Re: [Lcms-user] Building a profile with a Rec 709 transfer curve

[Richard H. <hug...@gm...>]

On 24 December 2012 17:38, Marti Maria <mar...@li...> wrote:
> Obviously this is not the case. What really happens is
> parametric curve type 5 has aX raised to gamma, whilst
> in Rec709  only L is raised to the 0.45 exponent.

Right. I couldn't find any of the pre-supplied parametric curves that
would work. I did find some commented out code in testbed/testcms2.c
for a custom Rec. 709 curve. I've tried to use the modified code in
colord, but it threw some errors:

LCMS error 8: Unsupported parametric curve
LCMS error 7: Couldn't write type 'para'
LCMS error 8: Unsupported parametric curve
LCMS error 7: Couldn't write type 'para'

I've attached the patch for colord that I've tried. I *think* I'm
registering the plugin correctly, but I've never done an lcms plugin
before. It might be I'm doing something batshit-insane, in which case
I'd appreciate some clue. :)

Thanks,

Richard.