diff --git a/include/wx/dcbuffer.h b/include/wx/dcbuffer.h index 521113e0c8..40cb8179cd 100644 --- a/include/wx/dcbuffer.h +++ b/include/wx/dcbuffer.h @@ -134,6 +134,8 @@ private: // the buffering style int m_style; + wxSize m_area; + DECLARE_DYNAMIC_CLASS(wxBufferedDC) wxDECLARE_NO_COPY_CLASS(wxBufferedDC); }; diff --git a/src/common/dcbufcmn.cpp b/src/common/dcbufcmn.cpp index 2a8314d43e..d625c72f8f 100644 --- a/src/common/dcbufcmn.cpp +++ b/src/common/dcbufcmn.cpp @@ -114,7 +114,10 @@ void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h) m_buffer = wxSharedDCBufferManager::GetBuffer(w, h); m_style |= wxBUFFER_USES_SHARED_BUFFER; + m_area.Set(w,h); } + else + m_area = m_buffer->GetSize(); SelectObject(*m_buffer); @@ -138,21 +141,24 @@ void wxBufferedDC::UnMask() if ( m_style & wxBUFFER_CLIENT_AREA ) GetDeviceOrigin(&x, &y); - // avoid blitting too much: if we were created for a bigger bitmap (and - // reused for a smaller one later) we should only blit the real bitmap area - // and not the full allocated back buffer - int widthDC, - heightDC; + // It's possible that the buffer may be bigger than the area that needs to + // be drawn (the client size of the window is smaller than the bitmap, or + // a shared bitmap has been reused for a smaller area, etc.) so avoid + // blitting too much if possible, but only use the real DC size if the + // wxBUFFER_VIRTUAL_AREA style is not set. + int width = m_area.GetWidth(), + height = m_area.GetHeight(); - m_dc->GetSize(&widthDC, &heightDC); + if (! m_style & wxBUFFER_VIRTUAL_AREA) + { + int widthDC, + heightDC; + m_dc->GetSize(&widthDC, &heightDC); + width = wxMin(width, widthDC); + height = wxMin(height, heightDC); + } - int widthBuf = m_buffer->GetWidth(), - heightBuf = m_buffer->GetHeight(); - - m_dc->Blit(0, 0, - wxMin(widthDC, widthBuf), wxMin(heightDC, heightBuf), - this, - -x, -y); + m_dc->Blit(0, 0, width, height, this, -x, -y); m_dc = NULL; if ( m_style & wxBUFFER_USES_SHARED_BUFFER )