X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/5d6dcfb3273b11322e5b1754fda4550b363a5dae..aaa6f9ba6bd0be1fe6a34800e6f753ffdc49900c:/docs/latex/wx/vscroll.tex

diff --git a/docs/latex/wx/vscroll.tex b/docs/latex/wx/vscroll.tex
index 1a647fc704..b965f1fd15 100644
--- a/docs/latex/wx/vscroll.tex
+++ b/docs/latex/wx/vscroll.tex
@@ -33,7 +33,7 @@ moment on the scrolling is handled entirely by wxVScrolledWindow, you only
 need to draw the visible part of contents in your {\tt OnPaint()} method as
 usual. You should use \helpref{GetFirstVisibleLine()}{wxvscrolledwindowgetfirstvisibleline} 
 and \helpref{GetLastVisibleLine()}{wxvscrolledwindowgetlastvisibleline} to
-select the lines to display. ote that the device context origin is not shifted
+select the lines to display. Note that the device context origin is not shifted
 so the first visible line always appears at the point $(0, 0)$ in physical as
 well as logical coordinates.
 
@@ -90,18 +90,47 @@ Just as with the ctor above, {\tt wxVSCROLL} style is always used, there is no
 need to specify it explicitly.
 
 
+\membersection{wxVScrolledWindow::EstimateTotalHeight}\label{wxvscrolledwindowestimatetotalheight}
+
+\constfunc{virtual wxCoord}{EstimateTotalHeight}{\void}
+
+This protected function is used internally by wxVScrolledWindow to estimate the
+total height of the window when \helpref{SetLineCount}{wxvscrolledwindowsetlinecount} 
+is called. The default implementation uses the brute force approach if the
+number of the items in the control is small enough. Otherwise, it tries to find
+the average line height using some lines in the beginning, middle and the end.
+
+If it is undesirable to access all these lines (some of which might be never
+shown) just for the total height calculation, you may override the function and
+provide your own guess better and/or faster.
+
+Note that although returning a totally wrong value would still work, it risks
+to result in very strange scrollbar behaviour so this function should really
+try to make the best guess possible.
+
+
 \membersection{wxVScrolledWindow::GetFirstVisibleLine}\label{wxvscrolledwindowgetfirstvisibleline}
 
 \constfunc{size\_t}{GetFirstVisibleLine}{\void}
 
 Returns the index of the first currently visible line.
 
+This is same as \helpref{GetVisibleBegin}{wxvscrolledwindowgetvisiblebegin} and
+exists only for symmetry with \helpref{GetLastVisibleLine}{wxvscrolledwindowgetlastvisibleline}.
+
 
 \membersection{wxVScrolledWindow::GetLastVisibleLine}\label{wxvscrolledwindowgetlastvisibleline}
 
 \constfunc{size\_t}{GetLastVisibleLine}{\void}
 
-Returns the index of the last currently visible line.
+Returns the index of the last currently visible line. Note that this method
+returns \texttt{(size\_t)-1} (i.e. a huge positive number) if the control is
+empty so if this is possible you should use \helpref{GetVisibleEnd}{wxvscrolledwindowgetvisibleend} 
+instead.
+
+\wxheading{See also}
+
+\helpref{GetFirstVisibleLine}{wxvscrolledwindowgetfirstvisibleline}
 
 
 \membersection{wxVScrolledWindow::GetLineCount}\label{wxvscrolledwindowgetlinecount}
@@ -112,6 +141,31 @@ Get the number of lines this window contains (previously set by
 \helpref{SetLineCount()}{wxvscrolledwindowsetlinecount})
 
 
+\membersection{wxVScrolledWindow::GetVisibleBegin}\label{wxvscrolledwindowgetvisiblebegin}
+
+\constfunc{size\_t}{GetVisibleBegin}{\void}
+
+Returns the index of the first currently visible line.
+
+\wxheading{See also}
+
+\helpref{GetVisibleEnd}{wxvscrolledwindowgetvisibleend}
+
+
+\membersection{wxVScrolledWindow::GetVisibleEnd}\label{wxvscrolledwindowgetvisibleend}
+
+\constfunc{size\_t}{GetVisibleEnd}{\void}
+
+Returns the index of the first line after the currently visible one. If the
+return value is $0$ it means that no lines are currently shown (which only
+happens if the control is empty). Note that the index returned by this method
+is not always a valid index as it may be equal to \helpref{GetLineCount}{wxvscrolledwindowgetlinecount}.
+
+\wxheading{See also}
+
+\helpref{GetVisibleBegin}{wxvscrolledwindowgetvisiblebegin}
+
+
 \membersection{wxVScrolledWindow::HitTest}\label{wxvscrolledwindowhittest}
 
 \constfunc{int}{HitTest}{\param{wxCoord }{x}, \param{wxCoord }{y}}
@@ -132,7 +186,7 @@ Returns {\tt true} if the given line is (at least partially) visible or
 
 \membersection{wxVScrolledWindow::OnGetLineHeight}\label{wxvscrolledwindowongetlineheight}
 
-\constfunc{wxCoord}{OnGetLineHeight}{\param{size\_t }{n}}
+\constfunc{virtual wxCoord}{OnGetLineHeight}{\param{size\_t }{n}}
 
 This protected virtual function must be overridden in the derived class and it
 should return the height of the given line in pixels.
@@ -144,7 +198,7 @@ should return the height of the given line in pixels.
 
 \membersection{wxVScrolledWindow::OnGetLinesHint}\label{wxvscrolledwindowongetlineshint}
 
-\constfunc{void}{OnGetLinesHint}{\param{size\_t }{lineMin}, \param{size\_t }{lineMax}}
+\constfunc{virtual void}{OnGetLinesHint}{\param{size\_t }{lineMin}, \param{size\_t }{lineMax}}
 
 This function doesn't have to be overridden but it may be useful to do
 it if calculating the lines heights is a relatively expensive operation
@@ -191,7 +245,7 @@ should be less than or equal to {\it to}.
 \func{void}{RefreshAll}{\void}
 
 This function completely refreshes the control, recalculating the number of
-items shown on screen and repaining them. It should be called when the values
+items shown on screen and repainting them. It should be called when the values
 returned by \helpref{OnGetLineHeight}{wxvscrolledwindowongetlineheight} change
 for some reason and the window must be updated to reflect this.