[wxWidgets.git] / docs / latex / wx / eraseevt.tex

\section{\class{wxEraseEvent}}\label{wxeraseevent}

An erase event is sent when a window's background needs to be repainted.

On some platforms, such as GTK+, this event is simulated (simply generated just before the
paint event) and may cause flicker. It is therefore recommended that
you set the text background colour explicitly in order to prevent flicker.
The default background colour under GTK+ is grey.

To intercept this event, use the EVT\_ERASE\_BACKGROUND macro in an event table definition.

You must call wxEraseEvent::GetDC and use the returned device context if it is non-NULL.
If it is NULL, create your own temporary wxClientDC object. 

\wxheading{Derived from}

\helpref{wxEvent}{wxevent}\\
\helpref{wxObject}{wxobject}

\wxheading{Include files}

<wx/event.h>

\wxheading{Event table macros}

To process an erase event, use this event handler macro to direct input to a member
function that takes a wxEraseEvent argument.

\twocolwidtha{7cm}
\begin{twocollist}\itemsep=0pt
\twocolitem{{\bf EVT\_ERASE\_BACKGROUND(func)}}{Process a wxEVT\_ERASE\_BACKGROUND event.}
\end{twocollist}%

\wxheading{Remarks}

Use the device context returned by \helpref{GetDC}{wxeraseeventgetdc} to draw on,
don't create a wxPaintDC in the event handler.

\wxheading{See also}

%\helpref{wxWindow::OnEraseBackground}{wxwindowonerasebackground},
\helpref{Event handling overview}{eventhandlingoverview}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxEraseEvent::wxEraseEvent}\label{wxeraseeventctor}

\func{}{wxEraseEvent}{\param{int }{id = 0}, \param{wxDC* }{dc = NULL}}

Constructor.

\membersection{wxEraseEvent::GetDC}\label{wxeraseeventgetdc}

\constfunc{wxDC*}{GetDC}{\void}

Returns the device context associated with the erase event to draw on.
Commit	Line	Data
a660d684 KB	1	\section{\class{wxEraseEvent}}\label{wxeraseevent}
	2
	3	An erase event is sent when a window's background needs to be repainted.
	4
f4fcc291 JS	5	On some platforms, such as GTK+, this event is simulated (simply generated just before the
	6	paint event) and may cause flicker. It is therefore recommended that
	7	you set the text background colour explicitly in order to prevent flicker.
	8	The default background colour under GTK+ is grey.
	9
	10	To intercept this event, use the EVT\_ERASE\_BACKGROUND macro in an event table definition.
	11
	12	You must call wxEraseEvent::GetDC and use the returned device context if it is non-NULL.
	13	If it is NULL, create your own temporary wxClientDC object.
	14
a660d684 KB	15	\wxheading{Derived from}
	16
	17	\helpref{wxEvent}{wxevent}\\
	18	\helpref{wxObject}{wxobject}
	19
954b8ae6 JS	20	\wxheading{Include files}
	21
	22	<wx/event.h>
	23
a660d684 KB	24	\wxheading{Event table macros}
	25
	26	To process an erase event, use this event handler macro to direct input to a member
	27	function that takes a wxEraseEvent argument.
	28
	29	\twocolwidtha{7cm}
	30	\begin{twocollist}\itemsep=0pt
884360bc	31	\twocolitem{{\bf EVT\_ERASE\_BACKGROUND(func)}}{Process a wxEVT\_ERASE\_BACKGROUND event.}
a660d684 KB	32	\end{twocollist}%
	33
	34	\wxheading{Remarks}
	35
05994861 KH	36	Use the device context returned by \helpref{GetDC}{wxeraseeventgetdc} to draw on,
05994861 KH	37	don't create a wxPaintDC in the event handler.
a660d684 KB	38
	39	\wxheading{See also}
	40
f4fcc291 JS	41	%\helpref{wxWindow::OnEraseBackground}{wxwindowonerasebackground},
f4fcc291 JS	42	\helpref{Event handling overview}{eventhandlingoverview}
a660d684 KB	43
	44	\latexignore{\rtfignore{\wxheading{Members}}}
	45
b236c10f	46	\membersection{wxEraseEvent::wxEraseEvent}\label{wxeraseeventctor}
a660d684 KB	47
	48	\func{}{wxEraseEvent}{\param{int }{id = 0}, \param{wxDC* }{dc = NULL}}
	49
	50	Constructor.
	51
a660d684 KB	52	\membersection{wxEraseEvent::GetDC}\label{wxeraseeventgetdc}
	53
	54	\constfunc{wxDC*}{GetDC}{\void}
	55
05994861	56	Returns the device context associated with the erase event to draw on.
a660d684	57