala.</p>
747<p>Permission is hereby granted, free of charge, to any person
748obtaining a copy of this software and associated documentation
749files (the "Software"), to deal in the Software without
750restriction, including without limitation the rights to use, copy,
751modify, merge, publish, distribute, distribute with modifications,
752sublicense, and/or sell copies of the Software, and to permit
753persons to whom the Software is furnished to do so, subject to the
754following conditions:</p>
755<p>The above copyright notice and this permission notice shall be
756included in all copies or substantial portions of the Software.</p>
757<p>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
758EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
759MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
760NONINFRINGEMENT. IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE
761LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
762ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
763CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
764SOFTWARE.</p>
765<p>Except as contained in this notice, the name(s) of the above
766copyright holders shall not be used in advertising or otherwise to
767promote the sale, use or other dealings in this Software without
768prior written authorization.</p>
769</div>
770</div>
771<div class="SECT1">
772<hr>
773<h2 class="SECT1"><a name="HELLOWORLD" id="HELLOWORLD">2. Hello
774World !!!</a></h2>
775<p>Welcome to the world of curses. Before we plunge into the
776library and look into its various features, let's write a simple
777program and say hello to the world.</p>
778<div class="SECT2">
779<hr>
780<h3 class="SECT2"><a name="COMPILECURSES" id="COMPILECURSES">2.1.
781Compiling With the NCURSES Library</a></h3>
782<p>To use ncurses library functions, you have to include ncurses.h
783in your programs. To link the program with ncurses the flag
784-lncurses should be added.</p>
785<table border="0" bgcolor="#E0E0E0" width="100%">
786<tr>
787<td>
788<pre class="PROGRAMLISTING">
789<font color="#000000"> #include &lt;ncurses.h&gt;
1467 NCURSES-ONE-BIG-FILE.html</PRE
1468></P
1469><P
1470>See <A
1471HREF="http://www.tldp.org/LDP/LDP-Author-Guide/"
1472TARGET="_top"
1473>LDP Author guide</A
1474> for more details. If all else failes, mail me at
1475<A
1476HREF="ppadala@gmail.com"
1477TARGET="_top"
1478>ppadala@gmail.com</A
1479></P
1480></DIV
1481></DIV
1482><DIV
1483CLASS="SECT2"
1484><HR><H3
1485CLASS="SECT2"
1486><A
1487NAME="CREDITS"
1488>1.7. Credits</A
1489></H3
1490><P
1491>I thank <A
1492HREF="mailto:sharath_1@usa.net"
1493TARGET="_top"
1494>Sharath</A
1495> and Emre Akbas for
1496helping me with few sections. The introduction was initially written by sharath.
1497I rewrote it with few excerpts taken from his initial work. Emre helped in
1498writing printw and scanw sections.</P
1499><P
1500>Perl equivalents of the example programs are contributed by <A
1501HREF="mailto:Aratnaweera@virtusa.com"
1502TARGET="_top"
1503>Anuradha Ratnaweera</A
1504>. </P
1505><P
1506>Then comes <A
1507HREF="mailto:parimi@ece.arizona.edu"
1508TARGET="_top"
1509>Ravi Parimi</A
1510>, my
1511dearest friend, who has been on this project before even one line was written.
1512He constantly bombarded me with suggestions and patiently reviewed the whole
1513text. He also checked each program on Linux and Solaris. </P
1514></DIV
1515><DIV
1516CLASS="SECT2"
1517><HR><H3
1518CLASS="SECT2"
1519><A
1520NAME="WISHLIST"
1521>1.8. Wish List</A
1522></H3
1523><P
1524>This is the wish list, in the order of priority. If you have a wish or you want
1525to work on completing the wish, mail <A
1526HREF="mailto:ppadala@gmail.com"
1527TARGET="_top"
1528>me</A
1529>. </P
1530><P
1531></P
1532><UL
1533><LI
1534><P
1535>Add examples to last parts of forms section.</P
1536></LI
1537><LI
1538><P
1539>Prepare a Demo showing all the programs and allow the user to browse through
1540description of each program. Let the user compile and see the program in action.
1541A dialog based interface is preferred.</P
1542></LI
1543><LI
1544><P
1545>Add debug info. _tracef, _tracemouse stuff.</P
1546></LI
1547><LI
1548><P
1549>Accessing termcap, terminfo using functions provided by ncurses
1550package.</P
1551></LI
1552><LI
1553><P
1554>Working on two terminals simultaneously.</P
1555></LI
1556><LI
1557><P
1558>Add more stuff to miscellaneous section.</P
1559></LI
1560></UL
1561></DIV
1562><DIV
1563CLASS="SECT2"
1564><HR><H3
1565CLASS="SECT2"
1566><A
1567NAME="COPYRIGHT"
1568>1.9. Copyright</A
1569></H3
1570><P
1571>Copyright &copy; 2001 by Pradeep Padala. </P
1572><P
1573>Permission is hereby granted, free of charge, to any person obtaining a copy
1574of this software and associated documentation files (the "Software"), to deal
1575in the Software without restriction, including without limitation the rights
1576to use, copy, modify, merge, publish, distribute, distribute with
1577modifications, sublicense, and/or sell copies of the Software, and to permit
1578persons to whom the Software is furnished to do so, subject to the following
1579conditions:</P
1580><P
1581>The above copyright notice and this permission notice shall be included in all
1582copies or substantial portions of the Software.</P
1583><P
1584>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
1585IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
1586FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
1587ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
1588WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
1589IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.</P
1590><P
1591>Except as contained in this notice, the name(s) of the above copyright holders
1592shall not be used in advertising or otherwise to promote the sale, use or
1593other dealings in this Software without prior written authorization. </P
1594></DIV
1595></DIV
1596><DIV
1597CLASS="SECT1"
1598><HR><H2
1599CLASS="SECT1"
1600><A
1601NAME="HELLOWORLD"
1602>2. Hello World !!!</A
1603></H2
1604><P
1605>Welcome to the world of curses. Before we plunge into the library and look into
1606its various features, let's write a simple program and say
1607hello to the world. </P
1608><DIV
1609CLASS="SECT2"
1610><HR><H3
1611CLASS="SECT2"
1612><A
1613NAME="COMPILECURSES"
1614>2.1. Compiling With the NCURSES Library</A
1615></H3
1616><P
1617>To use ncurses library functions, you have to include ncurses.h in your
1618programs. To link the
1619program with ncurses the flag -lncurses should be added.</P
1620><PRE
1621CLASS="PROGRAMLISTING"
1622> #include &lt;ncurses.h&gt;
790 .
791 .
792 .
793
1623 .
1624 .
1625 .
1626
794 compile and link: gcc &lt;program file&gt; -lncurses</font>
795</pre></td>
796</tr>
797</table>
798<div class="EXAMPLE"><a name="BHW" id="BHW"></a>
799<p><b>Example 1. The Hello World !!! Program</b></p>
800<table border="0" bgcolor="#E0E0E0" width="100%">
801<tr>
802<td>
803<pre class="PROGRAMLISTING">
804<font color="#000000"><span class=
805"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
1627 compile and link: gcc &lt;program file&gt; -lncurses</PRE
1628><DIV
1629CLASS="EXAMPLE"
1630><A
1631NAME="BHW"
1632></A
1633><P
1634><B
1635>Example 1. The Hello World !!! Program </B
1636></P
1637><PRE
1638CLASS="PROGRAMLISTING"
1639><SPAN
1640CLASS="INLINEMEDIAOBJECT"
1641>#include &#60;ncurses.h&#62;
806
807int main()
1642
1643int main()
808{
809 initscr(); /* Start curses mode */
810 printw("Hello World !!!"); /* Print Hello World */
811 refresh(); /* Print it on to the real screen */
812 getch(); /* Wait for user input */
813 endwin(); /* End curses mode */
1644{
1645 initscr(); /* Start curses mode */
1646 printw("Hello World !!!"); /* Print Hello World */
1647 refresh(); /* Print it on to the real screen */
1648 getch(); /* Wait for user input */
1649 endwin(); /* End curses mode */
814
1650
815 return 0;
816}</span></font>
817</pre></td>
818</tr>
819</table>
820</div>
821</div>
822<div class="SECT2">
823<hr>
824<h3 class="SECT2"><a name="DISSECTION" id="DISSECTION">2.2.
825Dissection</a></h3>
826<p>The above program prints "Hello World !!!" to the screen and
827exits. This program shows how to initialize curses and do screen
828manipulation and end curses mode. Let's dissect it line by
829line.</p>
830<div class="SECT3">
831<hr>
832<h4 class="SECT3"><a name="ABOUT-INITSCR" id="ABOUT-INITSCR">2.2.1.
833About initscr()</a></h4>
834<p>The function initscr() initializes the terminal in curses mode.
835In some implementations, it clears the screen and presents a blank
836screen. To do any screen manipulation using curses package this has
837to be called first. This function initializes the curses system and
838allocates memory for our present window (called <var class=
839"LITERAL">stdscr</var>) and some other data-structures. Under
840extreme cases this function might fail due to insufficient memory
841to allocate memory for curses library's data structures.</p>
842<p>After this is done, we can do a variety of initializations to
843customize our curses settings. These details will be explained
844<a href="#INIT">later</a> .</p>
845</div>
846<div class="SECT3">
847<hr>
848<h4 class="SECT3"><a name="MYST-REFRESH" id="MYST-REFRESH">2.2.2.
849The mysterious refresh()</a></h4>
850<p>The next line printw prints the string "Hello World !!!" on to
851the screen. This function is analogous to normal printf in all
852respects except that it prints the data on a window called stdscr
853at the current (y,x) co-ordinates. Since our present co-ordinates
854are at 0,0 the string is printed at the left hand corner of the
855window.</p>
856<p>This brings us to that mysterious refresh(). Well, when we
857called printw the data is actually written to an imaginary window,
858which is not updated on the screen yet. The job of printw is to
859update a few flags and data structures and write the data to a
860buffer corresponding to stdscr. In order to show it on the screen,
861we need to call refresh() and tell the curses system to dump the
862contents on the screen.</p>
863<p>The philosophy behind all this is to allow the programmer to do
864multiple updates on the imaginary screen or windows and do a
865refresh once all his screen update is done. refresh() checks the
866window and updates only the portion which has been changed. This
867improves performance and offers greater flexibility too. But, it is
868sometimes frustrating to beginners. A common mistake committed by
869beginners is to forget to call refresh() after they did some update
870through printw() class of functions. I still forget to add it
871sometimes :-)</p>
872</div>
873<div class="SECT3">
874<hr>
875<h4 class="SECT3"><a name="ABOUT-ENDWIN" id="ABOUT-ENDWIN">2.2.3.
876About endwin()</a></h4>
877<p>And finally don't forget to end the curses mode. Otherwise your
878terminal might behave strangely after the program quits. endwin()
879frees the memory taken by curses sub-system and its data structures
880and puts the terminal in normal mode. This function must be called
881after you are done with the curses mode.</p>
882</div>
883</div>
884</div>
885<div class="SECT1">
886<hr>
887<h2 class="SECT1"><a name="GORY" id="GORY">3. The Gory
888Details</a></h2>
889<p>Now that we have seen how to write a simple curses program let's
890get into the details. There are many functions that help customize
891what you see on screen and many features which can be put to full
892use.</p>
893<p>Here we go...</p>
894</div>
895<div class="SECT1">
896<hr>
897<h2 class="SECT1"><a name="INIT" id="INIT">4.
898Initialization</a></h2>
899<p>We now know that to initialize curses system the function
900initscr() has to be called. There are functions which can be called
901after this initialization to customize our curses session. We may
902ask the curses system to set the terminal in raw mode or initialize
903color or initialize the mouse etc.. Let's discuss some of the
904functions that are normally called immediately after initscr();</p>
905<div class="SECT2">
906<hr>
907<h3 class="SECT2"><a name="ABOUTINIT" id="ABOUTINIT">4.1.
908Initialization functions</a></h3>
909</div>
910<div class="SECT2">
911<hr>
912<h3 class="SECT2"><a name="RAWCBREAK" id="RAWCBREAK">4.2. raw() and
913cbreak()</a></h3>
914<p>Normally the terminal driver buffers the characters a user types
915until a new line or carriage return is encountered. But most
916programs require that the characters be available as soon as the
917user types them. The above two functions are used to disable line
918buffering. The difference between these two functions is in the way
919control characters like suspend (CTRL-Z), interrupt and quit
920(CTRL-C) are passed to the program. In the raw() mode these
921characters are directly passed to the program without generating a
922signal. In the <var class="LITERAL">cbreak()</var> mode these
923control characters are interpreted as any other character by the
924terminal driver. I personally prefer to use raw() as I can exercise
925greater control over what the user does.</p>
926</div>
927<div class="SECT2">
928<hr>
929<h3 class="SECT2"><a name="ECHONOECHO" id="ECHONOECHO">4.3. echo()
930and noecho()</a></h3>
931<p>These functions control the echoing of characters typed by the
932user to the terminal. <var class="LITERAL">noecho()</var> switches
933off echoing. The reason you might want to do this is to gain more
934control over echoing or to suppress unnecessary echoing while
935taking input from the user through the getch() etc. functions. Most
936of the interactive programs call <var class=
937"LITERAL">noecho()</var> at initialization and do the echoing of
938characters in a controlled manner. It gives the programmer the
939flexibility of echoing characters at any place in the window
940without updating current (y,x) co-ordinates.</p>
941</div>
942<div class="SECT2">
943<hr>
944<h3 class="SECT2"><a name="KEYPAD" id="KEYPAD">4.4.
945keypad()</a></h3>
946<p>This is my favorite initialization function. It enables the
947reading of function keys like F1, F2, arrow keys etc. Almost every
948interactive program enables this, as arrow keys are a major part of
949any User Interface. Do <var class="LITERAL">keypad(stdscr,
950TRUE)</var> to enable this feature for the regular screen (stdscr).
951You will learn more about key management in later sections of this
952document.</p>
953</div>
954<div class="SECT2">
955<hr>
956<h3 class="SECT2"><a name="HALFDELAY" id="HALFDELAY">4.5.
957halfdelay()</a></h3>
958<p>This function, though not used very often, is a useful one at
959times. halfdelay()is called to enable the half-delay mode, which is
960similar to the cbreak() mode in that characters typed are
961immediately available to program. However, it waits for 'X' tenths
962of a second for input and then returns ERR, if no input is
963available. 'X' is the timeout value passed to the function
964halfdelay(). This function is useful when you want to ask the user
965for input, and if he doesn't respond with in certain time, we can
966do some thing else. One possible example is a timeout at the
967password prompt.</p>
968</div>
969<div class="SECT2">
970<hr>
971<h3 class="SECT2"><a name="MISCINIT" id="MISCINIT">4.6.
972Miscellaneous Initialization functions</a></h3>
973<p>There are few more functions which are called at initialization
974to customize curses behavior. They are not used as extensively as
975those mentioned above. Some of them are explained where
976appropriate.</p>
977</div>
978<div class="SECT2">
979<hr>
980<h3 class="SECT2"><a name="INITEX" id="INITEX">4.7. An
981Example</a></h3>
982<p>Let's write a program which will clarify the usage of these
983functions.</p>
984<div class="EXAMPLE"><a name="BINFU" id="BINFU"></a>
985<p><b>Example 2. Initialization Function Usage example</b></p>
986<table border="0" bgcolor="#E0E0E0" width="100%">
987<tr>
988<td>
989<pre class="PROGRAMLISTING">
990<font color="#000000"><span class=
991"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
1651 return 0;
1652}</SPAN
1653></PRE
1654></DIV
1655></DIV
1656><DIV
1657CLASS="SECT2"
1658><HR><H3
1659CLASS="SECT2"
1660><A
1661NAME="DISSECTION"
1662>2.2. Dissection</A
1663></H3
1664><P
1665>
1666The above program prints "Hello World !!!" to the screen and exits. This
1667program shows how to initialize curses and do screen manipulation and
1668end curses mode. Let's dissect it line by line. </P
1669><DIV
1670CLASS="SECT3"
1671><HR><H4
1672CLASS="SECT3"
1673><A
1674NAME="ABOUT-INITSCR"
1675>2.2.1. About initscr()</A
1676></H4
1677><P
1678>The function initscr() initializes the terminal in curses mode. In some
1679implementations, it clears the screen and presents a blank screen. To do any
1680screen manipulation using curses package this has to be called first. This
1681function initializes the curses system and allocates memory for our present
1682window (called <TT
1683CLASS="LITERAL"
1684>stdscr</TT
1685>) and some other data-structures. Under extreme
1686cases this function might fail due to insufficient memory to allocate memory
1687for curses library's data structures. </P
1688><P
1689>
1690After this is done, we can do a variety of initializations to customize
1691our curses settings. These details will be explained <A
1692HREF="#INIT"
1693>later </A
1694>.</P
1695></DIV
1696><DIV
1697CLASS="SECT3"
1698><HR><H4
1699CLASS="SECT3"
1700><A
1701NAME="MYST-REFRESH"
1702>2.2.2. The mysterious refresh()</A
1703></H4
1704><P
1705>The next line printw prints the string "Hello World !!!" on to the screen. This
1706function is analogous to normal printf in all respects except that it prints
1707the data on a window called stdscr at the current (y,x) co-ordinates. Since our
1708present co-ordinates are at 0,0 the string is printed at the left hand corner
1709of the window.</P
1710><P
1711>This brings us to that mysterious refresh(). Well, when we called printw
1712the data is actually written to an imaginary window, which is not updated
1713on the screen yet. The job of printw is to update a few flags
1714and data structures and write the data to a buffer corresponding to stdscr.
1715In order to show it on the screen, we need to call refresh() and tell the
1716curses system to dump the contents on the screen.</P
1717><P
1718>The philosophy behind all this is to allow the programmer to do multiple updates
1719on the imaginary screen or windows and do a refresh once all his screen update
1720is done. refresh() checks the window and updates only the portion which has been
1721changed. This improves performance and offers greater flexibility too. But, it is
1722sometimes frustrating to beginners. A common mistake committed by beginners is
1723to forget to call refresh() after they did some update through printw() class of
1724functions. I still forget to add it sometimes :-) </P
1725></DIV
1726><DIV
1727CLASS="SECT3"
1728><HR><H4
1729CLASS="SECT3"
1730><A
1731NAME="ABOUT-ENDWIN"
1732>2.2.3. About endwin()</A
1733></H4
1734><P
1735>And finally don't forget to end the curses mode. Otherwise your terminal might
1736behave strangely after the program quits. endwin() frees the memory taken by
1737curses sub-system and its data structures and puts the terminal in normal
1738mode. This function must be called after you are done with the curses mode. </P
1739></DIV
1740></DIV
1741></DIV
1742><DIV
1743CLASS="SECT1"
1744><HR><H2
1745CLASS="SECT1"
1746><A
1747NAME="GORY"
1748>3. The Gory Details</A
1749></H2
1750><P
1751>Now that we have seen how to write a simple curses program let's get into the
1752details. There are many functions that help customize what you see on screen and
1753many features which can be put to full use. </P
1754><P
1755>Here we go...</P
1756></DIV
1757><DIV
1758CLASS="SECT1"
1759><HR><H2
1760CLASS="SECT1"
1761><A
1762NAME="INIT"
1763>4. Initialization</A
1764></H2
1765><P
1766>We now know that to initialize curses system the function initscr() has to be
1767called. There are functions which can be called after this initialization to
1768customize our curses session. We may ask the curses system to set the terminal
1769in raw mode or initialize color or initialize the mouse etc.. Let's discuss some
1770of the functions that are normally called immediately after initscr();</P
1771><DIV
1772CLASS="SECT2"
1773><HR><H3
1774CLASS="SECT2"
1775><A
1776NAME="ABOUTINIT"
1777>4.1. Initialization functions</A
1778></H3
1779><P
1780> </P
1781></DIV
1782><DIV
1783CLASS="SECT2"
1784><HR><H3
1785CLASS="SECT2"
1786><A
1787NAME="RAWCBREAK"
1788>4.2. raw() and cbreak()</A
1789></H3
1790><P
1791>Normally the terminal driver buffers the characters a user types until a new
1792line or carriage return is encountered. But most programs require that the
1793characters be available as soon as the user types them. The above two functions
1794are used to disable line buffering. The difference between these two functions
1795is in the way control characters like suspend (CTRL-Z), interrupt and quit
1796(CTRL-C) are passed to the program. In the raw() mode these characters are
1797directly passed to the program without generating a signal. In the
1798<TT
1799CLASS="LITERAL"
1800>cbreak()</TT
1801> mode these control characters are
1802interpreted as any other character by the terminal driver. I personally prefer
1803to use raw() as I can exercise greater control over what the user does.</P
1804></DIV
1805><DIV
1806CLASS="SECT2"
1807><HR><H3
1808CLASS="SECT2"
1809><A
1810NAME="ECHONOECHO"
1811>4.3. echo() and noecho()</A
1812></H3
1813><P
1814>
1815These functions control the echoing of characters typed by the user to the
1816terminal. <TT
1817CLASS="LITERAL"
1818>noecho()</TT
1819> switches off echoing. The
1820reason you might want to do this is to gain more control over echoing or to
1821suppress unnecessary echoing while taking input from the user through the
1822getch() etc. functions. Most of the interactive programs call
1823<TT
1824CLASS="LITERAL"
1825>noecho()</TT
1826> at initialization and do the echoing
1827of characters in a controlled manner. It gives the programmer the flexibility
1828of echoing characters at any place in the window without updating current (y,x)
1829co-ordinates. </P
1830></DIV
1831><DIV
1832CLASS="SECT2"
1833><HR><H3
1834CLASS="SECT2"
1835><A
1836NAME="KEYPAD"
1837>4.4. keypad()</A
1838></H3
1839><P
1840>This is my favorite initialization function. It enables the reading of function
1841keys like F1, F2, arrow keys etc. Almost every interactive program enables this,
1842as arrow keys are a major part of any User Interface. Do
1843<TT
1844CLASS="LITERAL"
1845>keypad(stdscr, TRUE) </TT
1846> to enable this feature
1847for the regular screen (stdscr). You will learn more about key management in
1848later sections of this document.</P
1849></DIV
1850><DIV
1851CLASS="SECT2"
1852><HR><H3
1853CLASS="SECT2"
1854><A
1855NAME="HALFDELAY"
1856>4.5. halfdelay()</A
1857></H3
1858><P
1859>This function, though not used very often, is a useful one at times.
1860halfdelay()is called to enable the half-delay mode, which is similar to the
1861cbreak() mode in that characters typed are immediately available to program.
1862However, it waits for 'X' tenths of a second for input and then returns ERR, if
1863no input is available. 'X' is the timeout value passed to the function
1864halfdelay(). This function is useful when you want to ask the user for input,
1865and if he doesn't respond with in certain time, we can do some thing else. One
1866possible example is a timeout at the password prompt. </P
1867></DIV
1868><DIV
1869CLASS="SECT2"
1870><HR><H3
1871CLASS="SECT2"
1872><A
1873NAME="MISCINIT"
1874>4.6. Miscellaneous Initialization functions</A
1875></H3
1876><P
1877>There are few more functions which are called at initialization to
1878customize curses behavior. They are not used as extensively as those mentioned
1879above. Some of them are explained where appropriate.</P
1880></DIV
1881><DIV
1882CLASS="SECT2"
1883><HR><H3
1884CLASS="SECT2"
1885><A
1886NAME="INITEX"
1887>4.7. An Example</A
1888></H3
1889><P
1890>Let's write a program which will clarify the usage of these functions.</P
1891><DIV
1892CLASS="EXAMPLE"
1893><A
1894NAME="BINFU"
1895></A
1896><P
1897><B
1898>Example 2. Initialization Function Usage example </B
1899></P
1900><PRE
1901CLASS="PROGRAMLISTING"
1902><SPAN
1903CLASS="INLINEMEDIAOBJECT"
1904>#include &#60;ncurses.h&#62;
992
993int main()
1905
1906int main()
994{ int ch;
1907{ int ch;
995
1908
996 initscr(); /* Start curses mode */
997 raw(); /* Line buffering disabled */
998 keypad(stdscr, TRUE); /* We get F1, F2 etc.. */
999 noecho(); /* Don't echo() while we do getch */
1909 initscr(); /* Start curses mode */
1910 raw(); /* Line buffering disabled */
1911 keypad(stdscr, TRUE); /* We get F1, F2 etc.. */
1912 noecho(); /* Don't echo() while we do getch */
1000
1913
1001 printw("Type any character to see it in bold\n");
1002 ch = getch(); /* If raw() hadn't been called
1003 * we have to press enter before it
1004 * gets to the program */
1005 if(ch == KEY_F(1)) /* Without keypad enabled this will */
1006 printw("F1 Key pressed");/* not get to us either */
1007 /* Without noecho() some ugly escape
1008 * charachters might have been printed
1009 * on screen */
1010 else
1011 { printw("The pressed key is ");
1012 attron(A_BOLD);
1013 printw("%c", ch);
1014 attroff(A_BOLD);
1015 }
1016 refresh(); /* Print it on to the real screen */
1017 getch(); /* Wait for user input */
1018 endwin(); /* End curses mode */
1914 printw("Type any character to see it in bold\n");
1915 ch = getch(); /* If raw() hadn't been called
1916 * we have to press enter before it
1917 * gets to the program */
1918 if(ch == KEY_F(1)) /* Without keypad enabled this will */
1919 printw("F1 Key pressed");/* not get to us either */
1920 /* Without noecho() some ugly escape
1921 * charachters might have been printed
1922 * on screen */
1923 else
1924 { printw("The pressed key is ");
1925 attron(A_BOLD);
1926 printw("%c", ch);
1927 attroff(A_BOLD);
1928 }
1929 refresh(); /* Print it on to the real screen */
1930 getch(); /* Wait for user input */
1931 endwin(); /* End curses mode */
1019
1932
1020 return 0;
1021}</span></font>
1022</pre></td>
1023</tr>
1024</table>
1025</div>
1026<p>This program is self-explanatory. But I used functions which
1027aren't explained yet. The function <var class=
1028"LITERAL">getch()</var> is used to get a character from user. It is
1029equivalent to normal <var class="LITERAL">getchar()</var> except
1030that we can disable the line buffering to avoid &lt;enter&gt; after
1031input. Look for more about <var class="LITERAL">getch()</var>and
1032reading keys in the <a href="#KEYS">key management section</a> .
1033The functions attron and attroff are used to switch some attributes
1034on and off respectively. In the example I used them to print the
1035character in bold. These functions are explained in detail
1036later.</p>
1037</div>
1038</div>
1039<div class="SECT1">
1040<hr>
1041<h2 class="SECT1"><a name="AWORDWINDOWS" id="AWORDWINDOWS">5. A
1042Word about Windows</a></h2>
1043<p>Before we plunge into the myriad ncurses functions, let me clear
1044few things about windows. Windows are explained in detail in
1045following <a href="#WINDOWS">sections</a></p>
1046<p>A Window is an imaginary screen defined by curses system. A
1047window does not mean a bordered window which you usually see on
1048Win9X platforms. When curses is initialized, it creates a default
1049window named <var class="LITERAL">stdscr</var> which represents
1050your 80x25 (or the size of window in which you are running) screen.
1051If you are doing simple tasks like printing few strings, reading
1052input etc., you can safely use this single window for all of your
1053purposes. You can also create windows and call functions which
1054explicitly work on the specified window.</p>
1055<p>For example, if you call</p>
1056<table border="0" bgcolor="#E0E0E0" width="100%">
1057<tr>
1058<td>
1059<pre class="PROGRAMLISTING">
1060<font color="#000000"> printw("Hi There !!!");
1061 refresh();</font>
1062</pre></td>
1063</tr>
1064</table>
1065<p>It prints the string on stdscr at the present cursor position.
1066Similarly the call to refresh(), works on stdscr only.</p>
1067<p>Say you have created <a href="#WINDOWS">windows</a> then you
1068have to call a function with a 'w' added to the usual function.</p>
1069<table border="0" bgcolor="#E0E0E0" width="100%">
1070<tr>
1071<td>
1072<pre class="PROGRAMLISTING">
1073<font color="#000000"> wprintw(win, "Hi There !!!");
1074 wrefresh(win);</font>
1075</pre></td>
1076</tr>
1077</table>
1078<p>As you will see in the rest of the document, naming of functions
1079follow the same convention. For each function there usually are
1080three more functions.</p>
1081<table border="0" bgcolor="#E0E0E0" width="100%">
1082<tr>
1083<td>
1084<pre class="PROGRAMLISTING">
1085<font color=
1086"#000000"> printw(string); /* Print on stdscr at present cursor position */
1933 return 0;
1934}</SPAN
1935></PRE
1936></DIV
1937><P
1938>This program is self-explanatory. But I used functions which aren't explained
1939yet. The function <TT
1940CLASS="LITERAL"
1941>getch()</TT
1942> is used to get a
1943character from user. It is equivalent to normal
1944<TT
1945CLASS="LITERAL"
1946>getchar()</TT
1947> except that we can disable the line
1948buffering to avoid &lt;enter&gt; after input. Look for more about
1949<TT
1950CLASS="LITERAL"
1951>getch()</TT
1952>and reading keys in the <A
1953HREF="#KEYS"
1954> key management section </A
1955>. The functions attron and attroff
1956are used to switch some attributes on and off respectively. In the example I
1957used them to print the character in bold. These functions are explained in detail
1958later.</P
1959></DIV
1960></DIV
1961><DIV
1962CLASS="SECT1"
1963><HR><H2
1964CLASS="SECT1"
1965><A
1966NAME="AWORDWINDOWS"
1967>5. A Word about Windows</A
1968></H2
1969><P
1970>
1971Before we plunge into the myriad ncurses functions, let me clear few things
1972about windows. Windows are explained in detail in following <A
1973HREF="#WINDOWS"
1974> sections </A
1975></P
1976><P
1977>A Window is an imaginary screen defined by curses system. A window does not mean
1978a bordered window which you usually see on Win9X platforms. When curses is
1979initialized, it creates a default window named
1980<TT
1981CLASS="LITERAL"
1982>stdscr</TT
1983> which represents your 80x25 (or the size
1984of window in which you are running) screen. If you are doing simple tasks like
1985printing few strings, reading input etc., you can safely use this single window
1986for all of your purposes. You can also create windows and call functions which
1987explicitly work on the specified window.</P
1988><P
1989>For example, if you call</P
1990><PRE
1991CLASS="PROGRAMLISTING"
1992> printw("Hi There !!!");
1993 refresh();</PRE
1994><P
1995>It prints the string on stdscr at the present cursor position. Similarly the
1996call to refresh(), works on stdscr only. </P
1997><P
1998>Say you have created <A
1999HREF="#WINDOWS"
2000>windows</A
2001> then you have to
2002call a function with a 'w' added to the usual function.</P
2003><PRE
2004CLASS="PROGRAMLISTING"
2005> wprintw(win, "Hi There !!!");
2006 wrefresh(win);</PRE
2007><P
2008>As you will see in the rest of the document, naming of functions follow the
2009same convention. For each function there usually are three more functions.</P
2010><PRE
2011CLASS="PROGRAMLISTING"
2012> printw(string); /* Print on stdscr at present cursor position */
1087 mvprintw(y, x, string);/* Move to (y, x) then print string */
1088 wprintw(win, string); /* Print on window win at present cursor position */
1089 /* in the window */
1090 mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */
2013 mvprintw(y, x, string);/* Move to (y, x) then print string */
2014 wprintw(win, string); /* Print on window win at present cursor position */
2015 /* in the window */
2016 mvwprintw(win, y, x, string); /* Move to (y, x) relative to window */
1091 /* co-ordinates and then print */</font>
1092</pre></td>
1093</tr>
1094</table>
1095<p>Usually the w-less functions are macros which expand to
1096corresponding w-function with stdscr as the window parameter.</p>
1097</div>
1098<div class="SECT1">
1099<hr>
1100<h2 class="SECT1"><a name="PRINTW" id="PRINTW">6. Output
1101functions</a></h2>
1102<p>I guess you can't wait any more to see some action. Back to our
1103odyssey of curses functions. Now that curses is initialized, let's
1104interact with world.</p>
1105<p>There are three classes of functions which you can use to do
1106output on screen.</p>
1107<ol type="1">
1108<li>
1109<p>addch() class: Print single character with attributes</p>
1110</li>
1111<li>
1112<p>printw() class: Print formatted output similar to printf()</p>
1113</li>
1114<li>
1115<p>addstr() class: Print strings</p>
1116</li>
1117</ol>
1118<p>These functions can be used interchangeably and it's a matter of
1119style as to which class is used. Let's see each one in detail.</p>
1120<div class="SECT2">
1121<hr>
1122<h3 class="SECT2"><a name="ADDCHCLASS" id="ADDCHCLASS">6.1. addch()
1123class of functions</a></h3>
1124<p>These functions put a single character into the current cursor
1125location and advance the position of the cursor. You can give the
1126character to be printed but they usually are used to print a
1127character with some attributes. Attributes are explained in detail
1128in later <a href="#ATTRIB">sections</a> of the document. If a
1129character is associated with an attribute(bold, reverse video
1130etc.), when curses prints the character, it is printed in that
1131attribute.</p>
1132<p>In order to combine a character with some attributes, you have
1133two options:</p>
1134<ul>
1135<li>
1136<p>By OR'ing a single character with the desired attribute macros.
1137These attribute macros could be found in the header file
1138<var class="LITERAL">ncurses.h</var>. For example, you want to
1139print a character ch(of type char) bold and underlined, you would
1140call addch() as below.</p>
1141<table border="0" bgcolor="#E0E0E0" width="90%">
1142<tr>
1143<td>
1144<pre class="PROGRAMLISTING">
1145<font color="#000000"> addch(ch | A_BOLD | A_UNDERLINE);</font>
1146</pre></td>
1147</tr>
1148</table>
1149</li>
1150<li>
1151<p>By using functions like <var class=
1152"LITERAL">attrset(),attron(),attroff()</var>. These functions are
1153explained in the <a href="#ATTRIB">Attributes</a> section. Briefly,
1154they manipulate the current attributes of the given window. Once
1155set, the character printed in the window are associated with the
1156attributes until it is turned off.</p>
1157</li>
1158</ul>
1159<p>Additionally, <var class="LITERAL">curses</var> provides some
1160special characters for character-based graphics. You can draw
1161tables, horizontal or vertical lines, etc. You can find all
1162avaliable characters in the header file <var class=
1163"LITERAL">ncurses.h</var>. Try looking for macros beginning with
1164<var class="LITERAL">ACS_</var> in this file.</p>
1165</div>
1166<div class="SECT2">
1167<hr>
1168<h3 class="SECT2"><a name="AEN298" id="AEN298">6.2. mvaddch(),
1169waddch() and mvwaddch()</a></h3>
1170<p><var class="LITERAL">mvaddch()</var> is used to move the cursor
1171to a given point, and then print. Thus, the calls:</p>
1172<table border="0" bgcolor="#E0E0E0" width="100%">
1173<tr>
1174<td>
1175<pre class="PROGRAMLISTING">
1176<font color=
1177"#000000"> move(row,col); /* moves the cursor to row<em>th</em> row and col<em>th</em> column */
1178 addch(ch);</font>
1179</pre></td>
1180</tr>
1181</table>
2017 /* co-ordinates and then print */</PRE
2018><P
2019>Usually the w-less functions are macros which expand to corresponding w-function
2020with stdscr as the window parameter.</P
2021></DIV
2022><DIV
2023CLASS="SECT1"
2024><HR><H2
2025CLASS="SECT1"
2026><A
2027NAME="PRINTW"
2028>6. Output functions</A
2029></H2
2030><P
2031>I guess you can't wait any more to see some action. Back to our odyssey of
2032curses functions. Now that curses is initialized, let's interact with
2033world.</P
2034><P
2035>There are three classes of functions which you can use to do output on screen.
2036<P
2037></P
2038><OL
2039TYPE="1"
2040><LI
2041><P
2042>addch() class: Print single character with attributes </P
2043></LI
2044><LI
2045><P
2046>printw() class: Print formatted output similar to printf()</P
2047></LI
2048><LI
2049><P
2050>addstr() class: Print strings</P
2051></LI
2052></OL
2053></P
2054><P
2055>These functions can be used interchangeably and it's a matter of style as to
2056which class is used. Let's see each one in detail.</P
2057><DIV
2058CLASS="SECT2"
2059><HR><H3
2060CLASS="SECT2"
2061><A
2062NAME="ADDCHCLASS"
2063>6.1. addch() class of functions</A
2064></H3
2065><P
2066>These functions put a single character into the current cursor location and
2067advance the position of the cursor. You can give the character to be printed but
2068they usually are used to print a character with some attributes. Attributes are
2069explained in detail in later <A
2070HREF="#ATTRIB"
2071> sections </A
2072> of the
2073document. If a character is associated with an attribute(bold, reverse video
2074etc.), when curses prints the character, it is printed in that attribute.</P
2075><P
2076>In order to combine a character with some attributes, you have two options:</P
2077><P
2078></P
2079><UL
2080><LI
2081><P
2082>By OR'ing a single character with the desired attribute macros. These attribute
2083macros could be found in the header file
2084<TT
2085CLASS="LITERAL"
2086>ncurses.h</TT
2087>. For example, you want to print a
2088character ch(of type char) bold and underlined, you would call addch() as below.
2089<PRE
2090CLASS="PROGRAMLISTING"
2091> addch(ch | A_BOLD | A_UNDERLINE);</PRE
2092></P
2093></LI
2094><LI
2095><P
2096>By using functions like <TT
2097CLASS="LITERAL"
2098>attrset(),attron(),attroff()</TT
2099>. These functions are explained in the <A
2100HREF="#ATTRIB"
2101>Attributes</A
2102> section. Briefly, they manipulate the current attributes of
2103the given window. Once set, the character printed in the window are associated
2104with the attributes until it is turned off.</P
2105></LI
2106></UL
2107><P
2108>Additionally, <TT
2109CLASS="LITERAL"
2110>curses</TT
2111> provides some special
2112characters for character-based graphics. You can draw tables, horizontal or
2113vertical lines, etc. You can find all avaliable characters in the header file
2114<TT
2115CLASS="LITERAL"
2116>ncurses.h</TT
2117>. Try looking for macros beginning
2118with <TT
2119CLASS="LITERAL"
2120>ACS_</TT
2121> in this file. </P
2122></DIV
2123><DIV
2124CLASS="SECT2"
2125><HR><H3
2126CLASS="SECT2"
2127><A
2128NAME="AEN298"
2129>6.2. mvaddch(), waddch() and mvwaddch()</A
2130></H3
2131><P
2132><TT
2133CLASS="LITERAL"
2134>mvaddch()</TT
2135> is used to move the cursor to a
2136given point, and then print. Thus, the calls:
2137<PRE
2138CLASS="PROGRAMLISTING"
2139> move(row,col); /* moves the cursor to row<SPAN
2140CLASS="emphasis"
2141><I
2142CLASS="EMPHASIS"
2143>th</I
2144></SPAN
2145> row and col<SPAN
2146CLASS="emphasis"
2147><I
2148CLASS="EMPHASIS"
2149>th</I
2150></SPAN
2151> column */
2152 addch(ch);</PRE
2153>
1182can be replaced by
2154can be replaced by
1183<table border="0" bgcolor="#E0E0E0" width="100%">
1184<tr>
1185<td>
1186<pre class="PROGRAMLISTING">
1187<font color="#000000"> mvaddch(row,col,ch);</font>
1188</pre></td>
1189</tr>
1190</table>
1191<p><var class="LITERAL">waddch()</var> is similar to <var class=
1192"LITERAL">addch()</var>, except that it adds a character into the
1193given window. (Note that <var class="LITERAL">addch()</var> adds a
1194character into the window <var class="LITERAL">stdscr</var>.)</p>
1195<p>In a similar fashion <var class="LITERAL">mvwaddch()</var>
1196function is used to add a character into the given window at the
1197given coordinates.</p>
1198<p>Now, we are familiar with the basic output function <var class=
1199"LITERAL">addch()</var>. But, if we want to print a string, it
1200would be very annoying to print it character by character.
1201Fortunately, <var class="LITERAL">ncurses</var> provides
1202<var class="LITERAL">printf</var><em>-like</em> or <var class=
1203"LITERAL">puts</var><em>-like</em> functions.</p>
1204</div>
1205<div class="SECT2">
1206<hr>
1207<h3 class="SECT2"><a name="PRINTWCLASS" id="PRINTWCLASS">6.3.
1208printw() class of functions</a></h3>
1209<p>These functions are similar to <var class=
1210"LITERAL">printf()</var> with the added capability of printing at
1211any position on the screen.</p>
1212<div class="SECT3">
1213<hr>
1214<h4 class="SECT3"><a name="PRINTWMVPRINTW" id=
1215"PRINTWMVPRINTW">6.3.1. printw() and mvprintw</a></h4>
1216<p>These two functions work much like <var class=
1217"LITERAL">printf()</var>. <var class="LITERAL">mvprintw()</var> can
1218be used to move the cursor to a position and then print. If you
1219want to move the cursor first and then print using <var class=
1220"LITERAL">printw()</var> function, use <var class=
1221"LITERAL">move()</var> first and then use <var class=
1222"LITERAL">printw()</var> though I see no point why one should avoid
1223using <var class="LITERAL">mvprintw()</var>, you have the
1224flexibility to manipulate.</p>
1225</div>
1226<div class="SECT3">
1227<hr>
1228<h4 class="SECT3"><a name="WPRINTWMVWPRINTW" id=
1229"WPRINTWMVWPRINTW">6.3.2. wprintw() and mvwprintw</a></h4>
1230<p>These two functions are similar to above two except that they
1231print in the corresponding window given as argument.</p>
1232</div>
1233<div class="SECT3">
1234<hr>
1235<h4 class="SECT3"><a name="VWPRINTW" id="VWPRINTW">6.3.3.
1236vwprintw()</a></h4>
1237<p>This function is similar to <var class=
1238"LITERAL">vprintf()</var>. This can be used when variable number of
1239arguments are to be printed.</p>
1240</div>
1241<div class="SECT3">
1242<hr>
1243<h4 class="SECT3"><a name="SIMPLEPRINTWEX" id=
1244"SIMPLEPRINTWEX">6.3.4. A Simple printw example</a></h4>
1245<div class="EXAMPLE"><a name="BPREX" id="BPREX"></a>
1246<p><b>Example 3. A Simple printw example</b></p>
1247<table border="0" bgcolor="#E0E0E0" width="100%">
1248<tr>
1249<td>
1250<pre class="PROGRAMLISTING">
1251<font color="#000000"><span class=
1252"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt; /* ncurses.h includes stdio.h */
1253#include &lt;string.h&gt;
2155<PRE
2156CLASS="PROGRAMLISTING"
2157> mvaddch(row,col,ch);</PRE
2158></P
2159><P
2160><TT
2161CLASS="LITERAL"
2162>waddch()</TT
2163> is similar to
2164<TT
2165CLASS="LITERAL"
2166>addch()</TT
2167>, except that it adds a character into
2168the given window. (Note that <TT
2169CLASS="LITERAL"
2170>addch()</TT
2171> adds a
2172character into the window <TT
2173CLASS="LITERAL"
2174>stdscr</TT
2175>.)</P
2176><P
2177>In a similar fashion <TT
2178CLASS="LITERAL"
2179>mvwaddch()</TT
2180> function is
2181used to add a character into the given window at the given coordinates.</P
2182><P
2183>Now, we are familiar with the basic output function
2184<TT
2185CLASS="LITERAL"
2186>addch()</TT
2187>. But, if we want to print a string, it
2188would be very annoying to print it character by character. Fortunately,
2189<TT
2190CLASS="LITERAL"
2191>ncurses</TT
2192> provides <TT
2193CLASS="LITERAL"
2194>printf</TT
2195><SPAN
2196CLASS="emphasis"
2197><I
2198CLASS="EMPHASIS"
2199>-like</I
2200></SPAN
2201> or
2202<TT
2203CLASS="LITERAL"
2204>puts</TT
2205><SPAN
2206CLASS="emphasis"
2207><I
2208CLASS="EMPHASIS"
2209>-like</I
2210></SPAN
2211> functions.</P
2212></DIV
2213><DIV
2214CLASS="SECT2"
2215><HR><H3
2216CLASS="SECT2"
2217><A
2218NAME="PRINTWCLASS"
2219>6.3. printw() class of functions</A
2220></H3
2221><P
2222>These functions are similar to <TT
2223CLASS="LITERAL"
2224>printf()</TT
2225> with
2226the added capability of printing at any position on the screen. </P
2227><DIV
2228CLASS="SECT3"
2229><HR><H4
2230CLASS="SECT3"
2231><A
2232NAME="PRINTWMVPRINTW"
2233>6.3.1. printw() and mvprintw</A
2234></H4
2235><P
2236>These two functions work much like <TT
2237CLASS="LITERAL"
2238>printf()</TT
2239>.
2240<TT
2241CLASS="LITERAL"
2242>mvprintw()</TT
2243> can be used to move the cursor to a
2244position and then print. If you want to move the cursor first and then print
2245using <TT
2246CLASS="LITERAL"
2247>printw()</TT
2248> function, use
2249<TT
2250CLASS="LITERAL"
2251>move() </TT
2252> first and then use
2253<TT
2254CLASS="LITERAL"
2255>printw()</TT
2256> though I see no point why one should
2257avoid using <TT
2258CLASS="LITERAL"
2259>mvprintw()</TT
2260>, you have the
2261flexibility to manipulate. </P
2262></DIV
2263><DIV
2264CLASS="SECT3"
2265><HR><H4
2266CLASS="SECT3"
2267><A
2268NAME="WPRINTWMVWPRINTW"
2269>6.3.2. wprintw() and mvwprintw</A
2270></H4
2271><P
2272>These two functions are similar to above two except that they print in the
2273corresponding window given as argument. </P
2274></DIV
2275><DIV
2276CLASS="SECT3"
2277><HR><H4
2278CLASS="SECT3"
2279><A
2280NAME="VWPRINTW"
2281>6.3.3. vwprintw()</A
2282></H4
2283><P
2284>This function is similar to <TT
2285CLASS="LITERAL"
2286>vprintf()</TT
2287>. This can
2288be used when variable number of arguments are to be printed.</P
2289></DIV
2290><DIV
2291CLASS="SECT3"
2292><HR><H4
2293CLASS="SECT3"
2294><A
2295NAME="SIMPLEPRINTWEX"
2296>6.3.4. A Simple printw example</A
2297></H4
2298><DIV
2299CLASS="EXAMPLE"
2300><A
2301NAME="BPREX"
2302></A
2303><P
2304><B
2305>Example 3. A Simple printw example </B
2306></P
2307><PRE
2308CLASS="PROGRAMLISTING"
2309><SPAN
2310CLASS="INLINEMEDIAOBJECT"
2311>#include &#60;ncurses.h&#62; /* ncurses.h includes stdio.h */
2312#include &#60;string.h&#62;
1254
1255int main()
1256{
2313
2314int main()
2315{
1257 char mesg[]="Just a string"; /* message to be appeared on the screen */
1258 int row,col; /* to store the number of rows and *
1259 * the number of colums of the screen */
1260 initscr(); /* start the curses mode */
1261 getmaxyx(stdscr,row,col); /* get the number of rows and columns */
2316 char mesg[]="Just a string"; /* message to be appeared on the screen */
2317 int row,col; /* to store the number of rows and *
2318 * the number of colums of the screen */
2319 initscr(); /* start the curses mode */
2320 getmaxyx(stdscr,row,col); /* get the number of rows and columns */
1262 mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
2321 mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
1263 /* print the message at the center of the screen */
2322 /* print the message at the center of the screen */
1264 mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col);
1265 printw("Try resizing your window(if possible) and then run this program again");
1266 refresh();
1267 getch();
1268 endwin();
1269
1270 return 0;
2323 mvprintw(row-2,0,"This screen has %d rows and %d columns\n",row,col);
2324 printw("Try resizing your window(if possible) and then run this program again");
2325 refresh();
2326 getch();
2327 endwin();
2328
2329 return 0;
1271}</span></font>
1272</pre></td>
1273</tr>
1274</table>
1275</div>
1276<p>Above program demonstrates how easy it is to use <var class=
1277"LITERAL">printw</var>. You just feed the coordinates and the
1278message to be appeared on the screen, then it does what you
1279want.</p>
1280<p>The above program introduces us to a new function <var class=
1281"LITERAL">getmaxyx()</var>, a macro defined in <var class=
1282"LITERAL">ncurses.h</var>. It gives the number of columns and the
1283number of rows in a given window. <var class=
1284"LITERAL">getmaxyx()</var> does this by updating the variables
1285given to it. Since <var class="LITERAL">getmaxyx()</var> is not a
1286function we don't pass pointers to it, we just give two integer
1287variables.</p>
1288</div>
1289</div>
1290<div class="SECT2">
1291<hr>
1292<h3 class="SECT2"><a name="ADDSTRCLASS" id="ADDSTRCLASS">6.4.
1293addstr() class of functions</a></h3>
1294<p><var class="LITERAL">addstr()</var> is used to put a character
1295string into a given window. This function is similar to calling
1296<var class="LITERAL">addch()</var> once for each character in a
1297given string. This is true for all output functions. There are
1298other functions from this family such as <var class=
1299"LITERAL">mvaddstr(),mvwaddstr()</var> and <var class=
1300"LITERAL">waddstr()</var>, which obey the naming convention of
1301curses.(e.g. mvaddstr() is similar to the respective calls move()
1302and then addstr().) Another function of this family is addnstr(),
1303which takes an integer parameter(say n) additionally. This function
1304puts at most n characters into the screen. If n is negative, then
1305the entire string will be added.</p>
1306</div>
1307<div class="SECT2">
1308<hr>
1309<h3 class="SECT2"><a name="ACAUTION" id="ACAUTION">6.5. A word of
1310caution</a></h3>
1311<p>All these functions take y co-ordinate first and then x in their
1312arguments. A common mistake by beginners is to pass x,y in that
1313order. If you are doing too many manipulations of (y,x)
1314co-ordinates, think of dividing the screen into windows and
1315manipulate each one separately. Windows are explained in the
1316<a href="#WINDOWS">windows</a> section.</p>
1317</div>
1318</div>
1319<div class="SECT1">
1320<hr>
1321<h2 class="SECT1"><a name="SCANW" id="SCANW">7. Input
1322functions</a></h2>
1323<p>Well, printing without taking input, is boring. Let's see
1324functions which allow us to get input from user. These functions
1325also can be divided into three categories.</p>
1326<ol type="1">
1327<li>
1328<p>getch() class: Get a character</p>
1329</li>
1330<li>
1331<p>scanw() class: Get formatted input</p>
1332</li>
1333<li>
1334<p>getstr() class: Get strings</p>
1335</li>
1336</ol>
1337<div class="SECT2">
1338<hr>
1339<h3 class="SECT2"><a name="GETCHCLASS" id="GETCHCLASS">7.1. getch()
1340class of functions</a></h3>
1341<p>These functions read a single character from the terminal. But
1342there are several subtle facts to consider. For example if you
1343don't use the function cbreak(), curses will not read your input
1344characters contiguously but will begin read them only after a new
1345line or an EOF is encountered. In order to avoid this, the cbreak()
1346function must used so that characters are immediately available to
1347your program. Another widely used function is noecho(). As the name
1348suggests, when this function is set (used), the characters that are
1349keyed in by the user will not show up on the screen. The two
1350functions cbreak() and noecho() are typical examples of key
1351management. Functions of this genre are explained in the <a href=
1352"#KEYS">key management section</a> .</p>
1353</div>
1354<div class="SECT2">
1355<hr>
1356<h3 class="SECT2"><a name="SCANWCLASS" id="SCANWCLASS">7.2. scanw()
1357class of functions</a></h3>
1358<p>These functions are similar to <var class=
1359"LITERAL">scanf()</var> with the added capability of getting the
1360input from any location on the screen.</p>
1361<div class="SECT3">
1362<hr>
1363<h4 class="SECT3"><a name="SCANWMVSCANW" id="SCANWMVSCANW">7.2.1.
1364scanw() and mvscanw</a></h4>
1365<p>The usage of these functions is similar to that of <var class=
1366"LITERAL">sscanf()</var>, where the line to be scanned is provided
1367by <var class="LITERAL">wgetstr()</var> function. That is, these
1368functions call to <var class="LITERAL">wgetstr()</var>
1369function(explained below) and uses the resulting line for a
1370scan.</p>
1371</div>
1372<div class="SECT3">
1373<hr>
1374<h4 class="SECT3"><a name="WSCANWMVWSCANW" id=
1375"WSCANWMVWSCANW">7.2.2. wscanw() and mvwscanw()</a></h4>
1376<p>These are similar to above two functions except that they read
1377from a window, which is supplied as one of the arguments to these
1378functions.</p>
1379</div>
1380<div class="SECT3">
1381<hr>
1382<h4 class="SECT3"><a name="VWSCANW" id="VWSCANW">7.2.3.
1383vwscanw()</a></h4>
1384<p>This function is similar to <var class="LITERAL">vscanf()</var>.
1385This can be used when a variable number of arguments are to be
1386scanned.</p>
1387</div>
1388</div>
1389<div class="SECT2">
1390<hr>
1391<h3 class="SECT2"><a name="GETSTRCLASS" id="GETSTRCLASS">7.3.
1392getstr() class of functions</a></h3>
1393<p>These functions are used to get strings from the terminal. In
1394essence, this function performs the same task as would be achieved
1395by a series of calls to <var class="LITERAL">getch()</var> until a
1396newline, carriage return, or end-of-file is received. The resulting
1397string of characters are pointed to by <var class=
1398"LITERAL">str</var>, which is a character pointer provided by the
1399user.</p>
1400</div>
1401<div class="SECT2">
1402<hr>
1403<h3 class="SECT2"><a name="GETSTREX" id="GETSTREX">7.4. Some
1404examples</a></h3>
1405<div class="EXAMPLE"><a name="BSCEX" id="BSCEX"></a>
1406<p><b>Example 4. A Simple scanw example</b></p>
1407<table border="0" bgcolor="#E0E0E0" width="100%">
1408<tr>
1409<td>
1410<pre class="PROGRAMLISTING">
1411<font color="#000000"><span class=
1412"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt; /* ncurses.h includes stdio.h */
1413#include &lt;string.h&gt;
2330}</SPAN
2331></PRE
2332></DIV
2333><P
2334>Above program demonstrates how easy it is to use <TT
2335CLASS="LITERAL"
2336>printw</TT
2337>. You just feed the coordinates and the message to be appeared
2338on the screen, then it does what you want.</P
2339><P
2340>The above program introduces us to a new function
2341<TT
2342CLASS="LITERAL"
2343>getmaxyx()</TT
2344>, a macro defined in
2345<TT
2346CLASS="LITERAL"
2347>ncurses.h</TT
2348>. It gives the number of columns and
2349the number of rows in a given window.
2350<TT
2351CLASS="LITERAL"
2352>getmaxyx()</TT
2353> does this by updating the variables
2354given to it. Since <TT
2355CLASS="LITERAL"
2356>getmaxyx()</TT
2357> is not a function
2358we don't pass pointers to it, we just give two integer variables. </P
2359></DIV
2360></DIV
2361><DIV
2362CLASS="SECT2"
2363><HR><H3
2364CLASS="SECT2"
2365><A
2366NAME="ADDSTRCLASS"
2367>6.4. addstr() class of functions</A
2368></H3
2369><P
2370><TT
2371CLASS="LITERAL"
2372>addstr()</TT
2373> is used to put a character string into
2374a given window. This function is similar to calling
2375<TT
2376CLASS="LITERAL"
2377>addch()</TT
2378> once for each character in a given
2379string. This is true for all output functions. There are other functions from
2380this family such as <TT
2381CLASS="LITERAL"
2382>mvaddstr(),mvwaddstr()</TT
2383> and
2384<TT
2385CLASS="LITERAL"
2386>waddstr()</TT
2387>, which obey the naming convention of
2388curses.(e.g. mvaddstr() is similar to the respective calls move() and then
2389addstr().) Another function of this family is addnstr(), which takes an integer
2390parameter(say n) additionally. This function puts at most n characters into the
2391screen. If n is negative, then the entire string will be added. </P
2392></DIV
2393><DIV
2394CLASS="SECT2"
2395><HR><H3
2396CLASS="SECT2"
2397><A
2398NAME="ACAUTION"
2399>6.5. A word of caution</A
2400></H3
2401><P
2402>All these functions take y co-ordinate first and then x in their arguments.
