this class only supports scrolling in one direction currently (this could
and probably will change in the future however).
-In any case, this is a generalization of the
+In any case, this is a generalization of the
\helpref{wxScrolledWindow}{wxscrolledwindow} class which can be only used when
all lines have the same height. It lacks some other wxScrolledWindow features
however, notably there is currently no support for horizontal scrolling; it
can't scroll another window nor only a rectangle of the window and not its
entire client area.
-
-To use this class, you need to derive from it and implement
+
+To use this class, you need to derive from it and implement
\helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight} pure virtual
-method. You also must call \helpref{SetLineCount}{wxvscrolledwindowsetlinecount}
+method. You also must call \helpref{SetLineCount}{wxvscrolledwindowsetlinecount}
to let the base class know how many lines it should display but from that
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}
+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.
\wxheading{Derived from}
-\helpref{wxPanel}{wxpanel}
+\helpref{wxPanel}{wxpanel}\\
+\helpref{wxWindow}{wxwindow}\\
+\helpref{wxEvtHandler}{wxevthandler}\\
+\helpref{wxObject}{wxobject}
\wxheading{Include files}
\func{}{wxVScrolledWindow}{\void}
-Default constructor, you must call \helpref{Create()}{wxvscrolledwindowcreate}
+Default constructor, you must call \helpref{Create()}{wxvscrolledwindowcreate}
later.
\wxheading{Parameters}
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}
\constfunc{size\_t}{GetLineCount}{\void}
-Get the number of lines this window contains (previously set by
+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}}
\constfunc{bool}{IsVisible}{\param{size\_t }{line}}
-Returns {\tt true} if the given line is (at least partially) visible or
+Returns {\tt true} if the given line is (at least partially) visible or
{\tt false} otherwise.
\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.
\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
as it gives the user code a possibility to calculate several of them at
once.
-{\tt OnGetLinesHint()} is normally called just before
+{\tt OnGetLinesHint()} is normally called just before
\helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight} but you
shouldn't rely on the latter being called for all lines in the interval
specified here. It is also possible that OnGetLineHeight() will be
\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.
provide the heights for all lines with indices up to the one given here
in its \helpref{OnGetLineHeight()}{wxvscrolledwindowongetlineheight}.
-
projects / wxWidgets.git / blobdiff