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Adding a native implementation for clearing bitmap/window contexts

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Filling a bitmap surface is filled with ARGB 0,0,0,0. This way eg buffered transparent layers can be properly cleared.
This commit is contained in:
Stefan Csomor
2017-06-25 22:48:58 +02:00
parent 40d77062b0
commit 6dfa897b4a
5 changed files with 72 additions and 28 deletions
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66
src/common/dcgraph.cpp
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@@ -1249,33 +1249,49 @@ wxCoord wxGCDCImpl::GetCharHeight(void) const
void wxGCDCImpl::Clear(void)
{
wxCHECK_RET( IsOk(), wxT("wxGCDC(cg)::Clear - invalid DC") );
m_graphicContext->SetBrush( m_backgroundBrush );
wxPen p = *wxTRANSPARENT_PEN;
m_graphicContext->SetPen( p );
wxCompositionMode formerMode = m_graphicContext->GetCompositionMode();
m_graphicContext->SetCompositionMode(wxCOMPOSITION_SOURCE);
if ( m_backgroundBrush.IsOk() )
{
m_graphicContext->SetBrush( m_backgroundBrush );
wxPen p = *wxTRANSPARENT_PEN;
m_graphicContext->SetPen( p );
wxCompositionMode formerMode = m_graphicContext->GetCompositionMode();
m_graphicContext->SetCompositionMode(wxCOMPOSITION_SOURCE);
#ifdef __WXOSX__
// This is a legacy implementation which doesn't take advantage
// of clipping region bounds retrieved by wxMacCoreGraphicsContext::GetClipBox
// because this function is not yet verified.
// Note: Legacy implmentation might not work work properly
// if graphics context is rotated
// TODO: Do the tests of wxMacCoreGraphicsContext::GetClipBox
// and switch to the implmenentation used by other renderers (code below).
//
// maximum positive coordinate Cairo can handle is 2^23 - 1
// Use a value slightly less than this to be sure we avoid the limit
DoDrawRectangle(
DeviceToLogicalX(0), DeviceToLogicalY(0),
DeviceToLogicalXRel(0x800000 - 64), DeviceToLogicalYRel(0x800000 - 64));
#else
double x, y, w, h;
m_graphicContext->GetClipBox(&x, &y, &w, &h);
m_graphicContext->DrawRectangle(x, y, w, h);
#endif // __WXOSX__ / !__WXOSX__
m_graphicContext->SetCompositionMode(formerMode);
m_graphicContext->SetPen( m_pen );
m_graphicContext->SetBrush( m_brush );
}
else
{
#ifdef __WXOSX__
// This is a legacy implementation which doesn't take advantage
// of clipping region bounds retrieved by wxMacCoreGraphicsContext::GetClipBox
// because this function is not yet verified.
// Note: Legacy implmentation might not work work properly
// if graphics context is rotated
// TODO: Do the tests of wxMacCoreGraphicsContext::GetClipBox
// and switch to the implmenentation used by other renderers (code below).
//
// maximum positive coordinate Cairo can handle is 2^23 - 1
// Use a value slightly less than this to be sure we avoid the limit
DoDrawRectangle(
DeviceToLogicalX(0), DeviceToLogicalY(0),
DeviceToLogicalXRel(0x800000 - 64), DeviceToLogicalYRel(0x800000 - 64));
// same comment as above applies
m_graphicContext->ClearRectangle(DeviceToLogicalX(0), DeviceToLogicalY(0),
DeviceToLogicalXRel(0x8000 - 64), DeviceToLogicalYRel(0x8000 - 64));
#else
double x, y, w, h;
m_graphicContext->GetClipBox(&x, &y, &w, &h);
m_graphicContext->DrawRectangle(x, y, w, h);
#endif // __WXOSX__ / !__WXOSX__
m_graphicContext->SetCompositionMode(formerMode);
m_graphicContext->SetPen( m_pen );
m_graphicContext->SetBrush( m_brush );
double x, y, w, h;
m_graphicContext->GetClipBox(&x, &y, &w, &h);
m_graphicContext->ClearRectangle(x, y, w, h);
#endif
}
}
void wxGCDCImpl::DoGetSize(int *width, int *height) const