2 additional interfaces that can be subclassed
IGrGraphicsDrawing for the functions that do drawing
IGrGraphicsFont for functions that get information out
of fonts.
This gives you the option of using the same font-info
system with different drawing systems - for linux this
will hopefully be freetype with various drawing systems.
The app developer can either subclass IGrGraphics
directly, or subclass IGrGraphicsDrawing and
IGrGraphicsFont and then create a GrGraphics that
inherits from both of these.
IGrGraphicsDrawing
IGrGraphicsFont