2403A common mistake by beginners is to pass x,y in that order. If you are
2404doing too many manipulations of (y,x) co-ordinates, think of dividing the
2405screen into windows and manipulate each one separately. Windows are explained
2406in the <A
2407HREF="#WINDOWS"
2408> windows </A
2409> section.</P
2410></DIV
2411></DIV
2412><DIV
2413CLASS="SECT1"
2414><HR><H2
2415CLASS="SECT1"
2416><A
2417NAME="SCANW"
2418>7. Input functions</A
2419></H2
2420><P
2421>Well, printing without taking input, is boring. Let's see functions which
2422allow us to get input from user. These functions also can be divided into
2423three categories.</P
2424><P
2425></P
2426><OL
2427TYPE="1"
2428><LI
2429><P
2430>getch() class: Get a character</P
2431></LI
2432><LI
2433><P
2434>scanw() class: Get formatted input</P
2435></LI
2436><LI
2437><P
2438>getstr() class: Get strings</P
2439></LI
2440></OL
2441><DIV
2442CLASS="SECT2"
2443><HR><H3
2444CLASS="SECT2"
2445><A
2446NAME="GETCHCLASS"
2447>7.1. getch() class of functions</A
2448></H3
2449><P
2450>These functions read a single character from the terminal. But there are several
2451subtle facts to consider. For example if you don't use the function cbreak(),
2452curses will not read your input characters contiguously but will begin read them
2453only after a new line or an EOF is encountered. In order to avoid this, the
2454cbreak() function must used so that characters are immediately available to your
2455program. Another widely used function is noecho(). As the name suggests, when
2456this function is set (used), the characters that are keyed in by the user will
2457not show up on the screen. The two functions cbreak() and noecho() are typical
2458examples of key management. Functions of this genre are explained in the
2459<A
2460HREF="#KEYS"
2461>key management section </A
2462>.</P
2463></DIV
2464><DIV
2465CLASS="SECT2"
2466><HR><H3
2467CLASS="SECT2"
2468><A
2469NAME="SCANWCLASS"
2470>7.2. scanw() class of functions</A
2471></H3
2472><P
2473>These functions are similar to <TT
2474CLASS="LITERAL"
2475>scanf()</TT
2476> with the
2477added capability of getting the input from any location on the screen.</P
2478><DIV
2479CLASS="SECT3"
2480><HR><H4
2481CLASS="SECT3"
2482><A
2483NAME="SCANWMVSCANW"
2484>7.2.1. scanw() and mvscanw</A
2485></H4
2486><P
2487>The usage of these functions is similar to that of
2488<TT
2489CLASS="LITERAL"
2490>sscanf()</TT
2491>, where the line to be scanned is
2492provided by <TT
2493CLASS="LITERAL"
2494>wgetstr()</TT
2495> function. That is, these
2496functions call to <TT
2497CLASS="LITERAL"
2498>wgetstr()</TT
2499> function(explained
2500below) and uses the resulting line for a scan. </P
2501></DIV
2502><DIV
2503CLASS="SECT3"
2504><HR><H4
2505CLASS="SECT3"
2506><A
2507NAME="WSCANWMVWSCANW"
2508>7.2.2. wscanw() and mvwscanw()</A
2509></H4
2510><P
2511>These are similar to above two functions except that they read from a window,
2512which is supplied as one of the arguments to these functions. </P
2513></DIV
2514><DIV
2515CLASS="SECT3"
2516><HR><H4
2517CLASS="SECT3"
2518><A
2519NAME="VWSCANW"
2520>7.2.3. vwscanw()</A
2521></H4
2522><P
2523>This function is similar to <TT
2524CLASS="LITERAL"
2525>vscanf()</TT
2526>. This can
2527be used when a variable number of arguments are to be scanned.</P
2528></DIV
2529></DIV
2530><DIV
2531CLASS="SECT2"
2532><HR><H3
2533CLASS="SECT2"
2534><A
2535NAME="GETSTRCLASS"
2536>7.3. getstr() class of functions</A
2537></H3
2538><P
2539>These functions are used to get strings from the terminal. In essence, this
2540function performs the same task as would be achieved by a series of calls to
2541<TT
2542CLASS="LITERAL"
2543>getch()</TT
2544> until a newline, carriage return, or
2545end-of-file is received. The resulting string of characters are pointed to by
2546<TT
2547CLASS="LITERAL"
2548>str</TT
2549>, which is a character pointer provided by
2550the user.</P
2551></DIV
2552><DIV
2553CLASS="SECT2"
2554><HR><H3
2555CLASS="SECT2"
2556><A
2557NAME="GETSTREX"
2558>7.4. Some examples</A
2559></H3
2560><DIV
2561CLASS="EXAMPLE"
2562><A
2563NAME="BSCEX"
2564></A
2565><P
2566><B
2567>Example 4. A Simple scanw example </B
2568></P
2569><PRE
2570CLASS="PROGRAMLISTING"
2571><SPAN
2572CLASS="INLINEMEDIAOBJECT"
2573>#include &#60;ncurses.h&#62; /* ncurses.h includes stdio.h */
2574#include &#60;string.h&#62;
1414
1415int main()
1416{
2575
2576int main()
2577{
1417 char mesg[]="Enter a string: "; /* message to be appeared on the screen */
2578 char mesg[]="Enter a string: "; /* message to be appeared on the screen */
1418 char str[80];
2579 char str[80];
1419 int row,col; /* to store the number of rows and *
1420 * the number of colums of the screen */
1421 initscr(); /* start the curses mode */
1422 getmaxyx(stdscr,row,col); /* get the number of rows and columns */
2580 int row,col; /* to store the number of rows and *
2581 * the number of colums of the screen */
2582 initscr(); /* start the curses mode */
2583 getmaxyx(stdscr,row,col); /* get the number of rows and columns */
1423 mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
2584 mvprintw(row/2,(col-strlen(mesg))/2,"%s",mesg);
1424 /* print the message at the center of the screen */
2585 /* print the message at the center of the screen */
1425 getstr(str);
1426 mvprintw(LINES - 2, 0, "You Entered: %s", str);
1427 getch();
1428 endwin();
1429
1430 return 0;
2586 getstr(str);
2587 mvprintw(LINES - 2, 0, "You Entered: %s", str);
2588 getch();
2589 endwin();
2590
2591 return 0;
1431}</span></font>
1432</pre></td>
1433</tr>
1434</table>
1435</div>
1436</div>
1437</div>
1438<div class="SECT1">
1439<hr>
1440<h2 class="SECT1"><a name="ATTRIB" id="ATTRIB">8.
1441Attributes</a></h2>
1442<p>We have seen an example of how attributes can be used to print
1443characters with some special effects. Attributes, when set
1444prudently, can present information in an easy, understandable
1445manner. The following program takes a C file as input and prints
1446the file with comments in bold. Scan through the code.</p>
1447<div class="EXAMPLE"><a name="BSIAT" id="BSIAT"></a>
1448<p><b>Example 5. A Simple Attributes example</b></p>
1449<table border="0" bgcolor="#E0E0E0" width="100%">
1450<tr>
1451<td>
1452<pre class="PROGRAMLISTING">
1453<font color="#000000"><span class=
1454"INLINEMEDIAOBJECT">/* pager functionality by Joseph Spainhour" &lt;spainhou@bellsouth.net&gt; */
1455#include &lt;ncurses.h&gt;
1456#include &lt;stdlib.h&gt;
2592}</SPAN
2593></PRE
2594></DIV
2595></DIV
2596></DIV
2597><DIV
2598CLASS="SECT1"
2599><HR><H2
2600CLASS="SECT1"
2601><A
2602NAME="ATTRIB"
2603>8. Attributes</A
2604></H2
2605><P
2606>We have seen an example of how attributes can be used to print characters with
2607some special effects. Attributes, when set prudently, can present information in
2608an easy, understandable manner. The following program takes a C file as input
2609and prints the file with comments in bold. Scan through the code. </P
2610><DIV
2611CLASS="EXAMPLE"
2612><A
2613NAME="BSIAT"
2614></A
2615><P
2616><B
2617>Example 5. A Simple Attributes example </B
2618></P
2619><PRE
2620CLASS="PROGRAMLISTING"
2621><SPAN
2622CLASS="INLINEMEDIAOBJECT"
2623>/* pager functionality by Joseph Spainhour" &#60;spainhou@bellsouth.net&#62; */
2624#include &#60;ncurses.h&#62;
2625#include &#60;stdlib.h&#62;
1457
1458int main(int argc, char *argv[])
1459{
1460 int ch, prev, row, col;
1461 prev = EOF;
1462 FILE *fp;
1463 int y, x;
1464
1465 if(argc != 2)
1466 {
2626
2627int main(int argc, char *argv[])
2628{
2629 int ch, prev, row, col;
2630 prev = EOF;
2631 FILE *fp;
2632 int y, x;
2633
2634 if(argc != 2)
2635 {
1467 printf("Usage: %s &lt;a c file name&gt;\n", argv[0]);
2636 printf("Usage: %s &#60;a c file name&#62;\n", argv[0]);
1468 exit(1);
1469 }
1470 fp = fopen(argv[1], "r");
1471 if(fp == NULL)
1472 {
1473 perror("Cannot open input file");
1474 exit(1);
1475 }
2637 exit(1);
2638 }
2639 fp = fopen(argv[1], "r");
2640 if(fp == NULL)
2641 {
2642 perror("Cannot open input file");
2643 exit(1);
2644 }
1476 initscr(); /* Start curses mode */
1477 getmaxyx(stdscr, row, col); /* find the boundaries of the screeen */
1478 while((ch = fgetc(fp)) != EOF) /* read the file till we reach the end */
2645 initscr(); /* Start curses mode */
2646 getmaxyx(stdscr, row, col); /* find the boundaries of the screeen */
2647 while((ch = fgetc(fp)) != EOF) /* read the file till we reach the end */
1479 {
2648 {
1480 getyx(stdscr, y, x); /* get the current curser position */
1481 if(y == (row - 1)) /* are we are at the end of the screen */
2649 getyx(stdscr, y, x); /* get the current curser position */
2650 if(y == (row - 1)) /* are we are at the end of the screen */
1482 {
2651 {
1483 printw("&lt;-Press Any Key-&gt;"); /* tell the user to press a key */
2652 printw("&#60;-Press Any Key-&#62;"); /* tell the user to press a key */
1484 getch();
2653 getch();
1485 clear(); /* clear the screen */
1486 move(0, 0); /* start at the beginning of the screen */
2654 clear(); /* clear the screen */
2655 move(0, 0); /* start at the beginning of the screen */
1487 }
2656 }
1488 if(prev == '/' &amp;&amp; ch == '*') /* If it is / and * then only
1489 * switch bold on */
2657 if(prev == '/' &#38;&#38; ch == '*') /* If it is / and * then only
2658 * switch bold on */
1490 {
2659 {
1491 attron(A_BOLD); /* cut bold on */
1492 getyx(stdscr, y, x); /* get the current curser position */
1493 move(y, x - 1); /* back up one space */
1494 printw("%c%c", '/', ch); /* The actual printing is done here */
2660 attron(A_BOLD); /* cut bold on */
2661 getyx(stdscr, y, x); /* get the current curser position */
2662 move(y, x - 1); /* back up one space */
2663 printw("%c%c", '/', ch); /* The actual printing is done here */
1495 }
1496 else
1497 printw("%c", ch);
1498 refresh();
2664 }
2665 else
2666 printw("%c", ch);
2667 refresh();
1499 if(prev == '*' &amp;&amp; ch == '/')
1500 attroff(A_BOLD); /* Switch it off once we got *
1501 * and then / */
2668 if(prev == '*' &#38;&#38; ch == '/')
2669 attroff(A_BOLD); /* Switch it off once we got *
2670 * and then / */
1502 prev = ch;
1503 }
2671 prev = ch;
2672 }
1504 endwin(); /* End curses mode */
2673 endwin(); /* End curses mode */
1505 fclose(fp);
1506 return 0;
2674 fclose(fp);
2675 return 0;
1507}</span></font>
1508</pre></td>
1509</tr>
1510</table>
1511</div>
1512<p>Don't worry about all those initialization and other crap.
1513Concentrate on the while loop. It reads each character in the file
1514and searches for the pattern /*. Once it spots the pattern, it
1515switches the BOLD attribute on with <var class=
1516"LITERAL">attron()</var> . When we get the pattern */ it is
1517switched off by <var class="LITERAL">attroff()</var> .</p>
1518<p>The above program also introduces us to two useful functions
1519<var class="LITERAL">getyx()</var> and <var class=
1520"LITERAL">move()</var>. The first function gets the co-ordinates of
1521the present cursor into the variables y, x. Since getyx() is a
2676}</SPAN
2677></PRE
2678></DIV
2679><P
2680>
2681Don't worry about all those initialization and other crap. Concentrate on
2682the while loop. It reads each character in the file and searches for the
2683pattern /*. Once it spots the pattern, it switches the BOLD attribute on with
2684<TT
2685CLASS="LITERAL"
2686> attron()</TT
2687> . When we get the pattern */ it is
2688switched off by <TT
2689CLASS="LITERAL"
2690> attroff()</TT
2691> .</P
2692><P
2693>
2694The above program also introduces us to two useful functions
2695<TT
2696CLASS="LITERAL"
2697>getyx() </TT
2698> and
2699<TT
2700CLASS="LITERAL"
2701>move()</TT
2702>. The first function gets the
2703co-ordinates of the present cursor into the variables y, x. Since getyx() is a
1522macro we don't have to pass pointers to variables. The function
2704macro we don't have to pass pointers to variables. The function
1523<var class="LITERAL">move()</var> moves the cursor to the
1524co-ordinates given to it.</p>
1525<p>The above program is really a simple one which doesn't do much.
1526On these lines one could write a more useful program which reads a
1527C file, parses it and prints it in different colors. One could even
1528extend it to other languages as well.</p>
1529<div class="SECT2">
1530<hr>
1531<h3 class="SECT2"><a name="ATTRIBDETAILS" id="ATTRIBDETAILS">8.1.
1532The details</a></h3>
1533<p>Let's get into more details of attributes. The functions
1534<var class="LITERAL">attron(), attroff(), attrset()</var> , and
1535their sister functions <var class="LITERAL">attr_get()</var> etc..
1536can be used to switch attributes on/off , get attributes and
1537produce a colorful display.</p>
1538<p>The functions attron and attroff take a bit-mask of attributes
1539and switch them on or off, respectively. The following video
1540attributes, which are defined in &lt;curses.h&gt; can be passed to
1541these functions.</p>
1542<table border="0" bgcolor="#E0E0E0" width="100%">
1543<tr>
1544<td>
1545<pre class="PROGRAMLISTING">
1546<font color="#000000">
2705<TT
2706CLASS="LITERAL"
2707>move()</TT
2708> moves the cursor to the co-ordinates
2709given to it. </P
2710><P
2711>
2712The above program is really a simple one which doesn't do much. On these lines
2713one could write a more useful program which reads a C file, parses it and prints
2714it in different colors. One could even extend it to other languages as well.</P
2715><DIV
2716CLASS="SECT2"
2717><HR><H3
2718CLASS="SECT2"
2719><A
2720NAME="ATTRIBDETAILS"
2721>8.1. The details</A
2722></H3
2723><P
2724>Let's get into more details of attributes. The functions <TT
2725CLASS="LITERAL"
2726>attron(), attroff(), attrset() </TT
2727>, and their sister functions
2728<TT
2729CLASS="LITERAL"
2730> attr_get()</TT
2731> etc.. can be used to switch
2732attributes on/off , get attributes and produce a colorful display.</P
2733><P
2734>The functions attron and attroff take a bit-mask of attributes and switch them
2735on or off, respectively. The following video attributes, which are defined in
2736&lt;curses.h&gt; can be passed to these functions. </P
2737><PRE
2738CLASS="PROGRAMLISTING"
2739>
1547 A_NORMAL Normal display (no highlight)
1548 A_STANDOUT Best highlighting mode of the terminal.
1549 A_UNDERLINE Underlining
1550 A_REVERSE Reverse video
1551 A_BLINK Blinking
1552 A_DIM Half bright
1553 A_BOLD Extra bright or bold
1554 A_PROTECT Protected mode
1555 A_INVIS Invisible or blank mode
1556 A_ALTCHARSET Alternate character set
1557 A_CHARTEXT Bit-mask to extract a character
1558 COLOR_PAIR(n) Color-pair number n
2740 A_NORMAL Normal display (no highlight)
2741 A_STANDOUT Best highlighting mode of the terminal.
2742 A_UNDERLINE Underlining
2743 A_REVERSE Reverse video
2744 A_BLINK Blinking
2745 A_DIM Half bright
2746 A_BOLD Extra bright or bold
2747 A_PROTECT Protected mode
2748 A_INVIS Invisible or blank mode
2749 A_ALTCHARSET Alternate character set
2750 A_CHARTEXT Bit-mask to extract a character
2751 COLOR_PAIR(n) Color-pair number n
1559 </font>
1560</pre></td>
1561</tr>
1562</table>
1563<p>The last one is the most colorful one :-) Colors are explained
1564in the <a href="#color" target="_top">next sections</a>.</p>
1565<p>We can OR(|) any number of above attributes to get a combined
1566effect. If you wanted reverse video with blinking characters you
1567can use</p>
1568<table border="0" bgcolor="#E0E0E0" width="100%">
1569<tr>
1570<td>
1571<pre class="PROGRAMLISTING">
1572<font color="#000000"> attron(A_REVERSE | A_BLINK);</font>
1573</pre></td>
1574</tr>
1575</table>
1576</div>
1577<div class="SECT2">
1578<hr>
1579<h3 class="SECT2"><a name="ATTRONVSATTRSET" id=
1580"ATTRONVSATTRSET">8.2. attron() vs attrset()</a></h3>
1581<p>Then what is the difference between attron() and attrset()?
1582attrset sets the attributes of window whereas attron just switches
1583on the attribute given to it. So attrset() fully overrides whatever
1584attributes the window previously had and sets it to the new
1585attribute(s). Similarly attroff() just switches off the
1586attribute(s) given to it as an argument. This gives us the
1587flexibility of managing attributes easily.But if you use them
1588carelessly you may loose track of what attributes the window has
1589and garble the display. This is especially true while managing
1590menus with colors and highlighting. So decide on a consistent
1591policy and stick to it. You can always use <var class=
1592"LITERAL">standend()</var> which is equivalent to <var class=
1593"LITERAL">attrset(A_NORMAL)</var> which turns off all attributes
1594and brings you to normal mode.</p>
1595</div>
1596<div class="SECT2">
1597<hr>
1598<h3 class="SECT2"><a name="ATTR_GET" id="ATTR_GET">8.3.
1599attr_get()</a></h3>
1600<p>The function attr_get() gets the current attributes and color
1601pair of the window. Though we might not use this as often as the
1602above functions, this is useful in scanning areas of screen. Say we
1603wanted to do some complex update on screen and we are not sure what
1604attribute each character is associated with. Then this function can
1605be used with either attrset or attron to produce the desired
1606effect.</p>
1607</div>
1608<div class="SECT2">
1609<hr>
1610<h3 class="SECT2"><a name="ATTR_FUNCS" id="ATTR_FUNCS">8.4. attr_
1611functions</a></h3>
1612<p>There are series of functions like attr_set(), attr_on etc..
1613These are similar to above functions except that they take
1614parameters of type <var class="LITERAL">attr_t</var>.</p>
1615</div>
1616<div class="SECT2">
1617<hr>
1618<h3 class="SECT2"><a name="WATTRFUNCS" id="WATTRFUNCS">8.5. wattr
1619functions</a></h3>
1620<p>For each of the above functions we have a corresponding function
1621with 'w' which operates on a particular window. The above functions
1622operate on stdscr.</p>
1623</div>
1624<div class="SECT2">
1625<hr>
1626<h3 class="SECT2"><a name="CHGAT" id="CHGAT">8.6. chgat()
1627functions</a></h3>
1628<p>The function chgat() is listed in the end of the man page
1629curs_attr. It actually is a useful one. This function can be used
1630to set attributes for a group of characters without moving. I mean
1631it !!! without moving the cursor :-) It changes the attributes of a
1632given number of characters starting at the current cursor
1633location.</p>
1634<p>We can give -1 as the character count to update till end of
1635line. If you want to change attributes of characters from current
1636position to end of line, just use this.</p>
1637<table border="0" bgcolor="#E0E0E0" width="100%">
1638<tr>
1639<td>
1640<pre class="PROGRAMLISTING">
1641<font color="#000000"> chgat(-1, A_REVERSE, 0, NULL);</font>
1642</pre></td>
1643</tr>
1644</table>
1645<p>This function is useful when changing attributes for characters
1646that are already on the screen. Move to the character from which
1647you want to change and change the attribute.</p>
1648<p>Other functions wchgat(), mvchgat(), wchgat() behave similarly
1649except that the w functions operate on the particular window. The
1650mv functions first move the cursor then perform the work given to
1651them. Actually chgat is a macro which is replaced by a wchgat()
1652with stdscr as the window. Most of the "w-less" functions are
1653macros.</p>
1654<div class="EXAMPLE"><a name="BWICH" id="BWICH"></a>
1655<p><b>Example 6. Chgat() Usage example</b></p>
1656<table border="0" bgcolor="#E0E0E0" width="100%">
1657<tr>
1658<td>
1659<pre class="PROGRAMLISTING">
1660<font color="#000000"><span class=
1661"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
2752 </PRE
2753><P
2754>
2755The last one is the most colorful one :-) Colors are explained in the
2756<A
2757HREF="#color"
2758TARGET="_top"
2759>next sections</A
2760>.</P
2761><P
2762>We can OR(|) any number of above attributes to get a combined effect. If you
2763wanted reverse video with blinking characters you can use</P
2764><PRE
2765CLASS="PROGRAMLISTING"
2766> attron(A_REVERSE | A_BLINK);</PRE
2767></DIV
2768><DIV
2769CLASS="SECT2"
2770><HR><H3
2771CLASS="SECT2"
2772><A
2773NAME="ATTRONVSATTRSET"
2774>8.2. attron() vs attrset()</A
2775></H3
2776><P
2777>Then what is the difference between attron() and attrset()? attrset sets the
2778attributes of window whereas attron just switches on the attribute given to it.
2779So attrset() fully overrides whatever attributes the window previously had and
2780sets it to the new attribute(s). Similarly attroff() just switches off the
2781attribute(s) given to it as an argument. This gives us the flexibility of
2782managing attributes easily.But if you use them carelessly you may loose track of
2783what attributes the window has and garble the display. This is especially true
2784while managing menus with colors and highlighting. So decide on a consistent
2785policy and stick to it. You can always use <TT
2786CLASS="LITERAL"
2787> standend()</TT
2788> which is equivalent to <TT
2789CLASS="LITERAL"
2790> attrset(A_NORMAL)</TT
2791> which turns off all attributes and brings you to normal mode.</P
2792></DIV
2793><DIV
2794CLASS="SECT2"
2795><HR><H3
2796CLASS="SECT2"
2797><A
2798NAME="ATTR_GET"
2799>8.3. attr_get()</A
2800></H3
2801><P
2802>&#13;The function attr_get() gets the current attributes and color pair of the
2803window. Though we might not use this as often as the above functions, this is
2804useful in scanning areas of screen. Say we wanted to do some complex update on
2805screen and we are not sure what attribute each character is associated with.
2806Then this function can be used with either attrset or attron to produce the
2807desired effect.&#13;</P
2808></DIV
2809><DIV
2810CLASS="SECT2"
2811><HR><H3
2812CLASS="SECT2"
2813><A
2814NAME="ATTR_FUNCS"
2815>8.4. attr_ functions</A
2816></H3
2817><P
2818>There are series of functions like attr_set(), attr_on etc.. These are similar
2819to above functions except that they take parameters of type
2820<TT
2821CLASS="LITERAL"
2822>attr_t</TT
2823>.</P
2824></DIV
2825><DIV
2826CLASS="SECT2"
2827><HR><H3
2828CLASS="SECT2"
2829><A
2830NAME="WATTRFUNCS"
2831>8.5. wattr functions</A
2832></H3
2833><P
2834>For each of the above functions we have a corresponding function with 'w' which
2835operates on a particular window. The above functions operate on stdscr. </P
2836></DIV
2837><DIV
2838CLASS="SECT2"
2839><HR><H3
2840CLASS="SECT2"
2841><A
2842NAME="CHGAT"
2843>8.6. chgat() functions</A
2844></H3
2845><P
2846>The function chgat() is listed in the end of the man page curs_attr. It actually
2847is a useful one. This function can be used to set attributes for a group of
2848characters without moving. I mean it !!! without moving the cursor :-) It
2849changes the attributes of a given number of characters starting at the current
2850cursor location.</P
2851><P
2852>We can give -1 as the character count to update till end of line. If you want to
2853change attributes of characters from current position to end of line, just use
2854this.</P
2855><PRE
2856CLASS="PROGRAMLISTING"
2857> chgat(-1, A_REVERSE, 0, NULL);</PRE
2858><P
2859>
2860This function is useful when changing attributes for characters that are
2861already on the screen. Move to the character from which you want to change and
2862change the attribute. </P
2863><P
2864>Other functions wchgat(), mvchgat(), wchgat() behave similarly except that the w
2865functions operate on the particular window. The mv functions first move the
2866cursor then perform the work given to them. Actually chgat is a macro which is
2867replaced by a wchgat() with stdscr as the window. Most of the "w-less" functions
2868are macros.</P
2869><DIV
2870CLASS="EXAMPLE"
2871><A
2872NAME="BWICH"
2873></A
2874><P
2875><B
2876>Example 6. Chgat() Usage example </B
2877></P
2878><PRE
2879CLASS="PROGRAMLISTING"
2880><SPAN
2881CLASS="INLINEMEDIAOBJECT"
2882>#include &#60;ncurses.h&#62;
1662
1663int main(int argc, char *argv[])
2883
2884int main(int argc, char *argv[])
1664{ initscr(); /* Start curses mode */
1665 start_color(); /* Start color functionality */
1666
1667 init_pair(1, COLOR_CYAN, COLOR_BLACK);
1668 printw("A Big string which i didn't care to type fully ");
1669 mvchgat(0, 0, -1, A_BLINK, 1, NULL);
1670 /*
1671 * First two parameters specify the position at which to start
1672 * Third parameter number of characters to update. -1 means till
1673 * end of line
1674 * Forth parameter is the normal attribute you wanted to give
1675 * to the charcter
1676 * Fifth is the color index. It is the index given during init_pair()
1677 * use 0 if you didn't want color
1678 * Sixth one is always NULL
1679 */
1680 refresh();
1681 getch();
1682 endwin(); /* End curses mode */
1683 return 0;
1684}</span></font>
1685</pre></td>
1686</tr>
1687</table>
1688</div>
1689<p>This example also introduces us to the color world of curses.
1690Colors will be explained in detail later. Use 0 for no color.</p>
1691</div>
1692</div>
1693<div class="SECT1">
1694<hr>
1695<h2 class="SECT1"><a name="WINDOWS" id="WINDOWS">9.
1696Windows</a></h2>
1697<p>Windows form the most important concept in curses. You have seen
1698the standard window stdscr above where all the functions implicitly
1699operated on this window. Now to make design even a simplest GUI,
1700you need to resort to windows. The main reason you may want to use
1701windows is to manipulate parts of the screen separately, for better
1702efficiency, by updating only the windows that need to be changed
1703and for a better design. I would say the last reason is the most
1704important in going for windows. You should always strive for a
1705better and easy-to-manage design in your programs. If you are
1706writing big, complex GUIs this is of pivotal importance before you
1707start doing anything.</p>
1708<div class="SECT2">
1709<hr>
1710<h3 class="SECT2"><a name="WINDOWBASICS" id="WINDOWBASICS">9.1. The
1711basics</a></h3>
1712<p>A Window can be created by calling the function <var class=
1713"LITERAL">newwin()</var>. It doesn't create any thing on the screen
1714actually. It allocates memory for a structure to manipulate the
1715window and updates the structure with data regarding the window
1716like it's size, beginy, beginx etc.. Hence in curses, a window is
1717just an abstraction of an imaginary window, which can be
1718manipulated independent of other parts of screen. The function
1719newwin() returns a pointer to structure WINDOW, which can be passed
1720to window related functions like wprintw() etc.. Finally the window
1721can be destroyed with delwin(). It will deallocate the memory
1722associated with the window structure.</p>
1723</div>
1724<div class="SECT2">
1725<hr>
1726<h3 class="SECT2"><a name="LETBEWINDOW" id="LETBEWINDOW">9.2. Let
1727there be a Window !!!</a></h3>
1728<p>What fun is it, if a window is created and we can't see it. So
1729the fun part begins by displaying the window. The function
1730<var class="LITERAL">box()</var> can be used to draw a border
1731around the window. Let's explore these functions in more detail in
1732this example.</p>
1733<div class="EXAMPLE"><a name="BWIBO" id="BWIBO"></a>
1734<p><b>Example 7. Window Border example</b></p>
1735<table border="0" bgcolor="#E0E0E0" width="100%">
1736<tr>
1737<td>
1738<pre class="PROGRAMLISTING">
1739<font color="#000000"><span class=
1740"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
2885{ initscr(); /* Start curses mode */
2886 start_color(); /* Start color functionality */
2887
2888 init_pair(1, COLOR_CYAN, COLOR_BLACK);
2889 printw("A Big string which i didn't care to type fully ");
2890 mvchgat(0, 0, -1, A_BLINK, 1, NULL);
2891 /*
2892 * First two parameters specify the position at which to start
2893 * Third parameter number of characters to update. -1 means till
2894 * end of line
2895 * Forth parameter is the normal attribute you wanted to give
2896 * to the charcter
2897 * Fifth is the color index. It is the index given during init_pair()
2898 * use 0 if you didn't want color
2899 * Sixth one is always NULL
2900 */
2901 refresh();
2902 getch();
2903 endwin(); /* End curses mode */
2904 return 0;
2905}</SPAN
2906></PRE
2907></DIV
2908><P
2909>This example also introduces us to the color world of curses. Colors will be
2910explained in detail later. Use 0 for no color.</P
2911></DIV
2912></DIV
2913><DIV
2914CLASS="SECT1"
2915><HR><H2
2916CLASS="SECT1"
2917><A
2918NAME="WINDOWS"
2919>9. Windows</A
2920></H2
2921><P
2922>Windows form the most important concept in curses. You have seen the standard
2923window stdscr above where all the functions implicitly operated on this window.
2924Now to make design even a simplest GUI, you need to resort to windows. The main
2925reason you may want to use windows is to manipulate parts of the screen
2926separately, for better efficiency, by updating only the windows that need to be
2927changed and for a better design. I would say the last reason is the most
2928important in going for windows. You should always strive for a better and
2929easy-to-manage design in your programs. If you are writing big, complex GUIs
2930this is of pivotal importance before you start doing anything.</P
2931><DIV
2932CLASS="SECT2"
2933><HR><H3
2934CLASS="SECT2"
2935><A
2936NAME="WINDOWBASICS"
2937>9.1. The basics</A
2938></H3
2939><P
2940>A Window can be created by calling the function
2941<TT
2942CLASS="LITERAL"
2943>newwin()</TT
2944>. It doesn't create any thing on the
2945screen actually. It allocates memory for a structure to manipulate the window
2946and updates the structure with data regarding the window like it's size, beginy,
2947beginx etc.. Hence in curses, a window is just an abstraction of an imaginary
2948window, which can be manipulated independent of other parts of screen. The
2949function newwin() returns a pointer to structure WINDOW, which can be passed to
2950window related functions like wprintw() etc.. Finally the window can be
2951destroyed with delwin(). It will deallocate the memory associated with the
2952window structure.</P
2953></DIV
2954><DIV
2955CLASS="SECT2"
2956><HR><H3
2957CLASS="SECT2"
2958><A
2959NAME="LETBEWINDOW"
2960>9.2. Let there be a Window !!!</A
2961></H3
2962><P
2963>What fun is it, if a window is created and we can't see it. So the fun part
2964begins by displaying the window. The function
2965<TT
2966CLASS="LITERAL"
2967>box()</TT
2968> can be used to draw a border around the
2969window. Let's explore these functions in more detail in this example.</P
2970><DIV
2971CLASS="EXAMPLE"
2972><A
2973NAME="BWIBO"
2974></A
2975><P
2976><B
2977>Example 7. Window Border example </B
2978></P
2979><PRE
2980CLASS="PROGRAMLISTING"
2981><SPAN
2982CLASS="INLINEMEDIAOBJECT"
2983>#include &#60;ncurses.h&#62;
1741
1742
1743WINDOW *create_newwin(int height, int width, int starty, int startx);
1744void destroy_win(WINDOW *local_win);
1745
1746int main(int argc, char *argv[])
2984
2985
2986WINDOW *create_newwin(int height, int width, int starty, int startx);
2987void destroy_win(WINDOW *local_win);
2988
2989int main(int argc, char *argv[])
1747{ WINDOW *my_win;
1748 int startx, starty, width, height;
1749 int ch;
2990{ WINDOW *my_win;
2991 int startx, starty, width, height;
2992 int ch;
1750
2993
1751 initscr(); /* Start curses mode */
1752 cbreak(); /* Line buffering disabled, Pass on
1753 * everty thing to me */
1754 keypad(stdscr, TRUE); /* I need that nifty F1 */
2994 initscr(); /* Start curses mode */
2995 cbreak(); /* Line buffering disabled, Pass on
2996 * everty thing to me */
2997 keypad(stdscr, TRUE); /* I need that nifty F1 */
1755
2998
1756 height = 3;
1757 width = 10;
1758 starty = (LINES - height) / 2; /* Calculating for a center placement */
1759 startx = (COLS - width) / 2; /* of the window */
1760 printw("Press F1 to exit");
1761 refresh();
1762 my_win = create_newwin(height, width, starty, startx);
2999 height = 3;
3000 width = 10;
3001 starty = (LINES - height) / 2; /* Calculating for a center placement */
3002 startx = (COLS - width) / 2; /* of the window */
3003 printw("Press F1 to exit");
3004 refresh();
3005 my_win = create_newwin(height, width, starty, startx);
1763
3006
1764 while((ch = getch()) != KEY_F(1))
1765 { switch(ch)
1766 { case KEY_LEFT:
1767 destroy_win(my_win);
1768 my_win = create_newwin(height, width, starty,--startx);
1769 break;
1770 case KEY_RIGHT:
1771 destroy_win(my_win);
1772 my_win = create_newwin(height, width, starty,++startx);
1773 break;
1774 case KEY_UP:
1775 destroy_win(my_win);
1776 my_win = create_newwin(height, width, --starty,startx);
1777 break;
1778 case KEY_DOWN:
1779 destroy_win(my_win);
1780 my_win = create_newwin(height, width, ++starty,startx);
1781 break;
1782 }
1783 }
1784
1785 endwin(); /* End curses mode */
1786 return 0;
3007 while((ch = getch()) != KEY_F(1))
3008 { switch(ch)
3009 { case KEY_LEFT:
3010 destroy_win(my_win);
3011 my_win = create_newwin(height, width, starty,--startx);
3012 break;
3013 case KEY_RIGHT:
3014 destroy_win(my_win);
3015 my_win = create_newwin(height, width, starty,++startx);
3016 break;
3017 case KEY_UP:
3018 destroy_win(my_win);
3019 my_win = create_newwin(height, width, --starty,startx);
3020 break;
3021 case KEY_DOWN:
3022 destroy_win(my_win);
3023 my_win = create_newwin(height, width, ++starty,startx);
3024 break;
3025 }
3026 }
3027
3028 endwin(); /* End curses mode */
3029 return 0;
1787}
1788
1789WINDOW *create_newwin(int height, int width, int starty, int startx)
3030}
3031
3032WINDOW *create_newwin(int height, int width, int starty, int startx)
1790{ WINDOW *local_win;
3033{ WINDOW *local_win;
1791
3034
1792 local_win = newwin(height, width, starty, startx);
1793 box(local_win, 0 , 0); /* 0, 0 gives default characters
1794 * for the vertical and horizontal
1795 * lines */
1796 wrefresh(local_win); /* Show that box */
3035 local_win = newwin(height, width, starty, startx);
3036 box(local_win, 0 , 0); /* 0, 0 gives default characters
3037 * for the vertical and horizontal
3038 * lines */
3039 wrefresh(local_win); /* Show that box */
1797
3040
1798 return local_win;
3041 return local_win;
1799}
1800
1801void destroy_win(WINDOW *local_win)
3042}
3043
3044void destroy_win(WINDOW *local_win)
1802{
1803 /* box(local_win, ' ', ' '); : This won't produce the desired
1804 * result of erasing the window. It will leave it's four corners
1805 * and so an ugly remnant of window.
1806 */
1807 wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' ');
1808 /* The parameters taken are
1809 * 1. win: the window on which to operate
1810 * 2. ls: character to be used for the left side of the window
1811 * 3. rs: character to be used for the right side of the window
1812 * 4. ts: character to be used for the top side of the window
1813 * 5. bs: character to be used for the bottom side of the window
1814 * 6. tl: character to be used for the top left corner of the window
1815 * 7. tr: character to be used for the top right corner of the window
1816 * 8. bl: character to be used for the bottom left corner of the window
1817 * 9. br: character to be used for the bottom right corner of the window
1818 */
1819 wrefresh(local_win);
1820 delwin(local_win);
1821}</span></font>
1822</pre></td>
1823</tr>
1824</table>
1825</div>
1826</div>
1827<div class="SECT2">
1828<hr>
1829<h3 class="SECT2"><a name="BORDEREXEXPL" id="BORDEREXEXPL">9.3.
1830Explanation</a></h3>
1831<p>Don't scream. I know it's a big example. But I have to explain
1832some important things here :-). This program creates a rectangular
1833window that can be moved with left, right, up, down arrow keys. It
1834repeatedly creates and destroys windows as user press a key. Don't
1835go beyond the screen limits. Checking for those limits is left as
1836an exercise for the reader. Let's dissect it by line by line.</p>
1837<p>The <var class="LITERAL">create_newwin()</var> function creates
1838a window with <var class="LITERAL">newwin()</var> and displays a
1839border around it with box. The function <var class=
1840"LITERAL">destroy_win()</var> first erases the window from screen
1841by painting a border with ' ' character and then calling
1842<var class="LITERAL">delwin()</var> to deallocate memory related to
1843it. Depending on the key the user presses, starty or startx is
1844changed and a new window is created.</p>
1845<p>In the destroy_win, as you can see, I used wborder instead of
1846box. The reason is written in the comments (You missed it. I know.
1847Read the code :-)). wborder draws a border around the window with
1848the characters given to it as the 4 corner points and the 4 lines.
1849To put it clearly, if you have called wborder as below:</p>
1850<table border="0" bgcolor="#E0E0E0" width="100%">
1851<tr>
1852<td>
1853<pre class="PROGRAMLISTING">
1854<font color=
1855"#000000"> wborder(win, '|', '|', '-', '-', '+', '+', '+', '+');</font>
1856</pre></td>
1857</tr>
1858</table>
1859<p>it produces some thing like</p>
1860<table border="0" bgcolor="#E0E0E0" width="100%">
1861<tr>
1862<td>
1863<pre class="PROGRAMLISTING">
1864<font color="#000000"> +------------+
3045{
3046 /* box(local_win, ' ', ' '); : This won't produce the desired
3047 * result of erasing the window. It will leave it's four corners
3048 * and so an ugly remnant of window.
3049 */
3050 wborder(local_win, ' ', ' ', ' ',' ',' ',' ',' ',' ');
3051 /* The parameters taken are
3052 * 1. win: the window on which to operate
3053 * 2. ls: character to be used for the left side of the window
3054 * 3. rs: character to be used for the right side of the window
3055 * 4. ts: character to be used for the top side of the window
3056 * 5. bs: character to be used for the bottom side of the window
3057 * 6. tl: character to be used for the top left corner of the window
3058 * 7. tr: character to be used for the top right corner of the window
3059 * 8. bl: character to be used for the bottom left corner of the window
3060 * 9. br: character to be used for the bottom right corner of the window
3061 */
3062 wrefresh(local_win);
3063 delwin(local_win);
3064}</SPAN
3065></PRE
3066></DIV
3067></DIV
3068><DIV
3069CLASS="SECT2"
3070><HR><H3
3071CLASS="SECT2"
3072><A
3073NAME="BORDEREXEXPL"
3074>9.3. Explanation</A
3075></H3
3076><P
3077>Don't scream. I know it's a big example. But I have to explain some important
3078things here :-). This program creates a rectangular window that can be moved
3079with left, right, up, down arrow keys. It repeatedly creates and destroys
3080windows as user press a key. Don't go beyond the screen limits. Checking for
3081those limits is left as an exercise for the reader. Let's dissect it by line by line.</P
3082><P
3083>The <TT
3084CLASS="LITERAL"
3085>create_newwin()</TT
3086> function creates a window
3087with <TT
3088CLASS="LITERAL"
3089>newwin() </TT
3090> and displays a border around it
3091with box. The function <TT
3092CLASS="LITERAL"
3093> destroy_win()</TT
3094> first
3095erases the window from screen by painting a border with ' ' character and then
3096calling <TT
3097CLASS="LITERAL"
3098>delwin()</TT
3099> to deallocate memory related
3100to it. Depending on the key the user presses, starty or startx is changed and a
3101new window is created.</P
3102><P
3103>In the destroy_win, as you can see, I used wborder instead of box. The reason is
3104written in the comments (You missed it. I know. Read the code :-)). wborder
3105draws a border around the window with the characters given to it as the 4 corner
3106points and the 4 lines. To put it clearly, if you have called wborder as below:
3107<PRE
3108CLASS="PROGRAMLISTING"
3109> wborder(win, '|', '|', '-', '-', '+', '+', '+', '+');</PRE
3110></P
3111><P
3112>it produces some thing like </P
3113><PRE
3114CLASS="PROGRAMLISTING"
3115> +------------+
1865 | |
1866 | |
1867 | |
1868 | |
1869 | |
1870 | |
3116 | |
3117 | |
3118 | |
3119 | |
3120 | |
3121 | |
1871 +------------+</font>
1872</pre></td>
1873</tr>
1874</table>
1875</div>
1876<div class="SECT2">
1877<hr>
1878<h3 class="SECT2"><a name="OTHERSTUFF" id="OTHERSTUFF">9.4. The
1879other stuff in the example</a></h3>
1880<p>You can also see in the above examples, that I have used the
1881variables COLS, LINES which are initialized to the screen sizes
1882after initscr(). They can be useful in finding screen dimensions
1883and finding the center co-ordinate of the screen as above. The
1884function <var class="LITERAL">getch()</var> as usual gets the key
1885from keyboard and according to the key it does the corresponding
1886work. This type of switch- case is very common in any GUI based
1887programs.</p>
1888</div>
1889<div class="SECT2">
1890<hr>
1891<h3 class="SECT2"><a name="OTHERBORDERFUNCS" id=
1892"OTHERBORDERFUNCS">9.5. Other Border functions</a></h3>
1893<p>Above program is grossly inefficient in that with each press of
1894a key, a window is destroyed and another is created. So let's write
1895a more efficient program which uses other border related
1896functions.</p>
1897<p>The following program uses <var class="LITERAL">mvhline()</var>
1898and <var class="LITERAL">mvvline()</var> to achieve similar effect.
1899These two functions are simple. They create a horizontal or
1900vertical line of the specified length at the specified
1901position.</p>
1902<div class="EXAMPLE"><a name="BOTBO" id="BOTBO"></a>
1903<p><b>Example 8. More border functions</b></p>
1904<table border="0" bgcolor="#E0E0E0" width="100%">
1905<tr>
1906<td>
1907<pre class="PROGRAMLISTING">
1908<font color="#000000"><span class=
1909"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
3122 +------------+</PRE
3123></DIV
3124><DIV
3125CLASS="SECT2"
3126><HR><H3
3127CLASS="SECT2"
3128><A
3129NAME="OTHERSTUFF"
3130>9.4. The other stuff in the example</A
3131></H3
3132><P
3133>You can also see in the above examples, that I have used the variables COLS,
3134LINES which are initialized to the screen sizes after initscr(). They can be
3135useful in finding screen dimensions and finding the center co-ordinate of the
3136screen as above. The function <TT
3137CLASS="LITERAL"
3138>getch()</TT
3139> as usual
3140gets the key from keyboard and according to the key it does the corresponding
3141work. This type of switch- case is very common in any GUI based programs.</P
3142></DIV
3143><DIV
3144CLASS="SECT2"
3145><HR><H3
3146CLASS="SECT2"
3147><A
3148NAME="OTHERBORDERFUNCS"
3149>9.5. Other Border functions</A
3150></H3
3151><P
3152>Above program is grossly inefficient in that with each press of a key, a window
3153is destroyed and another is created. So let's write a more efficient program
3154which uses other border related functions.</P
3155><P
3156>The following program uses <TT
3157CLASS="LITERAL"
3158>mvhline()</TT
3159> and
3160<TT
3161CLASS="LITERAL"
3162>mvvline()</TT
3163> to achieve similar effect. These two
3164functions are simple. They create a horizontal or vertical line of the specified
3165length at the specified position.</P
3166><DIV
3167CLASS="EXAMPLE"
3168><A
3169NAME="BOTBO"
3170></A
3171><P
3172><B
3173>Example 8. More border functions</B
3174></P
3175><PRE
3176CLASS="PROGRAMLISTING"
3177><SPAN
3178CLASS="INLINEMEDIAOBJECT"
3179>#include &#60;ncurses.h&#62;
1910
1911typedef struct _win_border_struct {
3180
3181typedef struct _win_border_struct {
1912 chtype ls, rs, ts, bs,
1913 tl, tr, bl, br;
3182 chtype ls, rs, ts, bs,
3183 tl, tr, bl, br;
1914}WIN_BORDER;
1915
1916typedef struct _WIN_struct {
1917
3184}WIN_BORDER;
3185
3186typedef struct _WIN_struct {
3187
1918 int startx, starty;
1919 int height, width;
1920 WIN_BORDER border;
3188 int startx, starty;
3189 int height, width;
3190 WIN_BORDER border;
1921}WIN;
1922
1923void init_win_params(WIN *p_win);
1924void print_win_params(WIN *p_win);
1925void create_box(WIN *win, bool flag);
1926
1927int main(int argc, char *argv[])
3191}WIN;
3192
3193void init_win_params(WIN *p_win);
3194void print_win_params(WIN *p_win);
3195void create_box(WIN *win, bool flag);
3196
3197int main(int argc, char *argv[])
1928{ WIN win;
1929 int ch;
3198{ WIN win;
3199 int ch;
1930
3200
1931 initscr(); /* Start curses mode */
1932 start_color(); /* Start the color functionality */
1933 cbreak(); /* Line buffering disabled, Pass on
1934 * everty thing to me */
1935 keypad(stdscr, TRUE); /* I need that nifty F1 */
1936 noecho();
1937 init_pair(1, COLOR_CYAN, COLOR_BLACK);
3201 initscr(); /* Start curses mode */
3202 start_color(); /* Start the color functionality */
3203 cbreak(); /* Line buffering disabled, Pass on
3204 * everty thing to me */
3205 keypad(stdscr, TRUE); /* I need that nifty F1 */
3206 noecho();
3207 init_pair(1, COLOR_CYAN, COLOR_BLACK);
1938
3208
1939 /* Initialize the window parameters */
1940 init_win_params(&amp;win);
1941 print_win_params(&amp;win);
3209 /* Initialize the window parameters */
3210 init_win_params(&#38;win);
3211 print_win_params(&#38;win);
1942
3212
1943 attron(COLOR_PAIR(1));
1944 printw("Press F1 to exit");
1945 refresh();
1946 attroff(COLOR_PAIR(1));
1947
1948 create_box(&amp;win, TRUE);
1949 while((ch = getch()) != KEY_F(1))
1950 { switch(ch)
1951 { case KEY_LEFT:
1952 create_box(&amp;win, FALSE);
1953 --win.startx;
1954 create_box(&amp;win, TRUE);
1955 break;
1956 case KEY_RIGHT:
1957 create_box(&amp;win, FALSE);
1958 ++win.startx;
1959 create_box(&amp;win, TRUE);
1960 break;
1961 case KEY_UP:
1962 create_box(&amp;win, FALSE);
1963 --win.starty;
1964 create_box(&amp;win, TRUE);
1965 break;
1966 case KEY_DOWN:
1967 create_box(&amp;win, FALSE);
1968 ++win.starty;
1969 create_box(&amp;win, TRUE);
1970 break;
1971 }
1972 }
1973 endwin(); /* End curses mode */
1974 return 0;
3213 attron(COLOR_PAIR(1));
3214 printw("Press F1 to exit");
3215 refresh();
3216 attroff(COLOR_PAIR(1));
3217
3218 create_box(&#38;win, TRUE);
3219 while((ch = getch()) != KEY_F(1))
3220 { switch(ch)
3221 { case KEY_LEFT:
3222 create_box(&#38;win, FALSE);
3223 --win.startx;
3224 create_box(&#38;win, TRUE);
3225 break;
3226 case KEY_RIGHT:
3227 create_box(&#38;win, FALSE);
3228 ++win.startx;
3229 create_box(&#38;win, TRUE);
3230 break;
3231 case KEY_UP:
3232 create_box(&#38;win, FALSE);
3233 --win.starty;
3234 create_box(&#38;win, TRUE);
3235 break;
3236 case KEY_DOWN:
3237 create_box(&#38;win, FALSE);
3238 ++win.starty;
3239 create_box(&#38;win, TRUE);
3240 break;
3241 }
3242 }
3243 endwin(); /* End curses mode */
3244 return 0;
1975}
1976void init_win_params(WIN *p_win)
1977{
3245}
3246void init_win_params(WIN *p_win)
3247{
1978 p_win-&gt;height = 3;
1979 p_win-&gt;width = 10;
1980 p_win-&gt;starty = (LINES - p_win-&gt;height)/2;
1981 p_win-&gt;startx = (COLS - p_win-&gt;width)/2;
3248 p_win-&#62;height = 3;
3249 p_win-&#62;width = 10;
3250 p_win-&#62;starty = (LINES - p_win-&#62;height)/2;
3251 p_win-&#62;startx = (COLS - p_win-&#62;width)/2;
1982
3252
1983 p_win-&gt;border.ls = '|';
1984 p_win-&gt;border.rs = '|';
1985 p_win-&gt;border.ts = '-';
1986 p_win-&gt;border.bs = '-';
1987 p_win-&gt;border.tl = '+';
1988 p_win-&gt;border.tr = '+';
1989 p_win-&gt;border.bl = '+';
1990 p_win-&gt;border.br = '+';
3253 p_win-&#62;border.ls = '|';
3254 p_win-&#62;border.rs = '|';
3255 p_win-&#62;border.ts = '-';
3256 p_win-&#62;border.bs = '-';
3257 p_win-&#62;border.tl = '+';
3258 p_win-&#62;border.tr = '+';
3259 p_win-&#62;border.bl = '+';
3260 p_win-&#62;border.br = '+';
1991
1992}
1993void print_win_params(WIN *p_win)
1994{
1995#ifdef _DEBUG
3261
3262}
3263void print_win_params(WIN *p_win)
3264{
3265#ifdef _DEBUG
1996 mvprintw(25, 0, "%d %d %d %d", p_win-&gt;startx, p_win-&gt;starty,
1997 p_win-&gt;width, p_win-&gt;height);
1998 refresh();
3266 mvprintw(25, 0, "%d %d %d %d", p_win-&#62;startx, p_win-&#62;starty,
3267 p_win-&#62;width, p_win-&#62;height);
3268 refresh();
1999#endif
2000}
2001void create_box(WIN *p_win, bool flag)
3269#endif
3270}
3271void create_box(WIN *p_win, bool flag)
2002{ int i, j;
2003 int x, y, w, h;
3272{ int i, j;
3273 int x, y, w, h;
2004
3274
2005 x = p_win-&gt;startx;
2006 y = p_win-&gt;starty;
2007 w = p_win-&gt;width;
2008 h = p_win-&gt;height;
3275 x = p_win-&#62;startx;
3276 y = p_win-&#62;starty;
3277 w = p_win-&#62;width;
3278 h = p_win-&#62;height;
2009
3279
2010 if(flag == TRUE)
2011 { mvaddch(y, x, p_win-&gt;border.tl);
2012 mvaddch(y, x + w, p_win-&gt;border.tr);
2013 mvaddch(y + h, x, p_win-&gt;border.bl);
2014 mvaddch(y + h, x + w, p_win-&gt;border.br);
2015 mvhline(y, x + 1, p_win-&gt;border.ts, w - 1);
2016 mvhline(y + h, x + 1, p_win-&gt;border.bs, w - 1);
2017 mvvline(y + 1, x, p_win-&gt;border.ls, h - 1);
2018 mvvline(y + 1, x + w, p_win-&gt;border.rs, h - 1);
3280 if(flag == TRUE)
3281 { mvaddch(y, x, p_win-&#62;border.tl);
3282 mvaddch(y, x + w, p_win-&#62;border.tr);
3283 mvaddch(y + h, x, p_win-&#62;border.bl);
3284 mvaddch(y + h, x + w, p_win-&#62;border.br);
3285 mvhline(y, x + 1, p_win-&#62;border.ts, w - 1);
3286 mvhline(y + h, x + 1, p_win-&#62;border.bs, w - 1);
3287 mvvline(y + 1, x, p_win-&#62;border.ls, h - 1);
3288 mvvline(y + 1, x + w, p_win-&#62;border.rs, h - 1);
2019
3289
2020 }
2021 else
2022 for(j = y; j &lt;= y + h; ++j)
2023 for(i = x; i &lt;= x + w; ++i)
2024 mvaddch(j, i, ' ');
2025
2026 refresh();
3290 }
3291 else
3292 for(j = y; j &#60;= y + h; ++j)
3293 for(i = x; i &#60;= x + w; ++i)
3294 mvaddch(j, i, ' ');
3295
3296 refresh();
2027
3297
2028}</span></font>
2029</pre></td>
2030</tr>
2031</table>
2032</div>
2033</div>
2034</div>
2035<div class="SECT1">
2036<hr>
2037<h2 class="SECT1"><a name="COLOR" id="COLOR">10. Colors</a></h2>
2038<div class="SECT2">
2039<h3 class="SECT2"><a name="COLORBASICS" id="COLORBASICS">10.1. The
2040basics</a></h3>
2041<p>Life seems dull with no colors. Curses has a nice mechanism to
2042handle colors. Let's get into the thick of the things with a small
2043program.</p>
2044<div class="EXAMPLE"><a name="BSICO" id="BSICO"></a>
2045<p><b>Example 9. A Simple Color example</b></p>
2046<table border="0" bgcolor="#E0E0E0" width="100%">
2047<tr>
2048<td>
2049<pre class="PROGRAMLISTING">
2050<font color="#000000"><span class=
2051"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
3298}</SPAN
3299></PRE
3300></DIV
3301></DIV
3302></DIV
3303><DIV
3304CLASS="SECT1"
3305><HR><H2
3306CLASS="SECT1"
3307><A
3308NAME="COLOR"
3309>10. Colors</A
3310></H2
3311><DIV
3312CLASS="SECT2"
3313><H3
3314CLASS="SECT2"
3315><A
3316NAME="COLORBASICS"
3317>10.1. The basics</A
3318></H3
3319><P
3320>Life seems dull with no colors. Curses has a nice mechanism to handle colors.
