interface/wx/dcscreen.h

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