NSColorSpace: return ICC profile data for the generic RGB space (prototype) - #508
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Cover the model enum values, and the colour space model, component count, name and singleton identity of the standard colour spaces.
The generic RGB colour space now reports an ICC profile, loaded from the ICC sRGB v2 reference profile that ships as a gui library resource. This is a first step; the generic gray and CMYK spaces can follow the same pattern with their own reference profiles.
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Interesting. Would these profiles used somewhere? Usually they are considered when loading images, displaying, printing. To my knowledge, currently internally GNUstep doesn't use them How can I "test" this implementation? loading images with specific profiles? I wonder if this partial implementation could cause harm. |
Unless you were initialising the NSColorSpace specifically with initWithICCProfileData:; it would have no effect on you. MacOS supports ICC Color Spaces for graph designers and other production arts uses. I added this for AppKit API compatibility and wanted to put in an actual implementation (not just a stub), so I grabbed the open source ICC data for RGB as a default. Presumably you could take ICC data from any Mac machine (if you run a Mac) and use that as your profile data or if you had some ICC data from some other source. Where this is a GNU project I stuck with the most permissive data directly from the ICC. but can make an effort to provide more profiles (open source). AS for testing it - yes, if you have ICC color profiles available, call the method with a ICC source and you should eb able to see it work - if not, I have some bug fixes to do ! :) |
START_SET creates an autorelease pool and END_SET releases it, so the pool these tests create around the set is redundant.
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Prototype. NSColorSpace stored ICC data only when one was passed to initWithICCProfileData:; the standard colour spaces returned nil, where AppKit returns a profile for the generic spaces.
This adds the ICC sRGB v2 reference profile (sRGB2014.icc) as a gui library resource and loads it for +genericRGBColorSpace, so -ICCProfileData returns a valid profile. The profile is the International Color Consortium reference profile from https://registry.color.org/rgb-registry/srgbprofiles, redistributed unmodified under the ICC licence ("may be copied, distributed, embedded, made, used, and sold without restriction"); its provenance and licence are recorded in Resources/ColorSpaces/README. No Apple profile data is used (for obvious reasons).
Scope: only the generic RGB space is wired up, and this is deliberate. I looked at extending it to the generic gray and CMYK spaces and found no cleanly-licensed ICC-registry source for either:
So gray and CMYK are left returning nil for now. They could be added later either from a suitably-licensed profile or by synthesising minimal profiles, which is a maintainer call. The device spaces are also left without a profile, matching AppKit.
Whether sRGB is the right mapping for the generic RGB space, and whether to take on colour management more generally (e.g. via lcms2), is a design decision for the GNUStep team, but this at least puts the fraamework in place using a fully permissive licensed file.
Stacked on #507 (adds an assertion to its NSColorSpace test); merge that first.