[Drawkit] clipping paths?

[Rudy Richter]

For the work i've got in front of me i'm not actually using the  
entirety of DrawKit.  I'm using the demo app as a quick and easy way  
for our artist to create objects en masse, I'm then taking the  
resulting save file and reading that in in my app using DKDrawing  
drawingWithData to read it all in.  Once i've got my DKDrawing  
instance i can pick through the layers and extract the objects and  
styles he's created.  I've run into a case where i want to be able to  
take as an example the donut shape and create a clipping path from it  
that i can use to mask other drawing.  what ends up happening if i  
take the inverse of the donut's path and add it to the clipping path  
is i get the donut hole as i would expect, but i unfortunately  
additionally get the areas outside the donut that are part of the  
enclosing rectangle.  Within the scope of not changing DrawKit too  
much (to maintain my ability to easily sync with the DrawKit releases)  
is there any way i should look at hooking into DrawKit to accomplish  
the goal of only having the donut hole as the clipping path?

One thing i was looking at was possibly seeing if i could create  
something akin to DKFill/Stroke to allow specification of a clipping  
path for my use case. any suggestions on how i might accomplish those  
goals?

-rudy