1;;; disp-table.el --- functions for dealing with char tables
2
3;; Copyright (C) 1987, 1994, 1995, 1999, 2001, 2002, 2003, 2004,
4;;   2005, 2006, 2007 Free Software Foundation, Inc.
5
6;; Author: Erik Naggum <erik@naggum.no>
7;; Based on a previous version by Howard Gayle
8;; Maintainer: FSF
9;; Keywords: i18n
10
11;; This file is part of GNU Emacs.
12
13;; GNU Emacs is free software; you can redistribute it and/or modify
14;; it under the terms of the GNU General Public License as published by
15;; the Free Software Foundation; either version 2, or (at your option)
16;; any later version.
17
18;; GNU Emacs is distributed in the hope that it will be useful,
19;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21;; GNU General Public License for more details.
22
23;; You should have received a copy of the GNU General Public License
24;; along with GNU Emacs; see the file COPYING.  If not, write to the
25;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26;; Boston, MA 02110-1301, USA.
27
28;;; Commentary:
29
30;;; Code:
31
32(put 'display-table 'char-table-extra-slots 6)
33
34;;;###autoload
35(defun make-display-table ()
36  "Return a new, empty display table."
37  (make-char-table 'display-table nil))
38
39(or standard-display-table
40    (setq standard-display-table (make-display-table)))
41
42;;; Display-table slot names.  The property value says which slot.
43
44(put 'truncation 'display-table-slot 0)
45(put 'wrap 'display-table-slot 1)
46(put 'escape 'display-table-slot 2)
47(put 'control 'display-table-slot 3)
48(put 'selective-display 'display-table-slot 4)
49(put 'vertical-border 'display-table-slot 5)
50
51;;;###autoload
52(defun display-table-slot (display-table slot)
53  "Return the value of the extra slot in DISPLAY-TABLE named SLOT.
54SLOT may be a number from 0 to 5 inclusive, or a slot name (symbol).
55Valid symbols are `truncation', `wrap', `escape', `control',
56`selective-display', and `vertical-border'."
57  (let ((slot-number
58	 (if (numberp slot) slot
59	   (or (get slot 'display-table-slot)
60	       (error "Invalid display-table slot name: %s" slot)))))
61    (char-table-extra-slot display-table slot-number)))
62
63;;;###autoload
64(defun set-display-table-slot (display-table slot value)
65  "Set the value of the extra slot in DISPLAY-TABLE named SLOT to VALUE.
66SLOT may be a number from 0 to 5 inclusive, or a name (symbol).
67Valid symbols are `truncation', `wrap', `escape', `control',
68`selective-display', and `vertical-border'."
69  (let ((slot-number
70	 (if (numberp slot) slot
71	   (or (get slot 'display-table-slot)
72	       (error "Invalid display-table slot name: %s" slot)))))
73    (set-char-table-extra-slot display-table slot-number value)))
74
75;;;###autoload
76(defun describe-display-table (dt)
77  "Describe the display table DT in a help buffer."
78  (with-output-to-temp-buffer "*Help*"
79    (princ "\nTruncation glyph: ")
80    (prin1 (display-table-slot dt 'truncation))
81    (princ "\nWrap glyph: ")
82    (prin1 (display-table-slot dt 'wrap))
83    (princ "\nEscape glyph: ")
84    (prin1 (display-table-slot dt 'escape))
85    (princ "\nCtrl glyph: ")
86    (prin1 (display-table-slot dt 'control))
87    (princ "\nSelective display glyph sequence: ")
88    (prin1 (display-table-slot dt 'selective-display))
89    (princ "\nVertical window border glyph: ")
90    (prin1 (display-table-slot dt 'vertical-border))
91    (princ "\nCharacter display glyph sequences:\n")
92    (save-excursion
93      (set-buffer standard-output)
94      (let ((vector (make-vector 256 nil))
95	    (i 0))
96	(while (< i 256)
97	  (aset vector i (aref dt i))
98	  (setq i (1+ i)))
99	(describe-vector vector))
100      (help-mode))
101    (print-help-return-message)))
102
103;;;###autoload
104(defun describe-current-display-table ()
105  "Describe the display table in use in the selected window and buffer."
106  (interactive)
107  (let ((disptab (or (window-display-table (selected-window))
108		     buffer-display-table
109		     standard-display-table)))
110    (if disptab
111	(describe-display-table disptab)
112      (message "No display table"))))
113
114;;;###autoload
115(defun standard-display-8bit (l h)
116  "Display characters in the range L to H literally."
117  (or standard-display-table
118      (setq standard-display-table (make-display-table)))
119  (while (<= l h)
120    (aset standard-display-table l (if (or (< l ?\s) (>= l 127)) (vector l)))
121    (setq l (1+ l))))
122
123;;;###autoload
124(defun standard-display-default (l h)
125  "Display characters in the range L to H using the default notation."
126  (or standard-display-table
127      (setq standard-display-table (make-display-table)))
128  (while (<= l h)
129    (if (and (>= l ?\s) (char-valid-p l))
130	(aset standard-display-table l nil))
131    (setq l (1+ l))))
132
133;; This function does NOT take terminal-dependent escape sequences.
134;; For that, you need to go through create-glyph.  Use one of the
135;; other functions below, or roll your own.
136;;;###autoload
137(defun standard-display-ascii (c s)
138  "Display character C using printable string S."
