2008/2/22, Alexandre Prokoudine <alexandre.prokoudine@...400...>:
On Fri, Feb 22, 2008 at 6:38 PM, Aubanel MONNIER wrote:

> Hello all,
> I was looking at the cairo-pdf export code and wondered how hard it would be
> to output PDFs in CMYK(a) colorspace ? From what I've seen it shoudl be
> fairly easy on inkscape side. However the status of CMYK(a) support in Cairo
> looks unclear to me (found some references in cairo ML but nothing in the
> actual cairo headers, + a ruby (?) implementation for it). Does anyone have
> a some knowledge / pointers on that ?


Not implemented yet.

I spoke to Carl Worth and Behdad Esfahbod about it before (November
2007) and they basically told me that everyone asking about it has
his/her own understanding of what CMYK support means.

Specifically, Behdad told me that a good proposal coming from Inkscape
team might help designing API.

Alexandre


I'm not sure that I understand everything, but in terms of API i think the _rgba functions should be replaced by _color functions with
type color = | Rgba of int8 * int8 * int8 * int8 | Cmyka of int8 * int8 * int8 * int8* int8 | Spot of spot_color
Possibility to define a conversion function for back-ends whose do not know how to handle certain color types might prove useful I guess (defaults to returning an error "I do not know how to handle this color type"); Additional thought might be necessary for CMYK and TIFFs in CMYK, but I guess this could be handled transparently (just look at the data in the bitmap ?).
For me the only big question in terms of API is: should the colorspace be document specific or on a per color basis ? Is there any use case where you want to mix on the same document RGBs and CMYKs ? I don't think so, but I might be wrong.