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 #include "wx/dcbuffer.h"
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/module.h"
  31 #endif
  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         return ms_buffer;
  59     }
  60
  61 private:
  62     static wxBitmap *ms_buffer;
  63
  64     DECLARE_DYNAMIC_CLASS(wxSharedDCBufferManager)
  65 };
  66
  67 wxBitmap* wxSharedDCBufferManager::ms_buffer = NULL;
  68
  69 IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager, wxModule)
  70
  71 // ============================================================================
  72 // wxBufferedDC
  73 // ============================================================================
  74
  75 void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
  76 {
  77     if ( !m_buffer || !m_buffer->IsOk() )
  78     {
  79         if ( w == -1 || h == -1 )
  80             m_dc->GetSize(&w, &h);
  81
  82         m_buffer = wxSharedDCBufferManager::GetBuffer(w, h);
  83     }
  84
  85     SelectObject(*m_buffer);
  86 }
  87