Find percentage of rectangle covered by polygon

Hi,

I need to find an algorithm to figure out what percentage of a (fixed size) rectangle is covered by each polygon in a set of polygons. The polygons do not overlap.

I'm really lost with this one. Can anyone provide me with some references or possibly even an algorithm?

Thanks!

Cheers,

D Drmmr

Turned out I was using the wrong search terms. Here are some references to libraries.

It looks like I won't need to do this afterall, though.