[argyllcms] Re: Creating a null transform output device

Roger Breton wrote:
> Gerard (and Graeme),
>> You can certainly build a RGB = XYZ identity profile,
>
> Could you briefly describe how to go about building such a profile?

For instance, a profile created with

    #include <lcms.h>

    int
    main(int argc, char **argv)
    {
        cmsHPROFILE profile;
        LPGAMMATABLE gamma1[3];
        cmsCIExyY whitepoint = { 1.0/3.0, 1.0/3.0, 1.0 };
        cmsCIExyYTRIPLE primaries = {
            {1.0, 0.0, 1.0}, {0.0, 1.0, 1.0}, {0.0, 0.0, 1.0},
        };

        gamma1[0] = gamma1[1] = gamma1[2] = cmsBuildGamma(2, 1.0);
        profile = cmsCreateRGBProfile(&whitepoint, &primaries, gamma1);
        cmsSetRenderingIntent(profile, INTENT_RELATIVE_COLORIMETRIC);
        _cmsSaveProfile(profile, "RGB_XYZ_identity.icc");
        return 0;
    }

will do a RGB = XYZ mapping if it is applied with absolute colorimetric
intent
(assuming a normalization to a [0.0...1.0] range for both, the RGB and
XYZ numbers).

Regard,
Gerhard

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