3321Let's get into the thick of the things with a small program.</P
3322><DIV
3323CLASS="EXAMPLE"
3324><A
3325NAME="BSICO"
3326></A
3327><P
3328><B
3329>Example 9. A Simple Color example </B
3330></P
3331><PRE
3332CLASS="PROGRAMLISTING"
3333><SPAN
3334CLASS="INLINEMEDIAOBJECT"
3335>#include &#60;ncurses.h&#62;
2052
2053void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string);
2054int main(int argc, char *argv[])
3336
3337void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string);
3338int main(int argc, char *argv[])
2055{ initscr(); /* Start curses mode */
2056 if(has_colors() == FALSE)
2057 { endwin();
2058 printf("Your terminal does not support color\n");
2059 exit(1);
2060 }
2061 start_color(); /* Start color */
2062 init_pair(1, COLOR_RED, COLOR_BLACK);
3339{ initscr(); /* Start curses mode */
3340 if(has_colors() == FALSE)
3341 { endwin();
3342 printf("Your terminal does not support color\n");
3343 exit(1);
3344 }
3345 start_color(); /* Start color */
3346 init_pair(1, COLOR_RED, COLOR_BLACK);
2063
3347
2064 attron(COLOR_PAIR(1));
2065 print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ...");
2066 attroff(COLOR_PAIR(1));
2067 getch();
2068 endwin();
3348 attron(COLOR_PAIR(1));
3349 print_in_middle(stdscr, LINES / 2, 0, 0, "Viola !!! In color ...");
3350 attroff(COLOR_PAIR(1));
3351 getch();
3352 endwin();
2069}
2070void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string)
3353}
3354void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string)
2071{ int length, x, y;
2072 float temp;
3355{ int length, x, y;
3356 float temp;
2073
3357
2074 if(win == NULL)
2075 win = stdscr;
2076 getyx(win, y, x);
2077 if(startx != 0)
2078 x = startx;
2079 if(starty != 0)
2080 y = starty;
2081 if(width == 0)
2082 width = 80;
3358 if(win == NULL)
3359 win = stdscr;
3360 getyx(win, y, x);
3361 if(startx != 0)
3362 x = startx;
3363 if(starty != 0)
3364 y = starty;
3365 if(width == 0)
3366 width = 80;
2083
3367
2084 length = strlen(string);
2085 temp = (width - length)/ 2;
2086 x = startx + (int)temp;
2087 mvwprintw(win, y, x, "%s", string);
2088 refresh();
3368 length = strlen(string);
3369 temp = (width - length)/ 2;
3370 x = startx + (int)temp;
3371 mvwprintw(win, y, x, "%s", string);
3372 refresh();
2089}
3373}
2090</span></font>
2091</pre></td>
2092</tr>
2093</table>
2094</div>
2095<p>As you can see, to start using color, you should first call the
2096function <var class="LITERAL">start_color()</var>. After that, you
2097can use color capabilities of your terminals using various
2098functions. To find out whether a terminal has color capabilities or
2099not, you can use <var class="LITERAL">has_colors()</var> function,
2100which returns FALSE if the terminal does not support color.</p>
2101<p>Curses initializes all the colors supported by terminal when
2102start_color() is called. These can be accessed by the define
2103constants like <var class="LITERAL">COLOR_BLACK</var> etc. Now to
2104actually start using colors, you have to define pairs. Colors are
2105always used in pairs. That means you have to use the function
2106<var class="LITERAL">init_pair()</var> to define the foreground and
2107background for the pair number you give. After that that pair
2108number can be used as a normal attribute with <var class=
2109"LITERAL">COLOR_PAIR()</var>function. This may seem to be
2110cumbersome at first. But this elegant solution allows us to manage
2111color pairs very easily. To appreciate it, you have to look into
2112the the source code of "dialog", a utility for displaying dialog
2113boxes from shell scripts. The developers have defined foreground
2114and background combinations for all the colors they might need and
2115initialized at the beginning. This makes it very easy to set
2116attributes just by accessing a pair which we already have defined
2117as a constant.</p>
2118<p>The following colors are defined in <var class=
2119"LITERAL">curses.h</var>. You can use these as parameters for
2120various color functions.</p>
2121<table border="0" bgcolor="#E0E0E0" width="100%">
2122<tr>
2123<td>
2124<pre class="PROGRAMLISTING">
2125<font color="#000000"> COLOR_BLACK 0
3374</SPAN
3375></PRE
3376></DIV
3377><P
3378>As you can see, to start using color, you should first call the function
3379<TT
3380CLASS="LITERAL"
3381> start_color()</TT
3382>. After that, you can use color
3383capabilities of your terminals using various functions. To find out whether a
3384terminal has color capabilities or not, you can use
3385<TT
3386CLASS="LITERAL"
3387>has_colors()</TT
3388> function, which returns FALSE if
3389the terminal does not support color. </P
3390><P
3391>Curses initializes all the colors supported by terminal when start_color() is
3392called. These can be accessed by the define constants like
3393<TT
3394CLASS="LITERAL"
3395>COLOR_BLACK </TT
3396> etc. Now to actually start using
3397colors, you have to define pairs. Colors are always used in pairs. That means
3398you have to use the function <TT
3399CLASS="LITERAL"
3400>init_pair() </TT
3401> to
3402define the foreground and background for the pair number you give. After that
3403that pair number can be used as a normal attribute with <TT
3404CLASS="LITERAL"
3405>COLOR_PAIR()</TT
3406>function. This may seem to be cumbersome at first.
3407But this elegant solution allows us to manage color pairs very easily. To
3408appreciate it, you have to look into the the source code of "dialog", a utility
3409for displaying dialog boxes from shell scripts. The developers have defined
3410foreground and background combinations for all the colors they might need and
3411initialized at the beginning. This makes it very easy to set attributes just by
3412accessing a pair which we already have defined as a constant.</P
3413><P
3414>The following colors are defined in <TT
3415CLASS="LITERAL"
3416>curses.h</TT
3417>.
3418You can use these as parameters for various color functions.
3419<PRE
3420CLASS="PROGRAMLISTING"
3421> COLOR_BLACK 0
2126 COLOR_RED 1
2127 COLOR_GREEN 2
2128 COLOR_YELLOW 3
2129 COLOR_BLUE 4
2130 COLOR_MAGENTA 5
2131 COLOR_CYAN 6
3422 COLOR_RED 1
3423 COLOR_GREEN 2
3424 COLOR_YELLOW 3
3425 COLOR_BLUE 4
3426 COLOR_MAGENTA 5
3427 COLOR_CYAN 6
2132 COLOR_WHITE 7</font>
2133</pre></td>
2134</tr>
2135</table>
2136</div>
2137<div class="SECT2">
2138<hr>
2139<h3 class="SECT2"><a name="CHANGECOLORDEFS" id=
2140"CHANGECOLORDEFS">10.2. Changing Color Definitions</a></h3>
2141<p>The function <var class="LITERAL">init_color()</var>can be used
2142to change the rgb values for the colors defined by curses
2143initially. Say you wanted to lighten the intensity of red color by
2144a minuscule. Then you can use this function as</p>
2145<table border="0" bgcolor="#E0E0E0" width="100%">
2146<tr>
2147<td>
2148<pre class="PROGRAMLISTING">
2149<font color="#000000"> init_color(COLOR_RED, 700, 0, 0);
3428 COLOR_WHITE 7</PRE
3429></P
3430></DIV
3431><DIV
3432CLASS="SECT2"
3433><HR><H3
3434CLASS="SECT2"
3435><A
3436NAME="CHANGECOLORDEFS"
3437>10.2. Changing Color Definitions</A
3438></H3
3439><P
3440>The function <TT
3441CLASS="LITERAL"
3442>init_color()</TT
3443>can be used to change
3444the rgb values for the colors defined by curses initially. Say you wanted to
3445lighten the intensity of red color by a minuscule. Then you can use this
3446function as</P
3447><PRE
3448CLASS="PROGRAMLISTING"
3449> init_color(COLOR_RED, 700, 0, 0);
2150 /* param 1 : color name
3450 /* param 1 : color name
2151 * param 2, 3, 4 : rgb content min = 0, max = 1000 */</font>
2152</pre></td>
2153</tr>
2154</table>
2155<p>If your terminal cannot change the color definitions, the
2156function returns ERR. The function <var class=
2157"LITERAL">can_change_color()</var> can be used to find out whether
2158the terminal has the capability of changing color content or not.
2159The rgb content is scaled from 0 to 1000. Initially RED color is
2160defined with content 1000(r), 0(g), 0(b).</p>
2161</div>
2162<div class="SECT2">
2163<hr>
2164<h3 class="SECT2"><a name="COLORCONTENT" id="COLORCONTENT">10.3.
2165Color Content</a></h3>
2166<p>The functions <var class="LITERAL">color_content()</var> and
2167<var class="LITERAL">pair_content()</var> can be used to find the
2168color content and foreground, background combination for the
2169pair.</p>
2170</div>
2171</div>
2172<div class="SECT1">
2173<hr>
2174<h2 class="SECT1"><a name="KEYS" id="KEYS">11. Interfacing with the
2175key board</a></h2>
2176<div class="SECT2">
2177<h3 class="SECT2"><a name="KEYSBASICS" id="KEYSBASICS">11.1. The
2178Basics</a></h3>
2179<p>No GUI is complete without a strong user interface and to
2180interact with the user, a curses program should be sensitive to key
2181presses or the mouse actions done by the user. Let's deal with the
2182keys first.</p>
2183<p>As you have seen in almost all of the above examples, it's very
2184easy to get key input from the user. A simple way of getting key
2185presses is to use <var class="LITERAL">getch()</var> function. The
2186cbreak mode should be enabled to read keys when you are interested
2187in reading individual key hits rather than complete lines of text
2188(which usually end with a carriage return). keypad should be
2189enabled to get the Functions keys, arrow keys etc. See the
2190initialization section for details.</p>
2191<p><var class="LITERAL">getch()</var> returns an integer
2192corresponding to the key pressed. If it is a normal character, the
2193integer value will be equivalent to the character. Otherwise it
2194returns a number which can be matched with the constants defined in
2195<var class="LITERAL">curses.h</var>. For example if the user
2196presses F1, the integer returned is 265. This can be checked using
2197the macro KEY_F() defined in curses.h. This makes reading keys
2198portable and easy to manage.</p>
2199<p>For example, if you call getch() like this</p>
2200<table border="0" bgcolor="#E0E0E0" width="100%">
2201<tr>
2202<td>
2203<pre class="PROGRAMLISTING">
2204<font color="#000000"> int ch;
3451 * param 2, 3, 4 : rgb content min = 0, max = 1000 */</PRE
3452><P
3453>If your terminal cannot change the color definitions, the function returns ERR.
3454The function <TT
3455CLASS="LITERAL"
3456>can_change_color()</TT
3457> can be used to
3458find out whether the terminal has the capability of changing color content or
3459not. The rgb content is scaled from 0 to 1000. Initially RED color is defined
3460with content 1000(r), 0(g), 0(b). </P
3461></DIV
3462><DIV
3463CLASS="SECT2"
3464><HR><H3
3465CLASS="SECT2"
3466><A
3467NAME="COLORCONTENT"
3468>10.3. Color Content</A
3469></H3
3470><P
3471>The functions <TT
3472CLASS="LITERAL"
3473>color_content()</TT
3474> and
3475<TT
3476CLASS="LITERAL"
3477>pair_content()</TT
3478> can be used to find the color
3479content and foreground, background combination for the pair. </P
3480></DIV
3481></DIV
3482><DIV
3483CLASS="SECT1"
3484><HR><H2
3485CLASS="SECT1"
3486><A
3487NAME="KEYS"
3488>11. Interfacing with the key board</A
3489></H2
3490><DIV
3491CLASS="SECT2"
3492><H3
3493CLASS="SECT2"
3494><A
3495NAME="KEYSBASICS"
3496>11.1. The Basics</A
3497></H3
3498><P
3499>No GUI is complete without a strong user interface and to interact with the
3500user, a curses program should be sensitive to key presses or the mouse actions
3501done by the user. Let's deal with the keys first.</P
3502><P
3503>As you have seen in almost all of the above examples, it's very easy to get key
3504input from the user. A simple way of getting key presses is to use
3505<TT
3506CLASS="LITERAL"
3507>getch()</TT
3508> function. The cbreak mode should be
3509enabled to read keys when you are interested in reading individual key hits
3510rather than complete lines of text (which usually end with a carriage return).
3511keypad should be enabled to get the Functions keys, arrow keys etc. See the
3512initialization section for details.</P
3513><P
3514><TT
3515CLASS="LITERAL"
3516>getch()</TT
3517> returns an integer corresponding to the
3518key pressed. If it is a normal character, the integer value will be equivalent
3519to the character. Otherwise it returns a number which can be matched with the
3520constants defined in <TT
3521CLASS="LITERAL"
3522>curses.h</TT
3523>. For example if
3524the user presses F1, the integer returned is 265. This can be checked using the
3525macro KEY_F() defined in curses.h. This makes reading keys portable and easy to
3526manage.</P
3527><P
3528>For example, if you call getch() like this</P
3529><PRE
3530CLASS="PROGRAMLISTING"
3531> int ch;
2205
3532
2206 ch = getch();</font>
2207</pre></td>
2208</tr>
2209</table>
2210<p>getch() will wait for the user to press a key, (unless you
2211specified a timeout) and when user presses a key, the corresponding
2212integer is returned. Then you can check the value returned with the
2213constants defined in curses.h to match against the keys you
2214want.</p>
2215<p>The following code piece will do that job.</p>
2216<table border="0" bgcolor="#E0E0E0" width="100%">
2217<tr>
2218<td>
2219<pre class="PROGRAMLISTING">
2220<font color="#000000"> if(ch == KEY_LEFT)
2221 printw("Left arrow is pressed\n");</font>
2222</pre></td>
2223</tr>
2224</table>
2225<p>Let's write a small program which creates a menu which can be
2226navigated by up and down arrows.</p>
2227</div>
2228<div class="SECT2">
2229<hr>
2230<h3 class="SECT2"><a name="SIMPLEKEYEX" id="SIMPLEKEYEX">11.2. A
2231Simple Key Usage example</a></h3>
2232<div class="EXAMPLE"><a name="BSIKE" id="BSIKE"></a>
2233<p><b>Example 10. A Simple Key Usage example</b></p>
2234<table border="0" bgcolor="#E0E0E0" width="100%">
2235<tr>
2236<td>
2237<pre class="PROGRAMLISTING">
2238<font color="#000000"><span class=
2239"INLINEMEDIAOBJECT">#include &lt;stdio.h&gt;
2240#include &lt;ncurses.h&gt;
3533 ch = getch();</PRE
3534><P
3535>getch() will wait for the user to press a key, (unless you specified a timeout)
3536and when user presses a key, the corresponding integer is returned. Then you can
3537check the value returned with the constants defined in curses.h to match against
3538the keys you want.</P
3539><P
3540>The following code piece will do that job.</P
3541><PRE
3542CLASS="PROGRAMLISTING"
3543> if(ch == KEY_LEFT)
3544 printw("Left arrow is pressed\n");</PRE
3545><P
3546>Let's write a small program which creates a menu which can be navigated by up
3547and down arrows.</P
3548></DIV
3549><DIV
3550CLASS="SECT2"
3551><HR><H3
3552CLASS="SECT2"
3553><A
3554NAME="SIMPLEKEYEX"
3555>11.2. A Simple Key Usage example</A
3556></H3
3557><DIV
3558CLASS="EXAMPLE"
3559><A
3560NAME="BSIKE"
3561></A
3562><P
3563><B
3564>Example 10. A Simple Key Usage example </B
3565></P
3566><PRE
3567CLASS="PROGRAMLISTING"
3568><SPAN
3569CLASS="INLINEMEDIAOBJECT"
3570>#include &#60;stdio.h&#62;
3571#include &#60;ncurses.h&#62;
2241
2242#define WIDTH 30
2243#define HEIGHT 10
2244
2245int startx = 0;
2246int starty = 0;
2247
2248char *choices[] = {
3572
3573#define WIDTH 30
3574#define HEIGHT 10
3575
3576int startx = 0;
3577int starty = 0;
3578
3579char *choices[] = {
2249 "Choice 1",
2250 "Choice 2",
2251 "Choice 3",
2252 "Choice 4",
2253 "Exit",
2254 };
3580 "Choice 1",
3581 "Choice 2",
3582 "Choice 3",
3583 "Choice 4",
3584 "Exit",
3585 };
2255int n_choices = sizeof(choices) / sizeof(char *);
2256void print_menu(WINDOW *menu_win, int highlight);
2257
2258int main()
3586int n_choices = sizeof(choices) / sizeof(char *);
3587void print_menu(WINDOW *menu_win, int highlight);
3588
3589int main()
2259{ WINDOW *menu_win;
2260 int highlight = 1;
2261 int choice = 0;
2262 int c;
3590{ WINDOW *menu_win;
3591 int highlight = 1;
3592 int choice = 0;
3593 int c;
2263
3594
2264 initscr();
2265 clear();
2266 noecho();
2267 cbreak(); /* Line buffering disabled. pass on everything */
2268 startx = (80 - WIDTH) / 2;
2269 starty = (24 - HEIGHT) / 2;
2270
2271 menu_win = newwin(HEIGHT, WIDTH, starty, startx);
2272 keypad(menu_win, TRUE);
2273 mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice");
2274 refresh();
2275 print_menu(menu_win, highlight);
2276 while(1)
2277 { c = wgetch(menu_win);
2278 switch(c)
2279 { case KEY_UP:
2280 if(highlight == 1)
2281 highlight = n_choices;
2282 else
2283 --highlight;
2284 break;
2285 case KEY_DOWN:
2286 if(highlight == n_choices)
2287 highlight = 1;
2288 else
2289 ++highlight;
2290 break;
2291 case 10:
2292 choice = highlight;
2293 break;
2294 default:
2295 mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c);
2296 refresh();
2297 break;
2298 }
2299 print_menu(menu_win, highlight);
2300 if(choice != 0) /* User did a choice come out of the infinite loop */
2301 break;
2302 }
2303 mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]);
2304 clrtoeol();
2305 refresh();
2306 endwin();
2307 return 0;
3595 initscr();
3596 clear();
3597 noecho();
3598 cbreak(); /* Line buffering disabled. pass on everything */
3599 startx = (80 - WIDTH) / 2;
3600 starty = (24 - HEIGHT) / 2;
3601
3602 menu_win = newwin(HEIGHT, WIDTH, starty, startx);
3603 keypad(menu_win, TRUE);
3604 mvprintw(0, 0, "Use arrow keys to go up and down, Press enter to select a choice");
3605 refresh();
3606 print_menu(menu_win, highlight);
3607 while(1)
3608 { c = wgetch(menu_win);
3609 switch(c)
3610 { case KEY_UP:
3611 if(highlight == 1)
3612 highlight = n_choices;
3613 else
3614 --highlight;
3615 break;
3616 case KEY_DOWN:
3617 if(highlight == n_choices)
3618 highlight = 1;
3619 else
3620 ++highlight;
3621 break;
3622 case 10:
3623 choice = highlight;
3624 break;
3625 default:
3626 mvprintw(24, 0, "Charcter pressed is = %3d Hopefully it can be printed as '%c'", c, c);
3627 refresh();
3628 break;
3629 }
3630 print_menu(menu_win, highlight);
3631 if(choice != 0) /* User did a choice come out of the infinite loop */
3632 break;
3633 }
3634 mvprintw(23, 0, "You chose choice %d with choice string %s\n", choice, choices[choice - 1]);
3635 clrtoeol();
3636 refresh();
3637 endwin();
3638 return 0;
2308}
2309
2310
2311void print_menu(WINDOW *menu_win, int highlight)
2312{
3639}
3640
3641
3642void print_menu(WINDOW *menu_win, int highlight)
3643{
2313 int x, y, i;
3644 int x, y, i;
2314
3645
2315 x = 2;
2316 y = 2;
2317 box(menu_win, 0, 0);
2318 for(i = 0; i &lt; n_choices; ++i)
2319 { if(highlight == i + 1) /* High light the present choice */
2320 { wattron(menu_win, A_REVERSE);
2321 mvwprintw(menu_win, y, x, "%s", choices[i]);
2322 wattroff(menu_win, A_REVERSE);
2323 }
2324 else
2325 mvwprintw(menu_win, y, x, "%s", choices[i]);
2326 ++y;
2327 }
2328 wrefresh(menu_win);
3646 x = 2;
3647 y = 2;
3648 box(menu_win, 0, 0);
3649 for(i = 0; i &#60; n_choices; ++i)
3650 { if(highlight == i + 1) /* High light the present choice */
3651 { wattron(menu_win, A_REVERSE);
3652 mvwprintw(menu_win, y, x, "%s", choices[i]);
3653 wattroff(menu_win, A_REVERSE);
3654 }
3655 else
3656 mvwprintw(menu_win, y, x, "%s", choices[i]);
3657 ++y;
3658 }
3659 wrefresh(menu_win);
2329}
3660}
2330</span></font>
2331</pre></td>
2332</tr>
2333</table>
2334</div>
2335</div>
2336</div>
2337<div class="SECT1">
2338<hr>
2339<h2 class="SECT1"><a name="MOUSE" id="MOUSE">12. Interfacing with
2340the mouse</a></h2>
2341<p>Now that you have seen how to get keys, lets do the same thing
2342from mouse. Usually each UI allows the user to interact with both
2343keyboard and mouse.</p>
2344<div class="SECT2">
2345<hr>
2346<h3 class="SECT2"><a name="MOUSEBASICS" id="MOUSEBASICS">12.1. The
2347Basics</a></h3>
2348<p>Before you do any thing else, the events you want to receive
2349have to be enabled with <var class="LITERAL">mousemask()</var>.</p>
2350<table border="0" bgcolor="#E0E0E0" width="100%">
2351<tr>
2352<td>
2353<pre class="PROGRAMLISTING">
2354<font color=
2355"#000000"> mousemask( mmask_t newmask, /* The events you want to listen to */
2356 mmask_t *oldmask) /* The old events mask */</font>
2357</pre></td>
2358</tr>
2359</table>
2360<p>The first parameter to above function is a bit mask of events
2361you would like to listen. By default, all the events are turned
2362off. The bit mask <var class="LITERAL">ALL_MOUSE_EVENTS</var> can
2363be used to get all the events.</p>
2364<p>The following are all the event masks:</p>
2365<table border="0" bgcolor="#E0E0E0" width="100%">
2366<tr>
2367<td>
2368<pre class="PROGRAMLISTING">
2369<font color="#000000"> Name Description
3661</SPAN
3662></PRE
3663></DIV
3664></DIV
3665></DIV
3666><DIV
3667CLASS="SECT1"
3668><HR><H2
3669CLASS="SECT1"
3670><A
3671NAME="MOUSE"
3672>12. Interfacing with the mouse</A
3673></H2
3674><P
3675>Now that you have seen how to get keys, lets do the same thing from mouse.
3676Usually each UI allows the user to interact with both keyboard and mouse. </P
3677><DIV
3678CLASS="SECT2"
3679><HR><H3
3680CLASS="SECT2"
3681><A
3682NAME="MOUSEBASICS"
3683>12.1. The Basics</A
3684></H3
3685><P
3686>Before you do any thing else, the events you want to receive have to be enabled
3687with <TT
3688CLASS="LITERAL"
3689>mousemask()</TT
3690>.</P
3691><PRE
3692CLASS="PROGRAMLISTING"
3693> mousemask( mmask_t newmask, /* The events you want to listen to */
3694 mmask_t *oldmask) /* The old events mask */</PRE
3695><P
3696>The first parameter to above function is a bit mask of events you would like to
3697listen. By default, all the events are turned off. The bit mask <TT
3698CLASS="LITERAL"
3699> ALL_MOUSE_EVENTS</TT
3700> can be used to get all the events.</P
3701><P
3702>The following are all the event masks:</P
3703><PRE
3704CLASS="PROGRAMLISTING"
3705> Name Description
2370 ---------------------------------------------------------------------
2371 BUTTON1_PRESSED mouse button 1 down
2372 BUTTON1_RELEASED mouse button 1 up
2373 BUTTON1_CLICKED mouse button 1 clicked
2374 BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked
2375 BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked
2376 BUTTON2_PRESSED mouse button 2 down
2377 BUTTON2_RELEASED mouse button 2 up

--- 9 unchanged lines hidden (view full) ---

2387 BUTTON4_RELEASED mouse button 4 up
2388 BUTTON4_CLICKED mouse button 4 clicked
2389 BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked
2390 BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked
2391 BUTTON_SHIFT shift was down during button state change
2392 BUTTON_CTRL control was down during button state change
2393 BUTTON_ALT alt was down during button state change
2394 ALL_MOUSE_EVENTS report all button state changes
3706 ---------------------------------------------------------------------
3707 BUTTON1_PRESSED mouse button 1 down
3708 BUTTON1_RELEASED mouse button 1 up
3709 BUTTON1_CLICKED mouse button 1 clicked
3710 BUTTON1_DOUBLE_CLICKED mouse button 1 double clicked
3711 BUTTON1_TRIPLE_CLICKED mouse button 1 triple clicked
3712 BUTTON2_PRESSED mouse button 2 down
3713 BUTTON2_RELEASED mouse button 2 up

--- 9 unchanged lines hidden (view full) ---

3723 BUTTON4_RELEASED mouse button 4 up
3724 BUTTON4_CLICKED mouse button 4 clicked
3725 BUTTON4_DOUBLE_CLICKED mouse button 4 double clicked
3726 BUTTON4_TRIPLE_CLICKED mouse button 4 triple clicked
3727 BUTTON_SHIFT shift was down during button state change
3728 BUTTON_CTRL control was down during button state change
3729 BUTTON_ALT alt was down during button state change
3730 ALL_MOUSE_EVENTS report all button state changes
2395 REPORT_MOUSE_POSITION report mouse movement</font>
2396</pre></td>
2397</tr>
2398</table>
2399</div>
2400<div class="SECT2">
2401<hr>
2402<h3 class="SECT2"><a name="GETTINGEVENTS" id="GETTINGEVENTS">12.2.
2403Getting the events</a></h3>
2404<p>Once a class of mouse events have been enabled, getch() class of
2405functions return KEY_MOUSE every time some mouse event happens.
2406Then the mouse event can be retrieved with <var class=
2407"LITERAL">getmouse()</var>.</p>
2408<p>The code approximately looks like this:</p>
2409<table border="0" bgcolor="#E0E0E0" width="100%">
2410<tr>
2411<td>
2412<pre class="PROGRAMLISTING">
2413<font color="#000000"> MEVENT event;
3731 REPORT_MOUSE_POSITION report mouse movement</PRE
3732></DIV
3733><DIV
3734CLASS="SECT2"
3735><HR><H3
3736CLASS="SECT2"
3737><A
3738NAME="GETTINGEVENTS"
3739>12.2. Getting the events</A
3740></H3
3741><P
3742>Once a class of mouse events have been enabled, getch() class of functions
3743return KEY_MOUSE every time some mouse event happens. Then the mouse event can
3744be retrieved with <TT
3745CLASS="LITERAL"
3746>getmouse()</TT
3747>.</P
3748><P
3749>The code approximately looks like this:</P
3750><PRE
3751CLASS="PROGRAMLISTING"
3752> MEVENT event;
2414
2415 ch = getch();
2416 if(ch == KEY_MOUSE)
2417 if(getmouse(&amp;event) == OK)
2418 . /* Do some thing with the event */
2419 .
3753
3754 ch = getch();
3755 if(ch == KEY_MOUSE)
3756 if(getmouse(&amp;event) == OK)
3757 . /* Do some thing with the event */
3758 .
2420 .</font>
2421</pre></td>
2422</tr>
2423</table>
2424<p>getmouse() returns the event into the pointer given to it. It's
2425a structure which contains</p>
2426<table border="0" bgcolor="#E0E0E0" width="100%">
2427<tr>
2428<td>
2429<pre class="PROGRAMLISTING">
2430<font color="#000000"> typedef struct
3759 .</PRE
3760><P
3761>
3762getmouse() returns the event into the pointer given to it. It's a structure
3763which contains</P
3764><PRE
3765CLASS="PROGRAMLISTING"
3766> typedef struct
2431 {
2432 short id; /* ID to distinguish multiple devices */
2433 int x, y, z; /* event coordinates */
2434 mmask_t bstate; /* button state bits */
3767 {
3768 short id; /* ID to distinguish multiple devices */
3769 int x, y, z; /* event coordinates */
3770 mmask_t bstate; /* button state bits */
2435 } </font>
2436</pre></td>
2437</tr>
2438</table>
2439<p>The <var class="LITERAL">bstate</var> is the main variable we
2440are interested in. It tells the button state of the mouse.</p>
2441<p>Then with a code snippet like the following, we can find out
2442what happened.</p>
2443<table border="0" bgcolor="#E0E0E0" width="100%">
2444<tr>
2445<td>
2446<pre class="PROGRAMLISTING">
2447<font color="#000000"> if(event.bstate &amp; BUTTON1_PRESSED)
2448 printw("Left Button Pressed");</font>
2449</pre></td>
2450</tr>
2451</table>
2452</div>
2453<div class="SECT2">
2454<hr>
2455<h3 class="SECT2"><a name="MOUSETOGETHER" id="MOUSETOGETHER">12.3.
2456Putting it all Together</a></h3>
2457<p>That's pretty much interfacing with mouse. Let's create the same
2458menu and enable mouse interaction. To make things simpler, key
2459handling is removed.</p>
2460<div class="EXAMPLE"><a name="BMOME" id="BMOME"></a>
2461<p><b>Example 11. Access the menu with mouse !!!</b></p>
2462<table border="0" bgcolor="#E0E0E0" width="100%">
2463<tr>
2464<td>
2465<pre class="PROGRAMLISTING">
2466<font color="#000000"><span class=
2467"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
3771 } </PRE
3772><P
3773>The <TT
3774CLASS="LITERAL"
3775>bstate</TT
3776> is the main variable we are
3777interested in. It tells the button state of the mouse.</P
3778><P
3779>Then with a code snippet like the following, we can find out what happened.</P
3780><PRE
3781CLASS="PROGRAMLISTING"
3782> if(event.bstate &amp; BUTTON1_PRESSED)
3783 printw("Left Button Pressed");</PRE
3784></DIV
3785><DIV
3786CLASS="SECT2"
3787><HR><H3
3788CLASS="SECT2"
3789><A
3790NAME="MOUSETOGETHER"
3791>12.3. Putting it all Together</A
3792></H3
3793><P
3794>That's pretty much interfacing with mouse. Let's create the same menu and enable
3795mouse interaction. To make things simpler, key handling is removed.</P
3796><DIV
3797CLASS="EXAMPLE"
3798><A
3799NAME="BMOME"
3800></A
3801><P
3802><B
3803>Example 11. Access the menu with mouse !!! </B
3804></P
3805><PRE
3806CLASS="PROGRAMLISTING"
3807><SPAN
3808CLASS="INLINEMEDIAOBJECT"
3809>#include &#60;ncurses.h&#62;
2468
2469#define WIDTH 30
2470#define HEIGHT 10
2471
2472int startx = 0;
2473int starty = 0;
2474
3810
3811#define WIDTH 30
3812#define HEIGHT 10
3813
3814int startx = 0;
3815int starty = 0;
3816
2475char *choices[] = { "Choice 1",
2476 "Choice 2",
2477 "Choice 3",
2478 "Choice 4",
2479 "Exit",
2480 };
3817char *choices[] = { "Choice 1",
3818 "Choice 2",
3819 "Choice 3",
3820 "Choice 4",
3821 "Exit",
3822 };
2481
2482int n_choices = sizeof(choices) / sizeof(char *);
2483
2484void print_menu(WINDOW *menu_win, int highlight);
2485void report_choice(int mouse_x, int mouse_y, int *p_choice);
2486
2487int main()
3823
3824int n_choices = sizeof(choices) / sizeof(char *);
3825
3826void print_menu(WINDOW *menu_win, int highlight);
3827void report_choice(int mouse_x, int mouse_y, int *p_choice);
3828
3829int main()
2488{ int c, choice = 0;
2489 WINDOW *menu_win;
2490 MEVENT event;
3830{ int c, choice = 0;
3831 WINDOW *menu_win;
3832 MEVENT event;
2491
3833
2492 /* Initialize curses */
2493 initscr();
2494 clear();
2495 noecho();
2496 cbreak(); //Line buffering disabled. pass on everything
3834 /* Initialize curses */
3835 initscr();
3836 clear();
3837 noecho();
3838 cbreak(); //Line buffering disabled. pass on everything
2497
3839
2498 /* Try to put the window in the middle of screen */
2499 startx = (80 - WIDTH) / 2;
2500 starty = (24 - HEIGHT) / 2;
2501
2502 attron(A_REVERSE);
2503 mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)");
2504 refresh();
2505 attroff(A_REVERSE);
3840 /* Try to put the window in the middle of screen */
3841 startx = (80 - WIDTH) / 2;
3842 starty = (24 - HEIGHT) / 2;
3843
3844 attron(A_REVERSE);
3845 mvprintw(23, 1, "Click on Exit to quit (Works best in a virtual console)");
3846 refresh();
3847 attroff(A_REVERSE);
2506
3848
2507 /* Print the menu for the first time */
2508 menu_win = newwin(HEIGHT, WIDTH, starty, startx);
2509 print_menu(menu_win, 1);
2510 /* Get all the mouse events */
2511 mousemask(ALL_MOUSE_EVENTS, NULL);
2512
2513 while(1)
2514 { c = wgetch(menu_win);
2515 switch(c)
2516 { case KEY_MOUSE:
2517 if(getmouse(&amp;event) == OK)
2518 { /* When the user clicks left mouse button */
2519 if(event.bstate &amp; BUTTON1_PRESSED)
2520 { report_choice(event.x + 1, event.y + 1, &amp;choice);
2521 if(choice == -1) //Exit chosen
2522 goto end;
2523 mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]);
2524 refresh();
2525 }
2526 }
2527 print_menu(menu_win, choice);
2528 break;
2529 }
2530 }
3849 /* Print the menu for the first time */
3850 menu_win = newwin(HEIGHT, WIDTH, starty, startx);
3851 print_menu(menu_win, 1);
3852 /* Get all the mouse events */
3853 mousemask(ALL_MOUSE_EVENTS, NULL);
3854
3855 while(1)
3856 { c = wgetch(menu_win);
3857 switch(c)
3858 { case KEY_MOUSE:
3859 if(getmouse(&#38;event) == OK)
3860 { /* When the user clicks left mouse button */
3861 if(event.bstate &#38; BUTTON1_PRESSED)
3862 { report_choice(event.x + 1, event.y + 1, &#38;choice);
3863 if(choice == -1) //Exit chosen
3864 goto end;
3865 mvprintw(22, 1, "Choice made is : %d String Chosen is \"%10s\"", choice, choices[choice - 1]);
3866 refresh();
3867 }
3868 }
3869 print_menu(menu_win, choice);
3870 break;
3871 }
3872 }
2531end:
3873end:
2532 endwin();
2533 return 0;
3874 endwin();
3875 return 0;
2534}
2535
2536
2537void print_menu(WINDOW *menu_win, int highlight)
2538{
3876}
3877
3878
3879void print_menu(WINDOW *menu_win, int highlight)
3880{
2539 int x, y, i;
3881 int x, y, i;
2540
3882
2541 x = 2;
2542 y = 2;
2543 box(menu_win, 0, 0);
2544 for(i = 0; i &lt; n_choices; ++i)
2545 { if(highlight == i + 1)
2546 { wattron(menu_win, A_REVERSE);
2547 mvwprintw(menu_win, y, x, "%s", choices[i]);
2548 wattroff(menu_win, A_REVERSE);
2549 }
2550 else
2551 mvwprintw(menu_win, y, x, "%s", choices[i]);
2552 ++y;
2553 }
2554 wrefresh(menu_win);
3883 x = 2;
3884 y = 2;
3885 box(menu_win, 0, 0);
3886 for(i = 0; i &#60; n_choices; ++i)
3887 { if(highlight == i + 1)
3888 { wattron(menu_win, A_REVERSE);
3889 mvwprintw(menu_win, y, x, "%s", choices[i]);
3890 wattroff(menu_win, A_REVERSE);
3891 }
3892 else
3893 mvwprintw(menu_win, y, x, "%s", choices[i]);
3894 ++y;
3895 }
3896 wrefresh(menu_win);
2555}
2556
2557/* Report the choice according to mouse position */
2558void report_choice(int mouse_x, int mouse_y, int *p_choice)
3897}
3898
3899/* Report the choice according to mouse position */
3900void report_choice(int mouse_x, int mouse_y, int *p_choice)
2559{ int i,j, choice;
3901{ int i,j, choice;
2560
3902
2561 i = startx + 2;
2562 j = starty + 3;
2563
2564 for(choice = 0; choice &lt; n_choices; ++choice)
2565 if(mouse_y == j + choice &amp;&amp; mouse_x &gt;= i &amp;&amp; mouse_x &lt;= i + strlen(choices[choice]))
2566 { if(choice == n_choices - 1)
2567 *p_choice = -1;
2568 else
2569 *p_choice = choice + 1;
2570 break;
2571 }
2572}</span></font>
2573</pre></td>
2574</tr>
2575</table>
2576</div>
2577</div>
2578<div class="SECT2">
2579<hr>
2580<h3 class="SECT2"><a name="MISCMOUSEFUNCS" id=
2581"MISCMOUSEFUNCS">12.4. Miscellaneous Functions</a></h3>
2582<p>The functions mouse_trafo() and wmouse_trafo() can be used to
2583convert to mouse co-ordinates to screen relative co-ordinates. See
2584curs_mouse(3X) man page for details.</p>
2585<p>The mouseinterval function sets the maximum time (in thousands
2586of a second) that can elapse between press and release events in
2587order for them to be recognized as a click. This function returns
2588the previous interval value. The default is one fifth of a
2589second.</p>
2590</div>
2591</div>
2592<div class="SECT1">
2593<hr>
2594<h2 class="SECT1"><a name="SCREEN" id="SCREEN">13. Screen
2595Manipulation</a></h2>
2596<p>In this section, we will look into some functions, which allow
2597us to manage the screen efficiently and to write some fancy
2598programs. This is especially important in writing games.</p>
2599<div class="SECT2">
2600<hr>
2601<h3 class="SECT2"><a name="GETYX" id="GETYX">13.1. getyx()
2602functions</a></h3>
2603<p>The function <var class="LITERAL">getyx()</var> can be used to
2604find out the present cursor co-ordinates. It will fill the values
2605of x and y co-ordinates in the arguments given to it. Since getyx()
2606is a macro you don't have to pass the address of the variables. It
2607can be called as</p>
2608<table border="0" bgcolor="#E0E0E0" width="100%">
2609<tr>
2610<td>
2611<pre class="PROGRAMLISTING">
2612<font color="#000000"> getyx(win, y, x);
3903 i = startx + 2;
3904 j = starty + 3;
3905
3906 for(choice = 0; choice &#60; n_choices; ++choice)
3907 if(mouse_y == j + choice &#38;&#38; mouse_x &#62;= i &#38;&#38; mouse_x &#60;= i + strlen(choices[choice]))
3908 { if(choice == n_choices - 1)
3909 *p_choice = -1;
3910 else
3911 *p_choice = choice + 1;
3912 break;
3913 }
3914}</SPAN
3915></PRE
3916></DIV
3917></DIV
3918><DIV
3919CLASS="SECT2"
3920><HR><H3
3921CLASS="SECT2"
3922><A
3923NAME="MISCMOUSEFUNCS"
3924>12.4. Miscellaneous Functions</A
3925></H3
3926><P
3927>The functions mouse_trafo() and wmouse_trafo() can be used to convert to mouse
3928co-ordinates to screen relative co-ordinates. See curs_mouse(3X) man page for details.</P
3929><P
3930>The mouseinterval function sets the maximum time (in thousands of a
3931second) that can elapse between press and release events in order for
3932them to be recognized as a click. This function returns the previous
3933interval value. The default is one fifth of a second.</P
3934></DIV
3935></DIV
3936><DIV
3937CLASS="SECT1"
3938><HR><H2
3939CLASS="SECT1"
3940><A
3941NAME="SCREEN"
3942>13. Screen Manipulation</A
3943></H2
3944><P
3945>In this section, we will look into some functions, which allow us to manage the
3946screen efficiently and to write some fancy programs. This is especially
3947important in writing games. </P
3948><DIV
3949CLASS="SECT2"
3950><HR><H3
3951CLASS="SECT2"
3952><A
3953NAME="GETYX"
3954>13.1. getyx() functions</A
3955></H3
3956><P
3957>&#13;The function <TT
3958CLASS="LITERAL"
3959>getyx()</TT
3960> can be used to find out
3961the present cursor co-ordinates. It will fill the values of x and y co-ordinates
3962in the arguments given to it. Since getyx() is a macro you don't have to pass
3963the address of the variables. It can be called as</P
3964><PRE
3965CLASS="PROGRAMLISTING"
3966> getyx(win, y, x);
2613 /* win: window pointer
2614 * y, x: y, x co-ordinates will be put into this variables
3967 /* win: window pointer
3968 * y, x: y, x co-ordinates will be put into this variables
2615 */</font>
2616</pre></td>
2617</tr>
2618</table>
2619<p>The function getparyx() gets the beginning co-ordinates of the
2620sub window relative to the main window. This is some times useful
2621to update a sub window. When designing fancy stuff like writing
2622multiple menus, it becomes difficult to store the menu positions,
2623their first option co-ordinates etc. A simple solution to this
2624problem, is to create menus in sub windows and later find the
2625starting co-ordinates of the menus by using getparyx().</p>
2626<p>The functions getbegyx() and getmaxyx() store current window's
2627beginning and maximum co-ordinates. These functions are useful in
2628the same way as above in managing the windows and sub windows
2629effectively.</p>
2630</div>
2631<div class="SECT2">
2632<hr>
2633<h3 class="SECT2"><a name="SCREENDUMP" id="SCREENDUMP">13.2. Screen
2634Dumping</a></h3>
2635<p>While writing games, some times it becomes necessary to store
2636the state of the screen and restore it back to the same state. The
2637function scr_dump() can be used to dump the screen contents to a
2638file given as an argument. Later it can be restored by scr_restore
2639function. These two simple functions can be used effectively to
2640maintain a fast moving game with changing scenarios.</p>
2641</div>
2642<div class="SECT2">
2643<hr>
2644<h3 class="SECT2"><a name="WINDOWDUMP" id="WINDOWDUMP">13.3. Window
2645Dumping</a></h3>
2646<p>To store and restore windows, the functions <var class=
2647"LITERAL">putwin()</var> and <var class="LITERAL">getwin()</var>
2648can be used. <var class="LITERAL">putwin()</var> puts the present
2649window state into a file, which can be later restored by
2650<var class="LITERAL">getwin()</var>.</p>
2651<p>The function <var class="LITERAL">copywin()</var> can be used to
2652copy a window completely onto another window. It takes the source
2653and destination windows as parameters and according to the
2654rectangle specified, it copies the rectangular region from source
2655to destination window. It's last parameter specifies whether to
2656overwrite or just overlay the contents on to the destination
2657window. If this argument is true, then the copying is
2658non-destructive.</p>
2659</div>
2660</div>
2661<div class="SECT1">
2662<hr>
2663<h2 class="SECT1"><a name="MISC" id="MISC">14. Miscellaneous
2664features</a></h2>
2665<p>Now you know enough features to write a good curses program,
2666with all bells and whistles. There are some miscellaneous functions
2667which are useful in various cases. Let's go headlong into some of
2668those.</p>
2669<div class="SECT2">
2670<hr>
2671<h3 class="SECT2"><a name="CURSSET" id="CURSSET">14.1.
2672curs_set()</a></h3>
2673<p>This function can be used to make the cursor invisible. The
2674parameter to this function should be</p>
2675<table border="0" bgcolor="#E0E0E0" width="100%">
2676<tr>
2677<td>
2678<pre class="PROGRAMLISTING">
2679<font color="#000000"> 0 : invisible or
3969 */</PRE
3970><P
3971>The function getparyx() gets the beginning co-ordinates of the sub window
3972relative to the main window. This is some times useful to update a sub window.
3973When designing fancy stuff like writing multiple menus, it becomes difficult to
3974store the menu positions, their first option co-ordinates etc. A simple solution
3975to this problem, is to create menus in sub windows and later find the starting
3976co-ordinates of the menus by using getparyx().</P
3977><P
3978>The functions getbegyx() and getmaxyx() store current window's beginning and
3979maximum co-ordinates. These functions are useful in the same way as above in
3980managing the windows and sub windows effectively.</P
3981></DIV
3982><DIV
3983CLASS="SECT2"
3984><HR><H3
3985CLASS="SECT2"
3986><A
3987NAME="SCREENDUMP"
3988>13.2. Screen Dumping</A
3989></H3
3990><P
3991>While writing games, some times it becomes necessary to store the state of the
3992screen and restore it back to the same state. The function scr_dump() can be
3993used to dump the screen contents to a file given as an argument. Later it can be
3994restored by scr_restore function. These two simple functions can be used
3995effectively to maintain a fast moving game with changing scenarios. </P
3996></DIV
3997><DIV
3998CLASS="SECT2"
3999><HR><H3
4000CLASS="SECT2"
4001><A
4002NAME="WINDOWDUMP"
4003>13.3. Window Dumping</A
4004></H3
4005><P
4006>To store and restore windows, the functions
4007<TT
4008CLASS="LITERAL"
4009>putwin()</TT
4010> and <TT
4011CLASS="LITERAL"
4012>getwin()</TT
4013> can be used. <TT
4014CLASS="LITERAL"
4015>putwin()</TT
4016> puts
4017the present window state into a file, which can be later restored by
4018<TT
4019CLASS="LITERAL"
4020>getwin()</TT
4021>.</P
4022><P
4023>
4024The function <TT
4025CLASS="LITERAL"
4026>copywin()</TT
4027> can be used to copy a
4028window completely onto another window. It takes the source and destination
4029windows as parameters and according to the rectangle specified, it copies the
4030rectangular region from source to destination window. It's last parameter
4031specifies whether to overwrite or just overlay the contents on to the
4032destination window. If this argument is true, then the copying is
4033non-destructive.</P
4034></DIV
4035></DIV
4036><DIV
4037CLASS="SECT1"
4038><HR><H2
4039CLASS="SECT1"
4040><A
4041NAME="MISC"
4042>14. Miscellaneous features</A
4043></H2
4044><P
4045>Now you know enough features to write a good curses program, with all bells and
4046whistles. There are some miscellaneous functions which are useful in various
4047cases. Let's go headlong into some of those.</P
4048><DIV
4049CLASS="SECT2"
4050><HR><H3
4051CLASS="SECT2"
4052><A
4053NAME="CURSSET"
4054>14.1. curs_set()</A
4055></H3
4056><P
4057>This function can be used to make the cursor invisible. The parameter to this
4058function should be </P
4059><PRE
4060CLASS="PROGRAMLISTING"
4061> 0 : invisible or
2680 1 : normal or
4062 1 : normal or
2681 2 : very visible.</font>
2682</pre></td>
2683</tr>
2684</table>
2685</div>
2686<div class="SECT2">
2687<hr>
2688<h3 class="SECT2"><a name="TEMPLEAVE" id="TEMPLEAVE">14.2.
2689Temporarily Leaving Curses mode</a></h3>
2690<p>Some times you may want to get back to cooked mode (normal line
2691buffering mode) temporarily. In such a case you will first need to
2692save the tty modes with a call to <var class=
2693"LITERAL">def_prog_mode()</var> and then call <var class=
2694"LITERAL">endwin()</var> to end the curses mode. This will leave
2695you in the original tty mode. To get back to curses once you are
2696done, call <var class="LITERAL">reset_prog_mode()</var> . This
2697function returns the tty to the state stored by <var class=
2698"LITERAL">def_prog_mode()</var>. Then do refresh(), and you are
2699back to the curses mode. Here is an example showing the sequence of
2700things to be done.</p>
2701<div class="EXAMPLE"><a name="BTELE" id="BTELE"></a>
2702<p><b>Example 12. Temporarily Leaving Curses Mode</b></p>
2703<table border="0" bgcolor="#E0E0E0" width="100%">
2704<tr>
2705<td>
2706<pre class="PROGRAMLISTING">
2707<font color="#000000"><span class=
2708"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
4063 2 : very visible.</PRE
4064></DIV
4065><DIV
4066CLASS="SECT2"
4067><HR><H3
4068CLASS="SECT2"
4069><A
4070NAME="TEMPLEAVE"
4071>14.2. Temporarily Leaving Curses mode</A
4072></H3
4073><P
4074>Some times you may want to get back to cooked mode (normal line buffering mode)
4075temporarily. In such a case you will first need to save the tty modes with a
4076call to <TT
4077CLASS="LITERAL"
4078>def_prog_mode()</TT
4079> and then call
4080<TT
4081CLASS="LITERAL"
4082>endwin()</TT
4083> to end the curses mode. This will
4084leave you in the original tty mode. To get back to curses once you are done,
4085call <TT
4086CLASS="LITERAL"
4087>reset_prog_mode() </TT
4088>. This function returns
4089the tty to the state stored by <TT
4090CLASS="LITERAL"
4091>def_prog_mode()</TT
4092>. Then do refresh(), and you are back to the curses mode. Here
4093is an example showing the sequence of things to be done.</P
4094><DIV
4095CLASS="EXAMPLE"
4096><A
4097NAME="BTELE"
4098></A
4099><P
4100><B
4101>Example 12. Temporarily Leaving Curses Mode </B
4102></P
4103><PRE
4104CLASS="PROGRAMLISTING"
4105><SPAN
4106CLASS="INLINEMEDIAOBJECT"
4107>#include &#60;ncurses.h&#62;
2709
2710int main()
4108
4109int main()
2711{
2712 initscr(); /* Start curses mode */
2713 printw("Hello World !!!\n"); /* Print Hello World */
2714 refresh(); /* Print it on to the real screen */
2715 def_prog_mode(); /* Save the tty modes */
2716 endwin(); /* End curses mode temporarily */
2717 system("/bin/sh"); /* Do whatever you like in cooked mode */
2718 reset_prog_mode(); /* Return to the previous tty mode*/
2719 /* stored by def_prog_mode() */
2720 refresh(); /* Do refresh() to restore the */
2721 /* Screen contents */
2722 printw("Another String\n"); /* Back to curses use the full */
2723 refresh(); /* capabilities of curses */
2724 endwin(); /* End curses mode */
4110{
4111 initscr(); /* Start curses mode */
4112 printw("Hello World !!!\n"); /* Print Hello World */
4113 refresh(); /* Print it on to the real screen */
4114 def_prog_mode(); /* Save the tty modes */
4115 endwin(); /* End curses mode temporarily */
4116 system("/bin/sh"); /* Do whatever you like in cooked mode */
4117 reset_prog_mode(); /* Return to the previous tty mode*/
4118 /* stored by def_prog_mode() */
4119 refresh(); /* Do refresh() to restore the */
4120 /* Screen contents */
4121 printw("Another String\n"); /* Back to curses use the full */
4122 refresh(); /* capabilities of curses */
4123 endwin(); /* End curses mode */
2725
4124
2726 return 0;
2727}</span></font>
2728</pre></td>
2729</tr>
2730</table>
2731</div>
2732</div>
2733<div class="SECT2">
2734<hr>
2735<h3 class="SECT2"><a name="ACSVARS" id="ACSVARS">14.3. ACS_
2736variables</a></h3>
2737<p>If you have ever programmed in DOS, you know about those nifty
2738characters in extended character set. They are printable only on
2739some terminals. NCURSES functions like <var class=
2740"LITERAL">box()</var> use these characters. All these variables
2741start with ACS meaning alternative character set. You might have
2742noticed me using these characters in some of the programs above.
2743Here's an example showing all the characters.</p>
2744<div class="EXAMPLE"><a name="BACSVARS" id="BACSVARS"></a>
2745<p><b>Example 13. ACS Variables Example</b></p>
2746<table border="0" bgcolor="#E0E0E0" width="100%">
2747<tr>
2748<td>
2749<pre class="PROGRAMLISTING">
2750<font color="#000000"><span class=
2751"INLINEMEDIAOBJECT">#include &lt;ncurses.h&gt;
4125 return 0;
4126}</SPAN
4127></PRE
4128></DIV
4129></DIV
4130><DIV
4131CLASS="SECT2"
4132><HR><H3
4133CLASS="SECT2"
4134><A
4135NAME="ACSVARS"
4136>14.3. ACS_ variables</A
4137></H3
4138><P
4139>If you have ever programmed in DOS, you know about those nifty characters in
4140extended character set. They are printable only on some terminals. NCURSES
4141functions like <TT
4142CLASS="LITERAL"
4143>box()</TT
4144> use these characters. All
4145these variables start with ACS meaning alternative character set. You might have
4146noticed me using these characters in some of the programs above. Here's an example
4147showing all the characters.</P
4148><DIV
4149CLASS="EXAMPLE"
4150><A
4151NAME="BACSVARS"
4152></A
4153><P
4154><B
4155>Example 13. ACS Variables Example </B
4156></P
4157><PRE
4158CLASS="PROGRAMLISTING"
4159><SPAN
4160CLASS="INLINEMEDIAOBJECT"
4161>#include &#60;ncurses.h&#62;
2752
2753int main()
2754{
2755 initscr();
2756
2757 printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n");
2758 printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n");
2759 printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n");

--- 25 unchanged lines hidden (view full) ---

2785 printw("Pi "); addch(ACS_PI); printw("\n");
2786 printw("Not equal "); addch(ACS_NEQUAL); printw("\n");
2787 printw("UK pound sign "); addch(ACS_STERLING); printw("\n");
2788
2789 refresh();
2790 getch();
2791 endwin();
2792
4162
4163int main()
4164{
4165 initscr();
4166
4167 printw("Upper left corner "); addch(ACS_ULCORNER); printw("\n");
4168 printw("Lower left corner "); addch(ACS_LLCORNER); printw("\n");
4169 printw("Lower right corner "); addch(ACS_LRCORNER); printw("\n");

--- 25 unchanged lines hidden (view full) ---

4195 printw("Pi "); addch(ACS_PI); printw("\n");
4196 printw("Not equal "); addch(ACS_NEQUAL); printw("\n");
4197 printw("UK pound sign "); addch(ACS_STERLING); printw("\n");
4198
4199 refresh();
4200 getch();
4201 endwin();
4202
2793 return 0;
2794}</span></font>
2795</pre></td>
2796</tr>
2797</table>
2798</div>
2799</div>
2800</div>
2801<div class="SECT1">
2802<hr>
2803<h2 class="SECT1"><a name="OTHERLIB" id="OTHERLIB">15. Other
2804libraries</a></h2>
2805<p>Apart from the curses library, there are few text mode
2806libraries, which provide more functionality and a lot of features.
2807The following sections explain three standard libraries which are
2808usually distributed along with curses.</p>
2809</div>
2810<div class="SECT1">
2811<hr>
2812<h2 class="SECT1"><a name="PANELS" id="PANELS">16. Panel
2813Library</a></h2>
2814<p>Now that you are proficient in curses, you wanted to do some
2815thing big. You created a lot of overlapping windows to give a
2816professional windows-type look. Unfortunately, it soon becomes
2817difficult to manage these. The multiple refreshes, updates plunge
2818you into a nightmare. The overlapping windows create blotches,
2819whenever you forget to refresh the windows in the proper order.</p>
2820<p>Don't despair. There's an elegant solution provided in panels
2821library. In the words of developers of ncurses</p>
2822<p><em>When your interface design is such that windows may dive
2823deeper into the visibility stack or pop to the top at runtime, the
2824resulting book-keeping can be tedious and difficult to get right.
