[cairo] Spot colors (and CMYK)

[ecir hana]

On Thu, Feb 18, 2010 at 5:45 PM, Kai-Uwe Behrmann <ku.b at gmx.de> wrote:
> Am 18.02.10, 17:21 +0100 schrieb ecir hana:
>>
>> - What would happen if I don't provide a hook to Cairo? What will
>
> That would mean using the color toy API and no direct colour management.
>
>> happen if I wan to draw CMYK on RGB surface and I wont provide a hook?
>
> It would not work. Your application has to link to the hook lib and its CMS.

That's the problem. Because a hook requires a profiles and a profile
might not be available. So if I want to use some Pantone I don't have
profile for I should be able to type in some values manually, so at
least something appears or the screen preview.

>> Or more common, I have Pantone duotone and want to look at it? I guess
>> there should be some really basic, toy, hook by default, no? But that
>> would be the start of Cairo's own CMS, no?
>
> Thats up to cairo maintainers. Once a hook API is decided for, I guess they
> prefere less dependencies. Mosularity is sometimes really nice.

What I meant was, that if there are always required profiles, there
should be a way of building a very simple profile which would take
care of the most basic and crude transformations. Alternatively, by
supplying a LUT (instead of a profile) you could immediately export
this LUT to PDF as tintTransform.

Off topic: I have to write it down here, so I don't forget. For
supporting multi-channel images it would be really great if Cairo
adopted your proposal for image constants:

http://www.behrmann.name/wind/imaging/pixel_naming_2007.11.13.html