datpete@daimi.aau.dk (Peter Andersen) (11/28/90)
We are porting an advanced graphics system to the Mac. The graphics system supports two different fill rules for polygons: even-odd and zero-winding. The difference between the two fill rules can be seen when you make the following polygon |-------------| | | | | | |---| | | | | | |----|---| | | | |--------| Even-odd fill rule Zero-winding fill rule |-------------| |-------------| |*************| |*************| |*************| |*************| |****|---|****| |****|---|****| |****| |****| |****|***|****| |----|---|****| |----|---|****| |********| |********| |--------| |--------| Note: the rectangle Note: the rectangle in in the middle is NOT the middle IS filled filled As far as we can see the Mac only uses even-odd fillrule when determining what is inside and outside of a polygon (or a region for that matter). Now to the question: Does anybody know of a way to simulate the zero-winding fill rule on the Mac, short of implementing your own scan-algorithm?! Any clues are appreciated! /Kim, Jorgen & Peter.