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 IMPLEMENT_DYNAMIC_CLASS(wxBufferedDC,wxMemoryDC)
  38 IMPLEMENT_ABSTRACT_CLASS(wxBufferedPaintDC,wxBufferedDC)
  39
  40 // ----------------------------------------------------------------------------
  41 // wxSharedDCBufferManager: helper class maintaining backing store bitmap
  42 // ----------------------------------------------------------------------------
  43
  44 class wxSharedDCBufferManager : public wxModule
  45 {
  46 public:
  47     wxSharedDCBufferManager() { }
  48
  49     virtual bool OnInit() { return true; }
  50     virtual void OnExit() { wxDELETE(ms_buffer); }
  51
  52     static wxBitmap* GetBuffer(int w, int h)
  53     {
  54         if ( ms_usingSharedBuffer )
  55             return new wxBitmap(w, h);
  56
  57         if ( !ms_buffer ||
  58                 w > ms_buffer->GetWidth() ||
  59                     h > ms_buffer->GetHeight() )
  60         {
  61             delete ms_buffer;
  62             ms_buffer = new wxBitmap(w, h);
  63         }
  64
  65         ms_usingSharedBuffer = true;
  66         return ms_buffer;
  67     }
  68
  69     static void ReleaseBuffer(wxBitmap* buffer)
  70     {
  71         if ( buffer == ms_buffer )
  72         {
  73             wxASSERT_MSG( ms_usingSharedBuffer, wxT("shared buffer already released") );
  74             ms_usingSharedBuffer = false;
  75         }
  76         else
  77         {
  78             delete buffer;
  79         }
  80     }
  81
  82 private:
  83     static wxBitmap *ms_buffer;
  84     static bool ms_usingSharedBuffer;
  85
  86     DECLARE_DYNAMIC_CLASS(wxSharedDCBufferManager)
  87 };
  88
  89 wxBitmap* wxSharedDCBufferManager::ms_buffer = NULL;
  90 bool wxSharedDCBufferManager::ms_usingSharedBuffer = false;
  91
  92 IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager, wxModule)
  93
  94 // ============================================================================
  95 // wxBufferedDC
  96 // ============================================================================
  97
  98 void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
  99 {
 100     if ( !m_buffer || !m_buffer->IsOk() )
 101     {
 102         if ( w == -1 || h == -1 )
 103             m_dc->GetSize(&w, &h);
 104
 105         m_buffer = wxSharedDCBufferManager::GetBuffer(w, h);
 106         m_style |= wxBUFFER_USES_SHARED_BUFFER;
 107     }
 108
 109     SelectObject(*m_buffer);
 110 }
 111
 112 void wxBufferedDC::UnMask()
 113 {
 114     wxCHECK_RET( m_dc, _T("no underlying wxDC?") );
 115     wxASSERT_MSG( m_buffer && m_buffer->IsOk(), _T("invalid backing store") );
 116
 117     wxCoord x = 0,
 118             y = 0;
 119
 120     if ( m_style & wxBUFFER_CLIENT_AREA )
 121         GetDeviceOrigin(&x, &y);
 122
 123     m_dc->Blit(0, 0, m_buffer->GetWidth(), m_buffer->GetHeight(),
 124                this, -x, -y );
 125     m_dc = NULL;
 126
 127     if ( m_style & wxBUFFER_USES_SHARED_BUFFER )
 128         wxSharedDCBufferManager::ReleaseBuffer(m_buffer);
 129 }