.\" This is a wxWidgets manpage page generated from the XML docs
.TH wxMemoryDC 3wx 2005-02-15 "wxWidgets" "wxWidgets class documentation"
.SH NAME
wxMemoryDC \- 
  A device context for drawing into bitmaps
 
.SH DESCRIPTION

  


   A memory device context provides a means to draw graphics onto a bitmap. When
   drawing in to a mono-bitmap, using
   wxWHITE
   ,
   wxWHITE_PEN
   and
   wxWHITE_BRUSH
   will draw the background colour (i.e. 0) whereas all other colours will draw
   the foreground colour (i.e. 1).
  
 
.SH REMARKS

  
   A bitmap must be selected into the new memory DC before it may be used for
   anything. Typical usage is as follows:
  
  
  // Create a memory DC
  wxMemoryDC temp_dc;
  temp_dc.SelectObject(test_bitmap);

  // We can now draw into the memory DC...
  // Copy from this DC to another DC.
  old_dc.Blit(250, 50, BITMAP_WIDTH, BITMAP_HEIGHT, temp_dc, 0, 0);

  
   Note that the memory DC
   
    must
   
   be deleted (or the bitmap selected out of it) before a bitmap can be
   reselected into another memory DC.
  
 
.SH "PARENTS"

  wxDC
   
  wxObject
 
.SH "INCLUDE FILES"
wx/dcmemory.h
.SH MEMBERS

  
.SS  wxMemoryDC ()

     


      Constructs a new memory device context.
     
     


      Use the
      
       Ok
      
      member to test whether the constructor was successful in creating a usable
      device context. Don't forget to select a bitmap into the DC before drawing
      on it.
     
    
   
  
.SS void SelectObject (const wxBitmap& bitmap)

     


      Selects the given bitmap into the device context, to use as the memory
      bitmap. Selecting the bitmap into a memory DC allows you to draw into the
      DC (and therefore the bitmap) and also to use
      
       Blit
      
      to copy the bitmap to a window. For this purpose, you may find
      wxDC::DrawIcon
      easier to use instead.
     
     


      If the argument is wxNullBitmap (or some other uninitialised wxBitmap) the
      current bitmap is selected out of the device context, and the original
      bitmap restored, allowing the current bitmap to be destroyed safely.
     
    
 
.SH "SEE ALSO"

  wxDC
   
  wxObject
 
  wxBitmap
  wxDC
 
.SH "AUTHORS"
Documentation content by Julian Smart, Robert Roebling, Vadim Zeitlin, Robin Dunn, et al

Conversion to manpage format by Arnout Engelen (http://bzzt.net), bugreports welcome.