[cairo] [RFC] Color space API (partial proposal)

[Francois Robert]

Jonathan Morton wrote :
> As long as you stay in the same colour space, they're just 
> multidimensional Cartesian numbers that you can manipulate 
> using the Porter-Duff operations.

If Cairo is to support PDF 1.4 blending, it will have to go much beyond Porter-Duff operations. It will have to decompose alpha into shape and opacity. It will have to consider non linear operations on the components (eg PDF compositing can change hue...) It will have to consider transparency groups and the compositing rules inside each group and of the group against the backdrop. It will have to deal with multiple blending spaces, as each group can specify one...

François