[cairo] Spot colors (and CMYK)

Kai-Uwe Behrmann ku.b at gmx.de
Mon Feb 15 21:42:39 PST 2010

Am 15.02.10, 21:53 +0100 schrieb Kai-Uwe Behrmann:
> Am 15.02.10, 12:38 -0400 schrieb cu:
>> Others that do care, can and should deal with this, most likely by
>> adjusting a palette they use as an input to vector drawing, ahead of
>> time. This isn't a very difficult operation. Once performed, it should
>> result in visually similar result on any given platform.

I agree about the palette technic, but inside cairo, because each 
backend has different requirements. Adapting a palette for each backend 
strikes the spirit of cairo to have few code for many output formats.
Care is as well needed for proper multi monitor support. Supporting multi 
monitor setups in every application, which potentially wants this, is a 
waste of developer resources. Everywhere code to query monitor regions, 
adjust for them, get the ICC profiles and hunting bugs. Its comparedly 
easy to have that stuff in cairos backends.

How can Xlib, PDF and the others be tould to colour convert from a 
particular colour space to a end colour space? I have not seen code for 
that together with cairo.

Sticking colour managed applications to cairos image surfaces excludes 
them from accelerated backends.

It so easy to tell this stuff to a proper designed API, which cares about 
colour. Its a unproportional larger amount of work to do that stuff 
parallel to cairo calls if at all possible.

End to end colour management has a price. If well designed it can be 
supported. The cost rises, when major components are colour management 
unaware. Cairo comes with convenient features but currently completely 
excluding colour management without a adequate chance to circumvent that 
situation. Its like the toy API for fonts. Nothing serious.

kind regards
Kai-Uwe Behrmann
developing for colour management 
www.behrmann.name + www.oyranos.org

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