Allow using a memory dc (or a buffered dc) as the target of

a wx.GraphicsContext.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_8_BRANCH@44573 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/mac/carbon/graphics.cpp

@@ -2012,9 +2012,18 @@ wxGraphicsRenderer* wxGraphicsRenderer::GetDefaultRenderer()
 }
 
 wxGraphicsContext * wxMacCoreGraphicsRenderer::CreateContext( const wxWindowDC& dc)
+{
+    wxMemoryDC* mdc = wxDynamicCast(&dc, wxMemoryDC);
+    if ( mdc )
+    {
+        return new wxMacCoreGraphicsContext(this, 
+            (CGContextRef)mdc->GetGraphicsContext()->GetNativeContext());
+    }
+    else
     {
         return new wxMacCoreGraphicsContext(this,(CGContextRef)dc.GetWindow()->MacGetCGContextRef() );
     }
+}
 
 wxGraphicsContext * wxMacCoreGraphicsRenderer::CreateContextFromNativeContext( void * context )
 {