2825Hence the panels library.</em></p>
2826<p>If you have lot of overlapping windows, then panels library is
2827the way to go. It obviates the need of doing series of
2828wnoutrefresh(), doupdate() and relieves the burden of doing it
2829correctly(bottom up). The library maintains information about the
2830order of windows, their overlapping and update the screen properly.
2831So why wait? Let's take a close peek into panels.</p>
2832<div class="SECT2">
2833<hr>
2834<h3 class="SECT2"><a name="PANELBASICS" id="PANELBASICS">16.1. The
2835Basics</a></h3>
2836<p>Panel object is a window that is implicitly treated as part of a
2837deck including all other panel objects. The deck is treated as a
2838stack with the top panel being completely visible and the other
2839panels may or may not be obscured according to their positions. So
2840the basic idea is to create a stack of overlapping panels and use
2841panels library to display them correctly. There is a function
2842similar to refresh() which, when called , displays panels in the
2843correct order. Functions are provided to hide or show panels, move
2844panels, change its size etc.. The overlapping problem is managed by
2845the panels library during all the calls to these functions.</p>
2846<p>The general flow of a panel program goes like this:</p>
2847<ol type="1">
2848<li>
2849<p>Create the windows (with newwin()) to be attached to the
2850panels.</p>
2851</li>
2852<li>
2853<p>Create panels with the chosen visibility order. Stack them up
2854according to the desired visibility. The function new_panel() is
2855used to created panels.</p>
2856</li>
2857<li>
2858<p>Call update_panels() to write the panels to the virtual screen
2859in correct visibility order. Do a doupdate() to show it on the
2860screen.</p>
2861</li>
2862<li>
2863<p>Mainpulate the panels with show_panel(), hide_panel(),
2864move_panel() etc. Make use of helper functions like panel_hidden()
2865and panel_window(). Make use of user pointer to store custom data
2866for a panel. Use the functions set_panel_userptr() and
2867panel_userptr() to set and get the user pointer for a panel.</p>
2868</li>
2869<li>
2870<p>When you are done with the panel use del_panel() to delete the
2871panel.</p>
2872</li>
2873</ol>
2874<p>Let's make the concepts clear, with some programs. The following
2875is a simple program which creates 3 overlapping panels and shows
2876them on the screen.</p>
2877</div>
2878<div class="SECT2">
2879<hr>
2880<h3 class="SECT2"><a name="COMPILEPANELS" id="COMPILEPANELS">16.2.
2881Compiling With the Panels Library</a></h3>
2882<p>To use panels library functions, you have to include panel.h and
2883to link the program with panels library the flag -lpanel should be
2884added along with -lncurses in that order.</p>
2885<table border="0" bgcolor="#E0E0E0" width="100%">
2886<tr>
2887<td>
2888<pre class="PROGRAMLISTING">
2889<font color="#000000"> #include &lt;panel.h&gt;
4203 return 0;
4204}</SPAN
4205></PRE
4206></DIV
4207></DIV
4208></DIV
4209><DIV
4210CLASS="SECT1"
4211><HR><H2
4212CLASS="SECT1"
4213><A
4214NAME="OTHERLIB"
4215>15. Other libraries</A
4216></H2
4217><P
4218>Apart from the curses library, there are few text mode libraries, which provide
4219more functionality and a lot of features. The following sections explain three
4220standard libraries which are usually distributed along with curses. </P
4221></DIV
4222><DIV
4223CLASS="SECT1"
4224><HR><H2
4225CLASS="SECT1"
4226><A
4227NAME="PANELS"
4228>16. Panel Library</A
4229></H2
4230><P
4231>Now that you are proficient in curses, you wanted to do some thing big. You
4232created a lot of overlapping windows to give a professional windows-type look.
4233Unfortunately, it soon becomes difficult to manage these. The multiple
4234refreshes, updates plunge you into a nightmare. The overlapping windows create
4235blotches, whenever you forget to refresh the windows in the proper order. </P
4236><P
4237>Don't despair. There's an elegant solution provided in panels library. In the
4238words of developers of ncurses </P
4239><P
4240><SPAN
4241CLASS="emphasis"
4242><I
4243CLASS="EMPHASIS"
4244>When your interface design is such that windows may dive deeper into the
4245visibility stack or pop to the top at runtime, the resulting book-keeping can be
4246tedious and difficult to get right. Hence the panels library.</I
4247></SPAN
4248></P
4249><P
4250>If you have lot of overlapping windows, then panels library is the way to go. It
4251obviates the need of doing series of wnoutrefresh(), doupdate() and relieves the
4252burden of doing it correctly(bottom up). The library maintains information about
4253the order of windows, their overlapping and update the screen properly. So why
4254wait? Let's take a close peek into panels.</P
4255><DIV
4256CLASS="SECT2"
4257><HR><H3
4258CLASS="SECT2"
4259><A
4260NAME="PANELBASICS"
4261>16.1. The Basics</A
4262></H3
4263><P
4264>Panel object is a window that is implicitly treated as part of a deck including
4265all other panel objects. The deck is treated as a stack with the top panel being
4266completely visible and the other panels may or may not be obscured according to
4267their positions. So the basic idea is to create a stack of overlapping panels
4268and use panels library to display them correctly. There is a function similar to
4269refresh() which, when called , displays panels in the correct order. Functions
4270are provided to hide or show panels, move panels, change its size etc.. The
4271overlapping problem is managed by the panels library during all the calls to
4272these functions. </P
4273><P
4274>The general flow of a panel program goes like this:
4275
4276<P
4277></P
4278><OL
4279TYPE="1"
4280><LI
4281><P
4282>Create the windows (with newwin()) to be attached to the panels.</P
4283></LI
4284><LI
4285><P
4286>Create panels with the chosen visibility order. Stack them up according to the
4287desired visibility. The function new_panel() is used to created panels.</P
4288></LI
4289><LI
4290><P
4291>Call update_panels() to write the panels to the virtual screen in correct
4292visibility order. Do a doupdate() to show it on the screen. </P
4293></LI
4294><LI
4295><P
4296>Mainpulate the panels with show_panel(), hide_panel(), move_panel() etc. Make
4297use of helper functions like panel_hidden() and panel_window(). Make use of user
4298pointer to store custom data for a panel. Use the functions set_panel_userptr()
4299and panel_userptr() to set and get the user pointer for a panel.</P
4300></LI
4301><LI
4302><P
4303>When you are done with the panel use del_panel() to delete the panel.</P
4304></LI
4305></OL
4306></P
4307><P
4308>Let's make the concepts clear, with some programs. The following is a simple
4309program which creates 3 overlapping panels and shows them on the screen. </P
4310></DIV
4311><DIV
4312CLASS="SECT2"
4313><HR><H3
4314CLASS="SECT2"
4315><A
4316NAME="COMPILEPANELS"
4317>16.2. Compiling With the Panels Library</A
4318></H3
4319><P
4320>To use panels library functions, you have to include panel.h and to link the
4321program with panels library the flag -lpanel should be added along with
4322-lncurses in that order.</P
4323><PRE
4324CLASS="PROGRAMLISTING"
4325> #include &lt;panel.h&gt;
2890 .
2891 .
2892 .
2893
4326 .
4327 .
4328 .
4329
2894 compile and link: gcc &lt;program file&gt; -lpanel -lncurses</font>
2895</pre></td>
2896</tr>
2897</table>
2898<div class="EXAMPLE"><a name="PPASI" id="PPASI"></a>
2899<p><b>Example 14. Panel basics</b></p>
2900<table border="0" bgcolor="#E0E0E0" width="100%">
2901<tr>
2902<td>
2903<pre class="PROGRAMLISTING">
2904<font color="#000000"><span class=
2905"INLINEMEDIAOBJECT">#include &lt;panel.h&gt;
4330 compile and link: gcc &lt;program file&gt; -lpanel -lncurses</PRE
4331><DIV
4332CLASS="EXAMPLE"
4333><A
4334NAME="PPASI"
4335></A
4336><P
4337><B
4338>Example 14. Panel basics</B
4339></P
4340><PRE
4341CLASS="PROGRAMLISTING"
4342><SPAN
4343CLASS="INLINEMEDIAOBJECT"
4344>#include &#60;panel.h&#62;
2906
2907int main()
4345
4346int main()
2908{ WINDOW *my_wins[3];
2909 PANEL *my_panels[3];
2910 int lines = 10, cols = 40, y = 2, x = 4, i;
4347{ WINDOW *my_wins[3];
4348 PANEL *my_panels[3];
4349 int lines = 10, cols = 40, y = 2, x = 4, i;
2911
4350
2912 initscr();
2913 cbreak();
2914 noecho();
4351 initscr();
4352 cbreak();
4353 noecho();
2915
4354
2916 /* Create windows for the panels */
2917 my_wins[0] = newwin(lines, cols, y, x);
2918 my_wins[1] = newwin(lines, cols, y + 1, x + 5);
2919 my_wins[2] = newwin(lines, cols, y + 2, x + 10);
4355 /* Create windows for the panels */
4356 my_wins[0] = newwin(lines, cols, y, x);
4357 my_wins[1] = newwin(lines, cols, y + 1, x + 5);
4358 my_wins[2] = newwin(lines, cols, y + 2, x + 10);
2920
4359
2921 /*
2922 * Create borders around the windows so that you can see the effect
2923 * of panels
2924 */
2925 for(i = 0; i &lt; 3; ++i)
2926 box(my_wins[i], 0, 0);
4360 /*
4361 * Create borders around the windows so that you can see the effect
4362 * of panels
4363 */
4364 for(i = 0; i &#60; 3; ++i)
4365 box(my_wins[i], 0, 0);
2927
4366
2928 /* Attach a panel to each window */ /* Order is bottom up */
2929 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
2930 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
2931 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
4367 /* Attach a panel to each window */ /* Order is bottom up */
4368 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
4369 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
4370 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
2932
4371
2933 /* Update the stacking order. 2nd panel will be on top */
2934 update_panels();
4372 /* Update the stacking order. 2nd panel will be on top */
4373 update_panels();
2935
4374
2936 /* Show it on the screen */
2937 doupdate();
2938
2939 getch();
2940 endwin();
4375 /* Show it on the screen */
4376 doupdate();
4377
4378 getch();
4379 endwin();
2941}
4380}
2942</span></font>
2943</pre></td>
2944</tr>
2945</table>
2946</div>
2947<p>As you can see, above program follows a simple flow as
2948explained. The windows are created with newwin() and then they are
2949attached to panels with new_panel(). As we attach one panel after
2950another, the stack of panels gets updated. To put them on screen
2951update_panels() and doupdate() are called.</p>
2952</div>
2953<div class="SECT2">
2954<hr>
2955<h3 class="SECT2"><a name="PANELBROWSING" id="PANELBROWSING">16.3.
2956Panel Window Browsing</a></h3>
2957<p>A slightly complicated example is given below. This program
2958creates 3 windows which can be cycled through using tab. Have a
2959look at the code.</p>
2960<div class="EXAMPLE"><a name="PPABR" id="PPABR"></a>
2961<p><b>Example 15. Panel Window Browsing Example</b></p>
2962<table border="0" bgcolor="#E0E0E0" width="100%">
2963<tr>
2964<td>
2965<pre class="PROGRAMLISTING">
2966<font color="#000000"><span class=
2967"INLINEMEDIAOBJECT">#include &lt;panel.h&gt;
4381</SPAN
4382></PRE
4383></DIV
4384><P
4385>As you can see, above program follows a simple flow as explained. The windows
4386are created with newwin() and then they are attached to panels with new_panel().
4387As we attach one panel after another, the stack of panels gets updated. To put
4388them on screen update_panels() and doupdate() are called.</P
4389></DIV
4390><DIV
4391CLASS="SECT2"
4392><HR><H3
4393CLASS="SECT2"
4394><A
4395NAME="PANELBROWSING"
4396>16.3. Panel Window Browsing</A
4397></H3
4398><P
4399>A slightly complicated example is given below. This program creates 3
4400windows which can be cycled through using tab. Have a look at the code.</P
4401><DIV
4402CLASS="EXAMPLE"
4403><A
4404NAME="PPABR"
4405></A
4406><P
4407><B
4408>Example 15. Panel Window Browsing Example </B
4409></P
4410><PRE
4411CLASS="PROGRAMLISTING"
4412><SPAN
4413CLASS="INLINEMEDIAOBJECT"
4414>#include &#60;panel.h&#62;
2968
2969#define NLINES 10
2970#define NCOLS 40
2971
2972void init_wins(WINDOW **wins, int n);
2973void win_show(WINDOW *win, char *label, int label_color);
2974void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
2975
2976int main()
4415
4416#define NLINES 10
4417#define NCOLS 40
4418
4419void init_wins(WINDOW **wins, int n);
4420void win_show(WINDOW *win, char *label, int label_color);
4421void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
4422
4423int main()
2977{ WINDOW *my_wins[3];
2978 PANEL *my_panels[3];
2979 PANEL *top;
2980 int ch;
4424{ WINDOW *my_wins[3];
4425 PANEL *my_panels[3];
4426 PANEL *top;
4427 int ch;
2981
4428
2982 /* Initialize curses */
2983 initscr();
2984 start_color();
2985 cbreak();
2986 noecho();
2987 keypad(stdscr, TRUE);
4429 /* Initialize curses */
4430 initscr();
4431 start_color();
4432 cbreak();
4433 noecho();
4434 keypad(stdscr, TRUE);
2988
4435
2989 /* Initialize all the colors */
2990 init_pair(1, COLOR_RED, COLOR_BLACK);
2991 init_pair(2, COLOR_GREEN, COLOR_BLACK);
2992 init_pair(3, COLOR_BLUE, COLOR_BLACK);
2993 init_pair(4, COLOR_CYAN, COLOR_BLACK);
4436 /* Initialize all the colors */
4437 init_pair(1, COLOR_RED, COLOR_BLACK);
4438 init_pair(2, COLOR_GREEN, COLOR_BLACK);
4439 init_pair(3, COLOR_BLUE, COLOR_BLACK);
4440 init_pair(4, COLOR_CYAN, COLOR_BLACK);
2994
4441
2995 init_wins(my_wins, 3);
2996
2997 /* Attach a panel to each window */ /* Order is bottom up */
2998 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
2999 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
3000 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
4442 init_wins(my_wins, 3);
4443
4444 /* Attach a panel to each window */ /* Order is bottom up */
4445 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
4446 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
4447 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
3001
4448
3002 /* Set up the user pointers to the next panel */
3003 set_panel_userptr(my_panels[0], my_panels[1]);
3004 set_panel_userptr(my_panels[1], my_panels[2]);
3005 set_panel_userptr(my_panels[2], my_panels[0]);
4449 /* Set up the user pointers to the next panel */
4450 set_panel_userptr(my_panels[0], my_panels[1]);
4451 set_panel_userptr(my_panels[1], my_panels[2]);
4452 set_panel_userptr(my_panels[2], my_panels[0]);
3006
4453
3007 /* Update the stacking order. 2nd panel will be on top */
3008 update_panels();
4454 /* Update the stacking order. 2nd panel will be on top */
4455 update_panels();
3009
4456
3010 /* Show it on the screen */
3011 attron(COLOR_PAIR(4));
3012 mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
3013 attroff(COLOR_PAIR(4));
3014 doupdate();
4457 /* Show it on the screen */
4458 attron(COLOR_PAIR(4));
4459 mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
4460 attroff(COLOR_PAIR(4));
4461 doupdate();
3015
4462
3016 top = my_panels[2];
3017 while((ch = getch()) != KEY_F(1))
3018 { switch(ch)
3019 { case 9:
3020 top = (PANEL *)panel_userptr(top);
3021 top_panel(top);
3022 break;
3023 }
3024 update_panels();
3025 doupdate();
3026 }
3027 endwin();
3028 return 0;
4463 top = my_panels[2];
4464 while((ch = getch()) != KEY_F(1))
4465 { switch(ch)
4466 { case 9:
4467 top = (PANEL *)panel_userptr(top);
4468 top_panel(top);
4469 break;
4470 }
4471 update_panels();
4472 doupdate();
4473 }
4474 endwin();
4475 return 0;
3029}
3030
3031/* Put all the windows */
3032void init_wins(WINDOW **wins, int n)
4476}
4477
4478/* Put all the windows */
4479void init_wins(WINDOW **wins, int n)
3033{ int x, y, i;
3034 char label[80];
4480{ int x, y, i;
4481 char label[80];
3035
4482
3036 y = 2;
3037 x = 10;
3038 for(i = 0; i &lt; n; ++i)
3039 { wins[i] = newwin(NLINES, NCOLS, y, x);
3040 sprintf(label, "Window Number %d", i + 1);
3041 win_show(wins[i], label, i + 1);
3042 y += 3;
3043 x += 7;
3044 }
4483 y = 2;
4484 x = 10;
4485 for(i = 0; i &#60; n; ++i)
4486 { wins[i] = newwin(NLINES, NCOLS, y, x);
4487 sprintf(label, "Window Number %d", i + 1);
4488 win_show(wins[i], label, i + 1);
4489 y += 3;
4490 x += 7;
4491 }
3045}
3046
3047/* Show the window with a border and a label */
3048void win_show(WINDOW *win, char *label, int label_color)
4492}
4493
4494/* Show the window with a border and a label */
4495void win_show(WINDOW *win, char *label, int label_color)
3049{ int startx, starty, height, width;
4496{ int startx, starty, height, width;
3050
4497
3051 getbegyx(win, starty, startx);
3052 getmaxyx(win, height, width);
4498 getbegyx(win, starty, startx);
4499 getmaxyx(win, height, width);
3053
4500
3054 box(win, 0, 0);
3055 mvwaddch(win, 2, 0, ACS_LTEE);
3056 mvwhline(win, 2, 1, ACS_HLINE, width - 2);
3057 mvwaddch(win, 2, width - 1, ACS_RTEE);
3058
3059 print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
4501 box(win, 0, 0);
4502 mvwaddch(win, 2, 0, ACS_LTEE);
4503 mvwhline(win, 2, 1, ACS_HLINE, width - 2);
4504 mvwaddch(win, 2, width - 1, ACS_RTEE);
4505
4506 print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
3060}
3061
3062void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
4507}
4508
4509void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
3063{ int length, x, y;
3064 float temp;
4510{ int length, x, y;
4511 float temp;
3065
4512
3066 if(win == NULL)
3067 win = stdscr;
3068 getyx(win, y, x);
3069 if(startx != 0)
3070 x = startx;
3071 if(starty != 0)
3072 y = starty;
3073 if(width == 0)
3074 width = 80;
4513 if(win == NULL)
4514 win = stdscr;
4515 getyx(win, y, x);
4516 if(startx != 0)
4517 x = startx;
4518 if(starty != 0)
4519 y = starty;
4520 if(width == 0)
4521 width = 80;
3075
4522
3076 length = strlen(string);
3077 temp = (width - length)/ 2;
3078 x = startx + (int)temp;
3079 wattron(win, color);
3080 mvwprintw(win, y, x, "%s", string);
3081 wattroff(win, color);
3082 refresh();
3083}</span></font>
3084</pre></td>
3085</tr>
3086</table>
3087</div>
3088</div>
3089<div class="SECT2">
3090<hr>
3091<h3 class="SECT2"><a name="USERPTRUSING" id="USERPTRUSING">16.4.
3092Using User Pointers</a></h3>
3093<p>In the above example I used user pointers to find out the next
3094window in the cycle. We can attach custom information to the panel
3095by specifying a user pointer, which can point to any information
3096you want to store. In this case I stored the pointer to the next
3097panel in the cycle. User pointer for a panel can be set with the
3098function <var class="LITERAL">set_panel_userptr()</var>. It can be
3099accessed using the function <var class=
3100"LITERAL">panel_userptr()</var> which will return the user pointer
3101for the panel given as argument. After finding the next panel in
3102the cycle It's brought to the top by the function top_panel(). This
3103function brings the panel given as argument to the top of the panel
3104stack.</p>
3105</div>
3106<div class="SECT2">
3107<hr>
3108<h3 class="SECT2"><a name="PANELMOVERESIZE" id=
3109"PANELMOVERESIZE">16.5. Moving and Resizing Panels</a></h3>
3110<p>The function <var class="LITERAL">move_panel()</var> can be used
3111to move a panel to the desired location. It does not change the
3112position of the panel in the stack. Make sure that you use
3113move_panel() instead mvwin() on the window associated with the
3114panel.</p>
3115<p>Resizing a panel is slightly complex. There is no straight
3116forward function just to resize the window associated with a panel.
3117A solution to resize a panel is to create a new window with the
3118desired sizes, change the window associated with the panel using
3119replace_panel(). Don't forget to delete the old window. The window
3120associated with a panel can be found by using the function
3121panel_window().</p>
3122<p>The following program shows these concepts, in supposedly simple
3123program. You can cycle through the window with &lt;TAB&gt; as
3124usual. To resize or move the active panel press 'r' for resize 'm'
3125for moving. Then use arrow keys to resize or move it to the desired
3126way and press enter to end your resizing or moving. This example
3127makes use of user data to get the required data to do the
3128operations.</p>
3129<div class="EXAMPLE"><a name="PPARE" id="PPARE"></a>
3130<p><b>Example 16. Panel Moving and Resizing example</b></p>
3131<table border="0" bgcolor="#E0E0E0" width="100%">
3132<tr>
3133<td>
3134<pre class="PROGRAMLISTING">
3135<font color="#000000"><span class=
3136"INLINEMEDIAOBJECT">#include &lt;panel.h&gt;
4523 length = strlen(string);
4524 temp = (width - length)/ 2;
4525 x = startx + (int)temp;
4526 wattron(win, color);
4527 mvwprintw(win, y, x, "%s", string);
4528 wattroff(win, color);
4529 refresh();
4530}</SPAN
4531></PRE
4532></DIV
4533></DIV
4534><DIV
4535CLASS="SECT2"
4536><HR><H3
4537CLASS="SECT2"
4538><A
4539NAME="USERPTRUSING"
4540>16.4. Using User Pointers</A
4541></H3
4542><P
4543>In the above example I used user pointers to find out the next window in the
4544cycle. We can attach custom information to the panel by specifying a user
4545pointer, which can point to any information you want to store. In this case I
4546stored the pointer to the next panel in the cycle. User pointer for a panel can
4547be set with the function <TT
4548CLASS="LITERAL"
4549> set_panel_userptr()</TT
4550>.
4551It can be accessed using the function <TT
4552CLASS="LITERAL"
4553>panel_userptr()</TT
4554> which will return the user pointer for the panel given as
4555argument. After finding the next panel in the cycle It's brought to the top by
4556the function top_panel(). This function brings the panel given as argument to
4557the top of the panel stack. </P
4558></DIV
4559><DIV
4560CLASS="SECT2"
4561><HR><H3
4562CLASS="SECT2"
4563><A
4564NAME="PANELMOVERESIZE"
4565>16.5. Moving and Resizing Panels</A
4566></H3
4567><P
4568>The function <TT
4569CLASS="LITERAL"
4570>move_panel()</TT
4571> can be used to move a
4572panel to the desired location. It does not change the position of the panel in
4573the stack. Make sure that you use move_panel() instead mvwin() on the window
4574associated with the panel.</P
4575><P
4576>Resizing a panel is slightly complex. There is no straight forward function
4577just to resize the window associated with a panel. A solution to resize a panel
4578is to create a new window with the desired sizes, change the window associated
4579with the panel using replace_panel(). Don't forget to delete the old window. The
4580window associated with a panel can be found by using the function
4581panel_window().</P
4582><P
4583>The following program shows these concepts, in supposedly simple program. You
4584can cycle through the window with &lt;TAB&gt; as usual. To resize or move the
4585active panel press 'r' for resize 'm' for moving. Then use arrow keys to resize
4586or move it to the desired way and press enter to end your resizing or moving.
4587This example makes use of user data to get the required data to do the
4588operations. </P
4589><DIV
4590CLASS="EXAMPLE"
4591><A
4592NAME="PPARE"
4593></A
4594><P
4595><B
4596>Example 16. Panel Moving and Resizing example </B
4597></P
4598><PRE
4599CLASS="PROGRAMLISTING"
4600><SPAN
4601CLASS="INLINEMEDIAOBJECT"
4602>#include &#60;panel.h&#62;
3137
3138typedef struct _PANEL_DATA {
4603
4604typedef struct _PANEL_DATA {
3139 int x, y, w, h;
3140 char label[80];
3141 int label_color;
3142 PANEL *next;
4605 int x, y, w, h;
4606 char label[80];
4607 int label_color;
4608 PANEL *next;
3143}PANEL_DATA;
3144
3145#define NLINES 10
3146#define NCOLS 40
3147
3148void init_wins(WINDOW **wins, int n);
3149void win_show(WINDOW *win, char *label, int label_color);
3150void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
3151void set_user_ptrs(PANEL **panels, int n);
3152
3153int main()
4609}PANEL_DATA;
4610
4611#define NLINES 10
4612#define NCOLS 40
4613
4614void init_wins(WINDOW **wins, int n);
4615void win_show(WINDOW *win, char *label, int label_color);
4616void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
4617void set_user_ptrs(PANEL **panels, int n);
4618
4619int main()
3154{ WINDOW *my_wins[3];
3155 PANEL *my_panels[3];
3156 PANEL_DATA *top;
3157 PANEL *stack_top;
3158 WINDOW *temp_win, *old_win;
3159 int ch;
3160 int newx, newy, neww, newh;
3161 int size = FALSE, move = FALSE;
4620{ WINDOW *my_wins[3];
4621 PANEL *my_panels[3];
4622 PANEL_DATA *top;
4623 PANEL *stack_top;
4624 WINDOW *temp_win, *old_win;
4625 int ch;
4626 int newx, newy, neww, newh;
4627 int size = FALSE, move = FALSE;
3162
4628
3163 /* Initialize curses */
3164 initscr();
3165 start_color();
3166 cbreak();
3167 noecho();
3168 keypad(stdscr, TRUE);
4629 /* Initialize curses */
4630 initscr();
4631 start_color();
4632 cbreak();
4633 noecho();
4634 keypad(stdscr, TRUE);
3169
4635
3170 /* Initialize all the colors */
3171 init_pair(1, COLOR_RED, COLOR_BLACK);
3172 init_pair(2, COLOR_GREEN, COLOR_BLACK);
3173 init_pair(3, COLOR_BLUE, COLOR_BLACK);
3174 init_pair(4, COLOR_CYAN, COLOR_BLACK);
4636 /* Initialize all the colors */
4637 init_pair(1, COLOR_RED, COLOR_BLACK);
4638 init_pair(2, COLOR_GREEN, COLOR_BLACK);
4639 init_pair(3, COLOR_BLUE, COLOR_BLACK);
4640 init_pair(4, COLOR_CYAN, COLOR_BLACK);
3175
4641
3176 init_wins(my_wins, 3);
3177
3178 /* Attach a panel to each window */ /* Order is bottom up */
3179 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
3180 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
3181 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
4642 init_wins(my_wins, 3);
4643
4644 /* Attach a panel to each window */ /* Order is bottom up */
4645 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
4646 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
4647 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
3182
4648
3183 set_user_ptrs(my_panels, 3);
3184 /* Update the stacking order. 2nd panel will be on top */
3185 update_panels();
4649 set_user_ptrs(my_panels, 3);
4650 /* Update the stacking order. 2nd panel will be on top */
4651 update_panels();
3186
4652
3187 /* Show it on the screen */
3188 attron(COLOR_PAIR(4));
3189 mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
3190 mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
3191 attroff(COLOR_PAIR(4));
3192 doupdate();
4653 /* Show it on the screen */
4654 attron(COLOR_PAIR(4));
4655 mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
4656 mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
4657 attroff(COLOR_PAIR(4));
4658 doupdate();
3193
4659
3194 stack_top = my_panels[2];
3195 top = (PANEL_DATA *)panel_userptr(stack_top);
3196 newx = top-&gt;x;
3197 newy = top-&gt;y;
3198 neww = top-&gt;w;
3199 newh = top-&gt;h;
3200 while((ch = getch()) != KEY_F(1))
3201 { switch(ch)
3202 { case 9: /* Tab */
3203 top = (PANEL_DATA *)panel_userptr(stack_top);
3204 top_panel(top-&gt;next);
3205 stack_top = top-&gt;next;
3206 top = (PANEL_DATA *)panel_userptr(stack_top);
3207 newx = top-&gt;x;
3208 newy = top-&gt;y;
3209 neww = top-&gt;w;
3210 newh = top-&gt;h;
3211 break;
3212 case 'r': /* Re-Size*/
3213 size = TRUE;
3214 attron(COLOR_PAIR(4));
3215 mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press &lt;ENTER&gt; to end resizing");
3216 refresh();
3217 attroff(COLOR_PAIR(4));
3218 break;
3219 case 'm': /* Move */
3220 attron(COLOR_PAIR(4));
3221 mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press &lt;ENTER&gt; to end moving");
3222 refresh();
3223 attroff(COLOR_PAIR(4));
3224 move = TRUE;
3225 break;
3226 case KEY_LEFT:
3227 if(size == TRUE)
3228 { --newx;
3229 ++neww;
3230 }
3231 if(move == TRUE)
3232 --newx;
3233 break;
3234 case KEY_RIGHT:
3235 if(size == TRUE)
3236 { ++newx;
3237 --neww;
3238 }
3239 if(move == TRUE)
3240 ++newx;
3241 break;
3242 case KEY_UP:
3243 if(size == TRUE)
3244 { --newy;
3245 ++newh;
3246 }
3247 if(move == TRUE)
3248 --newy;
3249 break;
3250 case KEY_DOWN:
3251 if(size == TRUE)
3252 { ++newy;
3253 --newh;
3254 }
3255 if(move == TRUE)
3256 ++newy;
3257 break;
3258 case 10: /* Enter */
3259 move(LINES - 4, 0);
3260 clrtoeol();
3261 refresh();
3262 if(size == TRUE)
3263 { old_win = panel_window(stack_top);
3264 temp_win = newwin(newh, neww, newy, newx);
3265 replace_panel(stack_top, temp_win);
3266 win_show(temp_win, top-&gt;label, top-&gt;label_color);
3267 delwin(old_win);
3268 size = FALSE;
3269 }
3270 if(move == TRUE)
3271 { move_panel(stack_top, newy, newx);
3272 move = FALSE;
3273 }
3274 break;
3275
3276 }
3277 attron(COLOR_PAIR(4));
3278 mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
3279 mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
3280 attroff(COLOR_PAIR(4));
3281 refresh();
3282 update_panels();
3283 doupdate();
3284 }
3285 endwin();
3286 return 0;
4660 stack_top = my_panels[2];
4661 top = (PANEL_DATA *)panel_userptr(stack_top);
4662 newx = top-&#62;x;
4663 newy = top-&#62;y;
4664 neww = top-&#62;w;
4665 newh = top-&#62;h;
4666 while((ch = getch()) != KEY_F(1))
4667 { switch(ch)
4668 { case 9: /* Tab */
4669 top = (PANEL_DATA *)panel_userptr(stack_top);
4670 top_panel(top-&#62;next);
4671 stack_top = top-&#62;next;
4672 top = (PANEL_DATA *)panel_userptr(stack_top);
4673 newx = top-&#62;x;
4674 newy = top-&#62;y;
4675 neww = top-&#62;w;
4676 newh = top-&#62;h;
4677 break;
4678 case 'r': /* Re-Size*/
4679 size = TRUE;
4680 attron(COLOR_PAIR(4));
4681 mvprintw(LINES - 4, 0, "Entered Resizing :Use Arrow Keys to resize and press &#60;ENTER&#62; to end resizing");
4682 refresh();
4683 attroff(COLOR_PAIR(4));
4684 break;
4685 case 'm': /* Move */
4686 attron(COLOR_PAIR(4));
4687 mvprintw(LINES - 4, 0, "Entered Moving: Use Arrow Keys to Move and press &#60;ENTER&#62; to end moving");
4688 refresh();
4689 attroff(COLOR_PAIR(4));
4690 move = TRUE;
4691 break;
4692 case KEY_LEFT:
4693 if(size == TRUE)
4694 { --newx;
4695 ++neww;
4696 }
4697 if(move == TRUE)
4698 --newx;
4699 break;
4700 case KEY_RIGHT:
4701 if(size == TRUE)
4702 { ++newx;
4703 --neww;
4704 }
4705 if(move == TRUE)
4706 ++newx;
4707 break;
4708 case KEY_UP:
4709 if(size == TRUE)
4710 { --newy;
4711 ++newh;
4712 }
4713 if(move == TRUE)
4714 --newy;
4715 break;
4716 case KEY_DOWN:
4717 if(size == TRUE)
4718 { ++newy;
4719 --newh;
4720 }
4721 if(move == TRUE)
4722 ++newy;
4723 break;
4724 case 10: /* Enter */
4725 move(LINES - 4, 0);
4726 clrtoeol();
4727 refresh();
4728 if(size == TRUE)
4729 { old_win = panel_window(stack_top);
4730 temp_win = newwin(newh, neww, newy, newx);
4731 replace_panel(stack_top, temp_win);
4732 win_show(temp_win, top-&#62;label, top-&#62;label_color);
4733 delwin(old_win);
4734 size = FALSE;
4735 }
4736 if(move == TRUE)
4737 { move_panel(stack_top, newy, newx);
4738 move = FALSE;
4739 }
4740 break;
4741
4742 }
4743 attron(COLOR_PAIR(4));
4744 mvprintw(LINES - 3, 0, "Use 'm' for moving, 'r' for resizing");
4745 mvprintw(LINES - 2, 0, "Use tab to browse through the windows (F1 to Exit)");
4746 attroff(COLOR_PAIR(4));
4747 refresh();
4748 update_panels();
4749 doupdate();
4750 }
4751 endwin();
4752 return 0;
3287}
3288
3289/* Put all the windows */
3290void init_wins(WINDOW **wins, int n)
4753}
4754
4755/* Put all the windows */
4756void init_wins(WINDOW **wins, int n)
3291{ int x, y, i;
3292 char label[80];
4757{ int x, y, i;
4758 char label[80];
3293
4759
3294 y = 2;
3295 x = 10;
3296 for(i = 0; i &lt; n; ++i)
3297 { wins[i] = newwin(NLINES, NCOLS, y, x);
3298 sprintf(label, "Window Number %d", i + 1);
3299 win_show(wins[i], label, i + 1);
3300 y += 3;
3301 x += 7;
3302 }
4760 y = 2;
4761 x = 10;
4762 for(i = 0; i &#60; n; ++i)
4763 { wins[i] = newwin(NLINES, NCOLS, y, x);
4764 sprintf(label, "Window Number %d", i + 1);
4765 win_show(wins[i], label, i + 1);
4766 y += 3;
4767 x += 7;
4768 }
3303}
3304
3305/* Set the PANEL_DATA structures for individual panels */
3306void set_user_ptrs(PANEL **panels, int n)
4769}
4770
4771/* Set the PANEL_DATA structures for individual panels */
4772void set_user_ptrs(PANEL **panels, int n)
3307{ PANEL_DATA *ptrs;
3308 WINDOW *win;
3309 int x, y, w, h, i;
3310 char temp[80];
3311
3312 ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA));
4773{ PANEL_DATA *ptrs;
4774 WINDOW *win;
4775 int x, y, w, h, i;
4776 char temp[80];
4777
4778 ptrs = (PANEL_DATA *)calloc(n, sizeof(PANEL_DATA));
3313
4779
3314 for(i = 0;i &lt; n; ++i)
3315 { win = panel_window(panels[i]);
3316 getbegyx(win, y, x);
3317 getmaxyx(win, h, w);
3318 ptrs[i].x = x;
3319 ptrs[i].y = y;
3320 ptrs[i].w = w;
3321 ptrs[i].h = h;
3322 sprintf(temp, "Window Number %d", i + 1);
3323 strcpy(ptrs[i].label, temp);
3324 ptrs[i].label_color = i + 1;
3325 if(i + 1 == n)
3326 ptrs[i].next = panels[0];
3327 else
3328 ptrs[i].next = panels[i + 1];
3329 set_panel_userptr(panels[i], &amp;ptrs[i]);
3330 }
4780 for(i = 0;i &#60; n; ++i)
4781 { win = panel_window(panels[i]);
4782 getbegyx(win, y, x);
4783 getmaxyx(win, h, w);
4784 ptrs[i].x = x;
4785 ptrs[i].y = y;
4786 ptrs[i].w = w;
4787 ptrs[i].h = h;
4788 sprintf(temp, "Window Number %d", i + 1);
4789 strcpy(ptrs[i].label, temp);
4790 ptrs[i].label_color = i + 1;
4791 if(i + 1 == n)
4792 ptrs[i].next = panels[0];
4793 else
4794 ptrs[i].next = panels[i + 1];
4795 set_panel_userptr(panels[i], &#38;ptrs[i]);
4796 }
3331}
3332
3333/* Show the window with a border and a label */
3334void win_show(WINDOW *win, char *label, int label_color)
4797}
4798
4799/* Show the window with a border and a label */
4800void win_show(WINDOW *win, char *label, int label_color)
3335{ int startx, starty, height, width;
4801{ int startx, starty, height, width;
3336
4802
3337 getbegyx(win, starty, startx);
3338 getmaxyx(win, height, width);
4803 getbegyx(win, starty, startx);
4804 getmaxyx(win, height, width);
3339
4805
3340 box(win, 0, 0);
3341 mvwaddch(win, 2, 0, ACS_LTEE);
3342 mvwhline(win, 2, 1, ACS_HLINE, width - 2);
3343 mvwaddch(win, 2, width - 1, ACS_RTEE);
3344
3345 print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
4806 box(win, 0, 0);
4807 mvwaddch(win, 2, 0, ACS_LTEE);
4808 mvwhline(win, 2, 1, ACS_HLINE, width - 2);
4809 mvwaddch(win, 2, width - 1, ACS_RTEE);
4810
4811 print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
3346}
3347
3348void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
4812}
4813
4814void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
3349{ int length, x, y;
3350 float temp;
4815{ int length, x, y;
4816 float temp;
3351
4817
3352 if(win == NULL)
3353 win = stdscr;
3354 getyx(win, y, x);
3355 if(startx != 0)
3356 x = startx;
3357 if(starty != 0)
3358 y = starty;
3359 if(width == 0)
3360 width = 80;
4818 if(win == NULL)
4819 win = stdscr;
4820 getyx(win, y, x);
4821 if(startx != 0)
4822 x = startx;
4823 if(starty != 0)
4824 y = starty;
4825 if(width == 0)
4826 width = 80;
3361
4827
3362 length = strlen(string);
3363 temp = (width - length)/ 2;
3364 x = startx + (int)temp;
3365 wattron(win, color);
3366 mvwprintw(win, y, x, "%s", string);
3367 wattroff(win, color);
3368 refresh();
3369}</span></font>
3370</pre></td>
3371</tr>
3372</table>
3373</div>
3374<p>Concentrate on the main while loop. Once it finds out the type
3375of key pressed, it takes appropriate action. If 'r' is pressed
3376resizing mode is started. After this the new sizes are updated as
3377the user presses the arrow keys. When the user presses
3378&lt;ENTER&gt; present selection ends and panel is resized by using
3379the concept explained. While in resizing mode the program doesn't
3380show how the window is getting resized. It's left as an exercise to
3381the reader to print a dotted border while it gets resized to a new
3382position.</p>
3383<p>When the user presses 'm' the move mode starts. This is a bit
3384simpler than resizing. As the arrow keys are pressed the new
3385position is updated and pressing of &lt;ENTER&gt; causes the panel
3386to be moved by calling the function move_panel().</p>
3387<p>In this program the user data which is represented as
3388PANEL_DATA, plays very important role in finding the associated
3389information with a panel. As written in the comments, the
3390PANEL_DATA stores the panel sizes, label, label color and a pointer
3391to the next panel in the cycle.</p>
3392</div>
3393<div class="SECT2">
3394<hr>
3395<h3 class="SECT2"><a name="PANELSHOWHIDE" id="PANELSHOWHIDE">16.6.
3396Hiding and Showing Panels</a></h3>
3397<p>A Panel can be hidden by using the function hide_panel(). This
3398function merely removes it form the stack of panels, thus hiding it
3399on the screen once you do update_panels() and doupdate(). It
3400doesn't destroy the PANEL structure associated with the hidden
3401panel. It can be shown again by using the show_panel()
3402function.</p>
3403<p>The following program shows the hiding of panels. Press 'a' or
3404'b' or 'c' to show or hide first, second and third windows
3405respectively. It uses a user data with a small variable hide, which
3406keeps track of whether the window is hidden or not. For some reason
3407the function <var class="LITERAL">panel_hidden()</var> which tells
3408whether a panel is hidden or not is not working. A bug report was
3409also presented by Michael Andres <a href=
3410"http://www.geocrawler.com/archives/3/344/1999/9/0/2643549/"
3411target="_top">here</a></p>
3412<div class="EXAMPLE"><a name="PPAHI" id="PPAHI"></a>
3413<p><b>Example 17. Panel Hiding and Showing example</b></p>
3414<table border="0" bgcolor="#E0E0E0" width="100%">
3415<tr>
3416<td>
3417<pre class="PROGRAMLISTING">
3418<font color="#000000"><span class=
3419"INLINEMEDIAOBJECT">#include &lt;panel.h&gt;
4828 length = strlen(string);
4829 temp = (width - length)/ 2;
4830 x = startx + (int)temp;
4831 wattron(win, color);
4832 mvwprintw(win, y, x, "%s", string);
4833 wattroff(win, color);
4834 refresh();
4835}</SPAN
4836></PRE
4837></DIV
4838><P
4839>Concentrate on the main while loop. Once it finds out the type of key pressed,
4840it takes appropriate action. If 'r' is pressed resizing mode is started. After
4841this the new sizes are updated as the user presses the arrow keys. When the user
4842presses &lt;ENTER&gt; present selection ends and panel is resized by using the
4843concept explained. While in resizing mode the program doesn't show how the
4844window is getting resized. It's left as an exercise to the reader to print a
4845dotted border while it gets resized to a new position. </P
4846><P
4847>When the user presses 'm' the move mode starts. This is a bit simpler than
4848resizing. As the arrow keys are pressed the new position is updated and
4849pressing of &lt;ENTER&gt; causes the panel to be moved by calling the function
4850move_panel().</P
4851><P
4852>In this program the user data which is represented as PANEL_DATA, plays very
4853important role in finding the associated information with a panel. As written in
4854the comments, the PANEL_DATA stores the panel sizes, label, label color and a
4855pointer to the next panel in the cycle.</P
4856></DIV
4857><DIV
4858CLASS="SECT2"
4859><HR><H3
4860CLASS="SECT2"
4861><A
4862NAME="PANELSHOWHIDE"
4863>16.6. Hiding and Showing Panels</A
4864></H3
4865><P
4866>A Panel can be hidden by using the function hide_panel(). This function merely
4867removes it form the stack of panels, thus hiding it on the screen once you do
4868update_panels() and doupdate(). It doesn't destroy the PANEL structure
4869associated with the hidden panel. It can be shown again by using the
4870show_panel() function.</P
4871><P
4872>The following program shows the hiding of panels. Press 'a' or 'b' or 'c' to
4873show or hide first, second and third windows respectively. It uses a user data
4874with a small variable hide, which keeps track of whether the window is hidden or
4875not. For some reason the function
4876<TT
4877CLASS="LITERAL"
4878>panel_hidden()</TT
4879> which tells whether a panel is
4880hidden or not is not working. A bug report was also presented by Michael Andres
4881<A
4882HREF="http://www.geocrawler.com/archives/3/344/1999/9/0/2643549/"
4883TARGET="_top"
4884> here</A
4885></P
4886><DIV
4887CLASS="EXAMPLE"
4888><A
4889NAME="PPAHI"
4890></A
4891><P
4892><B
4893>Example 17. Panel Hiding and Showing example </B
4894></P
4895><PRE
4896CLASS="PROGRAMLISTING"
4897><SPAN
4898CLASS="INLINEMEDIAOBJECT"
4899>#include &#60;panel.h&#62;
3420
3421typedef struct _PANEL_DATA {
4900
4901typedef struct _PANEL_DATA {
3422 int hide; /* TRUE if panel is hidden */
4902 int hide; /* TRUE if panel is hidden */
3423}PANEL_DATA;
3424
3425#define NLINES 10
3426#define NCOLS 40
3427
3428void init_wins(WINDOW **wins, int n);
3429void win_show(WINDOW *win, char *label, int label_color);
3430void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
3431
3432int main()
4903}PANEL_DATA;
4904
4905#define NLINES 10
4906#define NCOLS 40
4907
4908void init_wins(WINDOW **wins, int n);
4909void win_show(WINDOW *win, char *label, int label_color);
4910void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
4911
4912int main()
3433{ WINDOW *my_wins[3];
3434 PANEL *my_panels[3];
3435 PANEL_DATA panel_datas[3];
3436 PANEL_DATA *temp;
3437 int ch;
4913{ WINDOW *my_wins[3];
4914 PANEL *my_panels[3];
4915 PANEL_DATA panel_datas[3];
4916 PANEL_DATA *temp;
4917 int ch;
3438
4918
3439 /* Initialize curses */
3440 initscr();
3441 start_color();
3442 cbreak();
3443 noecho();
3444 keypad(stdscr, TRUE);
4919 /* Initialize curses */
4920 initscr();
4921 start_color();
4922 cbreak();
4923 noecho();
4924 keypad(stdscr, TRUE);
3445
4925
3446 /* Initialize all the colors */
3447 init_pair(1, COLOR_RED, COLOR_BLACK);
3448 init_pair(2, COLOR_GREEN, COLOR_BLACK);
3449 init_pair(3, COLOR_BLUE, COLOR_BLACK);
3450 init_pair(4, COLOR_CYAN, COLOR_BLACK);
4926 /* Initialize all the colors */
4927 init_pair(1, COLOR_RED, COLOR_BLACK);
4928 init_pair(2, COLOR_GREEN, COLOR_BLACK);
4929 init_pair(3, COLOR_BLUE, COLOR_BLACK);
4930 init_pair(4, COLOR_CYAN, COLOR_BLACK);
3451
4931
3452 init_wins(my_wins, 3);
3453
3454 /* Attach a panel to each window */ /* Order is bottom up */
3455 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
3456 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
3457 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
4932 init_wins(my_wins, 3);
4933
4934 /* Attach a panel to each window */ /* Order is bottom up */
4935 my_panels[0] = new_panel(my_wins[0]); /* Push 0, order: stdscr-0 */
4936 my_panels[1] = new_panel(my_wins[1]); /* Push 1, order: stdscr-0-1 */
4937 my_panels[2] = new_panel(my_wins[2]); /* Push 2, order: stdscr-0-1-2 */
3458
4938
3459 /* Initialize panel datas saying that nothing is hidden */
3460 panel_datas[0].hide = FALSE;
3461 panel_datas[1].hide = FALSE;
3462 panel_datas[2].hide = FALSE;
4939 /* Initialize panel datas saying that nothing is hidden */
4940 panel_datas[0].hide = FALSE;
4941 panel_datas[1].hide = FALSE;
4942 panel_datas[2].hide = FALSE;
3463
4943
3464 set_panel_userptr(my_panels[0], &amp;panel_datas[0]);
3465 set_panel_userptr(my_panels[1], &amp;panel_datas[1]);
3466 set_panel_userptr(my_panels[2], &amp;panel_datas[2]);
4944 set_panel_userptr(my_panels[0], &#38;panel_datas[0]);
4945 set_panel_userptr(my_panels[1], &#38;panel_datas[1]);
4946 set_panel_userptr(my_panels[2], &#38;panel_datas[2]);
3467
4947
3468 /* Update the stacking order. 2nd panel will be on top */
3469 update_panels();
4948 /* Update the stacking order. 2nd panel will be on top */
4949 update_panels();
3470
4950
3471 /* Show it on the screen */
3472 attron(COLOR_PAIR(4));
3473 mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)");
3474 mvprintw(LINES - 2, 0, "F1 to Exit");
4951 /* Show it on the screen */
4952 attron(COLOR_PAIR(4));
4953 mvprintw(LINES - 3, 0, "Show or Hide a window with 'a'(first window) 'b'(Second Window) 'c'(Third Window)");
4954 mvprintw(LINES - 2, 0, "F1 to Exit");
3475
4955
3476 attroff(COLOR_PAIR(4));
3477 doupdate();
3478
3479 while((ch = getch()) != KEY_F(1))
3480 { switch(ch)
3481 { case 'a':
3482 temp = (PANEL_DATA *)panel_userptr(my_panels[0]);
3483 if(temp-&gt;hide == FALSE)
3484 { hide_panel(my_panels[0]);
3485 temp-&gt;hide = TRUE;
3486 }
3487 else
3488 { show_panel(my_panels[0]);
3489 temp-&gt;hide = FALSE;
3490 }
3491 break;
3492 case 'b':
3493 temp = (PANEL_DATA *)panel_userptr(my_panels[1]);
3494 if(temp-&gt;hide == FALSE)
3495 { hide_panel(my_panels[1]);
3496 temp-&gt;hide = TRUE;
3497 }
3498 else
3499 { show_panel(my_panels[1]);
3500 temp-&gt;hide = FALSE;
3501 }
3502 break;
3503 case 'c':
3504 temp = (PANEL_DATA *)panel_userptr(my_panels[2]);
3505 if(temp-&gt;hide == FALSE)
3506 { hide_panel(my_panels[2]);
3507 temp-&gt;hide = TRUE;
3508 }
3509 else
3510 { show_panel(my_panels[2]);
3511 temp-&gt;hide = FALSE;
3512 }
3513 break;
3514 }
3515 update_panels();
3516 doupdate();
3517 }
3518 endwin();
3519 return 0;
4956 attroff(COLOR_PAIR(4));
4957 doupdate();
4958
4959 while((ch = getch()) != KEY_F(1))
4960 { switch(ch)
4961 { case 'a':
4962 temp = (PANEL_DATA *)panel_userptr(my_panels[0]);
4963 if(temp-&#62;hide == FALSE)
4964 { hide_panel(my_panels[0]);
4965 temp-&#62;hide = TRUE;
4966 }
4967 else
4968 { show_panel(my_panels[0]);
4969 temp-&#62;hide = FALSE;
4970 }
4971 break;
4972 case 'b':
4973 temp = (PANEL_DATA *)panel_userptr(my_panels[1]);
4974 if(temp-&#62;hide == FALSE)
4975 { hide_panel(my_panels[1]);
4976 temp-&#62;hide = TRUE;
4977 }
4978 else
4979 { show_panel(my_panels[1]);
4980 temp-&#62;hide = FALSE;
4981 }
4982 break;
4983 case 'c':
4984 temp = (PANEL_DATA *)panel_userptr(my_panels[2]);
4985 if(temp-&#62;hide == FALSE)
4986 { hide_panel(my_panels[2]);
4987 temp-&#62;hide = TRUE;
4988 }
4989 else
4990 { show_panel(my_panels[2]);
4991 temp-&#62;hide = FALSE;
4992 }
4993 break;
4994 }
4995 update_panels();
4996 doupdate();
4997 }
4998 endwin();
4999 return 0;
3520}
3521
3522/* Put all the windows */
3523void init_wins(WINDOW **wins, int n)
5000}
5001
5002/* Put all the windows */
5003void init_wins(WINDOW **wins, int n)
3524{ int x, y, i;
3525 char label[80];
5004{ int x, y, i;
5005 char label[80];
3526
5006
3527 y = 2;
3528 x = 10;
3529 for(i = 0; i &lt; n; ++i)
3530 { wins[i] = newwin(NLINES, NCOLS, y, x);
3531 sprintf(label, "Window Number %d", i + 1);
3532 win_show(wins[i], label, i + 1);
3533 y += 3;
3534 x += 7;
3535 }
5007 y = 2;
5008 x = 10;
5009 for(i = 0; i &#60; n; ++i)
5010 { wins[i] = newwin(NLINES, NCOLS, y, x);
5011 sprintf(label, "Window Number %d", i + 1);
5012 win_show(wins[i], label, i + 1);
5013 y += 3;
5014 x += 7;
5015 }
3536}
3537
3538/* Show the window with a border and a label */
3539void win_show(WINDOW *win, char *label, int label_color)
5016}
5017
5018/* Show the window with a border and a label */
5019void win_show(WINDOW *win, char *label, int label_color)
3540{ int startx, starty, height, width;
5020{ int startx, starty, height, width;
3541
5021
3542 getbegyx(win, starty, startx);
3543 getmaxyx(win, height, width);
5022 getbegyx(win, starty, startx);
5023 getmaxyx(win, height, width);
3544
5024
3545 box(win, 0, 0);
3546 mvwaddch(win, 2, 0, ACS_LTEE);
3547 mvwhline(win, 2, 1, ACS_HLINE, width - 2);
3548 mvwaddch(win, 2, width - 1, ACS_RTEE);
3549
3550 print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
5025 box(win, 0, 0);
5026 mvwaddch(win, 2, 0, ACS_LTEE);
5027 mvwhline(win, 2, 1, ACS_HLINE, width - 2);
5028 mvwaddch(win, 2, width - 1, ACS_RTEE);
5029
5030 print_in_middle(win, 1, 0, width, label, COLOR_PAIR(label_color));
3551}
3552
3553void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
5031}
5032
5033void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
3554{ int length, x, y;
3555 float temp;
5034{ int length, x, y;
5035 float temp;
3556
5036
3557 if(win == NULL)
3558 win = stdscr;
3559 getyx(win, y, x);
3560 if(startx != 0)
3561 x = startx;
3562 if(starty != 0)
3563 y = starty;
3564 if(width == 0)
3565 width = 80;
5037 if(win == NULL)
5038 win = stdscr;
5039 getyx(win, y, x);
5040 if(startx != 0)
5041 x = startx;
5042 if(starty != 0)
5043 y = starty;
5044 if(width == 0)
5045 width = 80;
3566
5046
3567 length = strlen(string);
3568 temp = (width - length)/ 2;
3569 x = startx + (int)temp;
3570 wattron(win, color);
3571 mvwprintw(win, y, x, "%s", string);
3572 wattroff(win, color);
3573 refresh();
3574}</span></font>
3575</pre></td>
3576</tr>
3577</table>
3578</div>
3579</div>
3580<div class="SECT2">
3581<hr>
3582<h3 class="SECT2"><a name="PANELABOVE" id="PANELABOVE">16.7.
3583panel_above() and panel_below() Functions</a></h3>
3584<p>The functions <var class="LITERAL">panel_above()</var> and
3585<var class="LITERAL">panel_below()</var> can be used to find out
3586the panel above and below a panel. If the argument to these
3587functions is NULL, then they return a pointer to bottom panel and
3588top panel respectively.</p>
3589</div>
3590</div>
3591<div class="SECT1">
3592<hr>
3593<h2 class="SECT1"><a name="MENUS" id="MENUS">17. Menus
3594Library</a></h2>
3595<p>The menus library provides a nice extension to basic curses,
3596through which you can create menus. It provides a set of functions
3597to create menus. But they have to be customized to give a nicer
3598look, with colors etc. Let's get into the details.</p>
3599<p>A menu is a screen display that assists the user to choose some
3600subset of a given set of items. To put it simple, a menu is a
3601collection of items from which one or more items can be chosen.
