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

[Bill Spitzak]

ecir hana wrote:

> - Not sure what good is to define color space in
> "cairo_color_space_create_device_n()" for if you are able to define
> alternative spaces in each of its colorant.

I think the intention is that this color space is the "blending" color 
space. When each color is specified with a color space it is immediately 
converted from that space to the deviceN blending space. The deviceN 
blending space is then used to figure out what (for instance) a 
combination of 50% of two spot colors amounts to (an average in blending 
space). If you then render onto another color space other than deviceN, 
the blending space result is converted from that to the destination 
space before blending there is done.