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Fix creating wxCairoContext from CGContext (wxOSX)

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Cairo surface works properly if origin of the clipping region of CGContext
is (0,0) so if it's not the case we need to apply a transformation to move
it to (0,0).
This shift needs to be applied as an offset added to the device coordinates
when drawing to surface.

Closes #22990.
This commit is contained in:
Artur Wieczorek 2022-11-24 22:33:45 +02:00
parent 4311bfeea7
commit dcc41a9c88
1 changed files with 54 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

59
src/generic/graphicc.cpp
View file

@ -530,7 +530,10 @@ protected:
#ifdef __WXMSW__
static wxPoint MSWAdjustHdcOrigin(HDC hdc);
#endif // __WXMSW__
#ifdef __WXMAC__
static wxPoint MacAdjustCgContextOrigin(CGContextRef cg);
#endif // __WXMAC__
#ifdef __WXQT__
QPainter* m_qtPainter;
QImage* m_qtImage;
@ -581,6 +584,10 @@ protected:
#endif // __WXGTK3__
#endif // __WXGTK__
#ifdef __WXMAC__
CGContextRef m_cgContext;
#endif // __WXMAC__
private:
cairo_t* m_context;
cairo_matrix_t m_internalTransform;
@ -2056,8 +2063,13 @@ wxCairoContext::wxCairoContext( wxGraphicsRenderer* renderer, const wxWindowDC&
if ( cr )
Init(cairo_reference(cr), true);
#elif defined(__WXMAC__)
CGContextRef cgcontext = (CGContextRef)dc.GetWindow()->MacGetCGContextRef();
cairo_surface_t* surface = cairo_quartz_surface_create_for_cg_context(cgcontext, width, height);
m_cgContext = (CGContextRef)dc.GetWindow()->MacGetCGContextRef();
CGContextSaveGState(m_cgContext);
// Cairo surface works properly if origin of the clipping region of CGContext is (0,0)
// so if it's not the cae we need to move it to (0,0) and apply corrective offset to the device coordinates.
wxPoint surfOffs = MacAdjustCgContextOrigin(m_cgContext);
cairo_surface_t* surface = cairo_quartz_surface_create_for_cg_context(m_cgContext, width, height);
cairo_surface_set_device_offset(surface, surfOffs.x, surfOffs.y);
Init( cairo_create( surface ) );
cairo_surface_destroy( surface );
#endif
@ -2258,8 +2270,13 @@ wxCairoContext::wxCairoContext( wxGraphicsRenderer* renderer, const wxMemoryDC&
#endif
#ifdef __WXMAC__
CGContextRef cgcontext = (CGContextRef)dc.GetGraphicsContext()->GetNativeContext();
cairo_surface_t* surface = cairo_quartz_surface_create_for_cg_context(cgcontext, width, height);
m_cgContext = (CGContextRef)dc.GetGraphicsContext()->GetNativeContext();
CGContextSaveGState(m_cgContext);
// Cairo surface works properly if origin of the clipping region of CGContext is (0,0)
// so if it's not the cae we need to move it to (0,0) and apply corrective offset to the device coordinates.
wxPoint surfOffs = MacAdjustCgContextOrigin(m_cgContext);
cairo_surface_t* surface = cairo_quartz_surface_create_for_cg_context(m_cgContext, width, height);
cairo_surface_set_device_offset(surface, surfOffs.x, surfOffs.y);
Init( cairo_create( surface ) );
cairo_surface_destroy( surface );
#endif
@ -2383,6 +2400,10 @@ wxCairoContext::wxCairoContext( wxGraphicsRenderer* renderer, cairo_t *context )
m_mswSurface = nullptr;
m_mswStateSavedDC = 0;
#endif // __WXMSW__
#ifdef __WXMAC__
m_cgContext = nullptr;
#endif // __WXMAC__
Init( cairo_reference(context), true );
m_width = 0;
m_height = 0;
@ -2425,6 +2446,10 @@ wxCairoContext::wxCairoContext( wxGraphicsRenderer* renderer, wxWindow *window)
m_height = sz.y;
#endif // __WXMSW__
#ifdef __WXMAC__
m_cgContext = nullptr;
#endif // __WXMAC__
#ifdef __WXQT__
// direct m_qtSurface is not being used yet (this needs cairo qt surface)
#endif
@ -2442,6 +2467,9 @@ wxCairoContext::wxCairoContext(wxGraphicsRenderer* renderer) :
m_mswSurface = nullptr;
m_mswStateSavedDC = 0;
#endif // __WXMSW__
#ifdef __WXMAC__
m_cgContext = nullptr;
#endif // __WXMAC__
Init(nullptr);
m_width = 0;
m_height = 0;
@ -2466,6 +2494,12 @@ wxCairoContext::~wxCairoContext()
::RestoreDC(hdc, m_mswStateSavedDC);
}
#endif
#ifdef __WXMAC__
if ( m_cgContext != nullptr )
{
CGContextRestoreGState(m_cgContext);
}
#endif // __WXMAC__
#ifdef __WXQT__
if ( m_qtPainter != nullptr )
{
@ -2592,6 +2626,21 @@ wxPoint wxCairoContext::MSWAdjustHdcOrigin(HDC hdc)
}
#endif // __WXMSW__
#ifdef __WXMAC__
/* static */
wxPoint wxCairoContext::MacAdjustCgContextOrigin(CGContextRef cg)
{
// Cairo surface works properly if origin of the clipping region of CGContext is (0,0)
// so if it's not the case we need to apply a transformation to move it to (0,0).
// This shift needs to be applied as an offset added to the device coordinates when drawing to surface.
CGRect clip = CGContextGetClipBoundingBox(cg);
CGAffineTransform cgTransform = CGAffineTransformMake(1, 0, 0, 1, clip.origin.x, clip.origin.y);
CGContextConcatCTM(cg, cgTransform);
return wxPoint(-clip.origin.x, -clip.origin.y);
}
#endif // __WXMAC__
void wxCairoContext::Clip( const wxRegion& region )
{
// Create a path with all the rectangles in the region