3602Some readers might not be aware of multiple item selection
3603capability. Menu library provides functionality to write menus from
3604which the user can chose more than one item as the preferred
3605choice. This is dealt with in a later section. Now it is time for
3606some rudiments.</p>
3607<div class="SECT2">
3608<hr>
3609<h3 class="SECT2"><a name="MENUBASICS" id="MENUBASICS">17.1. The
3610Basics</a></h3>
3611<p>To create menus, you first create items, and then post the menu
3612to the display. After that, all the processing of user responses is
3613done in an elegant function menu_driver() which is the work horse
3614of any menu program.</p>
3615<p>The general flow of control of a menu program looks like
3616this.</p>
3617<ol type="1">
3618<li>
3619<p>Initialize curses</p>
3620</li>
3621<li>
3622<p>Create items using new_item(). You can specify a name and
3623description for the items.</p>
3624</li>
3625<li>
3626<p>Create the menu with new_menu() by specifying the items to be
3627attached with.</p>
3628</li>
3629<li>
3630<p>Post the menu with menu_post() and refresh the screen.</p>
3631</li>
3632<li>
3633<p>Process the user requests with a loop and do necessary updates
3634to menu with menu_driver.</p>
3635</li>
3636<li>
3637<p>Unpost the menu with menu_unpost()</p>
3638</li>
3639<li>
3640<p>Free the memory allocated to menu by free_menu()</p>
3641</li>
3642<li>
3643<p>Free the memory allocated to the items with free_item()</p>
3644</li>
3645<li>
3646<p>End curses</p>
3647</li>
3648</ol>
3649<p>Let's see a program which prints a simple menu and updates the
3650current selection with up, down arrows.</p>
3651</div>
3652<div class="SECT2">
3653<hr>
3654<h3 class="SECT2"><a name="COMPILEMENUS" id="COMPILEMENUS">17.2.
3655Compiling With the Menu Library</a></h3>
3656<p>To use menu library functions, you have to include menu.h and to
3657link the program with menu library the flag -lmenu should be added
3658along with -lncurses in that order.</p>
3659<table border="0" bgcolor="#E0E0E0" width="100%">
3660<tr>
3661<td>
3662<pre class="PROGRAMLISTING">
3663<font color="#000000"> #include &lt;menu.h&gt;
5047 length = strlen(string);
5048 temp = (width - length)/ 2;
5049 x = startx + (int)temp;
5050 wattron(win, color);
5051 mvwprintw(win, y, x, "%s", string);
5052 wattroff(win, color);
5053 refresh();
5054}</SPAN
5055></PRE
5056></DIV
5057></DIV
5058><DIV
5059CLASS="SECT2"
5060><HR><H3
5061CLASS="SECT2"
5062><A
5063NAME="PANELABOVE"
5064>16.7. panel_above() and panel_below() Functions</A
5065></H3
5066><P
5067>The functions <TT
5068CLASS="LITERAL"
5069>panel_above()</TT
5070> and
5071<TT
5072CLASS="LITERAL"
5073>panel_below()</TT
5074> can be used to find out the panel
5075above and below a panel. If the argument to these functions is NULL, then they
5076return a pointer to bottom panel and top panel respectively.</P
5077></DIV
5078></DIV
5079><DIV
5080CLASS="SECT1"
5081><HR><H2
5082CLASS="SECT1"
5083><A
5084NAME="MENUS"
5085>17. Menus Library</A
5086></H2
5087><P
5088>The menus library provides a nice extension to basic curses, through which you
5089can create menus. It provides a set of functions to create menus. But they have
5090to be customized to give a nicer look, with colors etc. Let's get into the
5091details.</P
5092><P
5093>A menu is a screen display that assists the user to choose some subset of a
5094given set of items. To put it simple, a menu is a collection of items from which
5095one or more items can be chosen. Some readers might not be aware of multiple
5096item selection capability. Menu library provides functionality to write menus
5097from which the user can chose more than one item as the preferred choice. This
5098is dealt with in a later section. Now it is time for some rudiments.</P
5099><DIV
5100CLASS="SECT2"
5101><HR><H3
5102CLASS="SECT2"
5103><A
5104NAME="MENUBASICS"
5105>17.1. The Basics</A
5106></H3
5107><P
5108>To create menus, you first create items, and then post the menu to the display.
5109After that, all the processing of user responses is done in an elegant function
5110menu_driver() which is the work horse of any menu program. </P
5111><P
5112>The general flow of control of a menu program looks like this.
5113<P
5114></P
5115><OL
5116TYPE="1"
5117><LI
5118><P
5119>Initialize curses</P
5120></LI
5121><LI
5122><P
5123>Create items using new_item(). You can specify a name and description for the
5124items.</P
5125></LI
5126><LI
5127><P
5128>Create the menu with new_menu() by specifying the items to be attached with.</P
5129></LI
5130><LI
5131><P
5132>Post the menu with menu_post() and refresh the screen.</P
5133></LI
5134><LI
5135><P
5136>Process the user requests with a loop and do necessary updates to menu with
5137menu_driver.</P
5138></LI
5139><LI
5140><P
5141>Unpost the menu with menu_unpost()</P
5142></LI
5143><LI
5144><P
5145>Free the memory allocated to menu by free_menu()</P
5146></LI
5147><LI
5148><P
5149>Free the memory allocated to the items with free_item() </P
5150></LI
5151><LI
5152><P
5153>End curses </P
5154></LI
5155></OL
5156></P
5157><P
5158>Let's see a program which prints a simple menu and updates the current selection
5159with up, down arrows. </P
5160></DIV
5161><DIV
5162CLASS="SECT2"
5163><HR><H3
5164CLASS="SECT2"
5165><A
5166NAME="COMPILEMENUS"
5167>17.2. Compiling With the Menu Library</A
5168></H3
5169><P
5170>To use menu library functions, you have to include menu.h and to link the
5171program with menu library the flag -lmenu should be added along with -lncurses
5172in that order.</P
5173><PRE
5174CLASS="PROGRAMLISTING"
5175> #include &lt;menu.h&gt;
3664 .
3665 .
3666 .
3667
5176 .
5177 .
5178 .
5179
3668 compile and link: gcc &lt;program file&gt; -lmenu -lncurses</font>
3669</pre></td>
3670</tr>
3671</table>
3672<div class="EXAMPLE"><a name="MMESI" id="MMESI"></a>
3673<p><b>Example 18. Menu Basics</b></p>
3674<table border="0" bgcolor="#E0E0E0" width="100%">
3675<tr>
3676<td>
3677<pre class="PROGRAMLISTING">
3678<font color="#000000"><span class=
3679"INLINEMEDIAOBJECT">#include &lt;curses.h&gt;
3680#include &lt;menu.h&gt;
5180 compile and link: gcc &lt;program file&gt; -lmenu -lncurses</PRE
5181><DIV
5182CLASS="EXAMPLE"
5183><A
5184NAME="MMESI"
5185></A
5186><P
5187><B
5188>Example 18. Menu Basics </B
5189></P
5190><PRE
5191CLASS="PROGRAMLISTING"
5192><SPAN
5193CLASS="INLINEMEDIAOBJECT"
5194>#include &#60;curses.h&#62;
5195#include &#60;menu.h&#62;
3681
3682#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
5196
5197#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
3683#define CTRLD 4
5198#define CTRLD 4
3684
3685char *choices[] = {
3686 "Choice 1",
3687 "Choice 2",
3688 "Choice 3",
3689 "Choice 4",
3690 "Exit",
3691 };
3692
3693int main()
5199
5200char *choices[] = {
5201 "Choice 1",
5202 "Choice 2",
5203 "Choice 3",
5204 "Choice 4",
5205 "Exit",
5206 };
5207
5208int main()
3694{ ITEM **my_items;
3695 int c;
3696 MENU *my_menu;
3697 int n_choices, i;
3698 ITEM *cur_item;
3699
3700
3701 initscr();
3702 cbreak();
3703 noecho();
3704 keypad(stdscr, TRUE);
3705
3706 n_choices = ARRAY_SIZE(choices);
3707 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
5209{ ITEM **my_items;
5210 int c;
5211 MENU *my_menu;
5212 int n_choices, i;
5213 ITEM *cur_item;
5214
5215
5216 initscr();
5217 cbreak();
5218 noecho();
5219 keypad(stdscr, TRUE);
5220
5221 n_choices = ARRAY_SIZE(choices);
5222 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
3708
5223
3709 for(i = 0; i &lt; n_choices; ++i)
3710 my_items[i] = new_item(choices[i], choices[i]);
3711 my_items[n_choices] = (ITEM *)NULL;
5224 for(i = 0; i &#60; n_choices; ++i)
5225 my_items[i] = new_item(choices[i], choices[i]);
5226 my_items[n_choices] = (ITEM *)NULL;
3712
5227
3713 my_menu = new_menu((ITEM **)my_items);
3714 mvprintw(LINES - 2, 0, "F1 to Exit");
3715 post_menu(my_menu);
3716 refresh();
5228 my_menu = new_menu((ITEM **)my_items);
5229 mvprintw(LINES - 2, 0, "F1 to Exit");
5230 post_menu(my_menu);
5231 refresh();
3717
5232
3718 while((c = getch()) != KEY_F(1))
3719 { switch(c)
3720 { case KEY_DOWN:
3721 menu_driver(my_menu, REQ_DOWN_ITEM);
3722 break;
3723 case KEY_UP:
3724 menu_driver(my_menu, REQ_UP_ITEM);
3725 break;
3726 }
3727 }
5233 while((c = getch()) != KEY_F(1))
5234 { switch(c)
5235 { case KEY_DOWN:
5236 menu_driver(my_menu, REQ_DOWN_ITEM);
5237 break;
5238 case KEY_UP:
5239 menu_driver(my_menu, REQ_UP_ITEM);
5240 break;
5241 }
5242 }
3728
5243
3729 free_item(my_items[0]);
3730 free_item(my_items[1]);
3731 free_menu(my_menu);
3732 endwin();
5244 free_item(my_items[0]);
5245 free_item(my_items[1]);
5246 free_menu(my_menu);
5247 endwin();
3733}
5248}
3734 </span></font>
3735</pre></td>
3736</tr>
3737</table>
3738</div>
3739<p>This program demonstrates the basic concepts involved in
3740creating a menu using menus library. First we create the items
3741using new_item() and then attach them to the menu with new_menu()
3742function. After posting the menu and refreshing the screen, the
3743main processing loop starts. It reads user input and takes
3744corresponding action. The function menu_driver() is the main work
3745horse of the menu system. The second parameter to this function
3746tells what's to be done with the menu. According to the parameter,
3747menu_driver() does the corresponding task. The value can be either
3748a menu navigational request, an ascii character, or a KEY_MOUSE
3749special key associated with a mouse event.</p>
3750<p>The menu_driver accepts following navigational requests.</p>
3751<table border="0" bgcolor="#E0E0E0" width="100%">
3752<tr>
3753<td>
3754<pre class="PROGRAMLISTING">
3755<font color=
3756"#000000">&#13; REQ_LEFT_ITEM Move left to an item.
5249 </SPAN
5250></PRE
5251></DIV
5252><P
5253>This program demonstrates the basic concepts involved in creating a menu using
5254menus library. First we create the items using new_item() and then attach them
5255to the menu with new_menu() function. After posting the menu and refreshing the
5256screen, the main processing loop starts. It reads user input and takes
5257corresponding action. The function menu_driver() is the main work horse of the
5258menu system. The second parameter to this function tells what's to be done with
5259the menu. According to the parameter, menu_driver() does the corresponding task.
5260The value can be either a menu navigational request, an ascii character, or a
5261KEY_MOUSE special key associated with a mouse event.</P
5262><P
5263>The menu_driver accepts following navigational requests.
5264<PRE
5265CLASS="PROGRAMLISTING"
5266>&#13; REQ_LEFT_ITEM Move left to an item.
3757 REQ_RIGHT_ITEM Move right to an item.
3758 REQ_UP_ITEM Move up to an item.
3759 REQ_DOWN_ITEM Move down to an item.
3760 REQ_SCR_ULINE Scroll up a line.
3761 REQ_SCR_DLINE Scroll down a line.
3762 REQ_SCR_DPAGE Scroll down a page.
3763 REQ_SCR_UPAGE Scroll up a page.
3764 REQ_FIRST_ITEM Move to the first item.
3765 REQ_LAST_ITEM Move to the last item.
3766 REQ_NEXT_ITEM Move to the next item.
3767 REQ_PREV_ITEM Move to the previous item.
3768 REQ_TOGGLE_ITEM Select/deselect an item.
3769 REQ_CLEAR_PATTERN Clear the menu pattern buffer.
3770 REQ_BACK_PATTERN Delete the previous character from the pattern buffer.
3771 REQ_NEXT_MATCH Move to the next item matching the pattern match.
5267 REQ_RIGHT_ITEM Move right to an item.
5268 REQ_UP_ITEM Move up to an item.
5269 REQ_DOWN_ITEM Move down to an item.
5270 REQ_SCR_ULINE Scroll up a line.
5271 REQ_SCR_DLINE Scroll down a line.
5272 REQ_SCR_DPAGE Scroll down a page.
5273 REQ_SCR_UPAGE Scroll up a page.
5274 REQ_FIRST_ITEM Move to the first item.
5275 REQ_LAST_ITEM Move to the last item.
5276 REQ_NEXT_ITEM Move to the next item.
5277 REQ_PREV_ITEM Move to the previous item.
5278 REQ_TOGGLE_ITEM Select/deselect an item.
5279 REQ_CLEAR_PATTERN Clear the menu pattern buffer.
5280 REQ_BACK_PATTERN Delete the previous character from the pattern buffer.
5281 REQ_NEXT_MATCH Move to the next item matching the pattern match.
3772 REQ_PREV_MATCH Move to the previous item matching the pattern match.&#13;</font>
3773</pre></td>
3774</tr>
3775</table>
3776<p>Don't get overwhelmed by the number of options. We will see them
3777slowly one after another. The options of interest in this example
3778are REQ_UP_ITEM and REQ_DOWN_ITEM. These two options when passed to
3779menu_driver, menu driver updates the current item to one item up or
3780down respectively.</p>
3781</div>
3782<div class="SECT2">
3783<hr>
3784<h3 class="SECT2"><a name="MENUDRIVER" id="MENUDRIVER">17.3. Menu
3785Driver: The work horse of the menu system</a></h3>
3786<p>As you have seen in the above example, menu_driver plays an
3787important role in updating the menu. It is very important to
3788understand various options it takes and what they do. As explained
3789above, the second parameter to menu_driver() can be either a
3790navigational request, a printable character or a KEY_MOUSE key.
3791Let's dissect the different navigational requests.</p>
3792<ul>
3793<li>
3794<p><em>REQ_LEFT_ITEM and REQ_RIGHT_ITEM</em></p>
3795<p>A Menu can be displayed with multiple columns for more than one
3796item. This can be done by using the <var class=
3797"LITERAL">menu_format()</var>function. When a multi columnar menu
3798is displayed these requests cause the menu driver to move the
3799current selection to left or right.</p>
3800</li>
3801<li>
3802<p><em>REQ_UP_ITEM and REQ_DOWN_ITEM</em></p>
3803<p>These two options you have seen in the above example. These
3804options when given, makes the menu_driver to move the current
3805selection to an item up or down.</p>
3806</li>
3807<li>
3808<p><em>REQ_SCR_* options</em></p>
3809<p>The four options REQ_SCR_ULINE, REQ_SCR_DLINE, REQ_SCR_DPAGE,
3810REQ_SCR_UPAGE are related to scrolling. If all the items in the
3811menu cannot be displayed in the menu sub window, then the menu is
3812scrollable. These requests can be given to the menu_driver to do
3813the scrolling either one line up, down or one page down or up
3814respectively.</p>
3815</li>
3816<li>
3817<p><em>REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and
3818REQ_PREV_ITEM</em></p>
3819<p>These requests are self explanatory.</p>
3820</li>
3821<li>
3822<p><em>REQ_TOGGLE_ITEM</em></p>
3823<p>This request when given, toggles the present selection. This
3824option is to be used only in a multi valued menu. So to use this
3825request the option O_ONEVALUE must be off. This option can be made
3826off or on with set_menu_opts().</p>
3827</li>
3828<li>
3829<p><em>Pattern Requests</em></p>
3830<p>Every menu has an associated pattern buffer, which is used to
3831find the nearest match to the ascii characters entered by the user.
3832Whenever ascii characters are given to menu_driver, it puts in to
3833the pattern buffer. It also tries to find the nearest match to the
3834pattern in the items list and moves current selection to that item.
3835The request REQ_CLEAR_PATTERN clears the pattern buffer. The
3836request REQ_BACK_PATTERN deletes the previous character in the
3837pattern buffer. In case the pattern matches more than one item then
3838the matched items can be cycled through REQ_NEXT_MATCH and
3839REQ_PREV_MATCH which move the current selection to the next and
3840previous matches respectively.</p>
3841</li>
3842<li>
3843<p><em>Mouse Requests</em></p>
3844<p>In case of KEY_MOUSE requests, according to the mouse position
3845an action is taken accordingly. The action to be taken is explained
3846in the man page as,</p>
3847<table border="0" bgcolor="#E0E0E0" width="90%">
3848<tr>
3849<td>
3850<pre class="PROGRAMLISTING">
3851<font color=
3852"#000000"><em> If the second argument is the KEY_MOUSE special key, the
5282 REQ_PREV_MATCH Move to the previous item matching the pattern match.&#13;</PRE
5283></P
5284><P
5285>Don't get overwhelmed by the number of options. We will see them slowly one
5286after another. The options of interest in this example are REQ_UP_ITEM and
5287REQ_DOWN_ITEM. These two options when passed to menu_driver, menu driver
5288updates the current item to one item up or down respectively.</P
5289></DIV
5290><DIV
5291CLASS="SECT2"
5292><HR><H3
5293CLASS="SECT2"
5294><A
5295NAME="MENUDRIVER"
5296>17.3. Menu Driver: The work horse of the menu system</A
5297></H3
5298><P
5299>As you have seen in the above example, menu_driver plays an important role in
5300updating the menu. It is very important to understand various options it takes
5301and what they do. As explained above, the second parameter to menu_driver() can
5302be either a navigational request, a printable character or a KEY_MOUSE key.
5303Let's dissect the different navigational requests.</P
5304><P
5305></P
5306><UL
5307><LI
5308><P
5309><SPAN
5310CLASS="emphasis"
5311><I
5312CLASS="EMPHASIS"
5313>REQ_LEFT_ITEM and REQ_RIGHT_ITEM</I
5314></SPAN
5315></P
5316><P
5317>A Menu can be displayed with multiple columns for more than one item. This can
5318be done by using the <TT
5319CLASS="LITERAL"
5320>menu_format()</TT
5321>function.
5322When a multi columnar menu is displayed these requests cause the menu driver to
5323move the current selection to left or right.</P
5324></LI
5325><LI
5326><P
5327><SPAN
5328CLASS="emphasis"
5329><I
5330CLASS="EMPHASIS"
5331>REQ_UP_ITEM and REQ_DOWN_ITEM </I
5332></SPAN
5333> </P
5334><P
5335>These two options you have seen in the above example. These options when given,
5336makes the menu_driver to move the current selection to an item up or down.</P
5337></LI
5338><LI
5339><P
5340> <SPAN
5341CLASS="emphasis"
5342><I
5343CLASS="EMPHASIS"
5344>REQ_SCR_* options</I
5345></SPAN
5346> </P
5347><P
5348>The four options REQ_SCR_ULINE, REQ_SCR_DLINE, REQ_SCR_DPAGE, REQ_SCR_UPAGE are
5349related to scrolling. If all the items in the menu cannot be displayed in the
5350menu sub window, then the menu is scrollable. These requests can be given to the
5351menu_driver to do the scrolling either one line up, down or one page down or up
5352respectively. </P
5353></LI
5354><LI
5355><P
5356><SPAN
5357CLASS="emphasis"
5358><I
5359CLASS="EMPHASIS"
5360>REQ_FIRST_ITEM, REQ_LAST_ITEM, REQ_NEXT_ITEM and
5361REQ_PREV_ITEM </I
5362></SPAN
5363> </P
5364><P
5365>These requests are self explanatory.</P
5366></LI
5367><LI
5368><P
5369> <SPAN
5370CLASS="emphasis"
5371><I
5372CLASS="EMPHASIS"
5373>REQ_TOGGLE_ITEM</I
5374></SPAN
5375> </P
5376><P
5377>This request when given, toggles the present selection. This option is to be
5378used only in a multi valued menu. So to use this request the option O_ONEVALUE
5379must be off. This option can be made off or on with set_menu_opts().</P
5380></LI
5381><LI
5382><P
5383> <SPAN
5384CLASS="emphasis"
5385><I
5386CLASS="EMPHASIS"
5387>Pattern Requests </I
5388></SPAN
5389></P
5390><P
5391>Every menu has an associated pattern buffer, which is used to find the nearest
5392match to the ascii characters entered by the user. Whenever ascii characters are
5393given to menu_driver, it puts in to the pattern buffer. It also tries to find
5394the nearest match to the pattern in the items list and moves current selection
5395to that item. The request REQ_CLEAR_PATTERN clears the pattern buffer. The
5396request REQ_BACK_PATTERN deletes the previous character in the pattern buffer.
5397In case the pattern matches more than one item then the matched items can be
5398cycled through REQ_NEXT_MATCH and REQ_PREV_MATCH which move the current
5399selection to the next and previous matches respectively.</P
5400></LI
5401><LI
5402><P
5403> <SPAN
5404CLASS="emphasis"
5405><I
5406CLASS="EMPHASIS"
5407>Mouse Requests</I
5408></SPAN
5409></P
5410><P
5411>In case of KEY_MOUSE requests, according to the mouse position an action is
5412taken accordingly. The action to be taken is explained in the man page as, </P
5413><PRE
5414CLASS="PROGRAMLISTING"
5415><SPAN
5416CLASS="emphasis"
5417><I
5418CLASS="EMPHASIS"
5419> If the second argument is the KEY_MOUSE special key, the
3853 associated mouse event is translated into one of the above
3854 pre-defined requests. Currently only clicks in the user
3855 window (e.g. inside the menu display area or the decora&shy;
3856 tion window) are handled. If you click above the display
3857 region of the menu, a REQ_SCR_ULINE is generated, if you
3858 doubleclick a REQ_SCR_UPAGE is generated and if you
3859 tripleclick a REQ_FIRST_ITEM is generated. If you click
3860 below the display region of the menu, a REQ_SCR_DLINE is
3861 generated, if you doubleclick a REQ_SCR_DPAGE is generated
3862 and if you tripleclick a REQ_LAST_ITEM is generated. If
3863 you click at an item inside the display area of the menu,
5420 associated mouse event is translated into one of the above
5421 pre-defined requests. Currently only clicks in the user
5422 window (e.g. inside the menu display area or the decora&shy;
5423 tion window) are handled. If you click above the display
5424 region of the menu, a REQ_SCR_ULINE is generated, if you
5425 doubleclick a REQ_SCR_UPAGE is generated and if you
5426 tripleclick a REQ_FIRST_ITEM is generated. If you click
5427 below the display region of the menu, a REQ_SCR_DLINE is
5428 generated, if you doubleclick a REQ_SCR_DPAGE is generated
5429 and if you tripleclick a REQ_LAST_ITEM is generated. If
5430 you click at an item inside the display area of the menu,
3864 the menu cursor is positioned to that item.</em></font>
3865</pre></td>
3866</tr>
3867</table>
3868</li>
3869</ul>
3870<p>Each of the above requests will be explained in the following
3871lines with several examples whenever appropriate.</p>
3872</div>
3873<div class="SECT2">
3874<hr>
3875<h3 class="SECT2"><a name="MENUWINDOWS" id="MENUWINDOWS">17.4. Menu
3876Windows</a></h3>
3877<p>Every menu created is associated with a window and a sub window.
3878The menu window displays any title or border associated with the
3879menu. The menu sub window displays the menu items currently
3880available for selection. But we didn't specify any window or sub
3881window in the simple example. When a window is not specified,
3882stdscr is taken as the main window, and then menu system calculates
3883the sub window size required for the display of items. Then items
3884are displayed in the calculated sub window. So let's play with
3885these windows and display a menu with a border and a title.</p>
3886<div class="EXAMPLE"><a name="MMEWI" id="MMEWI"></a>
3887<p><b>Example 19. Menu Windows Usage example</b></p>
3888<table border="0" bgcolor="#E0E0E0" width="100%">
3889<tr>
3890<td>
3891<pre class="PROGRAMLISTING">
3892<font color="#000000"><span class=
3893"INLINEMEDIAOBJECT">#include &lt;menu.h&gt;
5431 the menu cursor is positioned to that item.</I
5432></SPAN
5433></PRE
5434></LI
5435></UL
5436><P
5437>Each of the above requests will be explained in the following lines with several
5438examples whenever appropriate.</P
5439></DIV
5440><DIV
5441CLASS="SECT2"
5442><HR><H3
5443CLASS="SECT2"
5444><A
5445NAME="MENUWINDOWS"
5446>17.4. Menu Windows</A
5447></H3
5448><P
5449>Every menu created is associated with a window and a sub window. The menu window
5450displays any title or border associated with the menu. The menu sub window
5451displays the menu items currently available for selection. But we didn't specify
5452any window or sub window in the simple example. When a window is not specified,
5453stdscr is taken as the main window, and then menu system calculates the sub
5454window size required for the display of items. Then items are displayed in the
5455calculated sub window. So let's play with these windows and display a menu with
5456a border and a title.</P
5457><DIV
5458CLASS="EXAMPLE"
5459><A
5460NAME="MMEWI"
5461></A
5462><P
5463><B
5464>Example 19. Menu Windows Usage example </B
5465></P
5466><PRE
5467CLASS="PROGRAMLISTING"
5468><SPAN
5469CLASS="INLINEMEDIAOBJECT"
5470>#include &#60;menu.h&#62;
3894
3895#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
5471
5472#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
3896#define CTRLD 4
5473#define CTRLD 4
3897
3898char *choices[] = {
3899 "Choice 1",
3900 "Choice 2",
3901 "Choice 3",
3902 "Choice 4",
3903 "Exit",
3904 (char *)NULL,
3905 };
3906void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
3907
3908int main()
5474
5475char *choices[] = {
5476 "Choice 1",
5477 "Choice 2",
5478 "Choice 3",
5479 "Choice 4",
5480 "Exit",
5481 (char *)NULL,
5482 };
5483void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
5484
5485int main()
3909{ ITEM **my_items;
3910 int c;
3911 MENU *my_menu;
5486{ ITEM **my_items;
5487 int c;
5488 MENU *my_menu;
3912 WINDOW *my_menu_win;
3913 int n_choices, i;
5489 WINDOW *my_menu_win;
5490 int n_choices, i;
3914
3915 /* Initialize curses */
3916 initscr();
3917 start_color();
5491
5492 /* Initialize curses */
5493 initscr();
5494 start_color();
3918 cbreak();
3919 noecho();
5495 cbreak();
5496 noecho();
3920 keypad(stdscr, TRUE);
3921 init_pair(1, COLOR_RED, COLOR_BLACK);
5497 keypad(stdscr, TRUE);
5498 init_pair(1, COLOR_RED, COLOR_BLACK);
3922
5499
3923 /* Create items */
5500 /* Create items */
3924 n_choices = ARRAY_SIZE(choices);
3925 my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
5501 n_choices = ARRAY_SIZE(choices);
5502 my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
3926 for(i = 0; i &lt; n_choices; ++i)
5503 for(i = 0; i &#60; n_choices; ++i)
3927 my_items[i] = new_item(choices[i], choices[i]);
3928
5504 my_items[i] = new_item(choices[i], choices[i]);
5505
3929 /* Crate menu */
3930 my_menu = new_menu((ITEM **)my_items);
5506 /* Crate menu */
5507 my_menu = new_menu((ITEM **)my_items);
3931
5508
3932 /* Create the window to be associated with the menu */
5509 /* Create the window to be associated with the menu */
3933 my_menu_win = newwin(10, 40, 4, 4);
3934 keypad(my_menu_win, TRUE);
3935
5510 my_menu_win = newwin(10, 40, 4, 4);
5511 keypad(my_menu_win, TRUE);
5512
3936 /* Set main window and sub window */
5513 /* Set main window and sub window */
3937 set_menu_win(my_menu, my_menu_win);
3938 set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
3939
5514 set_menu_win(my_menu, my_menu_win);
5515 set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
5516
3940 /* Set menu mark to the string " * " */
5517 /* Set menu mark to the string " * " */
3941 set_menu_mark(my_menu, " * ");
3942
5518 set_menu_mark(my_menu, " * ");
5519
3943 /* Print a border around the main window and print a title */
5520 /* Print a border around the main window and print a title */
3944 box(my_menu_win, 0, 0);
5521 box(my_menu_win, 0, 0);
3945 print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
3946 mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
3947 mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
3948 mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
3949 mvprintw(LINES - 2, 0, "F1 to exit");
3950 refresh();
5522 print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
5523 mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
5524 mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
5525 mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
5526 mvprintw(LINES - 2, 0, "F1 to exit");
5527 refresh();
3951
5528
3952 /* Post the menu */
3953 post_menu(my_menu);
3954 wrefresh(my_menu_win);
5529 /* Post the menu */
5530 post_menu(my_menu);
5531 wrefresh(my_menu_win);
3955
5532
3956 while((c = wgetch(my_menu_win)) != KEY_F(1))
3957 { switch(c)
3958 { case KEY_DOWN:
3959 menu_driver(my_menu, REQ_DOWN_ITEM);
3960 break;
3961 case KEY_UP:
3962 menu_driver(my_menu, REQ_UP_ITEM);
3963 break;
3964 }
5533 while((c = wgetch(my_menu_win)) != KEY_F(1))
5534 { switch(c)
5535 { case KEY_DOWN:
5536 menu_driver(my_menu, REQ_DOWN_ITEM);
5537 break;
5538 case KEY_UP:
5539 menu_driver(my_menu, REQ_UP_ITEM);
5540 break;
5541 }
3965 wrefresh(my_menu_win);
5542 wrefresh(my_menu_win);
3966 }
5543 }
3967
5544
3968 /* Unpost and free all the memory taken up */
5545 /* Unpost and free all the memory taken up */
3969 unpost_menu(my_menu);
3970 free_menu(my_menu);
5546 unpost_menu(my_menu);
5547 free_menu(my_menu);
3971 for(i = 0; i &lt; n_choices; ++i)
5548 for(i = 0; i &#60; n_choices; ++i)
3972 free_item(my_items[i]);
5549 free_item(my_items[i]);
3973 endwin();
5550 endwin();
3974}
3975
3976void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
5551}
5552
5553void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
3977{ int length, x, y;
3978 float temp;
5554{ int length, x, y;
5555 float temp;
3979
5556
3980 if(win == NULL)
3981 win = stdscr;
3982 getyx(win, y, x);
3983 if(startx != 0)
3984 x = startx;
3985 if(starty != 0)
3986 y = starty;
3987 if(width == 0)
3988 width = 80;
5557 if(win == NULL)
5558 win = stdscr;
5559 getyx(win, y, x);
5560 if(startx != 0)
5561 x = startx;
5562 if(starty != 0)
5563 y = starty;
5564 if(width == 0)
5565 width = 80;
3989
5566
3990 length = strlen(string);
3991 temp = (width - length)/ 2;
3992 x = startx + (int)temp;
3993 wattron(win, color);
3994 mvwprintw(win, y, x, "%s", string);
3995 wattroff(win, color);
3996 refresh();
3997}</span></font>
3998</pre></td>
3999</tr>
4000</table>
4001</div>
4002<p>This example creates a menu with a title, border, a fancy line
4003separating title and the items. As you can see, in order to attach
4004a window to a menu the function set_menu_win() has to be used. Then
4005we attach the sub window also. This displays the items in the sub
4006window. You can also set the mark string which gets displayed to
4007the left of the selected item with set_menu_mark().</p>
4008</div>
4009<div class="SECT2">
4010<hr>
4011<h3 class="SECT2"><a name="SCROLLMENUS" id="SCROLLMENUS">17.5.
4012Scrolling Menus</a></h3>
4013<p>If the sub window given for a window is not big enough to show
4014all the items, then the menu will be scrollable. When you are on
4015the last item in the present list, if you send REQ_DOWN_ITEM, it
4016gets translated into REQ_SCR_DLINE and the menu scrolls by one
4017item. You can manually give REQ_SCR_ operations to do scrolling.
4018Let's see how it can be done.</p>
4019<div class="EXAMPLE"><a name="MMESC" id="MMESC"></a>
4020<p><b>Example 20. Scrolling Menus example</b></p>
4021<table border="0" bgcolor="#E0E0E0" width="100%">
4022<tr>
4023<td>
4024<pre class="PROGRAMLISTING">
4025<font color="#000000"><span class=
4026"INLINEMEDIAOBJECT">#include &lt;curses.h&gt;
4027#include &lt;menu.h&gt;
5567 length = strlen(string);
5568 temp = (width - length)/ 2;
5569 x = startx + (int)temp;
5570 wattron(win, color);
5571 mvwprintw(win, y, x, "%s", string);
5572 wattroff(win, color);
5573 refresh();
5574}</SPAN
5575></PRE
5576></DIV
5577><P
5578>This example creates a menu with a title, border, a fancy line separating title
5579and the items. As you can see, in order to attach a window to a menu the
5580function set_menu_win() has to be used. Then we attach the sub window also. This
5581displays the items in the sub window. You can also set the mark string which
5582gets displayed to the left of the selected item with set_menu_mark().</P
5583></DIV
5584><DIV
5585CLASS="SECT2"
5586><HR><H3
5587CLASS="SECT2"
5588><A
5589NAME="SCROLLMENUS"
5590>17.5. Scrolling Menus</A
5591></H3
5592><P
5593>If the sub window given for a window is not big enough to show all the items,
5594then the menu will be scrollable. When you are on the last item in the present
5595list, if you send REQ_DOWN_ITEM, it gets translated into REQ_SCR_DLINE and the
5596menu scrolls by one item. You can manually give REQ_SCR_ operations to do
5597scrolling. Let's see how it can be done.</P
5598><DIV
5599CLASS="EXAMPLE"
5600><A
5601NAME="MMESC"
5602></A
5603><P
5604><B
5605>Example 20. Scrolling Menus example </B
5606></P
5607><PRE
5608CLASS="PROGRAMLISTING"
5609><SPAN
5610CLASS="INLINEMEDIAOBJECT"
5611>#include &#60;curses.h&#62;
5612#include &#60;menu.h&#62;
4028
4029#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
5613
5614#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
4030#define CTRLD 4
5615#define CTRLD 4
4031
4032char *choices[] = {
4033 "Choice 1",
4034 "Choice 2",
4035 "Choice 3",
4036 "Choice 4",
5616
5617char *choices[] = {
5618 "Choice 1",
5619 "Choice 2",
5620 "Choice 3",
5621 "Choice 4",
4037 "Choice 5",
4038 "Choice 6",
4039 "Choice 7",
4040 "Choice 8",
4041 "Choice 9",
4042 "Choice 10",
5622 "Choice 5",
5623 "Choice 6",
5624 "Choice 7",
5625 "Choice 8",
5626 "Choice 9",
5627 "Choice 10",
4043 "Exit",
4044 (char *)NULL,
4045 };
4046void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
4047
4048int main()
5628 "Exit",
5629 (char *)NULL,
5630 };
5631void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
5632
5633int main()
4049{ ITEM **my_items;
4050 int c;
4051 MENU *my_menu;
5634{ ITEM **my_items;
5635 int c;
5636 MENU *my_menu;
4052 WINDOW *my_menu_win;
4053 int n_choices, i;
5637 WINDOW *my_menu_win;
5638 int n_choices, i;
4054
4055 /* Initialize curses */
4056 initscr();
4057 start_color();
5639
5640 /* Initialize curses */
5641 initscr();
5642 start_color();
4058 cbreak();
4059 noecho();
5643 cbreak();
5644 noecho();
4060 keypad(stdscr, TRUE);
4061 init_pair(1, COLOR_RED, COLOR_BLACK);
4062 init_pair(2, COLOR_CYAN, COLOR_BLACK);
5645 keypad(stdscr, TRUE);
5646 init_pair(1, COLOR_RED, COLOR_BLACK);
5647 init_pair(2, COLOR_CYAN, COLOR_BLACK);
4063
5648
4064 /* Create items */
5649 /* Create items */
4065 n_choices = ARRAY_SIZE(choices);
4066 my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
5650 n_choices = ARRAY_SIZE(choices);
5651 my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
4067 for(i = 0; i &lt; n_choices; ++i)
5652 for(i = 0; i &#60; n_choices; ++i)
4068 my_items[i] = new_item(choices[i], choices[i]);
4069
5653 my_items[i] = new_item(choices[i], choices[i]);
5654
4070 /* Crate menu */
4071 my_menu = new_menu((ITEM **)my_items);
5655 /* Crate menu */
5656 my_menu = new_menu((ITEM **)my_items);
4072
5657
4073 /* Create the window to be associated with the menu */
5658 /* Create the window to be associated with the menu */
4074 my_menu_win = newwin(10, 40, 4, 4);
4075 keypad(my_menu_win, TRUE);
4076
5659 my_menu_win = newwin(10, 40, 4, 4);
5660 keypad(my_menu_win, TRUE);
5661
4077 /* Set main window and sub window */
5662 /* Set main window and sub window */
4078 set_menu_win(my_menu, my_menu_win);
4079 set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
5663 set_menu_win(my_menu, my_menu_win);
5664 set_menu_sub(my_menu, derwin(my_menu_win, 6, 38, 3, 1));
4080 set_menu_format(my_menu, 5, 1);
4081
4082 /* Set menu mark to the string " * " */
5665 set_menu_format(my_menu, 5, 1);
5666
5667 /* Set menu mark to the string " * " */
4083 set_menu_mark(my_menu, " * ");
4084
5668 set_menu_mark(my_menu, " * ");
5669
4085 /* Print a border around the main window and print a title */
5670 /* Print a border around the main window and print a title */
4086 box(my_menu_win, 0, 0);
5671 box(my_menu_win, 0, 0);
4087 print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
4088 mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
4089 mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
4090 mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
5672 print_in_middle(my_menu_win, 1, 0, 40, "My Menu", COLOR_PAIR(1));
5673 mvwaddch(my_menu_win, 2, 0, ACS_LTEE);
5674 mvwhline(my_menu_win, 2, 1, ACS_HLINE, 38);
5675 mvwaddch(my_menu_win, 2, 39, ACS_RTEE);
4091
5676
4092 /* Post the menu */
4093 post_menu(my_menu);
4094 wrefresh(my_menu_win);
4095
4096 attron(COLOR_PAIR(2));
4097 mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items");
4098 mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)");
4099 attroff(COLOR_PAIR(2));
4100 refresh();
5677 /* Post the menu */
5678 post_menu(my_menu);
5679 wrefresh(my_menu_win);
5680
5681 attron(COLOR_PAIR(2));
5682 mvprintw(LINES - 2, 0, "Use PageUp and PageDown to scoll down or up a page of items");
5683 mvprintw(LINES - 1, 0, "Arrow Keys to navigate (F1 to Exit)");
5684 attroff(COLOR_PAIR(2));
5685 refresh();
4101
5686
4102 while((c = wgetch(my_menu_win)) != KEY_F(1))
4103 { switch(c)
4104 { case KEY_DOWN:
4105 menu_driver(my_menu, REQ_DOWN_ITEM);
4106 break;
4107 case KEY_UP:
4108 menu_driver(my_menu, REQ_UP_ITEM);
4109 break;
4110 case KEY_NPAGE:
4111 menu_driver(my_menu, REQ_SCR_DPAGE);
4112 break;
4113 case KEY_PPAGE:
4114 menu_driver(my_menu, REQ_SCR_UPAGE);
4115 break;
4116 }
5687 while((c = wgetch(my_menu_win)) != KEY_F(1))
5688 { switch(c)
5689 { case KEY_DOWN:
5690 menu_driver(my_menu, REQ_DOWN_ITEM);
5691 break;
5692 case KEY_UP:
5693 menu_driver(my_menu, REQ_UP_ITEM);
5694 break;
5695 case KEY_NPAGE:
5696 menu_driver(my_menu, REQ_SCR_DPAGE);
5697 break;
5698 case KEY_PPAGE:
5699 menu_driver(my_menu, REQ_SCR_UPAGE);
5700 break;
5701 }
4117 wrefresh(my_menu_win);
5702 wrefresh(my_menu_win);
4118 }
5703 }
4119
5704
4120 /* Unpost and free all the memory taken up */
5705 /* Unpost and free all the memory taken up */
4121 unpost_menu(my_menu);
4122 free_menu(my_menu);
5706 unpost_menu(my_menu);
5707 free_menu(my_menu);
4123 for(i = 0; i &lt; n_choices; ++i)
5708 for(i = 0; i &#60; n_choices; ++i)
4124 free_item(my_items[i]);
5709 free_item(my_items[i]);
4125 endwin();
5710 endwin();
4126}
4127
4128void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
5711}
5712
5713void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
4129{ int length, x, y;
4130 float temp;
5714{ int length, x, y;
5715 float temp;
4131
5716
4132 if(win == NULL)
4133 win = stdscr;
4134 getyx(win, y, x);
4135 if(startx != 0)
4136 x = startx;
4137 if(starty != 0)
4138 y = starty;
4139 if(width == 0)
4140 width = 80;
5717 if(win == NULL)
5718 win = stdscr;
5719 getyx(win, y, x);
5720 if(startx != 0)
5721 x = startx;
5722 if(starty != 0)
5723 y = starty;
5724 if(width == 0)
5725 width = 80;
4141
5726
4142 length = strlen(string);
4143 temp = (width - length)/ 2;
4144 x = startx + (int)temp;
4145 wattron(win, color);
4146 mvwprintw(win, y, x, "%s", string);
4147 wattroff(win, color);
4148 refresh();
4149}</span></font>
4150</pre></td>
4151</tr>
4152</table>
4153</div>
4154<p>This program is self-explanatory. In this example the number of
4155choices has been increased to ten, which is larger than our sub
4156window size which can hold 6 items. This message has to be
4157explicitly conveyed to the menu system with the function
4158set_menu_format(). In here we specify the number of rows and
4159columns we want to be displayed for a single page. We can specify
4160any number of items to be shown, in the rows variables, if it is
4161less than the height of the sub window. If the key pressed by the
4162user is a PAGE UP or PAGE DOWN, the menu is scrolled a page due to
4163the requests (REQ_SCR_DPAGE and REQ_SCR_UPAGE) given to
4164menu_driver().</p>
4165</div>
4166<div class="SECT2">
4167<hr>
4168<h3 class="SECT2"><a name="MULTICOLUMN" id="MULTICOLUMN">17.6.
4169Multi Columnar Menus</a></h3>
4170<p>In the above example you have seen how to use the function
4171set_menu_format(). I didn't mention what the cols variable (third
4172parameter) does. Well, If your sub window is wide enough, you can
4173opt to display more than one item per row. This can be specified in
4174the cols variable. To make things simpler, the following example
4175doesn't show descriptions for the items.</p>
4176<div class="EXAMPLE"><a name="MMEMUCO" id="MMEMUCO"></a>
4177<p><b>Example 21. Milt Columnar Menus Example</b></p>
4178<table border="0" bgcolor="#E0E0E0" width="100%">
4179<tr>
4180<td>
4181<pre class="PROGRAMLISTING">
4182<font color="#000000"><span class=
4183"INLINEMEDIAOBJECT">#include &lt;curses.h&gt;
4184#include &lt;menu.h&gt;
5727 length = strlen(string);
5728 temp = (width - length)/ 2;
5729 x = startx + (int)temp;
5730 wattron(win, color);
5731 mvwprintw(win, y, x, "%s", string);
5732 wattroff(win, color);
5733 refresh();
5734}</SPAN
5735></PRE
5736></DIV
5737><P
5738>This program is self-explanatory. In this example the number of choices has been
5739increased to ten, which is larger than our sub window size which can hold 6
5740items. This message has to be explicitly conveyed to the menu system with the
5741function set_menu_format(). In here we specify the number of rows and columns we
5742want to be displayed for a single page. We can specify any number of items to be
5743shown, in the rows variables, if it is less than the height of the sub window.
5744If the key pressed by the user is a PAGE UP or PAGE DOWN, the menu is scrolled a
5745page due to the requests (REQ_SCR_DPAGE and REQ_SCR_UPAGE) given to
5746menu_driver().</P
5747></DIV
5748><DIV
5749CLASS="SECT2"
5750><HR><H3
5751CLASS="SECT2"
5752><A
5753NAME="MULTICOLUMN"
5754>17.6. Multi Columnar Menus</A
5755></H3
5756><P
5757>In the above example you have seen how to use the function set_menu_format(). I
5758didn't mention what the cols variable (third parameter) does. Well, If your sub
5759window is wide enough, you can opt to display more than one item per row. This
5760can be specified in the cols variable. To make things simpler, the following
5761example doesn't show descriptions for the items.</P
5762><DIV
5763CLASS="EXAMPLE"
5764><A
5765NAME="MMEMUCO"
5766></A
5767><P
5768><B
5769>Example 21. Milt Columnar Menus Example </B
5770></P
5771><PRE
5772CLASS="PROGRAMLISTING"
5773><SPAN
5774CLASS="INLINEMEDIAOBJECT"
5775>#include &#60;curses.h&#62;
5776#include &#60;menu.h&#62;
4185
4186#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
5777
5778#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
4187#define CTRLD 4
5779#define CTRLD 4
4188
4189char *choices[] = {
4190 "Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5",
5780
5781char *choices[] = {
5782 "Choice 1", "Choice 2", "Choice 3", "Choice 4", "Choice 5",
4191 "Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10",
4192 "Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15",
4193 "Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20",
5783 "Choice 6", "Choice 7", "Choice 8", "Choice 9", "Choice 10",
5784 "Choice 11", "Choice 12", "Choice 13", "Choice 14", "Choice 15",
5785 "Choice 16", "Choice 17", "Choice 18", "Choice 19", "Choice 20",
4194 "Exit",
4195 (char *)NULL,
4196 };
4197
4198int main()
5786 "Exit",
5787 (char *)NULL,
5788 };
5789
5790int main()
4199{ ITEM **my_items;
4200 int c;
4201 MENU *my_menu;
5791{ ITEM **my_items;
5792 int c;
5793 MENU *my_menu;
4202 WINDOW *my_menu_win;
4203 int n_choices, i;
5794 WINDOW *my_menu_win;
5795 int n_choices, i;
4204
4205 /* Initialize curses */
4206 initscr();
4207 start_color();
5796
5797 /* Initialize curses */
5798 initscr();
5799 start_color();
4208 cbreak();
4209 noecho();
5800 cbreak();
5801 noecho();
4210 keypad(stdscr, TRUE);
4211 init_pair(1, COLOR_RED, COLOR_BLACK);
4212 init_pair(2, COLOR_CYAN, COLOR_BLACK);
5802 keypad(stdscr, TRUE);
5803 init_pair(1, COLOR_RED, COLOR_BLACK);
5804 init_pair(2, COLOR_CYAN, COLOR_BLACK);
4213
5805
4214 /* Create items */
5806 /* Create items */
4215 n_choices = ARRAY_SIZE(choices);
4216 my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
5807 n_choices = ARRAY_SIZE(choices);
5808 my_items = (ITEM **)calloc(n_choices, sizeof(ITEM *));
4217 for(i = 0; i &lt; n_choices; ++i)
5809 for(i = 0; i &#60; n_choices; ++i)
4218 my_items[i] = new_item(choices[i], choices[i]);
4219
5810 my_items[i] = new_item(choices[i], choices[i]);
5811
4220 /* Crate menu */
4221 my_menu = new_menu((ITEM **)my_items);
5812 /* Crate menu */
5813 my_menu = new_menu((ITEM **)my_items);
4222
5814
4223 /* Set menu option not to show the description */
4224 menu_opts_off(my_menu, O_SHOWDESC);
5815 /* Set menu option not to show the description */
5816 menu_opts_off(my_menu, O_SHOWDESC);
4225
5817
4226 /* Create the window to be associated with the menu */
5818 /* Create the window to be associated with the menu */
4227 my_menu_win = newwin(10, 70, 4, 4);
4228 keypad(my_menu_win, TRUE);
4229
5819 my_menu_win = newwin(10, 70, 4, 4);
5820 keypad(my_menu_win, TRUE);
5821
4230 /* Set main window and sub window */
5822 /* Set main window and sub window */
4231 set_menu_win(my_menu, my_menu_win);
4232 set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1));
5823 set_menu_win(my_menu, my_menu_win);
5824 set_menu_sub(my_menu, derwin(my_menu_win, 6, 68, 3, 1));
4233 set_menu_format(my_menu, 5, 3);
4234 set_menu_mark(my_menu, " * ");
5825 set_menu_format(my_menu, 5, 3);
5826 set_menu_mark(my_menu, " * ");
4235
5827
4236 /* Print a border around the main window and print a title */
5828 /* Print a border around the main window and print a title */
4237 box(my_menu_win, 0, 0);
5829 box(my_menu_win, 0, 0);
4238
4239 attron(COLOR_PAIR(2));
4240 mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll");
4241 mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)");
4242 attroff(COLOR_PAIR(2));
4243 refresh();
5830
5831 attron(COLOR_PAIR(2));
5832 mvprintw(LINES - 3, 0, "Use PageUp and PageDown to scroll");
5833 mvprintw(LINES - 2, 0, "Use Arrow Keys to navigate (F1 to Exit)");
5834 attroff(COLOR_PAIR(2));
5835 refresh();
4244
5836
4245 /* Post the menu */
4246 post_menu(my_menu);
4247 wrefresh(my_menu_win);
4248
4249 while((c = wgetch(my_menu_win)) != KEY_F(1))
4250 { switch(c)
4251 { case KEY_DOWN:
4252 menu_driver(my_menu, REQ_DOWN_ITEM);
4253 break;
4254 case KEY_UP:
4255 menu_driver(my_menu, REQ_UP_ITEM);
4256 break;
4257 case KEY_LEFT:
4258 menu_driver(my_menu, REQ_LEFT_ITEM);
4259 break;
4260 case KEY_RIGHT:
4261 menu_driver(my_menu, REQ_RIGHT_ITEM);
4262 break;
4263 case KEY_NPAGE:
4264 menu_driver(my_menu, REQ_SCR_DPAGE);
4265 break;
4266 case KEY_PPAGE:
4267 menu_driver(my_menu, REQ_SCR_UPAGE);
4268 break;
4269 }
5837 /* Post the menu */
5838 post_menu(my_menu);
5839 wrefresh(my_menu_win);
5840
5841 while((c = wgetch(my_menu_win)) != KEY_F(1))
5842 { switch(c)
5843 { case KEY_DOWN:
5844 menu_driver(my_menu, REQ_DOWN_ITEM);
5845 break;
5846 case KEY_UP:
5847 menu_driver(my_menu, REQ_UP_ITEM);
5848 break;
5849 case KEY_LEFT:
5850 menu_driver(my_menu, REQ_LEFT_ITEM);
5851 break;
5852 case KEY_RIGHT:
5853 menu_driver(my_menu, REQ_RIGHT_ITEM);
5854 break;
5855 case KEY_NPAGE:
5856 menu_driver(my_menu, REQ_SCR_DPAGE);
5857 break;
5858 case KEY_PPAGE:
5859 menu_driver(my_menu, REQ_SCR_UPAGE);
5860 break;
5861 }
4270 wrefresh(my_menu_win);
5862 wrefresh(my_menu_win);
4271 }
5863 }
4272
5864
4273 /* Unpost and free all the memory taken up */
5865 /* Unpost and free all the memory taken up */
4274 unpost_menu(my_menu);
4275 free_menu(my_menu);
5866 unpost_menu(my_menu);
5867 free_menu(my_menu);
4276 for(i = 0; i &lt; n_choices; ++i)
5868 for(i = 0; i &#60; n_choices; ++i)
4277 free_item(my_items[i]);
5869 free_item(my_items[i]);
4278 endwin();
4279}</span></font>
4280</pre></td>
4281</tr>
4282</table>
4283</div>
4284<p>Watch the function call to set_menu_format(). It specifies the
4285number of columns to be 3, thus displaying 3 items per row. We have
4286also switched off the showing descriptions with the function
4287menu_opts_off(). There are couple of functions set_menu_opts(),
4288menu_opts_on() and menu_opts() which can be used to manipulate menu
4289options. The following menu options can be specified.</p>
4290<table border="0" bgcolor="#E0E0E0" width="100%">
4291<tr>
4292<td>
4293<pre class="PROGRAMLISTING">
4294<font color="#000000"> O_ONEVALUE
5870 endwin();
5871}</SPAN
5872></PRE
5873></DIV
5874><P
5875>Watch the function call to set_menu_format(). It specifies the number of columns
5876to be 3, thus displaying 3 items per row. We have also switched off the showing
5877descriptions with the function menu_opts_off(). There are couple of functions
5878set_menu_opts(), menu_opts_on() and menu_opts() which can be used to manipulate
5879menu options. The following menu options can be specified.</P
5880><PRE
5881CLASS="PROGRAMLISTING"
5882> O_ONEVALUE
4295 Only one item can be selected for this menu.
4296
4297 O_SHOWDESC
4298 Display the item descriptions when the menu is
4299 posted.
4300
4301 O_ROWMAJOR
4302 Display the menu in row-major order.
4303
4304 O_IGNORECASE
4305 Ignore the case when pattern-matching.
4306
4307 O_SHOWMATCH
4308 Move the cursor to within the item name while pat&shy;
4309 tern-matching.
4310
4311 O_NONCYCLIC
4312 Don't wrap around next-item and previous-item,
5883 Only one item can be selected for this menu.
5884
5885 O_SHOWDESC
5886 Display the item descriptions when the menu is
5887 posted.
5888
5889 O_ROWMAJOR
5890 Display the menu in row-major order.
5891
5892 O_IGNORECASE
5893 Ignore the case when pattern-matching.
5894
5895 O_SHOWMATCH
5896 Move the cursor to within the item name while pat&shy;
5897 tern-matching.
