docs/latex/wx/bufferdc.tex

   1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   2 %% Name:        bufferdc.tex
   3 %% Purpose:     wxBufferedDC documentation
   4 %% Author:      Vadim Zeitlin
   5 %% Modified by:
   6 %% Created:     07.02.04
   7 %% RCS-ID:      $Id$
   8 %% Copyright:   (c) 2004 Vadim Zeitlin
   9 %% License:     wxWindows license
  10 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  11
  12 \section{\class{wxBufferedDC}}\label{wxbuffereddc}
  13
  14 This simple class provides a simple way to avoid flicker: when drawing on it,
  15 everything is in fact first drawn on an in-memory buffer (a
  16 \helpref{wxBitmap}{wxbitmap}) and then copied to the screen only once, when this
  17 object is destroyed.
  18
  19 It can be used in the same way as any other device context. wxBufferedDC itself
  20 typically replaces \helpref{wxClientDC}{wxclientdc}, if you want to use it in
  21 your \texttt{OnPaint()} handler, you should look at
  22 \helpref{wxBufferedPaintDC}{wxbufferedpaintdc}.
  23
  24 \wxheading{Derived from}
  25
  26 \helpref{wxMemoryDC}{wxmemorydc}\\
  27 \helpref{wxDC}{wxdc}\\
  28 \helpref{wxObject}{wxobject}
  29
  30 \wxheading{Include files}
  31
  32 <wx/dcbuffer.h>
  33
  34 \wxheading{See also}
  35
  36 \helpref{wxDC}{wxdc}
  37
  38
  39 \latexignore{\rtfignore{\wxheading{Members}}}
  40
  41 \membersection{wxBufferedDC::wxBufferedDC}\label{wxbuffereddcctor}
  42
  43 \func{}{wxBufferedDC}{\void}
  44
  45 \func{}{wxBufferedDC}{\param{wxDC *}{dc}, \param{const wxSize\& }{area}, \param{int }{style = wxBUFFER\_CLIENT\_AREA}}
  46
  47 \func{}{wxBufferedDC}{\param{wxDC *}{dc}, \param{const wxBitmap\& }{buffer}, \param{int }{style = wxBUFFER\_CLIENT\_AREA}}
  48
  49 If you use the first, default, constructor, you must call one of the
  50 \helpref{Init}{wxbuffereddcinit} methods later in order to use the object.
  51
  52 The other constructors initialize the object immediately and \texttt{Init()}
  53 must not be called after using them.
  54
  55 \wxheading{Parameters}
  56
  57 \docparam{dc}{The underlying DC: everything drawn to this object will be
  58 flushed to this DC when this object is destroyed.  You may pass NULL
  59 in order to just initialize the buffer, and not flush it.}
  60
  61 \docparam{area}{The size of the bitmap to be used for buffering (this bitmap is
  62 created internally when it is not given explicitly).}
  63
  64 \docparam{buffer}{Explicitly provided bitmap to be used for buffering: this is
  65 the most efficient solution as the bitmap doesn't have to be recreated each
  66 time but it also requires more memory as the bitmap is never freed. The bitmap
  67 should have appropriate size, anything drawn outside of its bounds is clipped.}
  68
  69 \docparam{style}{wxBUFFER\_CLIENT\_AREA to indicate that just the client area of
  70 the window is buffered, or wxBUFFER\_VIRTUAL\_AREA to indicate that the buffer bitmap
  71 covers the virtual area (in which case PrepareDC is automatically called for the actual window
  72 device context).}
  73
  74 \membersection{wxBufferedDC::Init}\label{wxbuffereddcinit}
  75
  76 \func{void}{Init}{\param{wxDC *}{dc}, \param{const wxSize\& }{area}, \param{int }{style = wxBUFFER\_CLIENT\_AREA}}
  77
  78 \func{void}{Init}{\param{wxDC *}{dc}, \param{const wxBitmap\& }{buffer}, \param{int }{style = wxBUFFER\_CLIENT\_AREA}}
  79
  80 These functions initialize the object created using the default constructor.
  81 Please see \helpref{constructors documentation}{wxbuffereddcctor} for details.
  82
  83
  84 % VZ: UnMask() intentionally not documented, we might want to make it private
  85
  86
  87 \membersection{wxBufferedDC::\destruct{wxBufferedDC}}\label{wxbuffereddcdtor}
  88
  89 Copies everything drawn on the DC so far to the underlying DC associated with
  90 this object, if any.
  91
  92
  93 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  94
  95 \section{\class{wxBufferedPaintDC}}\label{wxbufferedpaintdc}
  96
  97 This is a subclass of \helpref{wxBufferedDC}{wxbuffereddc} which can be used
  98 inside of an \texttt{OnPaint()} event handler. Just create an object of this class instead
  99 of \helpref{wxPaintDC}{wxpaintdc} and that's all you have to do to (mostly)
 100 avoid flicker. The only thing to watch out for is that if you are using this
 101 class together with \helpref{wxScrolledWindow}{wxscrolledwindow}, you probably
 102 do \textbf{not} want to call \helpref{PrepareDC}{wxscrolledwindowpreparedc} on it as it
 103 already does this internally for the real underlying wxPaintDC.
 104
 105 \wxheading{Derived from}
 106
 107 \helpref{wxMemoryDC}{wxmemorydc}\\
 108 \helpref{wxDC}{wxdc}\\
 109 \helpref{wxObject}{wxobject}
 110
 111 \wxheading{Include files}
 112
 113 <wx/dcbuffer.h>
 114
 115
 116 \latexignore{\rtfignore{\wxheading{Members}}}
 117
 118 \membersection{wxBufferedPaintDC::wxBufferedPaintDC}\label{wxbufferedpaintdcctor}
 119
 120 \func{}{wxBufferedPaintDC}{\param{wxWindow *}{window}, \param{const wxBitmap\& }{buffer}, \param{int }{style = wxBUFFER\_CLIENT\_AREA}}
 121
 122 \func{}{wxBufferedPaintDC}{\param{wxWindow *}{window}, \param{int }{style = wxBUFFER\_CLIENT\_AREA}}
 123
 124 As with \helpref{wxBufferedDC}{wxbuffereddcctor}, you may either provide the
 125 bitmap to be used for buffering or let this object create one internally (in
 126 the latter case, the size of the client part of the window is used).
 127
 128 Pass wxBUFFER\_CLIENT\_AREA for the {\it style} parameter to indicate that just the client area of
 129 the window is buffered, or wxBUFFER\_VIRTUAL\_AREA to indicate that the buffer bitmap
 130 covers the virtual area (in which case PrepareDC is automatically called for the actual window
 131 device context).
 132
 133 \membersection{wxBufferedPaintDC::\destruct{wxBufferedPaintDC}}\label{wxbufferedpaintdcdtor}
 134
 135 Copies everything drawn on the DC so far to the window associated with this
 136 object, using a \helpref{wxPaintDC}{wxpaintdc}.
 137
 138