adding raster op hook to graphics context

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43761 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/graphcmn.cpp

@@ -495,6 +495,7 @@ IMPLEMENT_ABSTRACT_CLASS(wxGraphicsContext, wxObject)
 
 wxGraphicsContext::wxGraphicsContext(wxGraphicsRenderer* renderer) : wxGraphicsObject(renderer) 
 {
+    m_logicalFunction = wxCOPY;
 }
 
 wxGraphicsContext::~wxGraphicsContext() 
@@ -535,6 +536,16 @@ void wxGraphicsContext::SetFont( const wxGraphicsFont& font )
     m_font = font;
 }
 
+bool wxGraphicsContext::SetLogicalFunction( int function )
+{
+    if ( function == wxCOPY )
+    {
+        m_logicalFunction = function;
+        return true;
+    }
+    return false;
+}
+
 void wxGraphicsContext::SetFont( const wxFont& font, const wxColour& colour )
 {
     if ( font.Ok() )