interface/dcscreen.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dcscreen.h
   3 // Purpose:     interface of wxScreenDC
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxScreenDC
  11     @wxheader{dcscreen.h}
  12
  13     A wxScreenDC can be used to paint on the screen. This should normally be
  14     constructed as a temporary stack object; don't store a wxScreenDC object.
  15
  16     @library{wxcore}
  17     @category{dc}
  18
  19     @see wxDC, wxMemoryDC, wxPaintDC, wxClientDC, wxWindowDC
  20 */
  21 class wxScreenDC : public wxDC
  22 {
  23 public:
  24     /**
  25         Constructor.
  26     */
  27     wxScreenDC();
  28
  29     /**
  30         Use this in conjunction with StartDrawingOnTop().
  31
  32         This function destroys the temporary window created to implement on-top
  33         drawing (X only).
  34     */
  35     bool EndDrawingOnTop();
  36
  37     /**
  38         Use this in conjunction with EndDrawingOnTop() to ensure that drawing
  39         to the screen occurs on top of existing windows. Without this, some
  40         window systems (such as X) only allow drawing to take place underneath
  41         other windows.
  42
  43         This version of StartDrawingOnTop() is used to specify that the area
  44         that will be drawn on coincides with the given window. It is
  45         recommended that an area of the screen is specified with
  46         StartDrawingOnTop(wxRect*) because with large regions, flickering
  47         effects are noticeable when destroying the temporary transparent window
  48         used to implement this feature.
  49
  50         You might use this function when implementing a drag feature, for
  51         example as in the wxSplitterWindow implementation.
  52
  53         @remarks This function is probably obsolete since the X implementations
  54                  allow drawing directly on the screen now. However, the fact
  55                  that this function allows the screen to be refreshed
  56                  afterwards, may be useful to some applications.
  57     */
  58     bool StartDrawingOnTop(wxWindow* window);
  59     /**
  60         Use this in conjunction with EndDrawingOnTop() to ensure that drawing
  61         to the screen occurs on top of existing windows. Without this, some
  62         window systems (such as X) only allow drawing to take place underneath
  63         other windows.
  64
  65         This version of StartDrawingOnTop() is used to specify an area of the
  66         screen which is to be drawn on. If @NULL is passed, the whole screen is
  67         available. It is recommended that an area of the screen is specified
  68         with this function rather than with StartDrawingOnTop(wxWindow*),
  69         because with large regions, flickering effects are noticeable when
  70         destroying the temporary transparent window used to implement this
  71         feature.
  72
  73         You might use this function when implementing a drag feature, for
  74         example as in the wxSplitterWindow implementation.
  75
  76         @remarks This function is probably obsolete since the X implementations
  77                  allow drawing directly on the screen now. However, the fact
  78                  that this function allows the screen to be refreshed
  79                  afterwards, may be useful to some applications.
  80     */
  81     bool StartDrawingOnTop(wxRect* rect = NULL);
  82 };
  83