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			129 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			TeX
		
	
	
	
	
	
			
		
		
	
	
			129 lines
		
	
	
		
			4.4 KiB
		
	
	
	
		
			TeX
		
	
	
	
	
	
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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%% Name:        bufferdc.tex
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%% Purpose:     wxBufferedDC documentation
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%% Author:      Vadim Zeitlin
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%% Modified by:
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%% Created:     07.02.04
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%% RCS-ID:      $Id$
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%% Copyright:   (c) 2004 Vadim Zeitlin
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%% License:     wxWidgets license
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\section{\class{wxBufferedDC}}\label{wxbuffereddc}
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This simple class provides a simple way to avoid flicker: when drawing on it,
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everything is in fact first drawn on an in-memory buffer (a 
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\helpref{wxBitmap}{wxbitmap}) and then copied to the screen only once, when this
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object is destroyed.
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It can be used in the same way as any other device context. wxBufferedDC itself
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typically replaces \helpref{wxClientDC}{wxclientdc}, if you want to use it in
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your \texttt{OnPaint()} handler, you should look at
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\helpref{wxBufferedPaintDC}{wxbufferedpaintdc}.
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\wxheading{Derived from}
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\helpref{wxMemoryDC}{wxmemorydc}\\
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\helpref{wxDC}{wxdc}\\
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\helpref{wxObject}{wxobject}
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\wxheading{Include files}
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<wx/dcbuffer.h>
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\wxheading{See also}
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\helpref{wxDC}{wxdc}
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\latexignore{\rtfignore{\wxheading{Members}}}
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\membersection{wxBufferedDC::wxBufferedDC}\label{wxbuffereddcctor}
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\func{}{wxBufferedDC}{\void}
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\func{}{wxBufferedDC}{\param{wxDC *}{dc}, \param{const wxSize\& }{area}}
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\func{}{wxBufferedDC}{\param{wxDC *}{dc}, \param{const wxBitmap\& }{buffer}}
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If you use the first, default, constructor, you must call one of the 
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\helpref{Init}{wxbuffereddcinit} methods later in order to use the object.
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The other constructors initialize the object immediately and \texttt{Init()} 
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must not be called after using them.
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\wxheading{Parameters}
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\docparam{dc}{The underlying DC: everything drawn to this object will be
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flushed to this DC when this object is destroyed.  You may pass NULL
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in order to just initialize the buffer, and not flush it.}
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\docparam{area}{The size of the bitmap to be used for buffering (this bitmap is
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created internally when it is not given explicitly).}
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\docparam{buffer}{Explicitly provided bitmap to be used for buffering: this is
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the most efficient solution as the bitmap doesn't have to be recreated each
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time but it also requires more memory as the bitmap is never freed. The bitmap
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should have appropriate size, anything drawn outside of its bounds is clipped.}
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\membersection{wxBufferedDC::Init}\label{wxbuffereddcinit}
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\func{void}{Init}{\param{wxDC *}{dc}, \param{const wxSize\& }{area}}
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\func{void}{Init}{\param{wxDC *}{dc}, \param{const wxBitmap\& }{buffer}}
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These functions initialize the object created using the default constructor.
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Please see \helpref{constructors documentation}{wxbuffereddcctor} for details.
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% VZ: UnMask() intentionally not documented, we might want to make it private
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\membersection{wxBufferedDC::\destruct{wxBufferedDC}}\label{wxbuffereddcdtor}
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Copies everything drawn on the DC so far to the underlying DC associated with
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this object, if any.
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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\section{\class{wxBufferedPaintDC}}\label{wxbufferedpaintdc}
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This is a subclass of \helpref{wxBufferedDC}{wxbuffereddc} which can be used
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inside of an \texttt{OnPaint()} event handler. Just create an object of this class instead
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of \helpref{wxPaintDC}{wxpaintdc} and that's all you have to do to (mostly)
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avoid flicker. The only thing to watch out for is that if you are using this
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class together with \helpref{wxScrolledWindow}{wxscrolledwindow}, you probably
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do \textbf{not} want to call \helpref{PrepareDC}{wxscrolledwindowpreparedc} on it as it
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already does this internally for the real underlying wxPaintDC.
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\wxheading{Derived from}
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\helpref{wxMemoryDC}{wxmemorydc}\\
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\helpref{wxDC}{wxdc}\\
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\helpref{wxObject}{wxobject}
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\wxheading{Include files}
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<wx/dcbuffer.h>
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\latexignore{\rtfignore{\wxheading{Members}}}
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\membersection{wxBufferedPaintDC::wxBufferedPaintDC}\label{wxbufferedpaintdcctor}
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\func{}{wxBufferedPaintDC}{\param{wxWindow *}{window}, \param{const wxBitmap\& }{buffer = wxNullBitmap}}
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As with \helpref{wxBufferedDC}{wxbuffereddcctor}, you may either provide the
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bitmap to be used for buffering or let this object create one internally (in
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the latter case, the size of the client part of the window is used).
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\membersection{wxBufferedPaintDC::\destruct{wxBufferedPaintDC}}\label{wxbufferedpaintdcdtor}
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Copies everything drawn on the DC so far to the window associated with this
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object, using a \helpref{wxPaintDC}{wxpaintdc}.
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