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_usingSharedBuffer )
  52             return new wxBitmap(w, h);
  53
  54         if ( !ms_buffer ||
  55                 w > ms_buffer->GetWidth() ||
  56                     h > ms_buffer->GetHeight() )
  57         {
  58             delete ms_buffer;
  59             ms_buffer = new wxBitmap(w, h);
  60         }
  61
  62         ms_usingSharedBuffer = true;
  63         return ms_buffer;
  64     }
  65
  66     static void ReleaseBuffer(wxBitmap* buffer)
  67     {
  68         if ( buffer == ms_buffer )
  69         {
  70             wxASSERT_MSG( ms_usingSharedBuffer, wxT("shared buffer already released") );
  71             ms_usingSharedBuffer = false;
  72         }
  73         else
  74         {
  75             delete buffer;
  76         }
  77     }
  78
  79 private:
  80     static wxBitmap *ms_buffer;
  81     static bool ms_usingSharedBuffer;
  82
  83     DECLARE_DYNAMIC_CLASS(wxSharedDCBufferManager)
  84 };
  85
  86 wxBitmap* wxSharedDCBufferManager::ms_buffer = NULL;
  87 bool wxSharedDCBufferManager::ms_usingSharedBuffer = false;
  88
  89 IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager, wxModule)
  90
  91 // ============================================================================
  92 // wxBufferedDC
  93 // ============================================================================
  94
  95 void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
  96 {
  97     if ( !m_buffer || !m_buffer->IsOk() )
  98     {
  99         if ( w == -1 || h == -1 )
 100             m_dc->GetSize(&w, &h);
 101
 102         m_buffer = wxSharedDCBufferManager::GetBuffer(w, h);
 103         m_style |= wxBUFFER_USES_SHARED_BUFFER;
 104     }
 105
 106     SelectObject(*m_buffer);
 107 }
 108
 109 void wxBufferedDC::UnMask()
 110 {
 111     wxCHECK_RET( m_dc, _T("no underlying wxDC?") );
 112     wxASSERT_MSG( m_buffer && m_buffer->IsOk(), _T("invalid backing store") );
 113
 114     wxCoord x = 0,
 115             y = 0;
 116
 117     if ( m_style & wxBUFFER_CLIENT_AREA )
 118         GetDeviceOrigin(&x, &y);
 119
 120     m_dc->Blit(0, 0, m_buffer->GetWidth(), m_buffer->GetHeight(),
 121                this, -x, -y );
 122     m_dc = NULL;
 123
 124     if ( m_style & wxBUFFER_USES_SHARED_BUFFER )
 125         wxSharedDCBufferManager::ReleaseBuffer(m_buffer);
 126 }