5898
5899 O_NONCYCLIC
5900 Don't wrap around next-item and previous-item,
4313 requests to the other end of the menu.</font>
4314</pre></td>
4315</tr>
4316</table>
4317<p>All options are on by default. You can switch specific
4318attributes on or off with menu_opts_on() and menu_opts_off()
4319functions. You can also use set_menu_opts() to directly specify the
4320options. The argument to this function should be a OR ed value of
4321some of those above constants. The function menu_opts() can be used
4322to find out a menu's present options.</p>
4323</div>
4324<div class="SECT2">
4325<hr>
4326<h3 class="SECT2"><a name="MULTIVALUEMENUS" id=
4327"MULTIVALUEMENUS">17.7. Multi Valued Menus</a></h3>
4328<p>You might be wondering what if you switch off the option
4329O_ONEVALUE. Then the menu becomes multi-valued. That means you can
4330select more than one item. This brings us to the request
4331REQ_TOGGLE_ITEM. Let's see it in action.</p>
4332<div class="EXAMPLE"><a name="MMETO" id="MMETO"></a>
4333<p><b>Example 22. Multi Valued Menus example</b></p>
4334<table border="0" bgcolor="#E0E0E0" width="100%">
4335<tr>
4336<td>
4337<pre class="PROGRAMLISTING">
4338<font color="#000000"><span class=
4339"INLINEMEDIAOBJECT">#include &lt;curses.h&gt;
4340#include &lt;menu.h&gt;
5901 requests to the other end of the menu.</PRE
5902><P
5903>All options are on by default. You can switch specific attributes on or off with
5904menu_opts_on() and menu_opts_off() functions. You can also use set_menu_opts()
5905to directly specify the options. The argument to this function should be a OR ed
5906value of some of those above constants. The function menu_opts() can be used to
5907find out a menu's present options. </P
5908></DIV
5909><DIV
5910CLASS="SECT2"
5911><HR><H3
5912CLASS="SECT2"
5913><A
5914NAME="MULTIVALUEMENUS"
5915>17.7. Multi Valued Menus</A
5916></H3
5917><P
5918>You might be wondering what if you switch off the option O_ONEVALUE. Then the
5919menu becomes multi-valued. That means you can select more than one item. This
5920brings us to the request REQ_TOGGLE_ITEM. Let's see it in action.</P
5921><DIV
5922CLASS="EXAMPLE"
5923><A
5924NAME="MMETO"
5925></A
5926><P
5927><B
5928>Example 22. Multi Valued Menus example </B
5929></P
5930><PRE
5931CLASS="PROGRAMLISTING"
5932><SPAN
5933CLASS="INLINEMEDIAOBJECT"
5934>#include &#60;curses.h&#62;
5935#include &#60;menu.h&#62;
4341
4342#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
5936
5937#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
4343#define CTRLD 4
5938#define CTRLD 4
4344
4345char *choices[] = {
4346 "Choice 1",
4347 "Choice 2",
4348 "Choice 3",
4349 "Choice 4",
5939
5940char *choices[] = {
5941 "Choice 1",
5942 "Choice 2",
5943 "Choice 3",
5944 "Choice 4",
4350 "Choice 5",
4351 "Choice 6",
4352 "Choice 7",
5945 "Choice 5",
5946 "Choice 6",
5947 "Choice 7",
4353 "Exit",
4354 };
4355
4356int main()
5948 "Exit",
5949 };
5950
5951int main()
4357{ ITEM **my_items;
4358 int c;
4359 MENU *my_menu;
5952{ ITEM **my_items;
5953 int c;
5954 MENU *my_menu;
4360 int n_choices, i;
5955 int n_choices, i;
4361 ITEM *cur_item;
4362
4363 /* Initialize curses */
4364 initscr();
5956 ITEM *cur_item;
5957
5958 /* Initialize curses */
5959 initscr();
4365 cbreak();
4366 noecho();
5960 cbreak();
5961 noecho();
4367 keypad(stdscr, TRUE);
5962 keypad(stdscr, TRUE);
4368
5963
4369 /* Initialize items */
5964 /* Initialize items */
4370 n_choices = ARRAY_SIZE(choices);
4371 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
5965 n_choices = ARRAY_SIZE(choices);
5966 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
4372 for(i = 0; i &lt; n_choices; ++i)
5967 for(i = 0; i &#60; n_choices; ++i)
4373 my_items[i] = new_item(choices[i], choices[i]);
5968 my_items[i] = new_item(choices[i], choices[i]);
4374 my_items[n_choices] = (ITEM *)NULL;
5969 my_items[n_choices] = (ITEM *)NULL;
4375
5970
4376 my_menu = new_menu((ITEM **)my_items);
5971 my_menu = new_menu((ITEM **)my_items);
4377
5972
4378 /* Make the menu multi valued */
4379 menu_opts_off(my_menu, O_ONEVALUE);
5973 /* Make the menu multi valued */
5974 menu_opts_off(my_menu, O_ONEVALUE);
4380
5975
4381 mvprintw(LINES - 3, 0, "Use &lt;SPACE&gt; to select or unselect an item.");
4382 mvprintw(LINES - 2, 0, "&lt;ENTER&gt; to see presently selected items(F1 to Exit)");
4383 post_menu(my_menu);
4384 refresh();
5976 mvprintw(LINES - 3, 0, "Use &#60;SPACE&#62; to select or unselect an item.");
5977 mvprintw(LINES - 2, 0, "&#60;ENTER&#62; to see presently selected items(F1 to Exit)");
5978 post_menu(my_menu);
5979 refresh();
4385
5980
4386 while((c = getch()) != KEY_F(1))
4387 { switch(c)
4388 { case KEY_DOWN:
4389 menu_driver(my_menu, REQ_DOWN_ITEM);
4390 break;
4391 case KEY_UP:
4392 menu_driver(my_menu, REQ_UP_ITEM);
4393 break;
4394 case ' ':
4395 menu_driver(my_menu, REQ_TOGGLE_ITEM);
4396 break;
4397 case 10: /* Enter */
4398 { char temp[200];
4399 ITEM **items;
5981 while((c = getch()) != KEY_F(1))
5982 { switch(c)
5983 { case KEY_DOWN:
5984 menu_driver(my_menu, REQ_DOWN_ITEM);
5985 break;
5986 case KEY_UP:
5987 menu_driver(my_menu, REQ_UP_ITEM);
5988 break;
5989 case ' ':
5990 menu_driver(my_menu, REQ_TOGGLE_ITEM);
5991 break;
5992 case 10: /* Enter */
5993 { char temp[200];
5994 ITEM **items;
4400
5995
4401 items = menu_items(my_menu);
4402 temp[0] = '\0';
4403 for(i = 0; i &lt; item_count(my_menu); ++i)
4404 if(item_value(items[i]) == TRUE)
4405 { strcat(temp, item_name(items[i]));
4406 strcat(temp, " ");
4407 }
4408 move(20, 0);
4409 clrtoeol();
4410 mvprintw(20, 0, temp);
4411 refresh();
4412 }
4413 break;
4414 }
4415 }
5996 items = menu_items(my_menu);
5997 temp[0] = '\0';
5998 for(i = 0; i &#60; item_count(my_menu); ++i)
5999 if(item_value(items[i]) == TRUE)
6000 { strcat(temp, item_name(items[i]));
6001 strcat(temp, " ");
6002 }
6003 move(20, 0);
6004 clrtoeol();
6005 mvprintw(20, 0, temp);
6006 refresh();
6007 }
6008 break;
6009 }
6010 }
4416
6011
4417 free_item(my_items[0]);
6012 free_item(my_items[0]);
4418 free_item(my_items[1]);
6013 free_item(my_items[1]);
4419 free_menu(my_menu);
4420 endwin();
6014 free_menu(my_menu);
6015 endwin();
4421}
6016}
4422 </span></font>
4423</pre></td>
4424</tr>
4425</table>
4426</div>
4427<p>Whew, A lot of new functions. Let's take them one after another.
4428Firstly, the REQ_TOGGLE_ITEM. In a multi-valued menu, the user
4429should be allowed to select or un select more than one item. The
4430request REQ_TOGGLE_ITEM toggles the present selection. In this case
4431when space is pressed REQ_TOGGLE_ITEM request is sent to
4432menu_driver to achieve the result.</p>
4433<p>Now when the user presses &lt;ENTER&gt; we show the items he
4434presently selected. First we find out the items associated with the
4435menu using the function menu_items(). Then we loop through the
4436items to find out if the item is selected or not. The function
4437item_value() returns TRUE if an item is selected. The function
4438item_count() returns the number of items in the menu. The item name
4439can be found with item_name(). You can also find the description
4440associated with an item using item_description().</p>
4441</div>
4442<div class="SECT2">
4443<hr>
4444<h3 class="SECT2"><a name="MENUOPT" id="MENUOPT">17.8. Menu
4445Options</a></h3>
4446<p>Well, by this time you must be itching for some difference in
4447your menu, with lots of functionality. I know. You want Colors !!!.
4448You want to create nice menus similar to those text mode <a href=
4449"http://www.jersey.net/~debinjoe/games/" target="_top">dos
4450games</a>. The functions set_menu_fore() and set_menu_back() can be
4451used to change the attribute of the selected item and unselected
4452item. The names are misleading. They don't change menu's foreground
4453or background which would have been useless.</p>
4454<p>The function set_menu_grey() can be used to set the display
4455attribute for the non-selectable items in the menu. This brings us
4456to the interesting option for an item the one and only
4457O_SELECTABLE. We can turn it off by the function item_opts_off()
4458and after that that item is not selectable. It's like a grayed item
4459in those fancy windows menus. Let's put these concepts in practice
4460with this example</p>
4461<div class="EXAMPLE"><a name="MMEAT" id="MMEAT"></a>
4462<p><b>Example 23. Menu Options example</b></p>
4463<table border="0" bgcolor="#E0E0E0" width="100%">
4464<tr>
4465<td>
4466<pre class="PROGRAMLISTING">
4467<font color="#000000"><span class=
4468"INLINEMEDIAOBJECT">#include &lt;menu.h&gt;
6017 </SPAN
6018></PRE
6019></DIV
6020><P
6021>Whew, A lot of new functions. Let's take them one after another. Firstly, the
6022REQ_TOGGLE_ITEM. In a multi-valued menu, the user should be allowed to select
6023or un select more than one item. The request REQ_TOGGLE_ITEM toggles the present
6024selection. In this case when space is pressed REQ_TOGGLE_ITEM request is sent to
6025menu_driver to achieve the result.</P
6026><P
6027>Now when the user presses &lt;ENTER&gt; we show the items he presently selected.
6028First we find out the items associated with the menu using the function
6029menu_items(). Then we loop through the items to find out if the item is selected
6030or not. The function item_value() returns TRUE if an item is selected. The
6031function item_count() returns the number of items in the menu. The item name can
6032be found with item_name(). You can also find the description associated with an
6033item using item_description().</P
6034></DIV
6035><DIV
6036CLASS="SECT2"
6037><HR><H3
6038CLASS="SECT2"
6039><A
6040NAME="MENUOPT"
6041>17.8. Menu Options</A
6042></H3
6043><P
6044>Well, by this time you must be itching for some difference in your menu, with
6045lots of functionality. I know. You want Colors !!!. You want to create nice
6046menus similar to those text mode <A
6047HREF="http://www.jersey.net/~debinjoe/games/"
6048TARGET="_top"
6049>dos games</A
6050>. The functions
6051set_menu_fore() and set_menu_back() can be used to change the attribute of the
6052selected item and unselected item. The names are misleading. They don't change
6053menu's foreground or background which would have been useless. </P
6054><P
6055>The function set_menu_grey() can be used to set the display attribute for the
6056non-selectable items in the menu. This brings us to the interesting option for
6057an item the one and only O_SELECTABLE. We can turn it off by the function
6058item_opts_off() and after that that item is not selectable. It's like a grayed
6059item in those fancy windows menus. Let's put these concepts in practice with
6060this example</P
6061><DIV
6062CLASS="EXAMPLE"
6063><A
6064NAME="MMEAT"
6065></A
6066><P
6067><B
6068>Example 23. Menu Options example </B
6069></P
6070><PRE
6071CLASS="PROGRAMLISTING"
6072><SPAN
6073CLASS="INLINEMEDIAOBJECT"
6074>#include &#60;menu.h&#62;
4469
4470#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
6075
6076#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
4471#define CTRLD 4
6077#define CTRLD 4
4472
4473char *choices[] = {
4474 "Choice 1",
4475 "Choice 2",
4476 "Choice 3",
4477 "Choice 4",
6078
6079char *choices[] = {
6080 "Choice 1",
6081 "Choice 2",
6082 "Choice 3",
6083 "Choice 4",
4478 "Choice 5",
4479 "Choice 6",
4480 "Choice 7",
6084 "Choice 5",
6085 "Choice 6",
6086 "Choice 7",
4481 "Exit",
4482 };
4483
4484int main()
6087 "Exit",
6088 };
6089
6090int main()
4485{ ITEM **my_items;
4486 int c;
4487 MENU *my_menu;
6091{ ITEM **my_items;
6092 int c;
6093 MENU *my_menu;
4488 int n_choices, i;
6094 int n_choices, i;
4489 ITEM *cur_item;
4490
4491 /* Initialize curses */
4492 initscr();
4493 start_color();
6095 ITEM *cur_item;
6096
6097 /* Initialize curses */
6098 initscr();
6099 start_color();
4494 cbreak();
4495 noecho();
6100 cbreak();
6101 noecho();
4496 keypad(stdscr, TRUE);
4497 init_pair(1, COLOR_RED, COLOR_BLACK);
4498 init_pair(2, COLOR_GREEN, COLOR_BLACK);
4499 init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
6102 keypad(stdscr, TRUE);
6103 init_pair(1, COLOR_RED, COLOR_BLACK);
6104 init_pair(2, COLOR_GREEN, COLOR_BLACK);
6105 init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
4500
6106
4501 /* Initialize items */
6107 /* Initialize items */
4502 n_choices = ARRAY_SIZE(choices);
4503 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
6108 n_choices = ARRAY_SIZE(choices);
6109 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
4504 for(i = 0; i &lt; n_choices; ++i)
6110 for(i = 0; i &#60; n_choices; ++i)
4505 my_items[i] = new_item(choices[i], choices[i]);
6111 my_items[i] = new_item(choices[i], choices[i]);
4506 my_items[n_choices] = (ITEM *)NULL;
4507 item_opts_off(my_items[3], O_SELECTABLE);
4508 item_opts_off(my_items[6], O_SELECTABLE);
6112 my_items[n_choices] = (ITEM *)NULL;
6113 item_opts_off(my_items[3], O_SELECTABLE);
6114 item_opts_off(my_items[6], O_SELECTABLE);
4509
6115
4510 /* Create menu */
4511 my_menu = new_menu((ITEM **)my_items);
6116 /* Create menu */
6117 my_menu = new_menu((ITEM **)my_items);
4512
6118
4513 /* Set fore ground and back ground of the menu */
4514 set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE);
4515 set_menu_back(my_menu, COLOR_PAIR(2));
4516 set_menu_grey(my_menu, COLOR_PAIR(3));
6119 /* Set fore ground and back ground of the menu */
6120 set_menu_fore(my_menu, COLOR_PAIR(1) | A_REVERSE);
6121 set_menu_back(my_menu, COLOR_PAIR(2));
6122 set_menu_grey(my_menu, COLOR_PAIR(3));
4517
6123
4518 /* Post the menu */
4519 mvprintw(LINES - 3, 0, "Press &lt;ENTER&gt; to see the option selected");
4520 mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
4521 post_menu(my_menu);
4522 refresh();
6124 /* Post the menu */
6125 mvprintw(LINES - 3, 0, "Press &#60;ENTER&#62; to see the option selected");
6126 mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
6127 post_menu(my_menu);
6128 refresh();
4523
6129
4524 while((c = getch()) != KEY_F(1))
4525 { switch(c)
4526 { case KEY_DOWN:
4527 menu_driver(my_menu, REQ_DOWN_ITEM);
4528 break;
4529 case KEY_UP:
4530 menu_driver(my_menu, REQ_UP_ITEM);
4531 break;
4532 case 10: /* Enter */
4533 move(20, 0);
4534 clrtoeol();
4535 mvprintw(20, 0, "Item selected is : %s",
4536 item_name(current_item(my_menu)));
4537 pos_menu_cursor(my_menu);
4538 break;
4539 }
4540 }
4541 unpost_menu(my_menu);
4542 for(i = 0; i &lt; n_choices; ++i)
4543 free_item(my_items[i]);
4544 free_menu(my_menu);
4545 endwin();
6130 while((c = getch()) != KEY_F(1))
6131 { switch(c)
6132 { case KEY_DOWN:
6133 menu_driver(my_menu, REQ_DOWN_ITEM);
6134 break;
6135 case KEY_UP:
6136 menu_driver(my_menu, REQ_UP_ITEM);
6137 break;
6138 case 10: /* Enter */
6139 move(20, 0);
6140 clrtoeol();
6141 mvprintw(20, 0, "Item selected is : %s",
6142 item_name(current_item(my_menu)));
6143 pos_menu_cursor(my_menu);
6144 break;
6145 }
6146 }
6147 unpost_menu(my_menu);
6148 for(i = 0; i &#60; n_choices; ++i)
6149 free_item(my_items[i]);
6150 free_menu(my_menu);
6151 endwin();
4546}
6152}
4547 </span></font>
4548</pre></td>
4549</tr>
4550</table>
4551</div>
4552</div>
4553<div class="SECT2">
4554<hr>
4555<h3 class="SECT2"><a name="MENUUSERPTR" id="MENUUSERPTR">17.9. The
4556useful User Pointer</a></h3>
4557<p>We can associate a user pointer with each item in the menu. It
4558works the same way as user pointer in panels. It's not touched by
4559menu system. You can store any thing you like in that. I usually
4560use it to store the function to be executed when the menu option is
4561chosen (It's selected and may be the user pressed
4562&lt;ENTER&gt;);</p>
4563<div class="EXAMPLE"><a name="MMEUS" id="MMEUS"></a>
4564<p><b>Example 24. Menu User Pointer Usage</b></p>
4565<table border="0" bgcolor="#E0E0E0" width="100%">
4566<tr>
4567<td>
4568<pre class="PROGRAMLISTING">
4569<font color="#000000"><span class=
4570"INLINEMEDIAOBJECT">#include &lt;curses.h&gt;
4571#include &lt;menu.h&gt;
6153 </SPAN
6154></PRE
6155></DIV
6156></DIV
6157><DIV
6158CLASS="SECT2"
6159><HR><H3
6160CLASS="SECT2"
6161><A
6162NAME="MENUUSERPTR"
6163>17.9. The useful User Pointer</A
6164></H3
6165><P
6166>We can associate a user pointer with each item in the menu. It works the same
6167way as user pointer in panels. It's not touched by menu system. You can store
6168any thing you like in that. I usually use it to store the function to be
6169executed when the menu option is chosen (It's selected and may be the user
6170pressed &lt;ENTER&gt;);</P
6171><DIV
6172CLASS="EXAMPLE"
6173><A
6174NAME="MMEUS"
6175></A
6176><P
6177><B
6178>Example 24. Menu User Pointer Usage </B
6179></P
6180><PRE
6181CLASS="PROGRAMLISTING"
6182><SPAN
6183CLASS="INLINEMEDIAOBJECT"
6184>#include &#60;curses.h&#62;
6185#include &#60;menu.h&#62;
4572
4573#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
6186
6187#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
4574#define CTRLD 4
6188#define CTRLD 4
4575
4576char *choices[] = {
4577 "Choice 1",
4578 "Choice 2",
4579 "Choice 3",
4580 "Choice 4",
6189
6190char *choices[] = {
6191 "Choice 1",
6192 "Choice 2",
6193 "Choice 3",
6194 "Choice 4",
4581 "Choice 5",
4582 "Choice 6",
4583 "Choice 7",
6195 "Choice 5",
6196 "Choice 6",
6197 "Choice 7",
4584 "Exit",
4585 };
4586void func(char *name);
4587
4588int main()
6198 "Exit",
6199 };
6200void func(char *name);
6201
6202int main()
4589{ ITEM **my_items;
4590 int c;
4591 MENU *my_menu;
6203{ ITEM **my_items;
6204 int c;
6205 MENU *my_menu;
4592 int n_choices, i;
6206 int n_choices, i;
4593 ITEM *cur_item;
4594
4595 /* Initialize curses */
4596 initscr();
4597 start_color();
6207 ITEM *cur_item;
6208
6209 /* Initialize curses */
6210 initscr();
6211 start_color();
4598 cbreak();
4599 noecho();
6212 cbreak();
6213 noecho();
4600 keypad(stdscr, TRUE);
4601 init_pair(1, COLOR_RED, COLOR_BLACK);
4602 init_pair(2, COLOR_GREEN, COLOR_BLACK);
4603 init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
6214 keypad(stdscr, TRUE);
6215 init_pair(1, COLOR_RED, COLOR_BLACK);
6216 init_pair(2, COLOR_GREEN, COLOR_BLACK);
6217 init_pair(3, COLOR_MAGENTA, COLOR_BLACK);
4604
6218
4605 /* Initialize items */
6219 /* Initialize items */
4606 n_choices = ARRAY_SIZE(choices);
4607 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
6220 n_choices = ARRAY_SIZE(choices);
6221 my_items = (ITEM **)calloc(n_choices + 1, sizeof(ITEM *));
4608 for(i = 0; i &lt; n_choices; ++i)
4609 { my_items[i] = new_item(choices[i], choices[i]);
4610 /* Set the user pointer */
4611 set_item_userptr(my_items[i], func);
4612 }
4613 my_items[n_choices] = (ITEM *)NULL;
6222 for(i = 0; i &#60; n_choices; ++i)
6223 { my_items[i] = new_item(choices[i], choices[i]);
6224 /* Set the user pointer */
6225 set_item_userptr(my_items[i], func);
6226 }
6227 my_items[n_choices] = (ITEM *)NULL;
4614
6228
4615 /* Create menu */
4616 my_menu = new_menu((ITEM **)my_items);
6229 /* Create menu */
6230 my_menu = new_menu((ITEM **)my_items);
4617
6231
4618 /* Post the menu */
4619 mvprintw(LINES - 3, 0, "Press &lt;ENTER&gt; to see the option selected");
4620 mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
4621 post_menu(my_menu);
4622 refresh();
6232 /* Post the menu */
6233 mvprintw(LINES - 3, 0, "Press &#60;ENTER&#62; to see the option selected");
6234 mvprintw(LINES - 2, 0, "Up and Down arrow keys to naviage (F1 to Exit)");
6235 post_menu(my_menu);
6236 refresh();
4623
6237
4624 while((c = getch()) != KEY_F(1))
4625 { switch(c)
4626 { case KEY_DOWN:
4627 menu_driver(my_menu, REQ_DOWN_ITEM);
4628 break;
4629 case KEY_UP:
4630 menu_driver(my_menu, REQ_UP_ITEM);
4631 break;
4632 case 10: /* Enter */
4633 { ITEM *cur;
4634 void (*p)(char *);
6238 while((c = getch()) != KEY_F(1))
6239 { switch(c)
6240 { case KEY_DOWN:
6241 menu_driver(my_menu, REQ_DOWN_ITEM);
6242 break;
6243 case KEY_UP:
6244 menu_driver(my_menu, REQ_UP_ITEM);
6245 break;
6246 case 10: /* Enter */
6247 { ITEM *cur;
6248 void (*p)(char *);
4635
6249
4636 cur = current_item(my_menu);
4637 p = item_userptr(cur);
4638 p((char *)item_name(cur));
4639 pos_menu_cursor(my_menu);
4640 break;
4641 }
4642 break;
4643 }
4644 }
4645 unpost_menu(my_menu);
4646 for(i = 0; i &lt; n_choices; ++i)
4647 free_item(my_items[i]);
4648 free_menu(my_menu);
4649 endwin();
6250 cur = current_item(my_menu);
6251 p = item_userptr(cur);
6252 p((char *)item_name(cur));
6253 pos_menu_cursor(my_menu);
6254 break;
6255 }
6256 break;
6257 }
6258 }
6259 unpost_menu(my_menu);
6260 for(i = 0; i &#60; n_choices; ++i)
6261 free_item(my_items[i]);
6262 free_menu(my_menu);
6263 endwin();
4650}
4651
4652void func(char *name)
6264}
6265
6266void func(char *name)
4653{ move(20, 0);
4654 clrtoeol();
4655 mvprintw(20, 0, "Item selected is : %s", name);
4656} </span></font>
4657</pre></td>
4658</tr>
4659</table>
4660</div>
4661</div>
4662</div>
4663<div class="SECT1">
4664<hr>
4665<h2 class="SECT1"><a name="FORMS" id="FORMS">18. Forms
4666Library</a></h2>
4667<p>Well. If you have seen those forms on web pages which take input
4668from users and do various kinds of things, you might be wondering
4669how would any one create such forms in text mode display. It's
4670quite difficult to write those nifty forms in plain ncurses. Forms
4671library tries to provide a basic frame work to build and maintain
4672forms with ease. It has lot of features(functions) which manage
4673validation, dynamic expansion of fields etc.. Let's see it in full
4674flow.</p>
4675<p>A form is a collection of fields; each field can be either a
4676label(static text) or a data-entry location. The forms also library
4677provides functions to divide forms into multiple pages.</p>
4678<div class="SECT2">
4679<hr>
4680<h3 class="SECT2"><a name="FORMBASICS" id="FORMBASICS">18.1. The
4681Basics</a></h3>
4682<p>Forms are created in much the same way as menus. First the
4683fields related to the form are created with new_field(). You can
4684set options for the fields, so that they can be displayed with some
4685fancy attributes, validated before the field looses focus etc..
4686Then the fields are attached to form. After this, the form can be
4687posted to display and is ready to receive inputs. On the similar
4688lines to menu_driver(), the form is manipulated with form_driver().
4689We can send requests to form_driver to move focus to a certain
4690field, move cursor to end of the field etc.. After the user enters
4691values in the fields and validation done, form can be unposted and
4692memory allocated can be freed.</p>
4693<p>The general flow of control of a forms program looks like
4694this.</p>
4695<ol type="1">
4696<li>
4697<p>Initialize curses</p>
4698</li>
4699<li>
4700<p>Create fields using new_field(). You can specify the height and
4701width of the field, and its position on the form.</p>
4702</li>
4703<li>
4704<p>Create the forms with new_form() by specifying the fields to be
4705attached with.</p>
4706</li>
4707<li>
4708<p>Post the form with form_post() and refresh the screen.</p>
4709</li>
4710<li>
4711<p>Process the user requests with a loop and do necessary updates
4712to form with form_driver.</p>
4713</li>
4714<li>
4715<p>Unpost the menu with form_unpost()</p>
4716</li>
4717<li>
4718<p>Free the memory allocated to menu by free_form()</p>
4719</li>
4720<li>
4721<p>Free the memory allocated to the items with free_field()</p>
4722</li>
4723<li>
4724<p>End curses</p>
4725</li>
4726</ol>
4727<p>As you can see, working with forms library is much similar to
4728handling menu library. The following examples will explore various
4729aspects of form processing. Let's start the journey with a simple
4730example. first.</p>
4731</div>
4732<div class="SECT2">
4733<hr>
4734<h3 class="SECT2"><a name="COMPILEFORMS" id="COMPILEFORMS">18.2.
4735Compiling With the Forms Library</a></h3>
4736<p>To use forms library functions, you have to include form.h and
4737to link the program with forms library the flag -lform should be
4738added along with -lncurses in that order.</p>
4739<table border="0" bgcolor="#E0E0E0" width="100%">
4740<tr>
4741<td>
4742<pre class="PROGRAMLISTING">
4743<font color="#000000"> #include &lt;form.h&gt;
6267{ move(20, 0);
6268 clrtoeol();
6269 mvprintw(20, 0, "Item selected is : %s", name);
6270} </SPAN
6271></PRE
6272></DIV
6273></DIV
6274></DIV
6275><DIV
6276CLASS="SECT1"
6277><HR><H2
6278CLASS="SECT1"
6279><A
6280NAME="FORMS"
6281>18. Forms Library</A
6282></H2
6283><P
6284>Well. If you have seen those forms on web pages which take input from users and
6285do various kinds of things, you might be wondering how would any one create such
6286forms in text mode display. It's quite difficult to write those nifty forms in
6287plain ncurses. Forms library tries to provide a basic frame work to build and
6288maintain forms with ease. It has lot of features(functions) which manage
6289validation, dynamic expansion of fields etc.. Let's see it in full flow.</P
6290><P
6291>A form is a collection of fields; each field can be either a label(static text)
6292or a data-entry location. The forms also library provides functions to divide
6293forms into multiple pages. </P
6294><DIV
6295CLASS="SECT2"
6296><HR><H3
6297CLASS="SECT2"
6298><A
6299NAME="FORMBASICS"
6300>18.1. The Basics</A
6301></H3
6302><P
6303>Forms are created in much the same way as menus. First the fields related to the
6304form are created with new_field(). You can set options for the fields, so that
6305they can be displayed with some fancy attributes, validated before the field
6306looses focus etc.. Then the fields are attached to form. After this, the form
6307can be posted to display and is ready to receive inputs. On the similar lines to
6308menu_driver(), the form is manipulated with form_driver(). We can send requests
6309to form_driver to move focus to a certain field, move cursor to end of the field
6310etc.. After the user enters values in the fields and validation done, form can
6311be unposted and memory allocated can be freed.</P
6312><P
6313>The general flow of control of a forms program looks like this.
6314
6315<P
6316></P
6317><OL
6318TYPE="1"
6319><LI
6320><P
6321>Initialize curses</P
6322></LI
6323><LI
6324><P
6325>Create fields using new_field(). You can specify the height and
6326width of the field, and its position on the form.</P
6327></LI
6328><LI
6329><P
6330>Create the forms with new_form() by specifying the fields to be
6331attached with.</P
6332></LI
6333><LI
6334><P
6335>Post the form with form_post() and refresh the screen.</P
6336></LI
6337><LI
6338><P
6339>Process the user requests with a loop and do necessary updates
6340to form with form_driver.</P
6341></LI
6342><LI
6343><P
6344>Unpost the menu with form_unpost()</P
6345></LI
6346><LI
6347><P
6348>Free the memory allocated to menu by free_form()</P
6349></LI
6350><LI
6351><P
6352>Free the memory allocated to the items with free_field()</P
6353></LI
6354><LI
6355><P
6356>End curses</P
6357></LI
6358></OL
6359></P
6360><P
6361>As you can see, working with forms library is much similar to handling menu
6362library. The following examples will explore various aspects of form
6363processing. Let's start the journey with a simple example. first.</P
6364></DIV
6365><DIV
6366CLASS="SECT2"
6367><HR><H3
6368CLASS="SECT2"
6369><A
6370NAME="COMPILEFORMS"
6371>18.2. Compiling With the Forms Library</A
6372></H3
6373><P
6374>To use forms library functions, you have to include form.h and to link the
6375program with forms library the flag -lform should be added along with -lncurses
6376in that order.</P
6377><PRE
6378CLASS="PROGRAMLISTING"
6379> #include &lt;form.h&gt;
4744 .
4745 .
4746 .
4747
6380 .
6381 .
6382 .
6383
4748 compile and link: gcc &lt;program file&gt; -lform -lncurses</font>
4749</pre></td>
4750</tr>
4751</table>
4752<div class="EXAMPLE"><a name="FFOSI" id="FFOSI"></a>
4753<p><b>Example 25. Forms Basics</b></p>
4754<table border="0" bgcolor="#E0E0E0" width="100%">
4755<tr>
4756<td>
4757<pre class="PROGRAMLISTING">
4758<font color="#000000"><span class=
4759"INLINEMEDIAOBJECT">#include &lt;form.h&gt;
6384 compile and link: gcc &lt;program file&gt; -lform -lncurses</PRE
6385><DIV
6386CLASS="EXAMPLE"
6387><A
6388NAME="FFOSI"
6389></A
6390><P
6391><B
6392>Example 25. Forms Basics </B
6393></P
6394><PRE
6395CLASS="PROGRAMLISTING"
6396><SPAN
6397CLASS="INLINEMEDIAOBJECT"
6398>#include &#60;form.h&#62;
4760
4761int main()
6399
6400int main()
4762{ FIELD *field[3];
4763 FORM *my_form;
4764 int ch;
4765
4766 /* Initialize curses */
4767 initscr();
4768 cbreak();
4769 noecho();
4770 keypad(stdscr, TRUE);
6401{ FIELD *field[3];
6402 FORM *my_form;
6403 int ch;
6404
6405 /* Initialize curses */
6406 initscr();
6407 cbreak();
6408 noecho();
6409 keypad(stdscr, TRUE);
4771
6410
4772 /* Initialize the fields */
4773 field[0] = new_field(1, 10, 4, 18, 0, 0);
4774 field[1] = new_field(1, 10, 6, 18, 0, 0);
4775 field[2] = NULL;
6411 /* Initialize the fields */
6412 field[0] = new_field(1, 10, 4, 18, 0, 0);
6413 field[1] = new_field(1, 10, 6, 18, 0, 0);
6414 field[2] = NULL;
4776
6415
4777 /* Set field options */
4778 set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */
4779 field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
4780 /* Field is filled up */
4781 set_field_back(field[1], A_UNDERLINE);
4782 field_opts_off(field[1], O_AUTOSKIP);
6416 /* Set field options */
6417 set_field_back(field[0], A_UNDERLINE); /* Print a line for the option */
6418 field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
6419 /* Field is filled up */
6420 set_field_back(field[1], A_UNDERLINE);
6421 field_opts_off(field[1], O_AUTOSKIP);
4783
6422
4784 /* Create the form and post it */
4785 my_form = new_form(field);
4786 post_form(my_form);
4787 refresh();
4788
4789 mvprintw(4, 10, "Value 1:");
4790 mvprintw(6, 10, "Value 2:");
4791 refresh();
6423 /* Create the form and post it */
6424 my_form = new_form(field);
6425 post_form(my_form);
6426 refresh();
6427
6428 mvprintw(4, 10, "Value 1:");
6429 mvprintw(6, 10, "Value 2:");
6430 refresh();
4792
6431
4793 /* Loop through to get user requests */
4794 while((ch = getch()) != KEY_F(1))
4795 { switch(ch)
4796 { case KEY_DOWN:
4797 /* Go to next field */
4798 form_driver(my_form, REQ_NEXT_FIELD);
4799 /* Go to the end of the present buffer */
4800 /* Leaves nicely at the last character */
4801 form_driver(my_form, REQ_END_LINE);
4802 break;
4803 case KEY_UP:
4804 /* Go to previous field */
4805 form_driver(my_form, REQ_PREV_FIELD);
4806 form_driver(my_form, REQ_END_LINE);
4807 break;
4808 default:
4809 /* If this is a normal character, it gets */
4810 /* Printed */
4811 form_driver(my_form, ch);
4812 break;
4813 }
4814 }
6432 /* Loop through to get user requests */
6433 while((ch = getch()) != KEY_F(1))
6434 { switch(ch)
6435 { case KEY_DOWN:
6436 /* Go to next field */
6437 form_driver(my_form, REQ_NEXT_FIELD);
6438 /* Go to the end of the present buffer */
6439 /* Leaves nicely at the last character */
6440 form_driver(my_form, REQ_END_LINE);
6441 break;
6442 case KEY_UP:
6443 /* Go to previous field */
6444 form_driver(my_form, REQ_PREV_FIELD);
6445 form_driver(my_form, REQ_END_LINE);
6446 break;
6447 default:
6448 /* If this is a normal character, it gets */
6449 /* Printed */
6450 form_driver(my_form, ch);
6451 break;
6452 }
6453 }
4815
6454
4816 /* Un post form and free the memory */
4817 unpost_form(my_form);
4818 free_form(my_form);
4819 free_field(field[0]);
4820 free_field(field[1]);
6455 /* Un post form and free the memory */
6456 unpost_form(my_form);
6457 free_form(my_form);
6458 free_field(field[0]);
6459 free_field(field[1]);
4821
6460
4822 endwin();
4823 return 0;
4824}</span></font>
4825</pre></td>
4826</tr>
4827</table>
4828</div>
4829<p>Above example is pretty straight forward. It creates two fields
4830with <var class="LITERAL">new_field()</var>. new_field() takes
4831height, width, starty, startx, number of offscreen rows and number
4832of additional working buffers. The fifth argument number of
4833offscreen rows specifies how much of the field to be shown. If it
4834is zero, the entire field is always displayed otherwise the form
4835will be scrollable when the user accesses not displayed parts of
4836the field. The forms library allocates one buffer per field to
4837store the data user enters. Using the last parameter to new_field()
4838we can specify it to allocate some additional buffers. These can be
4839used for any purpose you like.</p>
4840<p>After creating the fields, back ground attribute of both of them
4841is set to an underscore with set_field_back(). The AUTOSKIP option
4842is turned off using field_opts_off(). If this option is turned on,
4843focus will move to the next field in the form once the active field
4844is filled up completely.</p>
4845<p>After attaching the fields to the form, it is posted. Here on,
4846user inputs are processed in the while loop, by making
4847corresponding requests to form_driver. The details of all the
4848requests to the form_driver() are explained later.</p>
4849</div>
4850<div class="SECT2">
4851<hr>
4852<h3 class="SECT2"><a name="PLAYFIELDS" id="PLAYFIELDS">18.3.
4853Playing with Fields</a></h3>
4854<p>Each form field is associated with a lot of attributes. They can
4855be manipulated to get the required effect and to have fun !!!. So
4856why wait?</p>
4857<div class="SECT3">
4858<hr>
4859<h4 class="SECT3"><a name="FETCHINFO" id="FETCHINFO">18.3.1.
4860Fetching Size and Location of Field</a></h4>
4861<p>The parameters we have given at the time of creation of a field
4862can be retrieved with field_info(). It returns height, width,
4863starty, startx, number of offscreen rows, and number of additional
4864buffers into the parameters given to it. It is a sort of inverse of
4865new_field().</p>
4866<table border="0" bgcolor="#E0E0E0" width="100%">
4867<tr>
4868<td>
4869<pre class="PROGRAMLISTING">
4870<font color=
4871"#000000">int field_info( FIELD *field, /* field from which to fetch */
6461 endwin();
6462 return 0;
6463}</SPAN
6464></PRE
6465></DIV
6466><P
6467>Above example is pretty straight forward. It creates two fields with
6468<TT
6469CLASS="LITERAL"
6470>new_field()</TT
6471>. new_field() takes height, width,
6472starty, startx, number of offscreen rows and number of additional working
6473buffers. The fifth argument number of offscreen rows specifies how much of the
6474field to be shown. If it is zero, the entire field is always displayed otherwise
6475the form will be scrollable when the user accesses not displayed parts of the
6476field. The forms library allocates one buffer per field to store the data user
6477enters. Using the last parameter to new_field() we can specify it to allocate
6478some additional buffers. These can be used for any purpose you like.</P
6479><P
6480>After creating the fields, back ground attribute of both of them is set to an
6481underscore with set_field_back(). The AUTOSKIP option is turned off using
6482field_opts_off(). If this option is turned on, focus will move to the next
6483field in the form once the active field is filled up completely.</P
6484><P
6485>After attaching the fields to the form, it is posted. Here on, user inputs are
6486processed in the while loop, by making corresponding requests to form_driver.
6487The details of all the requests to the form_driver() are explained later.</P
6488></DIV
6489><DIV
6490CLASS="SECT2"
6491><HR><H3
6492CLASS="SECT2"
6493><A
6494NAME="PLAYFIELDS"
6495>18.3. Playing with Fields</A
6496></H3
6497><P
6498>Each form field is associated with a lot of attributes. They can be manipulated
6499to get the required effect and to have fun !!!. So why wait? </P
6500><DIV
6501CLASS="SECT3"
6502><HR><H4
6503CLASS="SECT3"
6504><A
6505NAME="FETCHINFO"
6506>18.3.1. Fetching Size and Location of Field</A
6507></H4
6508><P
6509>The parameters we have given at the time of creation of a field can be retrieved
6510with field_info(). It returns height, width, starty, startx, number of offscreen
6511rows, and number of additional buffers into the parameters given to it. It is a
6512sort of inverse of new_field().</P
6513><PRE
6514CLASS="PROGRAMLISTING"
6515>int field_info( FIELD *field, /* field from which to fetch */
4872 int *height, *int width, /* field size */
4873 int *top, int *left, /* upper left corner */
4874 int *offscreen, /* number of offscreen rows */
6516 int *height, *int width, /* field size */
6517 int *top, int *left, /* upper left corner */
6518 int *offscreen, /* number of offscreen rows */
4875 int *nbuf); /* number of working buffers */</font>
4876</pre></td>
4877</tr>
4878</table>
4879</div>
4880<div class="SECT3">
4881<hr>
4882<h4 class="SECT3"><a name="MOVEFIELD" id="MOVEFIELD">18.3.2. Moving
4883the field</a></h4>
4884<p>The location of the field can be moved to a different position
4885with move_field().</p>
4886<table border="0" bgcolor="#E0E0E0" width="100%">
4887<tr>
4888<td>
4889<pre class="PROGRAMLISTING">
4890<font color=
4891"#000000">int move_field( FIELD *field, /* field to alter */
4892 int top, int left); /* new upper-left corner */</font>
4893</pre></td>
4894</tr>
4895</table>
4896<p>As usual, the changed position can be queried with
4897field_infor().</p>
4898</div>
4899<div class="SECT3">
4900<hr>
4901<h4 class="SECT3"><a name="JUSTIFYFIELD" id="JUSTIFYFIELD">18.3.3.
4902Field Justification</a></h4>
4903<p>The justification to be done for the field can be fixed using
4904the function set_field_just().</p>
4905<table border="0" bgcolor="#E0E0E0" width="100%">
4906<tr>
4907<td>
4908<pre class="PROGRAMLISTING">
4909<font color=
4910"#000000"> int set_field_just(FIELD *field, /* field to alter */
6519 int *nbuf); /* number of working buffers */</PRE
6520></DIV
6521><DIV
6522CLASS="SECT3"
6523><HR><H4
6524CLASS="SECT3"
6525><A
6526NAME="MOVEFIELD"
6527>18.3.2. Moving the field</A
6528></H4
6529><P
6530>The location of the field can be moved to a different position with
6531move_field().</P
6532><PRE
6533CLASS="PROGRAMLISTING"
6534>int move_field( FIELD *field, /* field to alter */
6535 int top, int left); /* new upper-left corner */</PRE
6536><P
6537>As usual, the changed position can be queried with field_infor().</P
6538></DIV
6539><DIV
6540CLASS="SECT3"
6541><HR><H4
6542CLASS="SECT3"
6543><A
6544NAME="JUSTIFYFIELD"
6545>18.3.3. Field Justification</A
6546></H4
6547><P
6548>The justification to be done for the field can be fixed using the function
6549set_field_just().</P
6550><PRE
6551CLASS="PROGRAMLISTING"
6552> int set_field_just(FIELD *field, /* field to alter */
4911 int justmode); /* mode to set */
6553 int justmode); /* mode to set */
4912 int field_just(FIELD *field); /* fetch justify mode of field */</font>
4913</pre></td>
4914</tr>
4915</table>
4916<p>The justification mode valued accepted and returned by these
4917functions are NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or
4918JUSTIFY_CENTER.</p>
4919</div>
4920<div class="SECT3">
4921<hr>
4922<h4 class="SECT3"><a name="FIELDDISPATTRIB" id=
4923"FIELDDISPATTRIB">18.3.4. Field Display Attributes</a></h4>
4924<p>As you have seen, in the above example, display attribute for
4925the fields can be set with set_field_fore() and setfield_back().
4926These functions set foreground and background attribute of the
4927fields. You can also specify a pad character which will be filled
4928in the unfilled portion of the field. The pad character is set with
4929a call to set_field_pad(). Default pad value is a space. The
4930functions field_fore(), field_back, field_pad() can be used to
4931query the present foreground, background attributes and pad
4932character for the field. The following list gives the usage of
4933functions.</p>
4934<table border="0" bgcolor="#E0E0E0" width="100%">
4935<tr>
4936<td>
4937<pre class="PROGRAMLISTING">
4938<font color=
4939"#000000">&#13;int set_field_fore(FIELD *field, /* field to alter */
6554 int field_just(FIELD *field); /* fetch justify mode of field */</PRE
6555><P
6556>The justification mode valued accepted and returned by these functions are
6557NO_JUSTIFICATION, JUSTIFY_RIGHT, JUSTIFY_LEFT, or JUSTIFY_CENTER.</P
6558></DIV
6559><DIV
6560CLASS="SECT3"
6561><HR><H4
6562CLASS="SECT3"
6563><A
6564NAME="FIELDDISPATTRIB"
6565>18.3.4. Field Display Attributes</A
6566></H4
6567><P
6568>As you have seen, in the above example, display attribute for the fields can be
6569set with set_field_fore() and setfield_back(). These functions set foreground
6570and background attribute of the fields. You can also specify a pad character
6571which will be filled in the unfilled portion of the field. The pad character is
6572set with a call to set_field_pad(). Default pad value is a space. The functions
6573field_fore(), field_back, field_pad() can be used to query the present
6574foreground, background attributes and pad character for the field. The following
6575list gives the usage of functions.</P
6576><PRE
6577CLASS="PROGRAMLISTING"
6578>&#13;int set_field_fore(FIELD *field, /* field to alter */
4940 chtype attr); /* attribute to set */
4941
4942chtype field_fore(FIELD *field); /* field to query */
4943 /* returns foreground attribute */
4944
4945int set_field_back(FIELD *field, /* field to alter */
4946 chtype attr); /* attribute to set */
4947
4948chtype field_back(FIELD *field); /* field to query */
4949 /* returns background attribute */
4950
4951int set_field_pad(FIELD *field, /* field to alter */
4952 int pad); /* pad character to set */
4953
4954chtype field_pad(FIELD *field); /* field to query */
6579 chtype attr); /* attribute to set */
6580
6581chtype field_fore(FIELD *field); /* field to query */
6582 /* returns foreground attribute */
6583
6584int set_field_back(FIELD *field, /* field to alter */
6585 chtype attr); /* attribute to set */
6586
6587chtype field_back(FIELD *field); /* field to query */
6588 /* returns background attribute */
6589
6590int set_field_pad(FIELD *field, /* field to alter */
6591 int pad); /* pad character to set */
6592
6593chtype field_pad(FIELD *field); /* field to query */
4955 /* returns present pad character */&#13;</font>
4956</pre></td>
4957</tr>
4958</table>
4959<p>Though above functions seem quite simple, using colors with
4960set_field_fore() may be frustrating in the beginning. Let me first
4961explain about foreground and background attributes of a field. The
4962foreground attribute is associated with the character. That means a
4963character in the field is printed with the attribute you have set
4964with set_field_fore(). Background attribute is the attribute used
4965to fill background of field, whether any character is there or not.
4966So what about colors? Since colors are always defined in pairs,
4967what is the right way to display colored fields? Here's an example
4968clarifying color attributes.</p>
4969<div class="EXAMPLE"><a name="FFOAT" id="FFOAT"></a>
4970<p><b>Example 26. Form Attributes example</b></p>
4971<table border="0" bgcolor="#E0E0E0" width="100%">
4972<tr>
4973<td>
4974<pre class="PROGRAMLISTING">
4975<font color="#000000"><span class=
4976"INLINEMEDIAOBJECT">#include &lt;form.h&gt;
6594 /* returns present pad character */&#13;</PRE
6595><P
6596>Though above functions seem quite simple, using colors with set_field_fore() may
6597be frustrating in the beginning. Let me first explain about foreground and
6598background attributes of a field. The foreground attribute is associated with
6599the character. That means a character in the field is printed with the attribute
6600you have set with set_field_fore(). Background attribute is the attribute used
6601to fill background of field, whether any character is there or not. So what
6602about colors? Since colors are always defined in pairs, what is the right way to
6603display colored fields? Here's an example clarifying color attributes.</P
6604><DIV
6605CLASS="EXAMPLE"
6606><A
6607NAME="FFOAT"
6608></A
6609><P
6610><B
6611>Example 26. Form Attributes example </B
6612></P
6613><PRE
6614CLASS="PROGRAMLISTING"
6615><SPAN
6616CLASS="INLINEMEDIAOBJECT"
6617>#include &#60;form.h&#62;
4977
4978int main()
6618
6619int main()
4979{ FIELD *field[3];
4980 FORM *my_form;
4981 int ch;
4982
4983 /* Initialize curses */
4984 initscr();
4985 start_color();
4986 cbreak();
4987 noecho();
4988 keypad(stdscr, TRUE);
6620{ FIELD *field[3];
6621 FORM *my_form;
6622 int ch;
6623
6624 /* Initialize curses */
6625 initscr();
6626 start_color();
6627 cbreak();
6628 noecho();
6629 keypad(stdscr, TRUE);
4989
6630
4990 /* Initialize few color pairs */
4991 init_pair(1, COLOR_WHITE, COLOR_BLUE);
4992 init_pair(2, COLOR_WHITE, COLOR_BLUE);
6631 /* Initialize few color pairs */
6632 init_pair(1, COLOR_WHITE, COLOR_BLUE);
6633 init_pair(2, COLOR_WHITE, COLOR_BLUE);
4993
6634
4994 /* Initialize the fields */
4995 field[0] = new_field(1, 10, 4, 18, 0, 0);
4996 field[1] = new_field(1, 10, 6, 18, 0, 0);
4997 field[2] = NULL;
6635 /* Initialize the fields */
6636 field[0] = new_field(1, 10, 4, 18, 0, 0);
6637 field[1] = new_field(1, 10, 6, 18, 0, 0);
6638 field[2] = NULL;
4998
6639
4999 /* Set field options */
5000 set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */
5001 set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */
5002 /* are printed in white */
5003 field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
5004 /* Field is filled up */
5005 set_field_back(field[1], A_UNDERLINE);
5006 field_opts_off(field[1], O_AUTOSKIP);
6640 /* Set field options */
6641 set_field_fore(field[0], COLOR_PAIR(1));/* Put the field with blue background */
6642 set_field_back(field[0], COLOR_PAIR(2));/* and white foreground (characters */
6643 /* are printed in white */
6644 field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
6645 /* Field is filled up */
6646 set_field_back(field[1], A_UNDERLINE);
6647 field_opts_off(field[1], O_AUTOSKIP);
5007
6648
5008 /* Create the form and post it */
5009 my_form = new_form(field);
5010 post_form(my_form);
5011 refresh();
5012
5013 set_current_field(my_form, field[0]); /* Set focus to the colored field */
5014 mvprintw(4, 10, "Value 1:");
5015 mvprintw(6, 10, "Value 2:");
5016 mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
5017 refresh();
6649 /* Create the form and post it */
6650 my_form = new_form(field);
6651 post_form(my_form);
6652 refresh();
6653
6654 set_current_field(my_form, field[0]); /* Set focus to the colored field */
6655 mvprintw(4, 10, "Value 1:");
6656 mvprintw(6, 10, "Value 2:");
6657 mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
6658 refresh();
5018
6659
5019 /* Loop through to get user requests */
5020 while((ch = getch()) != KEY_F(1))
5021 { switch(ch)
5022 { case KEY_DOWN:
5023 /* Go to next field */
5024 form_driver(my_form, REQ_NEXT_FIELD);
5025 /* Go to the end of the present buffer */
5026 /* Leaves nicely at the last character */
5027 form_driver(my_form, REQ_END_LINE);
5028 break;
5029 case KEY_UP:
5030 /* Go to previous field */
5031 form_driver(my_form, REQ_PREV_FIELD);
5032 form_driver(my_form, REQ_END_LINE);
5033 break;
5034 default:
5035 /* If this is a normal character, it gets */
5036 /* Printed */
5037 form_driver(my_form, ch);
5038 break;
5039 }
5040 }
6660 /* Loop through to get user requests */
6661 while((ch = getch()) != KEY_F(1))
6662 { switch(ch)
6663 { case KEY_DOWN:
6664 /* Go to next field */
6665 form_driver(my_form, REQ_NEXT_FIELD);
6666 /* Go to the end of the present buffer */
6667 /* Leaves nicely at the last character */
6668 form_driver(my_form, REQ_END_LINE);
6669 break;
6670 case KEY_UP:
6671 /* Go to previous field */
6672 form_driver(my_form, REQ_PREV_FIELD);
6673 form_driver(my_form, REQ_END_LINE);
6674 break;
6675 default:
6676 /* If this is a normal character, it gets */
6677 /* Printed */
6678 form_driver(my_form, ch);
6679 break;
6680 }
6681 }
5041
6682
5042 /* Un post form and free the memory */
5043 unpost_form(my_form);
5044 free_form(my_form);
5045 free_field(field[0]);
5046 free_field(field[1]);
6683 /* Un post form and free the memory */
6684 unpost_form(my_form);
6685 free_form(my_form);
6686 free_field(field[0]);
6687 free_field(field[1]);
5047
6688
5048 endwin();
5049 return 0;
5050}</span></font>
5051</pre></td>
5052</tr>
5053</table>
5054</div>
5055<p>Play with the color pairs and try to understand the foreground
5056and background attributes. In my programs using color attributes, I
5057usually set only the background with set_field_back(). Curses
5058simply doesn't allow defining individual color attributes.</p>
5059</div>
5060<div class="SECT3">
5061<hr>
5062<h4 class="SECT3"><a name="FIELDOPTIONBITS" id=
5063"FIELDOPTIONBITS">18.3.5. Field Option Bits</a></h4>
5064<p>There is also a large collection of field option bits you can
5065set to control various aspects of forms processing. You can
5066manipulate them with these functions:</p>
5067<table border="0" bgcolor="#E0E0E0" width="100%">
5068<tr>
5069<td>
5070<pre class="PROGRAMLISTING">
5071<font color=
5072"#000000">int set_field_opts(FIELD *field, /* field to alter */
6689 endwin();
6690 return 0;
6691}</SPAN
6692></PRE
6693></DIV
6694><P
6695>Play with the color pairs and try to understand the foreground and background
6696attributes. In my programs using color attributes, I usually set only the
6697background with set_field_back(). Curses simply doesn't allow defining
6698individual color attributes. </P
6699></DIV
6700><DIV
6701CLASS="SECT3"
6702><HR><H4
6703CLASS="SECT3"
6704><A
6705NAME="FIELDOPTIONBITS"
6706>18.3.5. Field Option Bits</A
6707></H4
6708><P
6709>There is also a large collection of field option bits you can set to control
6710various aspects of forms processing. You can manipulate them with these
6711functions:</P
6712><PRE
6713CLASS="PROGRAMLISTING"
6714>int set_field_opts(FIELD *field, /* field to alter */
5073 int attr); /* attribute to set */
5074
5075int field_opts_on(FIELD *field, /* field to alter */
5076 int attr); /* attributes to turn on */
5077
5078int field_opts_off(FIELD *field, /* field to alter */
5079 int attr); /* attributes to turn off */
5080
6715 int attr); /* attribute to set */
6716
6717int field_opts_on(FIELD *field, /* field to alter */
6718 int attr); /* attributes to turn on */
6719
6720int field_opts_off(FIELD *field, /* field to alter */
6721 int attr); /* attributes to turn off */
6722
5081int field_opts(FIELD *field); /* field to query */ </font>
5082</pre></td>
5083</tr>
5084</table>
5085<p>The function set_field_opts() can be used to directly set
5086attributes of a field or you can choose to switch a few attributes
5087on and off with field_opts_on() and field_opts_off() selectively.
5088Anytime you can query the attributes of a field with field_opts().
5089The following is the list of available options. By default, all
5090options are on.</p>
5091<div class="VARIABLELIST">
5092<dl>
5093<dt>O_VISIBLE</dt>
5094<dd>
5095<p>Controls whether the field is visible on the screen. Can be used
5096during form processing to hide or pop up fields depending on the
5097value of parent fields.</p>
5098</dd>
5099<dt>O_ACTIVE</dt>
5100<dd>
5101<p>Controls whether the field is active during forms processing
5102(i.e. visited by form navigation keys). Can be used to make labels
5103or derived fields with buffer values alterable by the forms
5104application, not the user.</p>
5105</dd>
5106<dt>O_PUBLIC</dt>
5107<dd>
5108<p>Controls whether data is displayed during field entry. If this
5109option is turned off on a field, the library will accept and edit
5110data in that field, but it will not be displayed and the visible
5111field cursor will not move. You can turn off the O_PUBLIC bit to
5112define password fields.</p>
5113</dd>
5114<dt>O_EDIT</dt>
5115<dd>
5116<p>Controls whether the field's data can be modified. When this
5117option is off, all editing requests except <var class=
5118"LITERAL">REQ_PREV_CHOICE</var> and <var class=
5119"LITERAL">REQ_NEXT_CHOICE</var>will fail. Such read-only fields may
5120be useful for help messages.</p>
5121</dd>
5122<dt>O_WRAP</dt>
5123<dd>
5124<p>Controls word-wrapping in multi-line fields. Normally, when any
5125character of a (blank-separated) word reaches the end of the
5126current line, the entire word is wrapped to the next line (assuming
5127there is one). When this option is off, the word will be split
5128across the line break.</p>
5129</dd>
5130<dt>O_BLANK</dt>
5131<dd>
5132<p>Controls field blanking. When this option is on, entering a
5133character at the first field position erases the entire field
5134(except for the just-entered character).</p>
5135</dd>
5136<dt>O_AUTOSKIP</dt>
5137<dd>
5138<p>Controls automatic skip to next field when this one fills.
5139Normally, when the forms user tries to type more data into a field
5140than will fit, the editing location jumps to next field. When this
5141option is off, the user's cursor will hang at the end of the field.
5142This option is ignored in dynamic fields that have not reached
5143their size limit.</p>
5144</dd>
5145<dt>O_NULLOK</dt>
5146<dd>
5147<p>Controls whether validation is applied to blank fields.
