Quartz: Expose methods for bridge with Opal

Expose methods for bridging Opal types and GUI classes. The new
relations are the following:

a) NSImage -> CGImage
b) NSColor -> CGColor
c) NSImageRep -> CGImage

The actual implementation for this bridge is implemented in the Backend
library.

This significantly improves compatibility with AppKit.

Headers/AppKit/NSColor.h

@@ -286,5 +286,12 @@ APPKIT_EXPORT NSString	*NSSystemColorsDidChangeNotification;
 @end
 #endif
 
+typedef struct CGColor *CGColorRef;
+@interface NSColor (GSQuartz)
+#if OS_API_VERSION(MAC_OS_X_VERSION_10_3, GS_API_LATEST)
+- (CGColorRef)CGColor;
+#endif
+@end
+
 #endif // _GNUstep_H_NSColor
 

Headers/AppKit/NSImage.h

@@ -485,6 +485,13 @@ APPKIT_EXTERN NSString *const NSImageNameFolder;
 
 @end
 
+@interface NSImage (GSQuartz)
+#if OS_API_VERSION(MAC_OS_X_VERSION_10_6, GS_API_LATEST)
+- (CGImageRef)CGImageForProposedRect: (NSRect *)proposedDestRect 
+                         context: (NSGraphicsContext *)referenceContext 
+                           hints: (NSDictionary *)hints;
+#endif
+@end
 
 @interface NSBundle (NSImageAdditions)
 

Headers/AppKit/NSImageRep.h

@@ -177,6 +177,15 @@ enum {
 
 @end
 
+typedef struct CGImage *CGImageRef;
+@interface NSImageRep (GSQuartz)
+#if OS_API_VERSION(MAC_OS_X_VERSION_10_6, GS_API_LATEST)
+- (CGImageRef)CGImageForProposedRect: (NSRect *)proposedDestRect 
+                         context: (NSGraphicsContext *)referenceContext 
+                           hints: (NSDictionary *)hints;
+#endif
+@end
+
 APPKIT_EXPORT NSString *NSImageRepRegistryChangedNotification;
 
 #endif // _GNUstep_H_NSImageRep