1%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 2%% Name: vscroll.tex 3%% Purpose: wxVScrolledWindow documentation 4%% Author: Vadim Zeitlin 5%% Modified by: 6%% Created: 30.05.03 7%% RCS-ID: $Id: vscroll.tex 41905 2006-10-10 17:46:49Z JS $ 8%% Copyright: (c) 2003 Vadim Zeitlin <vadim@wxwindows.org> 9%% License: wxWindows license 10%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 11 12\section{\class{wxVScrolledWindow}}\label{wxvscrolledwindow} 13 14In the name of this class, "V" may stand for "variable" because it can be 15used for scrolling lines of variable heights; "virtual" because it is not 16necessary to know the heights of all lines in advance -- only those which 17are shown on the screen need to be measured; or, even, "vertical" because 18this class only supports scrolling in one direction currently (this could 19and probably will change in the future however). 20 21In any case, this is a generalization of the 22\helpref{wxScrolledWindow}{wxscrolledwindow} class which can be only used when 23all lines have the same height. It lacks some other wxScrolledWindow features 24however, notably there is currently no support for horizontal scrolling; it 25can't scroll another window nor only a rectangle of the window and not its 26entire client area. 27 28To use this class, you need to derive from it and implement 29\helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight} pure virtual 30method. You also must call \helpref{SetLineCount}{wxvscrolledwindowsetlinecount} 31to let the base class know how many lines it should display but from that 32moment on the scrolling is handled entirely by wxVScrolledWindow, you only 33need to draw the visible part of contents in your {\tt OnPaint()} method as 34usual. You should use \helpref{GetFirstVisibleLine()}{wxvscrolledwindowgetfirstvisibleline} 35and \helpref{GetLastVisibleLine()}{wxvscrolledwindowgetlastvisibleline} to 36select the lines to display. Note that the device context origin is not shifted 37so the first visible line always appears at the point $(0, 0)$ in physical as 38well as logical coordinates. 39 40\wxheading{Derived from} 41 42\helpref{wxPanel}{wxpanel}\\ 43\helpref{wxWindow}{wxwindow}\\ 44\helpref{wxEvtHandler}{wxevthandler}\\ 45\helpref{wxObject}{wxobject} 46 47\wxheading{Include files} 48 49<wx/vscroll.h> 50 51 52\latexignore{\rtfignore{\wxheading{Members}}} 53 54 55\membersection{wxVScrolledWindow::wxVScrolledWindow}\label{wxvscrolledwindowctor} 56 57\func{}{wxVScrolledWindow}{\param{wxWindow* }{parent}, \param{wxWindowID }{id = wxID\_ANY}, \param{const wxPoint\& }{pos = wxDefaultPosition}, \param{const wxSize\& }{size = wxDefaultSize}, \param{long }{style = 0}, \param{const wxString\& }{name = wxPanelNameStr}} 58 59This is the normal constructor, no need to call Create() after using this one. 60 61Note that {\tt wxVSCROLL} is always automatically added to our style, there is 62no need to specify it explicitly. 63 64\func{}{wxVScrolledWindow}{\void} 65 66Default constructor, you must call \helpref{Create()}{wxvscrolledwindowcreate} 67later. 68 69\wxheading{Parameters} 70 71\docparam{parent}{The parent window, must not be {\tt NULL}} 72 73\docparam{id}{The identifier of this window, {\tt wxID\_ANY} by default} 74 75\docparam{pos}{The initial window position} 76 77\docparam{size}{The initial window size} 78 79\docparam{style}{The window style. There are no special style bits defined for 80this class.} 81 82\docparam{name}{The name for this window; usually not used} 83 84 85\membersection{wxVScrolledWindow::Create}\label{wxvscrolledwindowcreate} 86 87\func{bool}{Create}{\param{wxWindow* }{parent}, \param{wxWindowID }{id = wxID\_ANY}, \param{const wxPoint\& }{pos = wxDefaultPosition}, \param{const wxSize\& }{size = wxDefaultSize}, \param{long }{style = 0}, \param{const wxString\& }{name = wxPanelNameStr}} 88 89Same as the \helpref{non default ctor}{wxvscrolledwindowctor} but returns 90status code: {\tt true} if ok, {\tt false} if the window couldn't have been created. 