docs/latex/wx/vscroll.tex

   1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2 %% Name:        vscroll.tex
   3 %% Purpose:     wxVScrolledWindow documentation
   4 %% Author:      Vadim Zeitlin
   5 %% Modified by:
   6 %% Created:     30.05.03
   7 %% RCS-ID:      $Id$
   8 %% Copyright:   (c) 2003 Vadim Zeitlin <vadim@wxwindows.org>
   9 %% License:     wxWindows license
  10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  11
  12 \section{\class{wxVScrolledWindow}}\label{wxvscrolledwindow}
  13
  14 In the name of this class, "V" may stand for "variable" because it can be
  15 used for scrolling lines of variable heights; "virtual" because it is not
  16 necessary to know the heights of all lines in advance -- only those which
  17 are shown on the screen need to be measured; or, even, "vertical" because
  18 this class only supports scrolling in one direction currently (this could
  19 and probably will change in the future however).
  20
  21 In any case, this is a generalization of the
  22 \helpref{wxScrolledWindow}{wxScrolledWindow} class which can be only used when
  23 all lines have the same height. It lacks some other wxScrolledWindow features
  24 however, notably there is currently no support for horizontal scrolling; it
  25 can't scroll another window nor only a rectangle of the window and not its
  26 entire client area.
  27
  28 To use this class, you need to derive from it and implement
  29 \helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight} pure virtual
  30 method. You also must call \helpref{SetLineCount}{wxvscrolledwindowsetlinecount}
  31 to let the base class know how many lines it should display but from that
  32 moment on the scrolling is handled entirely by wxVScrolledWindow, you only
  33 need to draw the visible part of contents in your {\tt OnPaint()} method as
  34 usual. You should use \helpref{GetFirstVisibleLine()}{wxvscrolledwindowgetfirstvisibleline}
  35 and \helpref{GetLastVisibleLine()}{wxvscrolledwindowgetlastvisibleline} to
  36 select the lines to display. ote that the device context origin is not shifted
  37 so the first visible line always appears at the point $(0, 0)$ in physical as
  38 well as logical coordinates.
  39
  40 \wxheading{Derived from}
  41
  42 \helpref{wxPanel}{wxpanel}
  43
  44 \wxheading{Include files}
  45
  46 <wx/vscroll.h>
  47
  48
  49 \latexignore{\rtfignore{\wxheading{Members}}}
  50
  51
  52 \membersection{wxVScrolledWindow::wxVScrolledWindow}\label{wxvscrolledwindowctor}
  53
  54 \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}}
  55
  56 This is the normal constructor, no need to call Create() after using this one.
  57
  58 Note that {\tt wxVSCROLL} is always automatically added to our style, there is
  59 no need to specify it explicitly.
  60
  61 \func{}{wxVScrolledWindow}{\void}
  62
  63 Default constructor, you must call \helpref{Create()}{wxvscrolledwindowcreate}
  64 later.
  65
  66 \wxheading{Parameters}
  67
  68 \docparam{parent}{The parent window, must not be {\tt NULL}}
  69
  70 \docparam{id}{The identifier of this window, {\tt wxID\_ANY} by default}
  71
  72 \docparam{pos}{The initial window position}
  73
  74 \docparam{size}{The initial window size}
  75
  76 \docparam{style}{The window style. There are no special style bits defined for
  77 this class.}
  78
  79 \docparam{name}{The name for this window; usually not used}
  80
  81
  82 \membersection{wxVScrolledWindow::Create}\label{wxvscrolledwindowcreate}
  83
  84 \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}}
  85
  86 Same as the \helpref{non default ctor}{wxvscrolledwindowctor} but returns
  87 status code: {\tt true} if ok, {\tt false} if the window couldn't have been created.
  88
  89 Just as with the ctor above, {\tt wxVSCROLL} style is always used, there is no
  90 need to specify it explicitly.
