wxWidgets/docs/doxygen/overviews/dc.h

/////////////////////////////////////////////////////////////////////////////
// Name:        dc
// Purpose:     topic overview
// Author:      wxWidgets team
// RCS-ID:      $Id$
// Licence:     wxWindows license
/////////////////////////////////////////////////////////////////////////////

/*!

 @page dc_overview Device context overview

 Classes: #wxBufferedDC, #wxBufferedPaintDC, #wxDC, #wxPostScriptDC,
 #wxMetafileDC, #wxMemoryDC, #wxPrinterDC,
 #wxScreenDC, #wxClientDC, #wxPaintDC,
 #wxWindowDC.
 A wxDC is a @e device context onto which graphics and text can be drawn.
 The device context is intended to represent a number of output devices in a generic way,
 with the same API being used throughout.
 Some device contexts are created temporarily in order to draw on a window.
 This is @true of #wxScreenDC, #wxClientDC, #wxPaintDC,
 and #wxWindowDC. The following describes the differences between
 these device contexts and when you should use them.


  @b wxScreenDC. Use this to paint on the screen, as opposed to an individual window.
  @b wxClientDC. Use this to paint on the client area of window (the part without
 borders and other decorations), but do not use it from within an #wxPaintEvent.
  @b wxPaintDC. Use this to paint on the client area of a window, but @e only from
 within a #wxPaintEvent.
  @b wxWindowDC. Use this to paint on the whole area of a window, including decorations.
 This may not be available on non-Windows platforms.


 To use a client, paint or window device context, create an object on the stack with
 the window as argument, for example:

 @code
 void MyWindow::OnMyCmd(wxCommandEvent& event)
   {
     wxClientDC dc(window);
     DrawMyPicture(dc);
   }
 @endcode

 Try to write code so it is parameterised by wxDC - if you do this, the same piece of code may
 write to a number of different devices, by passing a different device context. This doesn't
 work for everything (for example not all device contexts support bitmap drawing) but
 will work most of the time.

 */