91 92Just as with the ctor above, {\tt wxVSCROLL} style is always used, there is no 93need to specify it explicitly. 94 95 96\membersection{wxVScrolledWindow::EstimateTotalHeight}\label{wxvscrolledwindowestimatetotalheight} 97 98\constfunc{virtual wxCoord}{EstimateTotalHeight}{\void} 99 100This protected function is used internally by wxVScrolledWindow to estimate the 101total height of the window when \helpref{SetLineCount}{wxvscrolledwindowsetlinecount} 102is called. The default implementation uses the brute force approach if the 103number of the items in the control is small enough. Otherwise, it tries to find 104the average line height using some lines in the beginning, middle and the end. 105 106If it is undesirable to access all these lines (some of which might be never 107shown) just for the total height calculation, you may override the function and 108provide your own guess better and/or faster. 109 110Note that although returning a totally wrong value would still work, it risks 111to result in very strange scrollbar behaviour so this function should really 112try to make the best guess possible. 113 114 115\membersection{wxVScrolledWindow::GetFirstVisibleLine}\label{wxvscrolledwindowgetfirstvisibleline} 116 117\constfunc{size\_t}{GetFirstVisibleLine}{\void} 118 119Returns the index of the first currently visible line. 120 121This is same as \helpref{GetVisibleBegin}{wxvscrolledwindowgetvisiblebegin} and 122exists only for symmetry with \helpref{GetLastVisibleLine}{wxvscrolledwindowgetlastvisibleline}. 123 124 125\membersection{wxVScrolledWindow::GetLastVisibleLine}\label{wxvscrolledwindowgetlastvisibleline} 126 127\constfunc{size\_t}{GetLastVisibleLine}{\void} 128 129Returns the index of the last currently visible line. Note that this method 130returns \texttt{(size\_t)-1} (i.e. a huge positive number) if the control is 131empty so if this is possible you should use \helpref{GetVisibleEnd}{wxvscrolledwindowgetvisibleend} 132instead. 133 134\wxheading{See also} 135 136\helpref{GetFirstVisibleLine}{wxvscrolledwindowgetfirstvisibleline} 137 138 139\membersection{wxVScrolledWindow::GetLineCount}\label{wxvscrolledwindowgetlinecount} 140 141\constfunc{size\_t}{GetLineCount}{\void} 142 143Get the number of lines this window contains (previously set by 144\helpref{SetLineCount()}{wxvscrolledwindowsetlinecount}) 145 146 147\membersection{wxVScrolledWindow::GetVisibleBegin}\label{wxvscrolledwindowgetvisiblebegin} 148 149\constfunc{size\_t}{GetVisibleBegin}{\void} 150 151Returns the index of the first currently visible line. 152 153\wxheading{See also} 154 155\helpref{GetVisibleEnd}{wxvscrolledwindowgetvisibleend} 156 157 158\membersection{wxVScrolledWindow::GetVisibleEnd}\label{wxvscrolledwindowgetvisibleend} 159 160\constfunc{size\_t}{GetVisibleEnd}{\void} 161 162Returns the index of the first line after the currently visible one. If the 163return value is $0$ it means that no lines are currently shown (which only 164happens if the control is empty). Note that the index returned by this method 165is not always a valid index as it may be equal to \helpref{GetLineCount}{wxvscrolledwindowgetlinecount}. 166 167\wxheading{See also} 168 169\helpref{GetVisibleBegin}{wxvscrolledwindowgetvisiblebegin} 170 171 172\membersection{wxVScrolledWindow::HitTest}\label{wxvscrolledwindowhittest} 173 174\constfunc{int}{HitTest}{\param{wxCoord }{x}, \param{wxCoord }{y}} 175 176\constfunc{int}{HitTest}{\param{const wxPoint\& }{pt}} 177 178Return the item at the specified (in physical coordinates) position or 179{\tt wxNOT\_FOUND} if none, i.e. if it is below the last item. 180 181 182\membersection{wxVScrolledWindow::IsVisible}\label{wxvscrolledwindowisvisible} 183 184\constfunc{bool}{IsVisible}{\param{size\_t }{line}} 185 186Returns {\tt true} if the given line is (at least partially) visible or 187{\tt false} otherwise. 