  91
  92
  93 \membersection{wxVScrolledWindow::GetFirstVisibleLine}\label{wxvscrolledwindowgetfirstvisibleline}
  94
  95 \constfunc{size\_t}{GetFirstVisibleLine}{\void}
  96
  97 Returns the index of the first currently visible line.
  98
  99
 100 \membersection{wxVScrolledWindow::GetLastVisibleLine}\label{wxvscrolledwindowgetlastvisibleline}
 101
 102 \constfunc{size\_t}{GetLastVisibleLine}{\void}
 103
 104 Returns the index of the last currently visible line.
 105
 106
 107 \membersection{wxVScrolledWindow::GetLineCount}\label{wxvscrolledwindowgetlinecount}
 108
 109 \constfunc{size\_t}{GetLineCount}{\void}
 110
 111 Get the number of lines this window contains (previously set by
 112 \helpref{SetLineCount()}{wxvscrolledwindowsetlinecount})
 113
 114
 115 \membersection{wxVScrolledWindow::OnGetLineHeight}\label{wxvscrolledwindowongetlineheight}
 116
 117 \constfunc{wxCoord}{OnGetLineHeight}{\param{size\_t }{n}}
 118
 119 This protected virtual function must be overridden in the derived class and it
 120 should return the height of the given line in pixels.
 121
 122 \wxheading{See also}
 123
 124 \helpref{OnGetLinesHint}{wxvscrolledwindowongetlineshint}
 125
 126
 127 \membersection{wxVScrolledWindow::OnGetLinesHint}\label{wxvscrolledwindowongetlineshint}
 128
 129 \constfunc{void}{OnGetLinesHint}{\param{size\_t }{lineMin}, \param{size\_t }{lineMax}}
 130
 131 This function doesn't have to be overridden but it may be useful to do
 132 it if calculating the lines heights is a relatively expensive operation
 133 as it gives the user code a possibility to calculate several of them at
 134 once.
 135
 136 {\tt OnGetLinesHint()} is normally called just before
 137 \helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight} but you
 138 shouldn't rely on the latter being called for all lines in the interval
 139 specified here. It is also possible that OnGetLineHeight() will be
 140 called for the lines outside of this interval, so this is really just a
 141 hint, not a promise.
 142
 143 Finally note that {\it lineMin} is inclusive, while {\it lineMax} is exclusive,
 144 as usual.
 145
 146
 147 \membersection{wxVScrolledWindow::ScrollLines}\label{wxvscrolledwindowscrolllines}
 148
 149 \func{bool}{ScrollLines}{\param{int }{lines}}
 150
 151 Scroll by the specified number of lines which may be positive (to scroll down)
 152 or negative (to scroll up).
 153
 154 Returns {\tt true} if the window was scrolled, {\tt false} otherwise (for
 155 example if we're trying to scroll down but we are already showing the last
 156 line).
 157
 158 \wxheading{See also}
 159
 160 \helpref{LineUp}{wxwindowlineup}, \helpref{LineDown}{wxwindowlinedown}
 161
 162
 163 \membersection{wxVScrolledWindow::ScrollPages}\label{wxvscrolledwindowscrollpages}
 164
 165 \func{bool}{ScrollPages}{\param{int }{pages}}
 166
 167 Scroll by the specified number of pages which may be positive (to scroll down)
 168 or negative (to scroll up).
 169
 170 \wxheading{See also}
 171
 172 \helpref{ScrollLines}{wxvscrolledwindowscrolllines},\\
 173 \helpref{PageUp}{wxwindowpageup}, \helpref{PageDown}{wxwindowpagedown}
 174
 175
 176 \membersection{wxVScrolledWindow::ScrollToLine}\label{wxvscrolledwindowscrolltoline}
 177
 178 \func{bool}{ScrollToLine}{\param{size\_t }{line}}
 179
 180 Scroll to the specified line: it will become the first visible line in
 181 the window.
 182
 183 Return {\tt true} if we scrolled the window, {\tt false} if nothing was done.
 184
 185
 186 \membersection{wxVScrolledWindow::SetLineCount}\label{wxvscrolledwindowsetlinecount}
 187
 188 \func{void}{SetLineCount}{\param{size\_t }{count}}
 189
 190 Set the number of lines the window contains: the derived class must
 191 provide the heights for all lines with indices up to the one given here
 192 in its \helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight}.
 193
 194