src/common/dcbufcmn.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/dcbufcmn.cpp
   3 // Purpose:     Buffered DC implementation
   4 // Author:      Ron Lee, Jaakko Salli
   5 // Modified by:
   6 // Created:     Sep-20-2006
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) wxWidgets team
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #ifndef WX_PRECOMP
  28     #include "wx/module.h"
  29 #endif
  30
  31 #include "wx/dcbuffer.h"
  32
  33 // ============================================================================
  34 // implementation
  35 // ============================================================================
  36
  37 // ----------------------------------------------------------------------------
  38 // wxSharedDCBufferManager: helper class maintaining backing store bitmap
  39 // ----------------------------------------------------------------------------
  40
  41 class wxSharedDCBufferManager : public wxModule
  42 {
  43 public:
  44     wxSharedDCBufferManager() { }
  45
  46     virtual bool OnInit() { return true; }
  47     virtual void OnExit() { wxDELETE(ms_buffer); }
  48
  49     static wxBitmap GetBuffer(int w, int h)
  50     {
  51         if ( !ms_buffer ||
  52                 w > ms_buffer->GetWidth() ||
  53                     h > ms_buffer->GetHeight() )
  54         {
  55             delete ms_buffer;
  56             ms_buffer = new wxBitmap(w, h);
  57         }
  58
  59         return *ms_buffer;
  60     }
  61
  62 private:
  63     static wxBitmap *ms_buffer;
  64
  65     DECLARE_DYNAMIC_CLASS(wxSharedDCBufferManager)
  66 };
  67
  68 IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager, wxModule)
  69
  70 // ============================================================================
  71 // wxBufferedDC
  72 // ============================================================================
  73
  74 void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
  75 {
  76     if ( !m_buffer.IsOk() )
  77     {
  78         if ( w == -1 || h == -1 )
  79             m_dc->GetSize(&w, &h);
  80
  81         m_buffer = wxSharedDCBufferManager::GetBuffer(w, h);
  82     }
  83
  84     SelectObject(m_buffer);
  85 }
  86