5148Normally, it is not; the user can leave a field blank without
5149invoking the usual validation check on exit. If this option is off
5150on a field, exit from it will invoke a validation check.</p>
5151</dd>
5152<dt>O_PASSOK</dt>
5153<dd>
5154<p>Controls whether validation occurs on every exit, or only after
5155the field is modified. Normally the latter is true. Setting
5156O_PASSOK may be useful if your field's validation function may
5157change during forms processing.</p>
5158</dd>
5159<dt>O_STATIC</dt>
5160<dd>
5161<p>Controls whether the field is fixed to its initial dimensions.
5162If you turn this off, the field becomes dynamic and will stretch to
5163fit entered data.</p>
5164</dd>
5165</dl>
5166</div>
5167<p>A field's options cannot be changed while the field is currently
5168selected. However, options may be changed on posted fields that are
5169not current.</p>
5170<p>The option values are bit-masks and can be composed with
5171logical-or in the obvious way. You have seen the usage of switching
5172off O_AUTOSKIP option. The following example clarifies usage of
5173some more options. Other options are explained where
5174appropriate.</p>
5175<div class="EXAMPLE"><a name="FFOOP" id="FFOOP"></a>
5176<p><b>Example 27. Field Options Usage example</b></p>
5177<table border="0" bgcolor="#E0E0E0" width="100%">
5178<tr>
5179<td>
5180<pre class="PROGRAMLISTING">
5181<font color="#000000"><span class=
5182"INLINEMEDIAOBJECT">#include &lt;form.h&gt;
6723int field_opts(FIELD *field); /* field to query */ </PRE
6724><P
6725>The function set_field_opts() can be used to directly set attributes of a field
6726or you can choose to switch a few attributes on and off with field_opts_on() and
6727field_opts_off() selectively. Anytime you can query the attributes of a field
6728with field_opts(). The following is the list of available options. By default,
6729all options are on.</P
6730><P
6731></P
6732><DIV
6733CLASS="VARIABLELIST"
6734><DL
6735><DT
6736>O_VISIBLE</DT
6737><DD
6738><P
6739>Controls whether the field is visible on the screen. Can be used
6740during form processing to hide or pop up fields depending on the value
6741of parent fields.</P
6742></DD
6743><DT
6744>O_ACTIVE</DT
6745><DD
6746><P
6747>Controls whether the field is active during forms processing (i.e.
6748visited by form navigation keys). Can be used to make labels or derived
6749fields with buffer values alterable by the forms application, not the user.</P
6750></DD
6751><DT
6752>O_PUBLIC</DT
6753><DD
6754><P
6755>Controls whether data is displayed during field entry. If this option is
6756turned off on a field, the library will accept and edit data in that field,
6757but it will not be displayed and the visible field cursor will not move.
6758You can turn off the O_PUBLIC bit to define password fields.</P
6759></DD
6760><DT
6761>O_EDIT</DT
6762><DD
6763><P
6764>Controls whether the field's data can be modified. When this option is
6765off, all editing requests except <TT
6766CLASS="LITERAL"
6767>REQ_PREV_CHOICE</TT
6768> and <TT
6769CLASS="LITERAL"
6770>REQ_NEXT_CHOICE</TT
6771>will
6772fail. Such read-only fields may be useful for help messages.</P
6773></DD
6774><DT
6775>O_WRAP</DT
6776><DD
6777><P
6778>Controls word-wrapping in multi-line fields. Normally, when any
6779character of a (blank-separated) word reaches the end of the current line, the
6780entire word is wrapped to the next line (assuming there is one). When this
6781option is off, the word will be split across the line break.</P
6782></DD
6783><DT
6784>O_BLANK</DT
6785><DD
6786><P
6787>Controls field blanking. When this option is on, entering a character at
6788the first field position erases the entire field (except for the just-entered
6789character).</P
6790></DD
6791><DT
6792>O_AUTOSKIP</DT
6793><DD
6794><P
6795>Controls automatic skip to next field when this one fills. Normally,
6796when the forms user tries to type more data into a field than will fit,
6797the editing location jumps to next field. When this option is off, the
6798user's cursor will hang at the end of the field. This option is ignored
6799in dynamic fields that have not reached their size limit.</P
6800></DD
6801><DT
6802>O_NULLOK</DT
6803><DD
6804><P
6805>Controls whether validation is applied to
6806blank fields. Normally, it is not; the user can leave a field blank
6807without invoking the usual validation check on exit. If this option is
6808off on a field, exit from it will invoke a validation check.</P
6809></DD
6810><DT
6811>O_PASSOK</DT
6812><DD
6813><P
6814>Controls whether validation occurs on every exit, or only after
6815the field is modified. Normally the latter is true. Setting O_PASSOK
6816may be useful if your field's validation function may change during
6817forms processing.</P
6818></DD
6819><DT
6820>O_STATIC</DT
6821><DD
6822><P
6823>Controls whether the field is fixed to its initial dimensions. If you
6824turn this off, the field becomes dynamic and will
6825stretch to fit entered data.</P
6826></DD
6827></DL
6828></DIV
6829><P
6830>A field's options cannot be changed while the field is currently selected.
6831However, options may be changed on posted fields that are not current. </P
6832><P
6833>The option values are bit-masks and can be composed with logical-or in
6834the obvious way. You have seen the usage of switching off O_AUTOSKIP option.
6835The following example clarifies usage of some more options. Other options
6836are explained where appropriate.</P
6837><DIV
6838CLASS="EXAMPLE"
6839><A
6840NAME="FFOOP"
6841></A
6842><P
6843><B
6844>Example 27. Field Options Usage example </B
6845></P
6846><PRE
6847CLASS="PROGRAMLISTING"
6848><SPAN
6849CLASS="INLINEMEDIAOBJECT"
6850>#include &#60;form.h&#62;
5183
5184#define STARTX 15
5185#define STARTY 4
5186#define WIDTH 25
5187
5188#define N_FIELDS 3
5189
5190int main()
6851
6852#define STARTX 15
6853#define STARTY 4
6854#define WIDTH 25
6855
6856#define N_FIELDS 3
6857
6858int main()
5191{ FIELD *field[N_FIELDS];
5192 FORM *my_form;
5193 int ch, i;
5194
5195 /* Initialize curses */
5196 initscr();
5197 cbreak();
5198 noecho();
5199 keypad(stdscr, TRUE);
6859{ FIELD *field[N_FIELDS];
6860 FORM *my_form;
6861 int ch, i;
6862
6863 /* Initialize curses */
6864 initscr();
6865 cbreak();
6866 noecho();
6867 keypad(stdscr, TRUE);
5200
6868
5201 /* Initialize the fields */
5202 for(i = 0; i &lt; N_FIELDS - 1; ++i)
5203 field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0);
5204 field[N_FIELDS - 1] = NULL;
6869 /* Initialize the fields */
6870 for(i = 0; i &#60; N_FIELDS - 1; ++i)
6871 field[i] = new_field(1, WIDTH, STARTY + i * 2, STARTX, 0, 0);
6872 field[N_FIELDS - 1] = NULL;
5205
6873
5206 /* Set field options */
5207 set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */
5208
5209 field_opts_off(field[0], O_ACTIVE); /* This field is a static label */
5210 field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/
5211 field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */
5212 /* after last character is entered */
5213
5214 /* Create the form and post it */
5215 my_form = new_form(field);
5216 post_form(my_form);
5217 refresh();
5218
5219 set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */
5220 set_field_buffer(field[0], 0, "This is a static Field");
5221 /* Initialize the field */
5222 mvprintw(STARTY, STARTX - 10, "Field 1:");
5223 mvprintw(STARTY + 2, STARTX - 10, "Field 2:");
5224 refresh();
6874 /* Set field options */
6875 set_field_back(field[1], A_UNDERLINE); /* Print a line for the option */
6876
6877 field_opts_off(field[0], O_ACTIVE); /* This field is a static label */
6878 field_opts_off(field[1], O_PUBLIC); /* This filed is like a password field*/
6879 field_opts_off(field[1], O_AUTOSKIP); /* To avoid entering the same field */
6880 /* after last character is entered */
6881
6882 /* Create the form and post it */
6883 my_form = new_form(field);
6884 post_form(my_form);
6885 refresh();
6886
6887 set_field_just(field[0], JUSTIFY_CENTER); /* Center Justification */
6888 set_field_buffer(field[0], 0, "This is a static Field");
6889 /* Initialize the field */
6890 mvprintw(STARTY, STARTX - 10, "Field 1:");
6891 mvprintw(STARTY + 2, STARTX - 10, "Field 2:");
6892 refresh();
5225
6893
5226 /* Loop through to get user requests */
5227 while((ch = getch()) != KEY_F(1))
5228 { switch(ch)
5229 { case KEY_DOWN:
5230 /* Go to next field */
5231 form_driver(my_form, REQ_NEXT_FIELD);
5232 /* Go to the end of the present buffer */
5233 /* Leaves nicely at the last character */
5234 form_driver(my_form, REQ_END_LINE);
5235 break;
5236 case KEY_UP:
5237 /* Go to previous field */
5238 form_driver(my_form, REQ_PREV_FIELD);
5239 form_driver(my_form, REQ_END_LINE);
5240 break;
5241 default:
5242 /* If this is a normal character, it gets */
5243 /* Printed */
5244 form_driver(my_form, ch);
5245 break;
5246 }
5247 }
6894 /* Loop through to get user requests */
6895 while((ch = getch()) != KEY_F(1))
6896 { switch(ch)
6897 { case KEY_DOWN:
6898 /* Go to next field */
6899 form_driver(my_form, REQ_NEXT_FIELD);
6900 /* Go to the end of the present buffer */
6901 /* Leaves nicely at the last character */
6902 form_driver(my_form, REQ_END_LINE);
6903 break;
6904 case KEY_UP:
6905 /* Go to previous field */
6906 form_driver(my_form, REQ_PREV_FIELD);
6907 form_driver(my_form, REQ_END_LINE);
6908 break;
6909 default:
6910 /* If this is a normal character, it gets */
6911 /* Printed */
6912 form_driver(my_form, ch);
6913 break;
6914 }
6915 }
5248
6916
5249 /* Un post form and free the memory */
5250 unpost_form(my_form);
5251 free_form(my_form);
5252 free_field(field[0]);
5253 free_field(field[1]);
6917 /* Un post form and free the memory */
6918 unpost_form(my_form);
6919 free_form(my_form);
6920 free_field(field[0]);
6921 free_field(field[1]);
5254
6922
5255 endwin();
5256 return 0;
5257}</span></font>
5258</pre></td>
5259</tr>
5260</table>
5261</div>
5262<p>This example, though useless, shows the usage of options. If
5263used properly, they can present information very effectively in a
5264form. The second field being not O_PUBLIC, does not show the
5265characters you are typing.</p>
5266</div>
5267<div class="SECT3">
5268<hr>
5269<h4 class="SECT3"><a name="FIELDSTATUS" id="FIELDSTATUS">18.3.6.
5270Field Status</a></h4>
5271<p>The field status specifies whether the field has got edited or
5272not. It is initially set to FALSE and when user enters something
5273and the data buffer gets modified it becomes TRUE. So a field's
5274status can be queried to find out whether it has been modified or
5275not. The following functions can assist in those operations.</p>
5276<table border="0" bgcolor="#E0E0E0" width="100%">
5277<tr>
5278<td>
5279<pre class="PROGRAMLISTING">
5280<font color=
5281"#000000">int set_field_status(FIELD *field, /* field to alter */
6923 endwin();
6924 return 0;
6925}</SPAN
6926></PRE
6927></DIV
6928><P
6929>This example, though useless, shows the usage of options. If used properly, they
6930can present information very effectively in a form. The second field being not
6931O_PUBLIC, does not show the characters you are typing.</P
6932></DIV
6933><DIV
6934CLASS="SECT3"
6935><HR><H4
6936CLASS="SECT3"
6937><A
6938NAME="FIELDSTATUS"
6939>18.3.6. Field Status</A
6940></H4
6941><P
6942>The field status specifies whether the field has got edited or not. It is
6943initially set to FALSE and when user enters something and the data buffer gets
6944modified it becomes TRUE. So a field's status can be queried to find out whether
6945it has been modified or not. The following functions can assist in those
6946operations.</P
6947><PRE
6948CLASS="PROGRAMLISTING"
6949>int set_field_status(FIELD *field, /* field to alter */
5282 int status); /* status to set */
5283
6950 int status); /* status to set */
6951
5284int field_status(FIELD *field); /* fetch status of field */</font>
5285</pre></td>
5286</tr>
5287</table>
5288<p>It's better to check the field's status only after after leaving
5289the field, as data buffer might not have been updated yet as the
5290validation is still due. To guarantee that right status is
5291returned, call field_status() either (1) in the field's exit
5292validation check routine, (2) from the field's or form's
5293initialization or termination hooks, or (3) just after a
5294REQ_VALIDATION request has been processed by the forms driver</p>
5295</div>
5296<div class="SECT3">
5297<hr>
5298<h4 class="SECT3"><a name="FIELDUSERPTR" id="FIELDUSERPTR">18.3.7.
5299Field User Pointer</a></h4>
5300<p>Every field structure contains one pointer that can be used by
5301the user for various purposes. It is not touched by forms library
5302and can be used for any purpose by the user. The following
5303functions set and fetch user pointer.</p>
5304<table border="0" bgcolor="#E0E0E0" width="100%">
5305<tr>
5306<td>
5307<pre class="PROGRAMLISTING">
5308<font color="#000000">int set_field_userptr(FIELD *field,
6952int field_status(FIELD *field); /* fetch status of field */</PRE
6953><P
6954>It's better to check the field's status only after after leaving the field, as
6955data buffer might not have been updated yet as the validation is still due. To
6956guarantee that right status is returned, call field_status() either (1) in the
6957field's exit validation check routine, (2) from the field's or form's
6958initialization or termination hooks, or (3) just after a REQ_VALIDATION request
6959has been processed by the forms driver</P
6960></DIV
6961><DIV
6962CLASS="SECT3"
6963><HR><H4
6964CLASS="SECT3"
6965><A
6966NAME="FIELDUSERPTR"
6967>18.3.7. Field User Pointer</A
6968></H4
6969><P
6970>Every field structure contains one pointer that can be used by the user for
6971various purposes. It is not touched by forms library and can be used for any
6972purpose by the user. The following functions set and fetch user pointer.</P
6973><PRE
6974CLASS="PROGRAMLISTING"
6975>int set_field_userptr(FIELD *field,
5309 char *userptr); /* the user pointer you wish to associate */
5310 /* with the field */
5311
6976 char *userptr); /* the user pointer you wish to associate */
6977 /* with the field */
6978
5312char *field_userptr(FIELD *field); /* fetch user pointer of the field */</font>
5313</pre></td>
5314</tr>
5315</table>
5316</div>
5317<div class="SECT3">
5318<hr>
5319<h4 class="SECT3"><a name="VARIABLESIZEFIELDS" id=
5320"VARIABLESIZEFIELDS">18.3.8. Variable-Sized Fields</a></h4>
5321<p>If you want a dynamically changing field with variable width,
5322this is the feature you want to put to full use. This will allow
5323the user to enter more data than the original size of the field and
5324let the field grow. According to the field orientation it will
5325scroll horizontally or vertically to incorporate the new data.</p>
5326<p>To make a field dynamically growable, the option O_STATIC should
5327be turned off. This can be done with a</p>
5328<table border="0" bgcolor="#E0E0E0" width="100%">
5329<tr>
5330<td>
5331<pre class="PROGRAMLISTING">
5332<font color=
5333"#000000"> field_opts_off(field_pointer, O_STATIC);</font>
5334</pre></td>
5335</tr>
5336</table>
5337<p>But it's usually not advisable to allow a field to grow
5338infinitely. You can set a maximum limit to the growth of the field
5339with</p>
5340<table border="0" bgcolor="#E0E0E0" width="100%">
5341<tr>
5342<td>
5343<pre class="PROGRAMLISTING">
5344<font color=
5345"#000000">int set_max_field(FIELD *field, /* Field on which to operate */
5346 int max_growth); /* maximum growth allowed for the field */</font>
5347</pre></td>
5348</tr>
5349</table>
5350<p>The field info for a dynamically growable field can be retrieved
5351by</p>
5352<table border="0" bgcolor="#E0E0E0" width="100%">
5353<tr>
5354<td>
5355<pre class="PROGRAMLISTING">
5356<font color=
5357"#000000">int dynamic_field_info( FIELD *field, /* Field on which to operate */
6979char *field_userptr(FIELD *field); /* fetch user pointer of the field */</PRE
6980></DIV
6981><DIV
6982CLASS="SECT3"
6983><HR><H4
6984CLASS="SECT3"
6985><A
6986NAME="VARIABLESIZEFIELDS"
6987>18.3.8. Variable-Sized Fields</A
6988></H4
6989><P
6990>If you want a dynamically changing field with variable width, this is the
6991feature you want to put to full use. This will allow the user to enter more data
6992than the original size of the field and let the field grow. According to the
6993field orientation it will scroll horizontally or vertically to incorporate the
6994new data.</P
6995><P
6996>To make a field dynamically growable, the option O_STATIC should be turned off.
6997This can be done with a
6998<PRE
6999CLASS="PROGRAMLISTING"
7000> field_opts_off(field_pointer, O_STATIC);</PRE
7001></P
7002><P
7003>But it's usually not advisable to allow a field to grow infinitely. You can set
7004a maximum limit to the growth of the field with
7005<PRE
7006CLASS="PROGRAMLISTING"
7007>int set_max_field(FIELD *field, /* Field on which to operate */
7008 int max_growth); /* maximum growth allowed for the field */</PRE
7009></P
7010><P
7011>The field info for a dynamically growable field can be retrieved by
7012<PRE
7013CLASS="PROGRAMLISTING"
7014>int dynamic_field_info( FIELD *field, /* Field on which to operate */
5358 int *prows, /* number of rows will be filled in this */
5359 int *pcols, /* number of columns will be filled in this*/
5360 int *pmax) /* maximum allowable growth will be filled */
7015 int *prows, /* number of rows will be filled in this */
7016 int *pcols, /* number of columns will be filled in this*/
7017 int *pmax) /* maximum allowable growth will be filled */
5361 /* in this */</font>
5362</pre></td>
5363</tr>
5364</table>
5365Though field_info work as usual, it is advisable to use this
5366function to get the proper attributes of a dynamically growable
5367field.
5368<p>Recall the library routine new_field; a new field created with
5369height set to one will be defined to be a one line field. A new
5370field created with height greater than one will be defined to be a
5371multi line field.</p>
5372<p>A one line field with O_STATIC turned off (dynamically growable
5373field) will contain a single fixed row, but the number of columns
5374can increase if the user enters more data than the initial field
5375will hold. The number of columns displayed will remain fixed and
5376the additional data will scroll horizontally.</p>
5377<p>A multi line field with O_STATIC turned off (dynamically
5378growable field) will contain a fixed number of columns, but the
5379number of rows can increase if the user enters more data than the
5380initial field will hold. The number of rows displayed will remain
5381fixed and the additional data will scroll vertically.</p>
5382<p>The above two paragraphs pretty much describe a dynamically
5383growable field's behavior. The way other parts of forms library
5384behaves is described below:</p>
5385<ol type="1">
5386<li>
5387<p>The field option O_AUTOSKIP will be ignored if the option
5388O_STATIC is off and there is no maximum growth specified for the
5389field. Currently, O_AUTOSKIP generates an automatic REQ_NEXT_FIELD
5390form driver request when the user types in the last character
5391position of a field. On a growable field with no maximum growth
5392specified, there is no last character position. If a maximum growth
5393is specified, the O_AUTOSKIP option will work as normal if the
5394field has grown to its maximum size.</p>
5395</li>
5396<li>
5397<p>The field justification will be ignored if the option O_STATIC
5398is off. Currently, set_field_just can be used to JUSTIFY_LEFT,
5399JUSTIFY_RIGHT, JUSTIFY_CENTER the contents of a one line field. A
5400growable one line field will, by definition, grow and scroll
5401horizontally and may contain more data than can be justified. The
5402return from field_just will be unchanged.</p>
5403</li>
5404<li>
5405<p>The overloaded form driver request REQ_NEW_LINE will operate the
5406same way regardless of the O_NL_OVERLOAD form option if the field
5407option O_STATIC is off and there is no maximum growth specified for
5408the field. Currently, if the form option O_NL_OVERLOAD is on,
5409REQ_NEW_LINE implicitly generates a REQ_NEXT_FIELD if called from
5410the last line of a field. If a field can grow without bound, there
5411is no last line, so REQ_NEW_LINE will never implicitly generate a
5412REQ_NEXT_FIELD. If a maximum growth limit is specified and the
5413O_NL_OVERLOAD form option is on, REQ_NEW_LINE will only implicitly
5414generate REQ_NEXT_FIELD if the field has grown to its maximum size
5415and the user is on the last line.</p>
5416</li>
5417<li>
5418<p>The library call dup_field will work as usual; it will duplicate
5419the field, including the current buffer size and contents of the
5420field being duplicated. Any specified maximum growth will also be
5421duplicated.</p>
5422</li>
5423<li>
5424<p>The library call link_field will work as usual; it will
5425duplicate all field attributes and share buffers with the field
5426being linked. If the O_STATIC field option is subsequently changed
5427by a field sharing buffers, how the system reacts to an attempt to
5428enter more data into the field than the buffer will currently hold
5429will depend on the setting of the option in the current field.</p>
5430</li>
5431<li>
5432<p>The library call field_info will work as usual; the variable
5433nrow will contain the value of the original call to new_field. The
5434user should use dynamic_field_info, described above, to query the
5435current size of the buffer.</p>
5436</li>
5437</ol>
5438<p>Some of the above points make sense only after explaining form
5439driver. We will be looking into that in next few sections.</p>
5440</div>
5441</div>
5442<div class="SECT2">
5443<hr>
5444<h3 class="SECT2"><a name="FORMWINDOWS" id="FORMWINDOWS">18.4. Form
5445Windows</a></h3>
5446<p>The form windows concept is pretty much similar to menu windows.
5447Every form is associated with a main window and a sub window. The
5448form main window displays any title or border associated or
5449whatever the user wishes. Then the sub window contains all the
5450fields and displays them according to their position. This gives
5451the flexibility of manipulating fancy form displaying very
5452easily.</p>
5453<p>Since this is pretty much similar to menu windows, I am
5454providing an example with out much explanation. The functions are
5455similar and they work the same way.</p>
5456<div class="EXAMPLE"><a name="FFOWI" id="FFOWI"></a>
5457<p><b>Example 28. Form Windows Example</b></p>
5458<table border="0" bgcolor="#E0E0E0" width="100%">
5459<tr>
5460<td>
5461<pre class="PROGRAMLISTING">
5462<font color="#000000"><span class=
5463"INLINEMEDIAOBJECT">#include &lt;form.h&gt;
7018 /* in this */</PRE
7019>
7020Though field_info work as usual, it is advisable to use this function to get the
7021proper attributes of a dynamically growable field.</P
7022><P
7023>Recall the library routine new_field; a new field created with height set to one
7024will be defined to be a one line field. A new field created with height greater
7025than one will be defined to be a multi line field. </P
7026><P
7027>A one line field with O_STATIC turned off (dynamically growable field) will
7028contain a single fixed row, but the number of columns can increase if the user
7029enters more data than the initial field will hold. The number of columns
7030displayed will remain fixed and the additional data will scroll horizontally. </P
7031><P
7032>A multi line field with O_STATIC turned off (dynamically growable field) will
7033contain a fixed number of columns, but the number of rows can increase if the
7034user enters more data than the initial field will hold. The number of rows
7035displayed will remain fixed and the additional data will scroll vertically.</P
7036><P
7037>The above two paragraphs pretty much describe a dynamically growable field's
7038behavior. The way other parts of forms library behaves is described below:</P
7039><P
7040></P
7041><OL
7042TYPE="1"
7043><LI
7044><P
7045>The field option O_AUTOSKIP will be ignored if the option O_STATIC is off and
7046there is no maximum growth specified for the field. Currently, O_AUTOSKIP
7047generates an automatic REQ_NEXT_FIELD form driver request when the user types in
7048the last character position of a field. On a growable field with no maximum
7049growth specified, there is no last character position. If a maximum growth is
7050specified, the O_AUTOSKIP option will work as normal if the field has grown to
7051its maximum size. </P
7052></LI
7053><LI
7054><P
7055>The field justification will be ignored if the option O_STATIC is off.
7056Currently, set_field_just can be used to JUSTIFY_LEFT, JUSTIFY_RIGHT,
7057JUSTIFY_CENTER the contents of a one line field. A growable one line field will,
7058by definition, grow and scroll horizontally and may contain more data than can
7059be justified. The return from field_just will be unchanged. </P
7060></LI
7061><LI
7062><P
7063>The overloaded form driver request REQ_NEW_LINE will operate the same way
7064regardless of the O_NL_OVERLOAD form option if the field option O_STATIC is off
7065and there is no maximum growth specified for the field. Currently, if the form
7066option O_NL_OVERLOAD is on, REQ_NEW_LINE implicitly generates a REQ_NEXT_FIELD
7067if called from the last line of a field. If a field can grow without bound,
7068there is no last line, so REQ_NEW_LINE will never implicitly generate a
7069REQ_NEXT_FIELD. If a maximum growth limit is specified and the O_NL_OVERLOAD
7070form option is on, REQ_NEW_LINE will only implicitly generate REQ_NEXT_FIELD if
7071the field has grown to its maximum size and the user is on the last line. </P
7072></LI
7073><LI
7074><P
7075>The library call dup_field will work as usual; it will duplicate the field,
7076including the current buffer size and contents of the field being duplicated.
7077Any specified maximum growth will also be duplicated. </P
7078></LI
7079><LI
7080><P
7081>The library call link_field will work as usual; it will duplicate all field
7082attributes and share buffers with the field being linked. If the O_STATIC field
7083option is subsequently changed by a field sharing buffers, how the system reacts
7084to an attempt to enter more data into the field than the buffer will currently
7085hold will depend on the setting of the option in the current field. </P
7086></LI
7087><LI
7088><P
7089>The library call field_info will work as usual; the variable nrow will contain
7090the value of the original call to new_field. The user should use
7091dynamic_field_info, described above, to query the current size of the buffer.</P
7092></LI
7093></OL
7094><P
7095>Some of the above points make sense only after explaining form driver. We will
7096be looking into that in next few sections.</P
7097></DIV
7098></DIV
7099><DIV
7100CLASS="SECT2"
7101><HR><H3
7102CLASS="SECT2"
7103><A
7104NAME="FORMWINDOWS"
7105>18.4. Form Windows</A
7106></H3
7107><P
7108>The form windows concept is pretty much similar to menu windows. Every form is
7109associated with a main window and a sub window. The form main window displays
7110any title or border associated or whatever the user wishes. Then the sub window
7111contains all the fields and displays them according to their position. This
7112gives the flexibility of manipulating fancy form displaying very easily. </P
7113><P
7114>Since this is pretty much similar to menu windows, I am providing an example
7115with out much explanation. The functions are similar and they work the same way.</P
7116><DIV
7117CLASS="EXAMPLE"
7118><A
7119NAME="FFOWI"
7120></A
7121><P
7122><B
7123>Example 28. Form Windows Example </B
7124></P
7125><PRE
7126CLASS="PROGRAMLISTING"
7127><SPAN
7128CLASS="INLINEMEDIAOBJECT"
7129>#include &#60;form.h&#62;
5464
5465void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
5466
5467int main()
5468{
7130
7131void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color);
7132
7133int main()
7134{
5469 FIELD *field[3];
5470 FORM *my_form;
5471 WINDOW *my_form_win;
5472 int ch, rows, cols;
5473
5474 /* Initialize curses */
5475 initscr();
5476 start_color();
5477 cbreak();
5478 noecho();
5479 keypad(stdscr, TRUE);
7135 FIELD *field[3];
7136 FORM *my_form;
7137 WINDOW *my_form_win;
7138 int ch, rows, cols;
7139
7140 /* Initialize curses */
7141 initscr();
7142 start_color();
7143 cbreak();
7144 noecho();
7145 keypad(stdscr, TRUE);
5480
7146
5481 /* Initialize few color pairs */
5482 init_pair(1, COLOR_RED, COLOR_BLACK);
7147 /* Initialize few color pairs */
7148 init_pair(1, COLOR_RED, COLOR_BLACK);
5483
7149
5484 /* Initialize the fields */
5485 field[0] = new_field(1, 10, 6, 1, 0, 0);
5486 field[1] = new_field(1, 10, 8, 1, 0, 0);
5487 field[2] = NULL;
7150 /* Initialize the fields */
7151 field[0] = new_field(1, 10, 6, 1, 0, 0);
7152 field[1] = new_field(1, 10, 8, 1, 0, 0);
7153 field[2] = NULL;
5488
7154
5489 /* Set field options */
5490 set_field_back(field[0], A_UNDERLINE);
5491 field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
5492 /* Field is filled up */
5493 set_field_back(field[1], A_UNDERLINE);
5494 field_opts_off(field[1], O_AUTOSKIP);
5495
5496 /* Create the form and post it */
5497 my_form = new_form(field);
5498
5499 /* Calculate the area required for the form */
5500 scale_form(my_form, &amp;rows, &amp;cols);
7155 /* Set field options */
7156 set_field_back(field[0], A_UNDERLINE);
7157 field_opts_off(field[0], O_AUTOSKIP); /* Don't go to next field when this */
7158 /* Field is filled up */
7159 set_field_back(field[1], A_UNDERLINE);
7160 field_opts_off(field[1], O_AUTOSKIP);
7161
7162 /* Create the form and post it */
7163 my_form = new_form(field);
7164
7165 /* Calculate the area required for the form */
7166 scale_form(my_form, &#38;rows, &#38;cols);
5501
7167
5502 /* Create the window to be associated with the form */
7168 /* Create the window to be associated with the form */
5503 my_form_win = newwin(rows + 4, cols + 4, 4, 4);
5504 keypad(my_form_win, TRUE);
5505
7169 my_form_win = newwin(rows + 4, cols + 4, 4, 4);
7170 keypad(my_form_win, TRUE);
7171
5506 /* Set main window and sub window */
7172 /* Set main window and sub window */
5507 set_form_win(my_form, my_form_win);
5508 set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2));
5509
7173 set_form_win(my_form, my_form_win);
7174 set_form_sub(my_form, derwin(my_form_win, rows, cols, 2, 2));
7175
5510 /* Print a border around the main window and print a title */
7176 /* Print a border around the main window and print a title */
5511 box(my_form_win, 0, 0);
7177 box(my_form_win, 0, 0);
5512 print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1));
5513
5514 post_form(my_form);
5515 wrefresh(my_form_win);
7178 print_in_middle(my_form_win, 1, 0, cols + 4, "My Form", COLOR_PAIR(1));
7179
7180 post_form(my_form);
7181 wrefresh(my_form_win);
5516
7182
5517 mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
5518 refresh();
7183 mvprintw(LINES - 2, 0, "Use UP, DOWN arrow keys to switch between fields");
7184 refresh();
5519
7185
5520 /* Loop through to get user requests */
5521 while((ch = wgetch(my_form_win)) != KEY_F(1))
5522 { switch(ch)
5523 { case KEY_DOWN:
5524 /* Go to next field */
5525 form_driver(my_form, REQ_NEXT_FIELD);
5526 /* Go to the end of the present buffer */
5527 /* Leaves nicely at the last character */
5528 form_driver(my_form, REQ_END_LINE);
5529 break;
5530 case KEY_UP:
5531 /* Go to previous field */
5532 form_driver(my_form, REQ_PREV_FIELD);
5533 form_driver(my_form, REQ_END_LINE);
5534 break;
5535 default:
5536 /* If this is a normal character, it gets */
5537 /* Printed */
5538 form_driver(my_form, ch);
5539 break;
5540 }
5541 }
7186 /* Loop through to get user requests */
7187 while((ch = wgetch(my_form_win)) != KEY_F(1))
7188 { switch(ch)
7189 { case KEY_DOWN:
7190 /* Go to next field */
7191 form_driver(my_form, REQ_NEXT_FIELD);
7192 /* Go to the end of the present buffer */
7193 /* Leaves nicely at the last character */
7194 form_driver(my_form, REQ_END_LINE);
7195 break;
7196 case KEY_UP:
7197 /* Go to previous field */
7198 form_driver(my_form, REQ_PREV_FIELD);
7199 form_driver(my_form, REQ_END_LINE);
7200 break;
7201 default:
7202 /* If this is a normal character, it gets */
7203 /* Printed */
7204 form_driver(my_form, ch);
7205 break;
7206 }
7207 }
5542
7208
5543 /* Un post form and free the memory */
5544 unpost_form(my_form);
5545 free_form(my_form);
5546 free_field(field[0]);
5547 free_field(field[1]);
7209 /* Un post form and free the memory */
7210 unpost_form(my_form);
7211 free_form(my_form);
7212 free_field(field[0]);
7213 free_field(field[1]);
5548
7214
5549 endwin();
5550 return 0;
7215 endwin();
7216 return 0;
5551}
5552
5553void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
7217}
7218
7219void print_in_middle(WINDOW *win, int starty, int startx, int width, char *string, chtype color)
5554{ int length, x, y;
5555 float temp;
7220{ int length, x, y;
7221 float temp;
5556
7222
5557 if(win == NULL)
5558 win = stdscr;
5559 getyx(win, y, x);
5560 if(startx != 0)
5561 x = startx;
5562 if(starty != 0)
5563 y = starty;
5564 if(width == 0)
5565 width = 80;
7223 if(win == NULL)
7224 win = stdscr;
7225 getyx(win, y, x);
7226 if(startx != 0)
7227 x = startx;
7228 if(starty != 0)
7229 y = starty;
7230 if(width == 0)
7231 width = 80;
5566
7232
5567 length = strlen(string);
5568 temp = (width - length)/ 2;
5569 x = startx + (int)temp;
5570 wattron(win, color);
5571 mvwprintw(win, y, x, "%s", string);
5572 wattroff(win, color);
5573 refresh();
5574}</span></font>
5575</pre></td>
5576</tr>
5577</table>
5578</div>
5579</div>
5580<div class="SECT2">
5581<hr>
5582<h3 class="SECT2"><a name="FILEDVALIDATE" id="FILEDVALIDATE">18.5.
5583Field Validation</a></h3>
5584<p>By default, a field will accept any data input by the user. It
5585is possible to attach validation to the field. Then any attempt by
5586the user to leave the field, while it contains data that doesn't
5587match the validation type will fail. Some validation types also
5588have a character-validity check for each time a character is
5589entered in the field.</p>
5590<p>Validation can be attached to a field with the following
5591function.</p>
5592<table border="0" bgcolor="#E0E0E0" width="100%">
5593<tr>
5594<td>
5595<pre class="PROGRAMLISTING">
5596<font color=
5597"#000000">int set_field_type(FIELD *field, /* field to alter */
7233 length = strlen(string);
7234 temp = (width - length)/ 2;
7235 x = startx + (int)temp;
7236 wattron(win, color);
7237 mvwprintw(win, y, x, "%s", string);
7238 wattroff(win, color);
7239 refresh();
7240}</SPAN
7241></PRE
7242></DIV
7243></DIV
7244><DIV
7245CLASS="SECT2"
7246><HR><H3
7247CLASS="SECT2"
7248><A
7249NAME="FILEDVALIDATE"
7250>18.5. Field Validation</A
7251></H3
7252><P
7253>By default, a field will accept any data input by the user. It is possible to
7254attach validation to the field. Then any attempt by the user to leave the field,
7255while it contains data that doesn't match the validation type will fail. Some
7256validation types also have a character-validity check for each time a character
7257is entered in the field.</P
7258><P
7259>Validation can be attached to a field with the following function.
7260<PRE
7261CLASS="PROGRAMLISTING"
7262>int set_field_type(FIELD *field, /* field to alter */
5598 FIELDTYPE *ftype, /* type to associate */
7263 FIELDTYPE *ftype, /* type to associate */
5599 ...); /* additional arguments*/</font>
5600</pre></td>
5601</tr>
5602</table>
7264 ...); /* additional arguments*/</PRE
7265>
5603Once set, the validation type for a field can be queried with
7266Once set, the validation type for a field can be queried with
5604<table border="0" bgcolor="#E0E0E0" width="100%">
5605<tr>
5606<td>
5607<pre class="PROGRAMLISTING">
5608<font color=
5609"#000000">FIELDTYPE *field_type(FIELD *field); /* field to query */</font>
5610</pre></td>
5611</tr>
5612</table>
5613<p>The form driver validates the data in a field only when data is
5614entered by the end-user. Validation does not occur when</p>
5615<ul>
5616<li>
5617<p>the application program changes the field value by calling
5618set_field_buffer.</p>
5619</li>
5620<li>
5621<p>linked field values are changed indirectly -- by changing the
5622field to which they are linked</p>
5623</li>
5624</ul>
5625<p>The following are the pre-defined validation types. You can also
5626specify custom validation, though it's a bit tricky and
5627cumbersome.</p>
5628<h1 class="BRIDGEHEAD"><a name="AEN1069" id=
5629"AEN1069"></a>TYPE_ALPHA</h1>
5630<p>This field type accepts alphabetic data; no blanks, no digits,
5631no special characters (this is checked at character-entry time). It
5632is set up with:</p>
5633<table border="0" bgcolor="#E0E0E0" width="100%">
5634<tr>
5635<td>
5636<pre class="PROGRAMLISTING">
5637<font color=
5638"#000000">int set_field_type(FIELD *field, /* field to alter */
7267<PRE
7268CLASS="PROGRAMLISTING"
7269>FIELDTYPE *field_type(FIELD *field); /* field to query */</PRE
7270></P
7271><P
7272>The form driver validates the data in a field only when data is entered by the
7273end-user. Validation does not occur when </P
7274><P
7275></P
7276><UL
7277><LI
7278><P
7279>the application program changes the field value by calling set_field_buffer. </P
7280></LI
7281><LI
7282><P
7283>linked field values are changed indirectly -- by changing the field to which
7284they are linked</P
7285></LI
7286></UL
7287><P
7288>The following are the pre-defined validation types. You can also specify custom
7289validation, though it's a bit tricky and cumbersome.</P
7290><H1
7291CLASS="BRIDGEHEAD"
7292><A
7293NAME="AEN1069"
7294></A
7295>TYPE_ALPHA</H1
7296><P
7297>This field type accepts alphabetic data; no blanks, no digits, no special
7298characters (this is checked at character-entry time). It is set up with: </P
7299><PRE
7300CLASS="PROGRAMLISTING"
7301>int set_field_type(FIELD *field, /* field to alter */
5639 TYPE_ALPHA, /* type to associate */
7302 TYPE_ALPHA, /* type to associate */
5640 int width); /* maximum width of field */</font>
5641</pre></td>
5642</tr>
5643</table>
5644<p>The width argument sets a minimum width of data. The user has to
5645enter at-least width number of characters before he can leave the
5646field. Typically you'll want to set this to the field width; if
5647it's greater than the field width, the validation check will always
5648fail. A minimum width of zero makes field completion optional.</p>
5649<h1 class="BRIDGEHEAD"><a name="AEN1073" id=
5650"AEN1073"></a>TYPE_ALNUM</h1>
5651<p>This field type accepts alphabetic data and digits; no blanks,
5652no special characters (this is checked at character-entry time). It
5653is set up with:</p>
5654<table border="0" bgcolor="#E0E0E0" width="100%">
5655<tr>
5656<td>
5657<pre class="PROGRAMLISTING">
5658<font color=
5659"#000000">int set_field_type(FIELD *field, /* field to alter */
7303 int width); /* maximum width of field */</PRE
7304><P
7305>The width argument sets a minimum width of data. The user has to enter at-least
7306width number of characters before he can leave the field. Typically
7307you'll want to set this to the field width; if it's greater than the
7308field width, the validation check will always fail. A minimum width
7309of zero makes field completion optional. </P
7310><H1
7311CLASS="BRIDGEHEAD"
7312><A
7313NAME="AEN1073"
7314></A
7315>TYPE_ALNUM</H1
7316><P
7317>This field type accepts alphabetic data and digits; no blanks, no special
7318characters (this is checked at character-entry time). It is set up with: </P
7319><PRE
7320CLASS="PROGRAMLISTING"
7321>int set_field_type(FIELD *field, /* field to alter */
5660 TYPE_ALNUM, /* type to associate */
7322 TYPE_ALNUM, /* type to associate */
5661 int width); /* maximum width of field */</font>
5662</pre></td>
5663</tr>
5664</table>
5665<p>The width argument sets a minimum width of data. As with
5666TYPE_ALPHA, typically you'll want to set this to the field width;
5667if it's greater than the field width, the validation check will
5668always fail. A minimum width of zero makes field completion
5669optional.</p>
5670<h1 class="BRIDGEHEAD"><a name="AEN1077" id=
5671"AEN1077"></a>TYPE_ENUM</h1>
5672<p>This type allows you to restrict a field's values to be among a
5673specified set of string values (for example, the two-letter postal
5674codes for U.S. states). It is set up with:</p>
5675<table border="0" bgcolor="#E0E0E0" width="100%">
5676<tr>
5677<td>
5678<pre class="PROGRAMLISTING">
5679<font color=
5680"#000000">int set_field_type(FIELD *field, /* field to alter */
7323 int width); /* maximum width of field */</PRE
7324><P
7325>The width argument sets a minimum width of data. As with
7326TYPE_ALPHA, typically you'll want to set this to the field width; if it's
7327greater than the field width, the validation check will always fail. A
7328minimum width of zero makes field completion optional. </P
7329><H1
7330CLASS="BRIDGEHEAD"
7331><A
7332NAME="AEN1077"
7333></A
7334>TYPE_ENUM</H1
7335><P
7336>This type allows you to restrict a field's values to be among a specified
7337set of string values (for example, the two-letter postal codes for U.S.
7338states). It is set up with: </P
7339><PRE
7340CLASS="PROGRAMLISTING"
7341>int set_field_type(FIELD *field, /* field to alter */
5681 TYPE_ENUM, /* type to associate */
5682 char **valuelist; /* list of possible values */
5683 int checkcase; /* case-sensitive? */
7342 TYPE_ENUM, /* type to associate */
7343 char **valuelist; /* list of possible values */
7344 int checkcase; /* case-sensitive? */
5684 int checkunique); /* must specify uniquely? */</font>
5685</pre></td>
5686</tr>
5687</table>
5688<p>The valuelist parameter must point at a NULL-terminated list of
5689valid strings. The checkcase argument, if true, makes comparison
5690with the string case-sensitive.</p>
5691<p>When the user exits a TYPE_ENUM field, the validation procedure
5692tries to complete the data in the buffer to a valid entry. If a
5693complete choice string has been entered, it is of course valid. But
5694it is also possible to enter a prefix of a valid string and have it
5695completed for you.</p>
5696<p>By default, if you enter such a prefix and it matches more than
5697one value in the string list, the prefix will be completed to the
5698first matching value. But the checkunique argument, if true,
5699requires prefix matches to be unique in order to be valid.</p>
5700<p>The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be
5701particularly useful with these fields.</p>
5702<h1 class="BRIDGEHEAD"><a name="AEN1084" id=
5703"AEN1084"></a>TYPE_INTEGER</h1>
5704<p>This field type accepts an integer. It is set up as follows:</p>
5705<table border="0" bgcolor="#E0E0E0" width="100%">
5706<tr>
5707<td>
5708<pre class="PROGRAMLISTING">
5709<font color=
5710"#000000">int set_field_type(FIELD *field, /* field to alter */
7345 int checkunique); /* must specify uniquely? */</PRE
7346><P
7347>The valuelist parameter must point at a NULL-terminated list of
7348valid strings. The checkcase argument, if true, makes comparison
7349with the string case-sensitive. </P
7350><P
7351>When the user exits a TYPE_ENUM field, the validation procedure tries to
7352complete the data in the buffer to a valid entry. If a complete choice string
7353has been entered, it is of course valid. But it is also possible to enter a
7354prefix of a valid string and have it completed for you. </P
7355><P
7356>By default, if you enter such a prefix and it matches more than one value
7357in the string list, the prefix will be completed to the first matching
7358value. But the checkunique argument, if true, requires prefix
7359matches to be unique in order to be valid. </P
7360><P
7361>The REQ_NEXT_CHOICE and REQ_PREV_CHOICE input requests can be particularly
7362useful with these fields. </P
7363><H1
7364CLASS="BRIDGEHEAD"
7365><A
7366NAME="AEN1084"
7367></A
7368>TYPE_INTEGER</H1
7369><P
7370>This field type accepts an integer. It is set up as follows: </P
7371><PRE
7372CLASS="PROGRAMLISTING"
7373>int set_field_type(FIELD *field, /* field to alter */
5711 TYPE_INTEGER, /* type to associate */
5712 int padding, /* # places to zero-pad to */
7374 TYPE_INTEGER, /* type to associate */
7375 int padding, /* # places to zero-pad to */
5713 int vmin, int vmax); /* valid range */</font>
5714</pre></td>
5715</tr>
5716</table>
5717<p>Valid characters consist of an optional leading minus and
5718digits. The range check is performed on exit. If the range maximum
5719is less than or equal to the minimum, the range is ignored.</p>
5720<p>If the value passes its range check, it is padded with as many
5721leading zero digits as necessary to meet the padding argument.</p>
5722<p>A TYPE_INTEGER value buffer can conveniently be interpreted with
5723the C library function atoi(3).</p>
5724<h1 class="BRIDGEHEAD"><a name="AEN1090" id=
5725"AEN1090"></a>TYPE_NUMERIC</h1>
5726<p>This field type accepts a decimal number. It is set up as
5727follows:</p>
5728<table border="0" bgcolor="#E0E0E0" width="100%">
5729<tr>
5730<td>
5731<pre class="PROGRAMLISTING">
5732<font color=
5733"#000000">int set_field_type(FIELD *field, /* field to alter */
7376 int vmin, int vmax); /* valid range */</PRE
7377><P
7378>Valid characters consist of an optional leading minus and digits.
7379The range check is performed on exit. If the range maximum is less
7380than or equal to the minimum, the range is ignored. </P
7381><P
7382>If the value passes its range check, it is padded with as many leading
7383zero digits as necessary to meet the padding argument. </P
7384><P
7385>A TYPE_INTEGER value buffer can conveniently be interpreted with the C library
7386function atoi(3).</P
7387><H1
7388CLASS="BRIDGEHEAD"
7389><A
7390NAME="AEN1090"
7391></A
7392>TYPE_NUMERIC</H1
7393><P
7394>This field type accepts a decimal number. It is set up as follows: </P
7395><PRE
7396CLASS="PROGRAMLISTING"
7397>int set_field_type(FIELD *field, /* field to alter */
5734 TYPE_NUMERIC, /* type to associate */
5735 int padding, /* # places of precision */
7398 TYPE_NUMERIC, /* type to associate */
7399 int padding, /* # places of precision */
5736 int vmin, int vmax); /* valid range */</font>
5737</pre></td>
5738</tr>
5739</table>
5740<p>Valid characters consist of an optional leading minus and
5741digits. possibly including a decimal point. The range check is
5742performed on exit. If the range maximum is less than or equal to
5743the minimum, the range is ignored.</p>
5744<p>If the value passes its range check, it is padded with as many
5745trailing zero digits as necessary to meet the padding argument.</p>
5746<p>A TYPE_NUMERIC value buffer can conveniently be interpreted with
5747the C library function atof(3).</p>
5748<h1 class="BRIDGEHEAD"><a name="AEN1096" id=
5749"AEN1096"></a>TYPE_REGEXP</h1>
5750<p>This field type accepts data matching a regular expression. It
5751is set up as follows:</p>
5752<table border="0" bgcolor="#E0E0E0" width="100%">
5753<tr>
5754<td>
5755<pre class="PROGRAMLISTING">
5756<font color=
5757"#000000">int set_field_type(FIELD *field, /* field to alter */
7400 int vmin, int vmax); /* valid range */</PRE
7401><P
7402>Valid characters consist of an optional leading minus and digits. possibly
7403including a decimal point. The range check is performed on exit. If the
7404range maximum is less than or equal to the minimum, the range is
7405ignored. </P
7406><P
7407>If the value passes its range check, it is padded with as many trailing
7408zero digits as necessary to meet the padding argument. </P
7409><P
7410>A TYPE_NUMERIC value buffer can conveniently be interpreted with the C library
7411function atof(3).</P
7412><H1
7413CLASS="BRIDGEHEAD"
7414><A
7415NAME="AEN1096"
7416></A
7417>TYPE_REGEXP</H1
7418><P
7419>This field type accepts data matching a regular expression. It is set up
7420as follows: </P
7421><PRE
7422CLASS="PROGRAMLISTING"
7423>int set_field_type(FIELD *field, /* field to alter */
5758 TYPE_REGEXP, /* type to associate */
7424 TYPE_REGEXP, /* type to associate */
5759 char *regexp); /* expression to match */</font>
5760</pre></td>
5761</tr>
5762</table>
5763<p>The syntax for regular expressions is that of regcomp(3). The
5764check for regular-expression match is performed on exit.</p>
5765</div>
5766<div class="SECT2">
5767<hr>
5768<h3 class="SECT2"><a name="FORMDRIVER" id="FORMDRIVER">18.6. Form
5769Driver: The work horse of the forms system</a></h3>
5770<p>As in the menu system, form_driver() plays a very important role
5771in forms system. All types of requests to forms system should be
5772funneled through form_driver().</p>
5773<table border="0" bgcolor="#E0E0E0" width="100%">
5774<tr>
5775<td>
5776<pre class="PROGRAMLISTING">
5777<font color=
5778"#000000">int form_driver(FORM *form, /* form on which to operate */
5779 int request) /* form request code */</font>
5780</pre></td>
5781</tr>
5782</table>
5783<p>As you have seen some of the examples above, you have to be in a
5784loop looking for user input and then decide whether it's a field
5785data or a form request. The form requests are then passed to
5786form_driver() to do the work.</p>
5787<p>The requests roughly can be divided into following categories.
5788Different requests and their usage is explained below:</p>
5789<div class="SECT3">
5790<hr>
5791<h4 class="SECT3"><a name="PAGENAVREQ" id="PAGENAVREQ">18.6.1. Page
5792Navigation Requests</a></h4>
5793<p>These requests cause page-level moves through the form,
5794triggering display of a new form screen. A form can be made of
5795multiple pages. If you have a big form with lot of fields and
5796logical sections, then you can divide the form into pages. The
5797function set_new_page() to set a new page at the field
5798specified.</p>
5799<table border="0" bgcolor="#E0E0E0" width="100%">
5800<tr>
5801<td>
5802<pre class="PROGRAMLISTING">
5803<font color=
5804"#000000">int set_new_page(FIELD *field,/* Field at which page break to be set or unset */
5805 bool new_page_flag); /* should be TRUE to put a break */</font>
5806</pre></td>
5807</tr>
5808</table>
5809<p>The following requests allow you to move to different pages</p>
5810<ul>
5811<li>
5812<p><em>REQ_NEXT_PAGE</em> Move to the next form page.</p>
5813</li>
5814<li>
5815<p><em>REQ_PREV_PAGE</em> Move to the previous form page.</p>
5816</li>
5817<li>
5818<p><em>REQ_FIRST_PAGE</em> Move to the first form page.</p>
5819</li>
5820<li>
5821<p><em>REQ_LAST_PAGE</em> Move to the last form page.</p>
5822</li>
5823</ul>
5824<p>These requests treat the list as cyclic; that is, REQ_NEXT_PAGE
5825from the last page goes to the first, and REQ_PREV_PAGE from the
5826first page goes to the last.</p>
5827</div>
5828<div class="SECT3">
5829<hr>
5830<h4 class="SECT3"><a name="INTERFIELDNAVREQ" id=
5831"INTERFIELDNAVREQ">18.6.2. Inter-Field Navigation Requests</a></h4>
5832<p>These requests handle navigation between fields on the same
5833page.</p>
5834<ul>
5835<li>
5836<p><em>REQ_NEXT_FIELD</em> Move to next field.</p>
5837</li>
5838<li>
5839<p><em>REQ_PREV_FIELD</em> Move to previous field.</p>
5840</li>
5841<li>
5842<p><em>REQ_FIRST_FIELD</em> Move to the first field.</p>
5843</li>
5844<li>
5845<p><em>REQ_LAST_FIELD</em> Move to the last field.</p>
5846</li>
5847<li>
5848<p><em>REQ_SNEXT_FIELD</em> Move to sorted next field.</p>
5849</li>
5850<li>
5851<p><em>REQ_SPREV_FIELD</em> Move to sorted previous field.</p>
5852</li>
5853<li>
5854<p><em>REQ_SFIRST_FIELD</em> Move to the sorted first field.</p>
5855</li>
5856<li>
5857<p><em>REQ_SLAST_FIELD</em> Move to the sorted last field.</p>
5858</li>
5859<li>
5860<p><em>REQ_LEFT_FIELD</em> Move left to field.</p>
5861</li>
5862<li>
5863<p><em>REQ_RIGHT_FIELD</em> Move right to field.</p>
5864</li>
5865<li>
5866<p><em>REQ_UP_FIELD</em> Move up to field.</p>
5867</li>
5868<li>
5869<p><em>REQ_DOWN_FIELD</em> Move down to field.</p>
5870</li>
5871</ul>
5872<p>These requests treat the list of fields on a page as cyclic;
5873that is, REQ_NEXT_FIELD from the last field goes to the first, and
5874REQ_PREV_FIELD from the first field goes to the last. The order of
5875the fields for these (and the REQ_FIRST_FIELD and REQ_LAST_FIELD
5876requests) is simply the order of the field pointers in the form
5877array (as set up by new_form() or set_form_fields()</p>
5878<p>It is also possible to traverse the fields as if they had been
5879sorted in screen-position order, so the sequence goes left-to-right
5880and top-to-bottom. To do this, use the second group of four
5881sorted-movement requests.</p>
5882<p>Finally, it is possible to move between fields using visual
5883directions up, down, right, and left. To accomplish this, use the
5884third group of four requests. Note, however, that the position of a
5885form for purposes of these requests is its upper-left corner.</p>
5886<p>For example, suppose you have a multi-line field B, and two
5887single-line fields A and C on the same line with B, with A to the
5888left of B and C to the right of B. A REQ_MOVE_RIGHT from A will go
5889to B only if A, B, and C all share the same first line; otherwise
5890it will skip over B to C.</p>
5891</div>
5892<div class="SECT3">
5893<hr>
5894<h4 class="SECT3"><a name="INTRAFIELDNAVREQ" id=
5895"INTRAFIELDNAVREQ">18.6.3. Intra-Field Navigation Requests</a></h4>
5896<p>These requests drive movement of the edit cursor within the
5897currently selected field.</p>
5898<ul>
5899<li>
5900<p><em>REQ_NEXT_CHAR</em> Move to next character.</p>
5901</li>
5902<li>
5903<p><em>REQ_PREV_CHAR</em> Move to previous character.</p>
5904</li>
5905<li>
5906<p><em>REQ_NEXT_LINE</em> Move to next line.</p>
5907</li>
5908<li>
5909<p><em>REQ_PREV_LINE</em> Move to previous line.</p>
5910</li>
5911<li>
5912<p><em>REQ_NEXT_WORD</em> Move to next word.</p>
5913</li>
5914<li>
5915<p><em>REQ_PREV_WORD</em> Move to previous word.</p>
5916</li>
5917<li>
5918<p><em>REQ_BEG_FIELD</em> Move to beginning of field.</p>
5919</li>
5920<li>
5921<p><em>REQ_END_FIELD</em> Move to end of field.</p>
5922</li>
5923<li>
5924<p><em>REQ_BEG_LINE</em> Move to beginning of line.</p>
5925</li>
5926<li>
5927<p><em>REQ_END_LINE</em> Move to end of line.</p>
5928</li>
5929<li>
5930<p><em>REQ_LEFT_CHAR</em> Move left in field.</p>
5931</li>
5932<li>
5933<p><em>REQ_RIGHT_CHAR</em> Move right in field.</p>
5934</li>
5935<li>
5936<p><em>REQ_UP_CHAR</em> Move up in field.</p>
5937</li>
5938<li>
5939<p><em>REQ_DOWN_CHAR</em> Move down in field.</p>
5940</li>
5941</ul>
5942<p>Each word is separated from the previous and next characters by
5943whitespace. The commands to move to beginning and end of line or
5944field look for the first or last non-pad character in their
5945ranges.</p>
5946</div>
5947<div class="SECT3">
5948<hr>
5949<h4 class="SECT3"><a name="SCROLLREQ" id="SCROLLREQ">18.6.4.