188 189 190\membersection{wxVScrolledWindow::OnGetLineHeight}\label{wxvscrolledwindowongetlineheight} 191 192\constfunc{virtual wxCoord}{OnGetLineHeight}{\param{size\_t }{n}} 193 194This protected virtual function must be overridden in the derived class and it 195should return the height of the given line in pixels. 196 197\wxheading{See also} 198 199\helpref{OnGetLinesHint}{wxvscrolledwindowongetlineshint} 200 201 202\membersection{wxVScrolledWindow::OnGetLinesHint}\label{wxvscrolledwindowongetlineshint} 203 204\constfunc{virtual void}{OnGetLinesHint}{\param{size\_t }{lineMin}, \param{size\_t }{lineMax}} 205 206This function doesn't have to be overridden but it may be useful to do 207it if calculating the lines heights is a relatively expensive operation 208as it gives the user code a possibility to calculate several of them at 209once. 210 211{\tt OnGetLinesHint()} is normally called just before 212\helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight} but you 213shouldn't rely on the latter being called for all lines in the interval 214specified here. It is also possible that OnGetLineHeight() will be 215called for the lines outside of this interval, so this is really just a 216hint, not a promise. 217 218Finally note that {\it lineMin} is inclusive, while {\it lineMax} is exclusive, 219as usual. 220 221 222\membersection{wxVScrolledWindow::RefreshLine}\label{wxvscrolledwindowrefreshline} 223 224\func{void}{RefreshLine}{\param{size\_t }{line}} 225 226Refreshes the specified line -- it will be redrawn during the next main loop 227iteration. 228 229\wxheading{See also} 230 231\helpref{RefreshLines}{wxvscrolledwindowrefreshlines} 232 233 234\membersection{wxVScrolledWindow::RefreshLines}\label{wxvscrolledwindowrefreshlines} 235 236\func{void}{RefreshLines}{\param{size\_t }{from}, \param{size\_t }{to}} 237 238Refreshes all lines between {\it from} and {\it to}, inclusive. {\it from} 239should be less than or equal to {\it to}. 240 241\wxheading{See also} 242 243\helpref{RefreshLine}{wxvscrolledwindowrefreshline} 244 245 246\membersection{wxVScrolledWindow::RefreshAll}\label{wxvscrolledwindowrefreshall} 247 248\func{void}{RefreshAll}{\void} 249 250This function completely refreshes the control, recalculating the number of 251items shown on screen and repainting them. It should be called when the values 252returned by \helpref{OnGetLineHeight}{wxvscrolledwindowongetlineheight} change 253for some reason and the window must be updated to reflect this. 254 255 256\membersection{wxVScrolledWindow::ScrollLines}\label{wxvscrolledwindowscrolllines} 257 258\func{bool}{ScrollLines}{\param{int }{lines}} 259 260Scroll by the specified number of lines which may be positive (to scroll down) 261or negative (to scroll up). 262 263Returns {\tt true} if the window was scrolled, {\tt false} otherwise (for 264example if we're trying to scroll down but we are already showing the last 265line). 266 267\wxheading{See also} 268 269\helpref{LineUp}{wxwindowlineup}, \helpref{LineDown}{wxwindowlinedown} 270 271 272\membersection{wxVScrolledWindow::ScrollPages}\label{wxvscrolledwindowscrollpages} 273 274\func{bool}{ScrollPages}{\param{int }{pages}} 275 276Scroll by the specified number of pages which may be positive (to scroll down) 277or negative (to scroll up). 278 279\wxheading{See also} 280 281\helpref{ScrollLines}{wxvscrolledwindowscrolllines},\\ 282\helpref{PageUp}{wxwindowpageup}, \helpref{PageDown}{wxwindowpagedown} 283 284 285\membersection{wxVScrolledWindow::ScrollToLine}\label{wxvscrolledwindowscrolltoline} 286 287\func{bool}{ScrollToLine}{\param{size\_t }{line}} 288 289Scroll to the specified line: it will become the first visible line in 290the window. 291 292Return {\tt true} if we scrolled the window, {\tt false} if nothing was done. 293 294 295\membersection{wxVScrolledWindow::SetLineCount}\label{wxvscrolledwindowsetlinecount} 296 297\func{void}{SetLineCount}{\param{size\_t }{count}} 298 299Set the number of lines the window contains: the derived class must 300provide the heights for all lines with indices up to the one given here 301in its \helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight}. 302 303