139  (or standard-display-table
140      (setq standard-display-table (make-display-table)))
141  (aset standard-display-table c (vconcat s)))
142
143;;;###autoload
144(defun standard-display-g1 (c sc)
145  "Display character C as character SC in the g1 character set.
146This function assumes that your terminal uses the SO/SI characters;
147it is meaningless for an X frame."
148  (if (memq window-system '(x w32 mac))
149      (error "Cannot use string glyphs in a windowing system"))
150  (or standard-display-table
151      (setq standard-display-table (make-display-table)))
152  (aset standard-display-table c
153	(vector (create-glyph (concat "\016" (char-to-string sc) "\017")))))
154
155;;;###autoload
156(defun standard-display-graphic (c gc)
157  "Display character C as character GC in graphics character set.
158This function assumes VT100-compatible escapes; it is meaningless for an
159X frame."
160  (if (memq window-system '(x w32 mac))
161      (error "Cannot use string glyphs in a windowing system"))
162  (or standard-display-table
163      (setq standard-display-table (make-display-table)))
164  (aset standard-display-table c
165	(vector (create-glyph (concat "\e(0" (char-to-string gc) "\e(B")))))
166
167;;;###autoload
168(defun standard-display-underline (c uc)
169  "Display character C as character UC plus underlining."
170  (or standard-display-table
171      (setq standard-display-table (make-display-table)))
172  (aset standard-display-table c
173	(vector
174	 (if window-system
175	     (make-glyph-code uc 'underline)
176	   (create-glyph (concat "\e[4m" (char-to-string uc) "\e[m"))))))
177
178;;;###autoload
179(defun create-glyph (string)
180  "Allocate a glyph code to display by sending STRING to the terminal."
181  (if (= (length glyph-table) 65536)
182      (error "No free glyph codes remain"))
183  ;; Don't use slots that correspond to ASCII characters.
184  (if (= (length glyph-table) 32)
185      (setq glyph-table (vconcat glyph-table (make-vector 224 nil))))
186  (setq glyph-table (vconcat glyph-table (list string)))
187  (1- (length glyph-table)))
188
189;;;###autoload
190(defun make-glyph-code (char &optional face)
191  "Return a glyph code representing char CHAR with face FACE."
192  ;; Due to limitations on Emacs integer values, faces with
193  ;; face id greater that 4091 are silently ignored.
194  (if (and face (<= (face-id face) #xfff))
195      (logior char (lsh (face-id face) 19))
196    char))
197
198;;;###autoload
199(defun glyph-char (glyph)
200  "Return the character of glyph code GLYPH."
201  (logand glyph #x7ffff))
202
203;;;###autoload
204(defun glyph-face (glyph)
205  "Return the face of glyph code GLYPH, or nil if glyph has default face."
206  (let ((face-id (lsh glyph -19)))
207    (and (> face-id 0)
208	 (car (delq nil (mapcar (lambda (face)
209				  (and (eq (get face 'face) face-id)
210				       face))
211				(face-list)))))))
212
213;;;###autoload
214(defun standard-display-european (arg)
215  "Semi-obsolete way to toggle display of ISO 8859 European characters.
216
217This function is semi-obsolete; if you want to do your editing with
218unibyte characters, it is better to `set-language-environment' coupled
219with either the `--unibyte' option or the EMACS_UNIBYTE environment
220variable, or else customize `enable-multibyte-characters'.
221
222With prefix argument, this command enables European character display
223if arg is positive, disables it otherwise.  Otherwise, it toggles
224European character display.
225
226When this mode is enabled, characters in the range of 160 to 255
227display not as octal escapes, but as accented characters.  Codes 146
228and 160 display as apostrophe and space, even though they are not the
229ASCII codes for apostrophe and space.
230
231Enabling European character display with this command noninteractively
232from Lisp code also selects Latin-1 as the language environment, and
233selects unibyte mode for all Emacs buffers \(both existing buffers and
234those created subsequently).  This provides increased compatibility
235for users who call this function in `.emacs'."
236
237  (if (or (<= (prefix-numeric-value arg) 0)
238	  (and (null arg)
239	       (char-table-p standard-display-table)
240	       ;; Test 161, because 160 displays as a space.
241	       (equal (aref standard-display-table 161) [161])))
242      (progn
243	(standard-display-default 160 255)
244	(unless (or (memq window-system '(x w32 mac)))
245	  (and (terminal-coding-system)
246	       (set-terminal-coding-system nil))))
247
248    (display-warning 'i18n
249		     "`standard-display-european' is semi-obsolete; see its doc string for details"
250		     :warning)
251
252    ;; Switch to Latin-1 language environment
253    ;; unless some other has been specified.
254    (if (equal current-language-environment "English")
255	(set-language-environment "latin-1"))
256    (unless (or noninteractive (memq window-system '(x w32 mac)))
257      ;; Send those codes literally to a character-based terminal.
258      ;; If we are using single-byte characters,
259      ;; it doesn't matter which coding system we use.
260      (set-terminal-coding-system
261       (let ((c (intern (downcase current-language-environment))))
262	 (if (coding-system-p c) c 'latin-1))))
263    (standard-display-european-internal)))
264
265(provide 'disp-table)
266
267;;; arch-tag: ffe4c28c-960c-47aa-b8a8-ae89d371ffc7
268;;; disp-table.el ends here
269