wxOSX: Implement function to retrieve pattern image for non-solid colour

Under wxOSX non-solid wxColour with NSColor backend is represented by
pattern image and it would be useful to have ability to get it e.g. to help
dealing with non-solid wxColours by frameworks not supporting such colours,
like e.g. Cairo.

include/wx/osx/core/colour.h

@@ -68,6 +68,7 @@ public:
     // This ctor does not take ownership of the color.
     explicit wxColour(WX_NSColor color);
     WX_NSColor OSXGetNSColor() const;
+    WX_NSImage OSXGetNSPatternImage() const;
 #endif
 
 protected :
@@ -102,6 +103,7 @@ public:
 
 #if wxOSX_USE_COCOA
     virtual WX_NSColor GetNSColor() const;
+    virtual WX_NSImage GetNSPatternImage() const;
 #endif
 };
 

src/osx/cocoa/colour.mm

@@ -35,6 +35,7 @@ public:
     virtual wxColourRefData* Clone() const wxOVERRIDE { return new wxNSColorRefData(*this); }
     
     virtual WX_NSColor GetNSColor() const wxOVERRIDE;
+    virtual WX_NSImage GetNSPatternImage() const wxOVERRIDE;
 private:
     WX_NSColor m_nsColour;
     
@@ -186,15 +187,33 @@ CGColorRef wxNSColorRefData::GetCGColor() const
     return cgcolor;
 }
 
+WX_NSImage wxNSColorRefData::GetNSPatternImage() const
+{
+    NSColor* colPat = [m_nsColour colorUsingColorSpaceName:NSPatternColorSpace];
+    if ( colPat )
+    {
+        NSImage* nsimage = [colPat patternImage];
+        if ( nsimage )
+        {
+            return nsimage;
+        }
+    }
+
+    return NULL;
+}
+
 WX_NSColor wxColourRefData::GetNSColor() const
 {
     wxOSXEffectiveAppearanceSetter helper;
     return [NSColor colorWithCalibratedRed:Red() green:Green() blue:Blue() alpha:Alpha() ];
 }
 
+WX_NSImage wxColourRefData::GetNSPatternImage() const
+{
+    return NULL;
+}
+
 wxColour::wxColour(WX_NSColor col)
 {
     m_refData = new wxNSColorRefData(col);
 }
-
-

src/osx/core/colour.cpp

@@ -222,6 +222,13 @@ WX_NSColor wxColour::OSXGetNSColor() const
 
     return M_COLDATA->GetNSColor();
 }
+
+WX_NSImage wxColour::OSXGetNSPatternImage() const
+{
+    wxCHECK_MSG( IsOk(), NULL, "invalid colour" );
+
+    return M_COLDATA->GetNSPatternImage();
+}
 #endif
 
 void wxColour::InitRGBA(ChannelType r, ChannelType g, ChannelType b, ChannelType a)