I am struggling with CG graphics myself.  The biggest problem for me  
is the totally different coordinate system required.  Once a context  
is created the bottom left is 0,0 and the x and y sizes need some  
magical scaling (my opinion due to my lack of knowledge yet) and seem  
to be expressed with numbers from 0-1 with a number like .80 meaning  
8/10 of the width of the context or a point being 8/10 from the left  
or bottom of the context port.  I would love to see the results of  
your efforts.

David