5950Scrolling Requests</a></h4>
5951<p>Fields that are dynamic and have grown and fields explicitly
5952created with offscreen rows are scrollable. One-line fields scroll
5953horizontally; multi-line fields scroll vertically. Most scrolling
5954is triggered by editing and intra-field movement (the library
5955scrolls the field to keep the cursor visible). It is possible to
5956explicitly request scrolling with the following requests:</p>
5957<ul>
5958<li>
5959<p><em>REQ_SCR_FLINE</em> Scroll vertically forward a line.</p>
5960</li>
5961<li>
5962<p><em>REQ_SCR_BLINE</em> Scroll vertically backward a line.</p>
5963</li>
5964<li>
5965<p><em>REQ_SCR_FPAGE</em> Scroll vertically forward a page.</p>
5966</li>
5967<li>
5968<p><em>REQ_SCR_BPAGE</em> Scroll vertically backward a page.</p>
5969</li>
5970<li>
5971<p><em>REQ_SCR_FHPAGE</em> Scroll vertically forward half a
5972page.</p>
5973</li>
5974<li>
5975<p><em>REQ_SCR_BHPAGE</em> Scroll vertically backward half a
5976page.</p>
5977</li>
5978<li>
5979<p><em>REQ_SCR_FCHAR</em> Scroll horizontally forward a
5980character.</p>
5981</li>
5982<li>
5983<p><em>REQ_SCR_BCHAR</em> Scroll horizontally backward a
5984character.</p>
5985</li>
5986<li>
5987<p><em>REQ_SCR_HFLINE</em> Scroll horizontally one field width
5988forward.</p>
5989</li>
5990<li>
5991<p><em>REQ_SCR_HBLINE</em> Scroll horizontally one field width
5992backward.</p>
5993</li>
5994<li>
5995<p><em>REQ_SCR_HFHALF</em> Scroll horizontally one half field width
5996forward.</p>
5997</li>
5998<li>
5999<p><em>REQ_SCR_HBHALF</em> Scroll horizontally one half field width
6000backward.</p>
6001</li>
6002</ul>
6003<p>For scrolling purposes, a page of a field is the height of its
6004visible part.</p>
6005</div>
6006<div class="SECT3">
6007<hr>
6008<h4 class="SECT3"><a name="EDITREQ" id="EDITREQ">18.6.5. Editing
6009Requests</a></h4>
6010<p>When you pass the forms driver an ASCII character, it is treated
6011as a request to add the character to the field's data buffer.
6012Whether this is an insertion or a replacement depends on the
6013field's edit mode (insertion is the default.</p>
6014<p>The following requests support editing the field and changing
6015the edit mode:</p>
6016<ul>
6017<li>
6018<p><em>REQ_INS_MODE</em> Set insertion mode.</p>
6019</li>
6020<li>
6021<p><em>REQ_OVL_MODE</em> Set overlay mode.</p>
6022</li>
6023<li>
6024<p><em>REQ_NEW_LINE</em> New line request (see below for
6025explanation).</p>
6026</li>
6027<li>
6028<p><em>REQ_INS_CHAR</em> Insert space at character location.</p>
6029</li>
6030<li>
6031<p><em>REQ_INS_LINE</em> Insert blank line at character
6032location.</p>
6033</li>
6034<li>
6035<p><em>REQ_DEL_CHAR</em> Delete character at cursor.</p>
6036</li>
6037<li>
6038<p><em>REQ_DEL_PREV</em> Delete previous word at cursor.</p>
6039</li>
6040<li>
6041<p><em>REQ_DEL_LINE</em> Delete line at cursor.</p>
6042</li>
6043<li>
6044<p><em>REQ_DEL_WORD</em> Delete word at cursor.</p>
6045</li>
6046<li>
6047<p><em>REQ_CLR_EOL</em> Clear to end of line.</p>
6048</li>
6049<li>
6050<p><em>REQ_CLR_EOF</em> Clear to end of field.</p>
6051</li>
6052<li>
6053<p><em>REQ_CLR_FIELD</em> Clear entire field.</p>
6054</li>
6055</ul>
6056<p>The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is
6057complicated and partly controlled by a pair of forms options. The
6058special cases are triggered when the cursor is at the beginning of
6059a field, or on the last line of the field.</p>
6060<p>First, we consider REQ_NEW_LINE:</p>
6061<p>The normal behavior of REQ_NEW_LINE in insert mode is to break
6062the current line at the position of the edit cursor, inserting the
6063portion of the current line after the cursor as a new line
6064following the current and moving the cursor to the beginning of
6065that new line (you may think of this as inserting a newline in the
6066field buffer).</p>
6067<p>The normal behavior of REQ_NEW_LINE in overlay mode is to clear
6068the current line from the position of the edit cursor to end of
6069line. The cursor is then moved to the beginning of the next
6070line.</p>
6071<p>However, REQ_NEW_LINE at the beginning of a field, or on the
6072last line of a field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD
6073option is off, this special action is disabled.</p>
6074<p>Now, let us consider REQ_DEL_PREV:</p>
6075<p>The normal behavior of REQ_DEL_PREV is to delete the previous
6076character. If insert mode is on, and the cursor is at the start of
6077a line, and the text on that line will fit on the previous one, it
6078instead appends the contents of the current line to the previous
6079one and deletes the current line (you may think of this as deleting
6080a newline from the field buffer).</p>
6081<p>However, REQ_DEL_PREV at the beginning of a field is instead
6082treated as a REQ_PREV_FIELD.</p>
6083<p>If the O_BS_OVERLOAD option is off, this special action is
6084disabled and the forms driver just returns E_REQUEST_DENIED.</p>
6085</div>
6086<div class="SECT3">
6087<hr>
6088<h4 class="SECT3"><a name="ORDERREQ" id="ORDERREQ">18.6.6. Order
6089Requests</a></h4>
6090<p>If the type of your field is ordered, and has associated
6091functions for getting the next and previous values of the type from
6092a given value, there are requests that can fetch that value into
6093the field buffer:</p>
6094<ul>
6095<li>
6096<p><em>REQ_NEXT_CHOICE</em> Place the successor value of the
6097current value in the buffer.</p>
6098</li>
6099<li>
6100<p><em>REQ_PREV_CHOICE</em> Place the predecessor value of the
6101current value in the buffer.</p>
6102</li>
6103</ul>
6104<p>Of the built-in field types, only TYPE_ENUM has built-in
6105successor and predecessor functions. When you define a field type
6106of your own (see Custom Validation Types), you can associate our
6107own ordering functions.</p>
6108</div>
6109<div class="SECT3">
6110<hr>
6111<h4 class="SECT3"><a name="APPLICCOMMANDS" id=
6112"APPLICCOMMANDS">18.6.7. Application Commands</a></h4>
6113<p>Form requests are represented as integers above the curses value
6114greater than KEY_MAX and less than or equal to the constant
6115MAX_COMMAND. A value within this range gets ignored by
6116form_driver(). So this can be used for any purpose by the
6117application. It can be treated as an application specific action
6118and take corresponding action.</p>
6119</div>
6120</div>
6121</div>
6122<div class="SECT1">
6123<hr>
6124<h2 class="SECT1"><a name="TOOLS" id="TOOLS">19. Tools and Widget
6125Libraries</a></h2>
6126<p>Now that you have seen the capabilities of ncurses and its
6127sister libraries, you are rolling your sleeves up and gearing for a
6128project that heavily manipulates screen. But wait.. It can be
6129pretty difficult to write and maintain complex GUI widgets in plain
6130ncurses or even with the additional libraries. There are some
6131ready-to-use tools and widget libraries that can be used instead of
6132writing your own widgets. You can use some of them, get ideas from
6133the code, or even extend them.</p>
6134<div class="SECT2">
6135<hr>
6136<h3 class="SECT2"><a name="CDK" id="CDK">19.1. CDK (Curses
6137Development Kit)</a></h3>
6138<p>In the author's words</p>
6139<p><em>CDK stands for 'Curses Development Kit' and it currently
6140contains 21 ready to use widgets which facilitate the speedy
6141development of full screen curses programs.</em></p>
6142<p>The kit provides some useful widgets, which can be used in your
6143programs directly. It's pretty well written and the documentation
6144is very good. The examples in the examples directory can be a good
6145place to start for beginners. The CDK can be downloaded from
6146<a href="http://invisible-island.net/cdk/" target=
6147"_top">http://invisible-island.net/cdk/</a> . Follow the
6148instructions in README file to install it.</p>
6149<div class="SECT3">
6150<hr>
6151<h4 class="SECT3"><a name="WIDGETLIST" id="WIDGETLIST">19.1.1.
6152Widget List</a></h4>
6153<p>The following is the list of widgets provided with cdk and their
6154description.</p>
6155<table border="0" bgcolor="#E0E0E0" width="100%">
6156<tr>
6157<td>
6158<pre class="PROGRAMLISTING">
6159<font color="#000000">Widget Type Quick Description
7425 char *regexp); /* expression to match */</PRE
7426><P
7427>The syntax for regular expressions is that of regcomp(3).
7428The check for regular-expression match is performed on exit.</P
7429></DIV
7430><DIV
7431CLASS="SECT2"
7432><HR><H3
7433CLASS="SECT2"
7434><A
7435NAME="FORMDRIVER"
7436>18.6. Form Driver: The work horse of the forms system</A
7437></H3
7438><P
7439>As in the menu system, form_driver() plays a very important role in forms
7440system. All types of requests to forms system should be funneled through
7441form_driver().</P
7442><PRE
7443CLASS="PROGRAMLISTING"
7444>int form_driver(FORM *form, /* form on which to operate */
7445 int request) /* form request code */</PRE
7446><P
7447>As you have seen some of the examples above, you have to be in a loop looking
7448for user input and then decide whether it's a field data or a form request. The
7449form requests are then passed to form_driver() to do the work.</P
7450><P
7451>The requests roughly can be divided into following categories. Different
7452requests and their usage is explained below:</P
7453><DIV
7454CLASS="SECT3"
7455><HR><H4
7456CLASS="SECT3"
7457><A
7458NAME="PAGENAVREQ"
7459>18.6.1. Page Navigation Requests</A
7460></H4
7461><P
7462>These requests cause page-level moves through the form, triggering display of a
7463new form screen. A form can be made of multiple pages. If you have a big form
7464with lot of fields and logical sections, then you can divide the form into
7465pages. The function set_new_page() to set a new page at the field specified.</P
7466><PRE
7467CLASS="PROGRAMLISTING"
7468>int set_new_page(FIELD *field,/* Field at which page break to be set or unset */
7469 bool new_page_flag); /* should be TRUE to put a break */</PRE
7470><P
7471>The following requests allow you to move to different pages</P
7472><P
7473></P
7474><UL
7475><LI
7476><P
7477><SPAN
7478CLASS="emphasis"
7479><I
7480CLASS="EMPHASIS"
7481>REQ_NEXT_PAGE</I
7482></SPAN
7483> Move to the next form page.</P
7484></LI
7485><LI
7486><P
7487><SPAN
7488CLASS="emphasis"
7489><I
7490CLASS="EMPHASIS"
7491>REQ_PREV_PAGE</I
7492></SPAN
7493> Move to the previous
7494form page.</P
7495></LI
7496><LI
7497><P
7498><SPAN
7499CLASS="emphasis"
7500><I
7501CLASS="EMPHASIS"
7502>REQ_FIRST_PAGE</I
7503></SPAN
7504> Move to the first form page.</P
7505></LI
7506><LI
7507><P
7508><SPAN
7509CLASS="emphasis"
7510><I
7511CLASS="EMPHASIS"
7512>REQ_LAST_PAGE</I
7513></SPAN
7514> Move to the last form page. </P
7515></LI
7516></UL
7517><P
7518>These requests treat the list as cyclic; that is, REQ_NEXT_PAGE from the
7519last page goes to the first, and REQ_PREV_PAGE from the first page goes to
7520the last.</P
7521></DIV
7522><DIV
7523CLASS="SECT3"
7524><HR><H4
7525CLASS="SECT3"
7526><A
7527NAME="INTERFIELDNAVREQ"
7528>18.6.2. Inter-Field Navigation Requests</A
7529></H4
7530><P
7531>These requests handle navigation between fields on the same page.</P
7532><P
7533></P
7534><UL
7535><LI
7536><P
7537><SPAN
7538CLASS="emphasis"
7539><I
7540CLASS="EMPHASIS"
7541>REQ_NEXT_FIELD</I
7542></SPAN
7543>
7544 Move to next field. </P
7545></LI
7546><LI
7547><P
7548><SPAN
7549CLASS="emphasis"
7550><I
7551CLASS="EMPHASIS"
7552>REQ_PREV_FIELD</I
7553></SPAN
7554>
7555 Move to previous field. </P
7556></LI
7557><LI
7558><P
7559><SPAN
7560CLASS="emphasis"
7561><I
7562CLASS="EMPHASIS"
7563>REQ_FIRST_FIELD</I
7564></SPAN
7565>
7566 Move to the first field. </P
7567></LI
7568><LI
7569><P
7570><SPAN
7571CLASS="emphasis"
7572><I
7573CLASS="EMPHASIS"
7574>REQ_LAST_FIELD</I
7575></SPAN
7576>
7577 Move to the last field. </P
7578></LI
7579><LI
7580><P
7581><SPAN
7582CLASS="emphasis"
7583><I
7584CLASS="EMPHASIS"
7585>REQ_SNEXT_FIELD</I
7586></SPAN
7587>
7588 Move to sorted next field. </P
7589></LI
7590><LI
7591><P
7592><SPAN
7593CLASS="emphasis"
7594><I
7595CLASS="EMPHASIS"
7596>REQ_SPREV_FIELD</I
7597></SPAN
7598>
7599 Move to sorted previous field. </P
7600></LI
7601><LI
7602><P
7603><SPAN
7604CLASS="emphasis"
7605><I
7606CLASS="EMPHASIS"
7607>REQ_SFIRST_FIELD</I
7608></SPAN
7609>
7610 Move to the sorted first field. </P
7611></LI
7612><LI
7613><P
7614><SPAN
7615CLASS="emphasis"
7616><I
7617CLASS="EMPHASIS"
7618>REQ_SLAST_FIELD</I
7619></SPAN
7620>
7621 Move to the sorted last field. </P
7622></LI
7623><LI
7624><P
7625><SPAN
7626CLASS="emphasis"
7627><I
7628CLASS="EMPHASIS"
7629>REQ_LEFT_FIELD</I
7630></SPAN
7631>
7632 Move left to field. </P
7633></LI
7634><LI
7635><P
7636><SPAN
7637CLASS="emphasis"
7638><I
7639CLASS="EMPHASIS"
7640>REQ_RIGHT_FIELD</I
7641></SPAN
7642>
7643 Move right to field. </P
7644></LI
7645><LI
7646><P
7647><SPAN
7648CLASS="emphasis"
7649><I
7650CLASS="EMPHASIS"
7651>REQ_UP_FIELD</I
7652></SPAN
7653>
7654 Move up to field. </P
7655></LI
7656><LI
7657><P
7658><SPAN
7659CLASS="emphasis"
7660><I
7661CLASS="EMPHASIS"
7662>REQ_DOWN_FIELD</I
7663></SPAN
7664>
7665 Move down to field. </P
7666></LI
7667></UL
7668><P
7669>These requests treat the list of fields on a page as cyclic; that is,
7670REQ_NEXT_FIELD from the last field goes to the first, and REQ_PREV_FIELD
7671from the first field goes to the last. The order of the fields for these
7672(and the REQ_FIRST_FIELD and REQ_LAST_FIELD requests) is simply the order of
7673the field pointers in the form array (as set up by new_form() or
7674set_form_fields()</P
7675><P
7676>It is also possible to traverse the fields as if they had been sorted in
7677screen-position order, so the sequence goes left-to-right and top-to-bottom.
7678To do this, use the second group of four sorted-movement requests.</P
7679><P
7680>Finally, it is possible to move between fields using visual directions up,
7681down, right, and left. To accomplish this, use the third group of four
7682requests. Note, however, that the position of a form for purposes of these
7683requests is its upper-left corner.</P
7684><P
7685>For example, suppose you have a multi-line field B, and two single-line
7686fields A and C on the same line with B, with A to the left of B and C to the
7687right of B. A REQ_MOVE_RIGHT from A will go to B only if A, B, and C all
7688share the same first line; otherwise it will skip over B to C.</P
7689></DIV
7690><DIV
7691CLASS="SECT3"
7692><HR><H4
7693CLASS="SECT3"
7694><A
7695NAME="INTRAFIELDNAVREQ"
7696>18.6.3. Intra-Field Navigation Requests</A
7697></H4
7698><P
7699>These requests drive movement of the edit cursor within the currently
7700selected field.</P
7701><P
7702></P
7703><UL
7704><LI
7705><P
7706><SPAN
7707CLASS="emphasis"
7708><I
7709CLASS="EMPHASIS"
7710>REQ_NEXT_CHAR</I
7711></SPAN
7712>
7713 Move to next character. </P
7714></LI
7715><LI
7716><P
7717><SPAN
7718CLASS="emphasis"
7719><I
7720CLASS="EMPHASIS"
7721>REQ_PREV_CHAR</I
7722></SPAN
7723>
7724 Move to previous character. </P
7725></LI
7726><LI
7727><P
7728><SPAN
7729CLASS="emphasis"
7730><I
7731CLASS="EMPHASIS"
7732>REQ_NEXT_LINE</I
7733></SPAN
7734>
7735 Move to next line. </P
7736></LI
7737><LI
7738><P
7739><SPAN
7740CLASS="emphasis"
7741><I
7742CLASS="EMPHASIS"
7743>REQ_PREV_LINE</I
7744></SPAN
7745>
7746 Move to previous line. </P
7747></LI
7748><LI
7749><P
7750><SPAN
7751CLASS="emphasis"
7752><I
7753CLASS="EMPHASIS"
7754>REQ_NEXT_WORD</I
7755></SPAN
7756>
7757 Move to next word. </P
7758></LI
7759><LI
7760><P
7761><SPAN
7762CLASS="emphasis"
7763><I
7764CLASS="EMPHASIS"
7765>REQ_PREV_WORD</I
7766></SPAN
7767>
7768 Move to previous word. </P
7769></LI
7770><LI
7771><P
7772><SPAN
7773CLASS="emphasis"
7774><I
7775CLASS="EMPHASIS"
7776>REQ_BEG_FIELD</I
7777></SPAN
7778>
7779 Move to beginning of field. </P
7780></LI
7781><LI
7782><P
7783><SPAN
7784CLASS="emphasis"
7785><I
7786CLASS="EMPHASIS"
7787>REQ_END_FIELD</I
7788></SPAN
7789>
7790 Move to end of field. </P
7791></LI
7792><LI
7793><P
7794><SPAN
7795CLASS="emphasis"
7796><I
7797CLASS="EMPHASIS"
7798>REQ_BEG_LINE</I
7799></SPAN
7800>
7801 Move to beginning of line. </P
7802></LI
7803><LI
7804><P
7805><SPAN
7806CLASS="emphasis"
7807><I
7808CLASS="EMPHASIS"
7809>REQ_END_LINE</I
7810></SPAN
7811>
7812 Move to end of line. </P
7813></LI
7814><LI
7815><P
7816><SPAN
7817CLASS="emphasis"
7818><I
7819CLASS="EMPHASIS"
7820>REQ_LEFT_CHAR</I
7821></SPAN
7822>
7823 Move left in field. </P
7824></LI
7825><LI
7826><P
7827><SPAN
7828CLASS="emphasis"
7829><I
7830CLASS="EMPHASIS"
7831>REQ_RIGHT_CHAR</I
7832></SPAN
7833>
7834 Move right in field. </P
7835></LI
7836><LI
7837><P
7838><SPAN
7839CLASS="emphasis"
7840><I
7841CLASS="EMPHASIS"
7842>REQ_UP_CHAR</I
7843></SPAN
7844>
7845 Move up in field. </P
7846></LI
7847><LI
7848><P
7849><SPAN
7850CLASS="emphasis"
7851><I
7852CLASS="EMPHASIS"
7853>REQ_DOWN_CHAR</I
7854></SPAN
7855>
7856 Move down in field. </P
7857></LI
7858></UL
7859><P
7860>Each word is separated from the previous and next characters by whitespace.
7861The commands to move to beginning and end of line or field look for the
7862first or last non-pad character in their ranges.</P
7863></DIV
7864><DIV
7865CLASS="SECT3"
7866><HR><H4
7867CLASS="SECT3"
7868><A
7869NAME="SCROLLREQ"
7870>18.6.4. Scrolling Requests</A
7871></H4
7872><P
7873>Fields that are dynamic and have grown and fields explicitly created with
7874offscreen rows are scrollable. One-line fields scroll horizontally;
7875multi-line fields scroll vertically. Most scrolling is triggered by editing
7876and intra-field movement (the library scrolls the field to keep the cursor
7877visible). It is possible to explicitly request scrolling with the following
7878requests:</P
7879><P
7880></P
7881><UL
7882><LI
7883><P
7884><SPAN
7885CLASS="emphasis"
7886><I
7887CLASS="EMPHASIS"
7888>REQ_SCR_FLINE</I
7889></SPAN
7890>
7891 Scroll vertically forward a line. </P
7892></LI
7893><LI
7894><P
7895><SPAN
7896CLASS="emphasis"
7897><I
7898CLASS="EMPHASIS"
7899>REQ_SCR_BLINE</I
7900></SPAN
7901>
7902 Scroll vertically backward a line. </P
7903></LI
7904><LI
7905><P
7906><SPAN
7907CLASS="emphasis"
7908><I
7909CLASS="EMPHASIS"
7910>REQ_SCR_FPAGE</I
7911></SPAN
7912>
7913 Scroll vertically forward a page. </P
7914></LI
7915><LI
7916><P
7917><SPAN
7918CLASS="emphasis"
7919><I
7920CLASS="EMPHASIS"
7921>REQ_SCR_BPAGE</I
7922></SPAN
7923>
7924 Scroll vertically backward a page. </P
7925></LI
7926><LI
7927><P
7928><SPAN
7929CLASS="emphasis"
7930><I
7931CLASS="EMPHASIS"
7932>REQ_SCR_FHPAGE</I
7933></SPAN
7934>
7935 Scroll vertically forward half a page. </P
7936></LI
7937><LI
7938><P
7939><SPAN
7940CLASS="emphasis"
7941><I
7942CLASS="EMPHASIS"
7943>REQ_SCR_BHPAGE</I
7944></SPAN
7945>
7946 Scroll vertically backward half a page. </P
7947></LI
7948><LI
7949><P
7950><SPAN
7951CLASS="emphasis"
7952><I
7953CLASS="EMPHASIS"
7954>REQ_SCR_FCHAR</I
7955></SPAN
7956>
7957 Scroll horizontally forward a character. </P
7958></LI
7959><LI
7960><P
7961><SPAN
7962CLASS="emphasis"
7963><I
7964CLASS="EMPHASIS"
7965>REQ_SCR_BCHAR</I
7966></SPAN
7967>
7968 Scroll horizontally backward a character. </P
7969></LI
7970><LI
7971><P
7972><SPAN
7973CLASS="emphasis"
7974><I
7975CLASS="EMPHASIS"
7976>REQ_SCR_HFLINE</I
7977></SPAN
7978>
7979 Scroll horizontally one field width forward. </P
7980></LI
7981><LI
7982><P
7983><SPAN
7984CLASS="emphasis"
7985><I
7986CLASS="EMPHASIS"
7987>REQ_SCR_HBLINE</I
7988></SPAN
7989>
7990 Scroll horizontally one field width backward. </P
7991></LI
7992><LI
7993><P
7994><SPAN
7995CLASS="emphasis"
7996><I
7997CLASS="EMPHASIS"
7998>REQ_SCR_HFHALF</I
7999></SPAN
8000>
8001 Scroll horizontally one half field width forward. </P
8002></LI
8003><LI
8004><P
8005><SPAN
8006CLASS="emphasis"
8007><I
8008CLASS="EMPHASIS"
8009>REQ_SCR_HBHALF</I
8010></SPAN
8011>
8012 Scroll horizontally one half field width backward. </P
8013></LI
8014></UL
8015><P
8016>For scrolling purposes, a page of a field is the height of its visible part.</P
8017></DIV
8018><DIV
8019CLASS="SECT3"
8020><HR><H4
8021CLASS="SECT3"
8022><A
8023NAME="EDITREQ"
8024>18.6.5. Editing Requests</A
8025></H4
8026><P
8027>When you pass the forms driver an ASCII character, it is treated as a
8028request to add the character to the field's data buffer. Whether this is an
8029insertion or a replacement depends on the field's edit mode (insertion is
8030the default.</P
8031><P
8032>The following requests support editing the field and changing the edit mode:</P
8033><P
8034></P
8035><UL
8036><LI
8037><P
8038><SPAN
8039CLASS="emphasis"
8040><I
8041CLASS="EMPHASIS"
8042>REQ_INS_MODE</I
8043></SPAN
8044>
8045 Set insertion mode. </P
8046></LI
8047><LI
8048><P
8049><SPAN
8050CLASS="emphasis"
8051><I
8052CLASS="EMPHASIS"
8053>REQ_OVL_MODE</I
8054></SPAN
8055>
8056 Set overlay mode. </P
8057></LI
8058><LI
8059><P
8060><SPAN
8061CLASS="emphasis"
8062><I
8063CLASS="EMPHASIS"
8064>REQ_NEW_LINE</I
8065></SPAN
8066>
8067 New line request (see below for explanation). </P
8068></LI
8069><LI
8070><P
8071><SPAN
8072CLASS="emphasis"
8073><I
8074CLASS="EMPHASIS"
8075>REQ_INS_CHAR</I
8076></SPAN
8077>
8078 Insert space at character location. </P
8079></LI
8080><LI
8081><P
8082><SPAN
8083CLASS="emphasis"
8084><I
8085CLASS="EMPHASIS"
8086>REQ_INS_LINE</I
8087></SPAN
8088>
8089 Insert blank line at character location. </P
8090></LI
8091><LI
8092><P
8093><SPAN
8094CLASS="emphasis"
8095><I
8096CLASS="EMPHASIS"
8097>REQ_DEL_CHAR</I
8098></SPAN
8099>
8100 Delete character at cursor. </P
8101></LI
8102><LI
8103><P
8104><SPAN
8105CLASS="emphasis"
8106><I
8107CLASS="EMPHASIS"
8108>REQ_DEL_PREV</I
8109></SPAN
8110>
8111 Delete previous word at cursor. </P
8112></LI
8113><LI
8114><P
8115><SPAN
8116CLASS="emphasis"
8117><I
8118CLASS="EMPHASIS"
8119>REQ_DEL_LINE</I
8120></SPAN
8121>
8122 Delete line at cursor. </P
8123></LI
8124><LI
8125><P
8126><SPAN
8127CLASS="emphasis"
8128><I
8129CLASS="EMPHASIS"
8130>REQ_DEL_WORD</I
8131></SPAN
8132>
8133 Delete word at cursor. </P
8134></LI
8135><LI
8136><P
8137><SPAN
8138CLASS="emphasis"
8139><I
8140CLASS="EMPHASIS"
8141>REQ_CLR_EOL</I
8142></SPAN
8143>
8144 Clear to end of line. </P
8145></LI
8146><LI
8147><P
8148><SPAN
8149CLASS="emphasis"
8150><I
8151CLASS="EMPHASIS"
8152>REQ_CLR_EOF</I
8153></SPAN
8154>
8155 Clear to end of field. </P
8156></LI
8157><LI
8158><P
8159><SPAN
8160CLASS="emphasis"
8161><I
8162CLASS="EMPHASIS"
8163>REQ_CLR_FIELD</I
8164></SPAN
8165>
8166 Clear entire field. </P
8167></LI
8168></UL
8169><P
8170>The behavior of the REQ_NEW_LINE and REQ_DEL_PREV requests is complicated
8171and partly controlled by a pair of forms options. The special cases are
8172triggered when the cursor is at the beginning of a field, or on the last
8173line of the field.</P
8174><P
8175>First, we consider REQ_NEW_LINE:</P
8176><P
8177>The normal behavior of REQ_NEW_LINE in insert mode is to break the current
8178line at the position of the edit cursor, inserting the portion of the
8179current line after the cursor as a new line following the current and moving
8180the cursor to the beginning of that new line (you may think of this as
8181inserting a newline in the field buffer).</P
8182><P
8183>The normal behavior of REQ_NEW_LINE in overlay mode is to clear the current
8184line from the position of the edit cursor to end of line. The cursor is then
8185moved to the beginning of the next line.</P
8186><P
8187>However, REQ_NEW_LINE at the beginning of a field, or on the last line of a
8188field, instead does a REQ_NEXT_FIELD. O_NL_OVERLOAD option is off, this
8189special action is disabled.</P
8190><P
8191>Now, let us consider REQ_DEL_PREV:</P
8192><P
8193>The normal behavior of REQ_DEL_PREV is to delete the previous character. If
8194insert mode is on, and the cursor is at the start of a line, and the text on
8195that line will fit on the previous one, it instead appends the contents of
8196the current line to the previous one and deletes the current line (you may
8197think of this as deleting a newline from the field buffer).</P
8198><P
8199>However, REQ_DEL_PREV at the beginning of a field is instead treated as a
8200REQ_PREV_FIELD.</P
8201><P
8202>If the O_BS_OVERLOAD option is off, this special action is disabled and the
8203forms driver just returns E_REQUEST_DENIED.</P
8204></DIV
8205><DIV
8206CLASS="SECT3"
8207><HR><H4
8208CLASS="SECT3"
8209><A
8210NAME="ORDERREQ"
8211>18.6.6. Order Requests</A
8212></H4
8213><P
8214>If the type of your field is ordered, and has associated functions for
8215getting the next and previous values of the type from a given value, there
8216are requests that can fetch that value into the field buffer:</P
8217><P
8218></P
8219><UL
8220><LI
8221><P
8222><SPAN
8223CLASS="emphasis"
8224><I
8225CLASS="EMPHASIS"
8226>REQ_NEXT_CHOICE</I
8227></SPAN
8228>
8229 Place the successor value of the current value in the buffer.
8230 </P
8231></LI
8232><LI
8233><P
8234><SPAN
8235CLASS="emphasis"
8236><I
8237CLASS="EMPHASIS"
8238>REQ_PREV_CHOICE</I
8239></SPAN
8240>
8241 Place the predecessor value of the current value in the buffer.
8242 </P
8243></LI
8244></UL
8245><P
8246>Of the built-in field types, only TYPE_ENUM has built-in successor and
8247predecessor functions. When you define a field type of your own (see Custom
8248Validation Types), you can associate our own ordering functions.</P
8249></DIV
8250><DIV
8251CLASS="SECT3"
8252><HR><H4
8253CLASS="SECT3"
8254><A
8255NAME="APPLICCOMMANDS"
8256>18.6.7. Application Commands</A
8257></H4
8258><P
8259>Form requests are represented as integers above the curses value greater than
8260KEY_MAX and less than or equal to the constant MAX_COMMAND. A value within this
8261range gets ignored by form_driver(). So this can be used for any purpose by the
8262application. It can be treated as an application specific action and take
8263corresponding action.</P
8264></DIV
8265></DIV
8266></DIV
8267><DIV
8268CLASS="SECT1"
8269><HR><H2
8270CLASS="SECT1"
8271><A
8272NAME="TOOLS"
8273>19. Tools and Widget Libraries</A
8274></H2
8275><P
8276>
8277Now that you have seen the capabilities of ncurses and its sister libraries, you
8278are rolling your sleeves up and gearing for a project that heavily manipulates
8279screen. But wait.. It can be pretty difficult to write and maintain complex GUI
8280widgets in plain ncurses or even with the additional libraries. There are some
8281ready-to-use tools and widget libraries that can be used instead of writing your
8282own widgets. You can use some of them, get ideas from the code, or even extend
8283them.</P
8284><DIV
8285CLASS="SECT2"
8286><HR><H3
8287CLASS="SECT2"
8288><A
8289NAME="CDK"
8290>19.1. CDK (Curses Development Kit)</A
8291></H3
8292><P
8293>In the author's words </P
8294><P
8295><SPAN
8296CLASS="emphasis"
8297><I
8298CLASS="EMPHASIS"
8299>
8300CDK stands for 'Curses Development Kit' and it currently contains 21 ready
8301to use widgets which facilitate the speedy development of full screen
8302curses programs. </I
8303></SPAN
8304></P
8305><P
8306>The kit provides some useful widgets, which can be used in your programs
8307directly. It's pretty well written and the documentation is very good. The
8308examples in the examples directory can be a good place to start for beginners.
8309The CDK can be downloaded from <A
8310HREF="http://invisible-island.net/cdk/"
8311TARGET="_top"
8312>http://invisible-island.net/cdk/</A
8313>
8314. Follow the instructions in
8315README file to install it.</P
8316><DIV
8317CLASS="SECT3"
8318><HR><H4
8319CLASS="SECT3"
8320><A
8321NAME="WIDGETLIST"
8322>19.1.1. Widget List</A
8323></H4
8324><P
8325>The following is the list of widgets provided with cdk and their description.</P
8326><PRE
8327CLASS="PROGRAMLISTING"
8328>Widget Type Quick Description
6160===========================================================================
6161Alphalist Allows a user to select from a list of words, with
6162 the ability to narrow the search list by typing in a
6163 few characters of the desired word.
6164Buttonbox This creates a multiple button widget.
6165Calendar Creates a little simple calendar widget.
6166Dialog Prompts the user with a message, and the user
6167 can pick an answer from the buttons provided.

--- 26 unchanged lines hidden (view full) ---

6194Selection List Creates a multiple option selection list.
6195Slider Akin to the scale widget, this widget provides a
6196 visual slide bar to represent the numeric value.
6197Template Creates a entry field with character sensitive
6198 positions. Used for pre-formatted fields like
6199 dates and phone numbers.
6200Viewer This is a file/information viewer. Very useful
6201 when you need to display loads of information.
8329===========================================================================
8330Alphalist Allows a user to select from a list of words, with
8331 the ability to narrow the search list by typing in a
8332 few characters of the desired word.
8333Buttonbox This creates a multiple button widget.
8334Calendar Creates a little simple calendar widget.
8335Dialog Prompts the user with a message, and the user
8336 can pick an answer from the buttons provided.

--- 26 unchanged lines hidden (view full) ---

8363Selection List Creates a multiple option selection list.
8364Slider Akin to the scale widget, this widget provides a
8365 visual slide bar to represent the numeric value.
8366Template Creates a entry field with character sensitive
8367 positions. Used for pre-formatted fields like
8368 dates and phone numbers.
8369Viewer This is a file/information viewer. Very useful
8370 when you need to display loads of information.
6202===========================================================================</font>
6203</pre></td>
6204</tr>
6205</table>
6206<p>A few of the widgets are modified by Thomas Dickey in recent
6207versions.</p>
6208</div>
6209<div class="SECT3">
6210<hr>
6211<h4 class="SECT3"><a name="CDKATTRACT" id="CDKATTRACT">19.1.2. Some
6212Attractive Features</a></h4>
6213<p>Apart from making our life easier with readily usable widgets,
6214cdk solves one frustrating problem with printing multi colored
6215strings, justified strings elegantly. Special formatting tags can
6216be embedded in the strings which are passed to CDK functions. For
6217Example</p>
6218<p>If the string</p>
6219<table border="0" bgcolor="#E0E0E0" width="100%">
6220<tr>
6221<td>
6222<pre class="PROGRAMLISTING">
6223<font color=
6224"#000000">"&lt;/B/1&gt;This line should have a yellow foreground and a blue
6225background.&lt;!1&gt;"</font>
6226</pre></td>
6227</tr>
6228</table>
6229<p>given as a parameter to newCDKLabel(), it prints the line with
6230yellow foreground and blue background. There are other tags
6231available for justifying string, embedding special drawing
6232characters etc.. Please refer to the man page cdk_display(3X) for
6233details. The man page explains the usage with nice examples.</p>
6234</div>
6235<div class="SECT3">
6236<hr>
6237<h4 class="SECT3"><a name="CDKCONCLUSION" id=
6238"CDKCONCLUSION">19.1.3. Conclusion</a></h4>
6239<p>All in all, CDK is a well-written package of widgets, which if
6240used properly can form a strong frame work for developing complex
6241GUI.</p>
6242</div>
6243</div>
6244<div class="SECT2">
6245<hr>
6246<h3 class="SECT2"><a name="DIALOG" id="DIALOG">19.2. The
6247dialog</a></h3>
6248<p>Long long ago, in September 1994, when few people knew linux,
6249Jeff Tranter wrote an <a href=
6250"http://www2.linuxjournal.com/lj-issues/issue5/2807.html" target=
6251"_top">article</a> on dialog in Linux Journal. He starts the
6252article with these words..</p>
6253<p><em>Linux is based on the Unix operating system, but also
6254features a number of unique and useful kernel features and
6255application programs that often go beyond what is available under
6256Unix. One little-known gem is "dialog", a utility for creating
6257professional-looking dialog boxes from within shell scripts. This
6258article presents a tutorial introduction to the dialog utility, and
6259shows examples of how and where it can be used</em></p>
6260<p>As he explains, dialog is a real gem in making
6261professional-looking dialog boxes with ease. It creates a variety
6262of dialog boxes, menus, check lists etc.. It is usually installed
6263by default. If not, you can download it from <a href=
6264"http://invisible-island.net/dialog/" target="_top">Thomas
6265Dickey</a>'s site.</p>
6266<p>The above-mentioned article gives a very good overview of its
6267uses and capabilites. The man page has more details. It can be used
6268in variety of situations. One good example is building of linux
6269kernel in text mode. Linux kernel uses a modified version of dialog
6270tailored for its needs.</p>
6271<p>dialog was initially designed to be used with shell scripts. If
6272you want to use its functionality in a c program, then you can use
6273libdialog. The documentation regarding this is sparse. Definitive
6274reference is the dialog.h header file which comes with the library.
6275You may need to hack here and there to get the required output. The
6276source is easily customizable. I have used it on a number of
6277occasions by modifying the code.</p>
6278</div>
6279<div class="SECT2">
6280<hr>
6281<h3 class="SECT2"><a name="PERLCURSES" id="PERLCURSES">19.3. Perl
6282Curses Modules CURSES::FORM and CURSES::WIDGETS</a></h3>
6283<p>The perl module Curses, Curses::Form and Curses::Widgets give
6284access to curses from perl. If you have curses and basic perl is
6285installed, you can get these modules from <a href=
6286"http://www.cpan.org/modules/01modules.index.html" target=
6287"_top">CPAN All Modules page</a>. Get the three zipped modules in
6288the Curses category. Once installed you can use these modules from
6289perl scripts like any other module. For more information on perl
6290modules see perlmod man page. The above modules come with good
6291documentation and they have some demo scripts to test the
6292functionality. Though the widgets provided are very rudimentary,
6293these modules provide good access to curses library from perl.</p>
6294<p>Some of my code examples are converted to perl by Anuradha
6295Ratnaweera and they are available in the <var class=
6296"LITERAL">perl</var> directory.</p>
6297<p>For more information see man pages Curses(3) , Curses::Form(3)
6298and Curses::Widgets(3). These pages are installed only when the
6299above modules are acquired and installed.</p>
6300</div>
6301</div>
6302<div class="SECT1">
6303<hr>
6304<h2 class="SECT1"><a name="JUSTFORFUN" id="JUSTFORFUN">20. Just For
6305Fun !!!</a></h2>
6306<p>This section contains few programs written by me just for fun.
6307They don't signify a better programming practice or the best way of
6308using ncurses. They are provided here so as to allow beginners to
6309get ideas and add more programs to this section. If you have
6310written a couple of nice, simple programs in curses and want them
6311to included here, contact <a href="mailto:ppadala@gmail.com"
6312target="_top">me</a>.</p>
6313<div class="SECT2">
6314<hr>
6315<h3 class="SECT2"><a name="GAMEOFLIFE" id="GAMEOFLIFE">20.1. The
6316Game of Life</a></h3>
6317<p>Game of life is a wonder of math. In <a href=
6318"http://www.math.com/students/wonders/life/life.html" target=
6319"_top">Paul Callahan</a>'s words</p>
6320<table border="0" bgcolor="#E0E0E0" width="100%">
6321<tr>
6322<td>
6323<pre class="PROGRAMLISTING">
6324<font color=
6325"#000000"><em>The Game of Life (or simply Life) is not a game in the conventional sense. There
8371===========================================================================</PRE
8372><P
8373>A few of the widgets are modified by Thomas Dickey in recent versions.</P
8374></DIV
8375><DIV
8376CLASS="SECT3"
8377><HR><H4
8378CLASS="SECT3"
8379><A
8380NAME="CDKATTRACT"
8381>19.1.2. Some Attractive Features</A
8382></H4
8383><P
8384>Apart from making our life easier with readily usable widgets, cdk solves one
8385frustrating problem with printing multi colored strings, justified strings
8386elegantly. Special formatting tags can be embedded in the strings which are
8387passed to CDK functions. For Example</P
8388><P
8389>If the string</P
8390><PRE
8391CLASS="PROGRAMLISTING"
8392>"&lt;/B/1&gt;This line should have a yellow foreground and a blue
8393background.&lt;!1&gt;"</PRE
8394><P
8395>given as a parameter to newCDKLabel(), it prints the line with yellow foreground
8396and blue background. There are other tags available for justifying string,
8397embedding special drawing characters etc.. Please refer to the man page
8398cdk_display(3X) for details. The man page explains the usage with nice examples.</P
8399></DIV
8400><DIV
8401CLASS="SECT3"
8402><HR><H4
8403CLASS="SECT3"
8404><A
8405NAME="CDKCONCLUSION"
8406>19.1.3. Conclusion</A
8407></H4
8408><P
8409>All in all, CDK is a well-written package of widgets, which if used properly can
8410form a strong frame work for developing complex GUI.</P
8411></DIV
8412></DIV
8413><DIV
8414CLASS="SECT2"
8415><HR><H3
8416CLASS="SECT2"
8417><A
8418NAME="DIALOG"
8419>19.2. The dialog</A
8420></H3
8421><P
8422>Long long ago, in September 1994, when few people knew linux, Jeff Tranter wrote
8423an <A
8424HREF="http://www2.linuxjournal.com/lj-issues/issue5/2807.html"
8425TARGET="_top"
8426>article</A
8427> on dialog in Linux Journal. He starts the article with these words..</P
8428><P
8429><SPAN
8430CLASS="emphasis"
8431><I
8432CLASS="EMPHASIS"
8433>Linux is based on the Unix operating system, but also features a number of
8434unique and useful kernel features and application programs that often go beyond
8435what is available under Unix. One little-known gem is "dialog", a utility for
8436creating professional-looking dialog boxes from within shell scripts. This
8437article presents a tutorial introduction to the dialog utility, and shows
8438examples of how and where it can be used</I
8439></SPAN
8440></P
8441><P
8442>
8443As he explains, dialog is a real gem in making professional-looking dialog boxes
8444with ease. It creates a variety of dialog boxes, menus, check lists etc.. It is
8445usually installed by default. If not, you can download it from <A
8446HREF="http://invisible-island.net/dialog/"
8447TARGET="_top"
8448>Thomas Dickey</A
8449>'s site. </P
8450><P
8451>The above-mentioned article gives a very good overview of its uses and
8452capabilites. The man page has more details. It can be used in variety of
8453situations. One good example is building of linux kernel in text mode. Linux
8454kernel uses a modified version of dialog tailored for its needs. </P
8455><P
8456>dialog was initially designed to be used with shell scripts. If you want to use
8457its functionality in a c program, then you can use libdialog. The documentation
8458regarding this is sparse. Definitive reference is the dialog.h header file which
8459comes with the library. You may need to hack here and there to get the required
8460output. The source is easily customizable. I have used it on a number of
8461occasions by modifying the code.</P
8462></DIV
8463><DIV
8464CLASS="SECT2"
8465><HR><H3
8466CLASS="SECT2"
8467><A
8468NAME="PERLCURSES"
8469>19.3. Perl Curses Modules CURSES::FORM and CURSES::WIDGETS</A
8470></H3
8471><P
8472>The perl module Curses, Curses::Form and Curses::Widgets give access to curses
8473from perl. If you have curses and basic perl is installed, you can get these
8474modules from <A
8475HREF="http://www.cpan.org/modules/01modules.index.html"
8476TARGET="_top"
8477> CPAN
8478All Modules page</A
8479>. Get the three zipped modules in the Curses category.
8480Once installed you can use these modules from perl scripts like any other
8481module. For more information on perl modules see perlmod man page. The above
8482modules come with good documentation and they have some demo scripts to test the
8483functionality. Though the widgets provided are very rudimentary, these modules
8484provide good access to curses library from perl.</P
8485><P
8486>Some of my code examples are converted to perl by Anuradha Ratnaweera and they
8487are available in the <TT
8488CLASS="LITERAL"
8489>perl</TT
8490> directory.</P
8491><P
8492>
8493For more information see man pages Curses(3) , Curses::Form(3) and
8494Curses::Widgets(3). These pages are installed only when the above modules are
8495acquired and installed.</P
8496></DIV
8497></DIV
8498><DIV
8499CLASS="SECT1"
8500><HR><H2
8501CLASS="SECT1"
8502><A
8503NAME="JUSTFORFUN"
8504>20. Just For Fun !!!</A
8505></H2
8506><P
8507>This section contains few programs written by me just for fun. They don't
8508signify a better programming practice or the best way of using ncurses. They are
8509provided here so as to allow beginners to get ideas and add more programs to
8510this section. If you have written a couple of nice, simple programs in curses
8511and want them to included here, contact <A
8512HREF="mailto:ppadala@gmail.com"
8513TARGET="_top"
8514>me</A
8515>.</P
8516><DIV
8517CLASS="SECT2"
8518><HR><H3
8519CLASS="SECT2"
8520><A
8521NAME="GAMEOFLIFE"
8522>20.1. The Game of Life</A
8523></H3
8524><P
8525>Game of life is a wonder of math. In
8526<A
8527HREF="http://www.math.com/students/wonders/life/life.html"
8528TARGET="_top"
8529>Paul Callahan</A
8530>'s words</P
8531><PRE
8532CLASS="PROGRAMLISTING"
8533><SPAN
8534CLASS="emphasis"
8535><I
8536CLASS="EMPHASIS"
8537>The Game of Life (or simply Life) is not a game in the conventional sense. There
6326are no players, and no winning or losing. Once the "pieces" are placed in the
6327starting position, the rules determine everything that happens later.
6328Nevertheless, Life is full of surprises! In most cases, it is impossible to look
6329at a starting position (or pattern) and see what will happen in the future. The
8538are no players, and no winning or losing. Once the "pieces" are placed in the
8539starting position, the rules determine everything that happens later.
8540Nevertheless, Life is full of surprises! In most cases, it is impossible to look
8541at a starting position (or pattern) and see what will happen in the future. The
6330only way to find out is to follow the rules of the game.</em></font>
6331</pre></td>
6332</tr>
6333</table>
6334<p>This program starts with a simple inverted U pattern and shows
6335how wonderful life works. There is a lot of room for improvement in
6336the program. You can let the user enter pattern of his choice or
6337even take input from a file. You can also change rules and play
6338with a lot of variations. Search on <a href="http://www.google.com"
6339target="_top">google</a> for interesting information on game of
6340life.</p>
6341<p><em>File Path: JustForFun/life.c</em></p>
6342</div>
6343<div class="SECT2">
6344<hr>
6345<h3 class="SECT2"><a name="MAGIC" id="MAGIC">20.2. Magic
6346Square</a></h3>
6347<p>Magic Square, another wonder of math, is very simple to
6348understand but very difficult to make. In a magic square sum of the
6349numbers in each row, each column is equal. Even diagnol sum can be
6350equal. There are many variations which have special properties.</p>
6351<p>This program creates a simple magic square of odd order.</p>
6352<p><em>File Path: JustForFun/magic.c</em></p>
6353</div>
6354<div class="SECT2">
6355<hr>
6356<h3 class="SECT2"><a name="HANOI" id="HANOI">20.3. Towers of
6357Hanoi</a></h3>
6358<p>The famous towers of hanoi solver. The aim of the game is to
6359move the disks on the first peg to last peg, using middle peg as a
6360temporary stay. The catch is not to place a larger disk over a
6361small disk at any time.</p>
6362<p><em>File Path: JustForFun/hanoi.c</em></p>
6363</div>
6364<div class="SECT2">
6365<hr>
6366<h3 class="SECT2"><a name="QUEENS" id="QUEENS">20.4. Queens
6367Puzzle</a></h3>
6368<p>The objective of the famous N-Queen puzzle is to put N queens on
6369a N X N chess board without attacking each other.</p>
6370<p>This program solves it with a simple backtracking technique.</p>
6371<p><em>File Path: JustForFun/queens.c</em></p>
6372</div>
6373<div class="SECT2">
6374<hr>
6375<h3 class="SECT2"><a name="SHUFFLE" id="SHUFFLE">20.5.
6376Shuffle</a></h3>
6377<p>A fun game, if you have time to kill.</p>
6378<p><em>File Path: JustForFun/shuffle.c</em></p>
6379</div>
6380<div class="SECT2">
6381<hr>
6382<h3 class="SECT2"><a name="TT" id="TT">20.6. Typing Tutor</a></h3>
6383<p>A simple typing tutor, I created more out of need than for ease
6384of use. If you know how to put your fingers correctly on the
6385keyboard, but lack practice, this can be helpful.</p>
6386<p><em>File Path: JustForFun/tt.c</em></p>
6387</div>
6388</div>
6389<div class="SECT1">
6390<hr>
6391<h2 class="SECT1"><a name="REF" id="REF">21. References</a></h2>
6392<ul>
6393<li>
6394<p>NCURSES man pages</p>
6395</li>
6396<li>
6397<p>NCURSES FAQ at <a href=
6398"http://invisible-island.net/ncurses/ncurses.faq.html" target=
6399"_top">http://invisible-island.net/ncurses/ncurses.faq.html</a></p>
6400</li>
6401<li>
6402<p>Writing programs with NCURSES by Eric Raymond and Zeyd M.
6403Ben-Halim at <a href=
6404"http://invisible-island.net/ncurses/ncurses-intro.html" target=
6405"_top">http://invisible-island.net/ncurses/ncurses-intro.html</a> -
6406somewhat obsolete. I was inspired by this document and the
6407structure of this HOWTO follows from the original document</p>
6408</li>
6409</ul>
6410</div>
6411</div>
6412</body>
6413</html>
8542only way to find out is to follow the rules of the game.</I
8543></SPAN
8544></PRE
8545><P
8546>This program starts with a simple inverted U pattern and shows how wonderful
8547life works. There is a lot of room for improvement in the program. You can let
8548the user enter pattern of his choice or even take input from a file. You can
8549also change rules and play with a lot of variations. Search on <A
8550HREF="http://www.google.com"
8551TARGET="_top"
8552>google</A
8553> for interesting information on game
8554of life.</P
8555><P
8556><SPAN
8557CLASS="emphasis"
8558><I
8559CLASS="EMPHASIS"
8560>File Path: JustForFun/life.c</I
8561></SPAN
8562></P
8563></DIV
8564><DIV
8565CLASS="SECT2"
8566><HR><H3
8567CLASS="SECT2"
8568><A
8569NAME="MAGIC"
8570>20.2. Magic Square</A
8571></H3
8572><P
8573>Magic Square, another wonder of math, is very simple to understand but very
8574difficult to make. In a magic square sum of the numbers in each row, each column
8575is equal. Even diagnol sum can be equal. There are many variations which have
8576special properties.</P
8577><P
8578>This program creates a simple magic square of odd order.</P
8579><P
8580><SPAN
8581CLASS="emphasis"
8582><I
8583CLASS="EMPHASIS"
8584>File Path: JustForFun/magic.c</I
8585></SPAN
8586></P
8587></DIV
8588><DIV
8589CLASS="SECT2"
8590><HR><H3
8591CLASS="SECT2"
8592><A
8593NAME="HANOI"
8594>20.3. Towers of Hanoi</A
8595></H3
8596><P
8597>The famous towers of hanoi solver. The aim of the game is to move the disks on
8598the first peg to last peg, using middle peg as a temporary stay. The catch is
8599not to place a larger disk over a small disk at any time.</P
8600><P
8601><SPAN
8602CLASS="emphasis"
8603><I
8604CLASS="EMPHASIS"
8605>File Path: JustForFun/hanoi.c</I
8606></SPAN
8607></P
8608></DIV
8609><DIV
8610CLASS="SECT2"
8611><HR><H3
8612CLASS="SECT2"
8613><A
8614NAME="QUEENS"
8615>20.4. Queens Puzzle</A
8616></H3
8617><P
8618>The objective of the famous N-Queen puzzle is to put N queens on a N X N chess
8619board without attacking each other. </P
8620><P
8621>This program solves it with a simple backtracking technique.</P
8622><P
8623><SPAN
8624CLASS="emphasis"
8625><I
8626CLASS="EMPHASIS"
8627>File Path: JustForFun/queens.c</I
8628></SPAN
8629></P
8630></DIV
8631><DIV
8632CLASS="SECT2"
8633><HR><H3
8634CLASS="SECT2"
8635><A
8636NAME="SHUFFLE"
8637>20.5. Shuffle</A
8638></H3
8639><P
8640>A fun game, if you have time to kill. </P
8641><P
8642><SPAN
8643CLASS="emphasis"
8644><I
8645CLASS="EMPHASIS"
8646>File Path: JustForFun/shuffle.c</I
8647></SPAN
8648></P
8649></DIV
8650><DIV
8651CLASS="SECT2"
8652><HR><H3
8653CLASS="SECT2"
8654><A
8655NAME="TT"
8656>20.6. Typing Tutor</A
8657></H3
8658><P
8659>A simple typing tutor, I created more out of need than for ease of use. If you
8660know how to put your fingers correctly on the keyboard, but lack practice, this
8661can be helpful. </P
8662><P
8663><SPAN
8664CLASS="emphasis"
8665><I
8666CLASS="EMPHASIS"
8667>File Path: JustForFun/tt.c</I
8668></SPAN
8669></P
8670></DIV
8671></DIV
8672><DIV
8673CLASS="SECT1"
8674><HR><H2
8675CLASS="SECT1"
8676><A
8677NAME="REF"
8678>21. References</A
8679></H2
8680><P
8681></P
8682><UL
8683><LI
8684><P
8685>NCURSES man pages </P
8686></LI
8687><LI
8688><P
8689>NCURSES FAQ at <A
8690HREF="http://invisible-island.net/ncurses/ncurses.faq.html"
8691TARGET="_top"
8692>http://invisible-island.net/ncurses/ncurses.faq.html</A
8693>
8694 </P
8695></LI
8696><LI
8697><P
8698>Writing programs with NCURSES by Eric Raymond and Zeyd M.
8699Ben-Halim at
8700<A
8701HREF="http://invisible-island.net/ncurses/ncurses-intro.html"
8702TARGET="_top"
8703>http://invisible-island.net/ncurses/ncurses-intro.html</A
8704> - somewhat
8705obsolete. I was inspired by this document and the structure of this HOWTO
8706follows from the original document</P
8707></LI
8708></UL
8709></DIV
8710></DIV
8711></BODY
8712></HTML
8713>