Preserve wxGraphicsContext settings while resetting the clipping

To reset the clipping there is necessary
to restore all CGContext settings so we need
to set them back to the previous values based
on the stored wxGraphicsContext attributes.

src/osx/carbon/graphics.cpp

@@ -1430,6 +1430,9 @@ public:
 private:
     bool EnsureIsValid();
     void CheckInvariants() const;
+    bool DoSetAntialiasMode(wxAntialiasMode antialias);
+    bool DoSetInterpolationQuality(wxInterpolationQuality interpolation);
+    bool DoSetCompositionMode(wxCompositionMode op);
 
     virtual void DoDrawText( const wxString &str, wxDouble x, wxDouble y ) wxOVERRIDE;
     virtual void DoDrawRotatedText( const wxString &str, wxDouble x, wxDouble y, wxDouble angle ) wxOVERRIDE;
@@ -1678,6 +1681,16 @@ bool wxMacCoreGraphicsContext::SetAntialiasMode(wxAntialiasMode antialias)
 
     m_antialias = antialias;
 
+    if ( !DoSetAntialiasMode(antialias) )
+    {
+        return false;
+    }
+    CheckInvariants();
+    return true;
+}
+
+bool wxMacCoreGraphicsContext::DoSetAntialiasMode(wxAntialiasMode antialias)
+{
     bool antialiasMode;
     switch (antialias)
     {
@@ -1691,7 +1704,6 @@ bool wxMacCoreGraphicsContext::SetAntialiasMode(wxAntialiasMode antialias)
             return false;
     }
     CGContextSetShouldAntialias(m_cgContext, antialiasMode);
-    CheckInvariants();
     return true;
 }
 
@@ -1704,6 +1716,17 @@ bool wxMacCoreGraphicsContext::SetInterpolationQuality(wxInterpolationQuality in
         return true;
 
     m_interpolation = interpolation;
+
+    if ( !DoSetInterpolationQuality(interpolation) )
+    {
+        return false;
+    }
+    CheckInvariants();
+    return true;
+}
+
+bool wxMacCoreGraphicsContext::DoSetInterpolationQuality(wxInterpolationQuality interpolation)
+{
     CGInterpolationQuality quality;
 
     switch (interpolation)
@@ -1727,7 +1750,6 @@ bool wxMacCoreGraphicsContext::SetInterpolationQuality(wxInterpolationQuality in
             return false;
     }
     CGContextSetInterpolationQuality(m_cgContext, quality);
-    CheckInvariants();
     return true;
 }
 
@@ -1741,7 +1763,17 @@ bool wxMacCoreGraphicsContext::SetCompositionMode(wxCompositionMode op)
 
     m_composition = op;
 
-    if (m_composition == wxCOMPOSITION_DEST)
+    if ( !DoSetCompositionMode(op) )
+    {
+        return false;
+    }
+    CheckInvariants();
+    return true;
+}
+
+bool wxMacCoreGraphicsContext::DoSetCompositionMode(wxCompositionMode op)
+{
+    if (op == wxCOMPOSITION_DEST)
         return true;
 
     // TODO REMOVE if we don't need it because of bugs in 10.5
@@ -1833,7 +1865,6 @@ bool wxMacCoreGraphicsContext::SetCompositionMode(wxCompositionMode op)
             case wxCOMPOSITION_XOR:
                 mode = kCGBlendModeExclusion; // Not kCGBlendModeXOR!
                 break;
-
             case wxCOMPOSITION_ADD:
                 mode = kCGBlendModePlusLighter ;
                 break;
@@ -1842,8 +1873,6 @@ bool wxMacCoreGraphicsContext::SetCompositionMode(wxCompositionMode op)
         }
         CGContextSetBlendMode(m_cgContext, mode);
     }
-
-    CheckInvariants();
     return true;
 }
 
@@ -1939,6 +1968,12 @@ void wxMacCoreGraphicsContext::ResetClip()
         transformNew = CGAffineTransformInvert( transformNew ) ;
         CGContextConcatCTM( m_cgContext, transformNew);
         CGContextConcatCTM( m_cgContext, transform);
+        // Retain antialiasing mode
+        DoSetAntialiasMode(m_antialias);
+        // Retain interpolation quality
+        DoSetInterpolationQuality(m_interpolation);
+        // Retain composition mode
+        DoSetCompositionMode(m_composition);
     }
     else
     {