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 #endif
  29
  30 #include "wx/dcbuffer.h"
  31
  32
  33 // ============================================================================
  34 // implementation
  35 // ============================================================================
  36
  37 // ============================================================================
  38 // wxSharedDCBufferManager
  39 //   Helper class to free shared buffer when the app exists.
  40 // ============================================================================
  41
  42 class wxSharedDCBufferManager
  43 {
  44     friend class wxBufferedDC;
  45 public:
  46
  47     wxSharedDCBufferManager()
  48     {
  49         m_buffer = NULL;
  50     }
  51
  52     ~wxSharedDCBufferManager()
  53     {
  54         delete m_buffer;
  55     }
  56
  57     wxBitmap* GetBuffer(wxWindow* win, const wxSize& area)
  58     {
  59         int width = area.x;
  60         int height = area.y;
  61
  62         if ( width <= 0 )
  63             win->GetClientSize(&width, &height);
  64
  65         if ( !m_buffer ||
  66              width > m_buffer->GetWidth() ||
  67              height > m_buffer->GetHeight() )
  68         {
  69             delete m_buffer;
  70
  71             // Create slightly larger bitmap so we don't need to
  72             // be reallocating constantly when the user enlarges
  73             // the frame for the first time.
  74             m_buffer = new wxBitmap(width+20, height+20);
  75         }
  76
  77         return m_buffer;
  78     }
  79
  80 private:
  81     wxBitmap*   m_buffer;
  82 };
  83
  84 static wxSharedDCBufferManager gs_sharedDCBufferManager;
  85
  86 // ============================================================================
  87 // wxBufferedDC
  88 // ============================================================================
  89
  90 // Blits the buffer to the dc, and detaches the dc from the buffer (so it
  91 // can be effectively used once only).
  92 //
  93 // Usually called in the dtor or by the dtor of derived classes if the
  94 // BufferedDC must blit before the derived class (which may own the dc it's
  95 // blitting to) is destroyed.
  96 void wxBufferedDC::UnMask()
  97 {
  98     if ( m_buffer )
  99     {
 100         wxASSERT_MSG( m_mainDc != NULL,
 101                       _T("No underlying DC associated with wxBufferedDC (anymore)") );
 102
 103         wxDC* bufferDc = DetachDC();
 104
 105         wxASSERT( bufferDc->IsKindOf(CLASSINFO(wxMemoryDC)) );
 106
 107         wxCoord x=0, y=0;
 108
 109         if (m_style & wxBUFFER_CLIENT_AREA)
 110             bufferDc->GetDeviceOrigin(& x, & y);
 111
 112         m_mainDc->Blit( 0, 0,
 113                         m_buffer->GetWidth(), m_buffer->GetHeight(), bufferDc,
 114                         -x, -y );
 115         m_mainDc = NULL;
 116         m_buffer = NULL;
 117         delete bufferDc;
 118     }
 119 }
 120
 121 void wxBufferedDC::PrepareBuffer(wxWindow* win, const wxSize& area)
 122 {
 123     m_buffer = gs_sharedDCBufferManager.GetBuffer(win, area);
 124 }
 125
 126 void wxBufferedDC::UseBuffer()
 127 {
 128     wxASSERT(m_buffer);
 129
 130     wxMemoryDC* memoryDc = new wxMemoryDC(m_mainDc);
 131     memoryDc->SelectObject(*m_buffer);
 132
 133     AttachDC(memoryDc);
 134 }
 135
 136