[cairo] Spot colors (and CMYK)

Bill Spitzak spitzak at gmail.com
Thu Feb 18 09:56:05 PST 2010

Apple and Adobe provide a FIXED conversion from sRGB to the display. 
This is the REAL solution and is exactly what everybody wants. Please 
look, there are apis in Cocoa to draw images that do not provide a "cms" 
but they WORK and you can actually adjust your screen to produce the 
correct color, and every program agrees! In the most recent versions 
they fixed it so OpenGL is also passed through this FIXED conversion and 
that has been a godsend, FINALLY we are getting matching images from all 
our software!

Yes there are apis to provide a cms so they can concatenate it with 
their internal one. However this is the PROBLEM, not the solution. We 
certainly never use this, but from our experience with other cms 
libraries I can be pretty certain there are a million bugs with this 
concatenation so that the result never matches what happens if I convert 
to the fixed sRGB space and send that, and this means images do not match.

Believe me I am very interested in emulating how Apple is doing things, 
and that I think your ideas are EXACTLY OPPOSITE this.

Kai-Uwe Behrmann wrote:
> Am 17.02.10, 11:30 -0800 schrieb Bill Spitzak:
>> I do not think Cairo should understand color profiles. This is an
>> ENORMOUS complication that will only cause grief. This is why I very
>> strongly reject any of Kai-Uwe Behrmann's ideas.
> So we have to admire Apple, Adobe and so on for getting this stuff done 
> and play with cairo in a toy world? Cairo would loose many use cases if 
> it completely rejects the idea of colour management. Most backends are 
> currently unuseable for CM work. But the trent to CM is very obvious in 
> graphic applications and on linux.
> kind regards
> Kai-Uwe Behrmann

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