How to apply profile with PCS = cmsSigXYZData, Color Space = cmsSigGrayData ?

[boxerab]

Hello,

I have a jpeg 2000 file with an ICC profile.

PCS is cmsSigXYZData and color space is cmsSigGrayData.

The file can be found here: https://github.com/GrokImageCompression/grok/issues/38

I am working on a library that decodes the jpeg 2000 file and applies the ICC profile, using LCMS.

Currently, I have this code:

in_type = TYPE_GRAY_8;
out_type = TYPE_RGB_8;
out_prof = cmsCreate_sRGBProfile();

and I can create the transform and apply the ICC profile, but the output is an RGB file.
What I would like is to output a grayscale file.

So, if I instead call

out_prof = cmsCreateGrayProfile(NULL,NULL);

then cmsCreateTransform returns NULL and I can't apply the profile.

What is the best way of creating a transform for this kind of grayscale image ?

Thanks so much,
Aaron

[mm2]

not an issue, cmsCreateGrayProfile(NULL,NULL) is not going to work because bad parameters.

[boxerab]

Thanks. Can you recommend a better way of doing this?

[boxerab]

Alright, will explore this issue further on user mailing list. Thanks.