Hello Martin,
You almost got it. It doesn't work because the order is wrong.
Ok, lets revise what you want to do. You said, you want to check if a
Lab color is withing an ICC profile gamut. That's fine, and this
functionality can be obtained by cmsCreateProofingTransform. Ok so far.
Then the question is how you want to mark this. One possible solution
would be to use an array of byes. If the color is withing, then the
byte would be set to '00'. If out of gamut 'FF'.
To do that, we could use the NULL profile. This is an special 1-channel
profile that always returns 0. Being 1-channel, this can be interpreted
as gray.
The trick comes now with the alarm color. NULL profile will return always
0, but the alarm color will bypass the transform and therefore give
whatever value you set. 'FF' for example.
So that's how the transform works. There are some leaks here since the
profiles are created and never set free, but you can take the idea.
There is no softproofing here, only gamut check. And then you could
do the check by calling cmsDoTransforms in this way;
cmsHTRANSFORM xfrm =
cmsCreateProofingTransform(cmsCreateLab4Profile(NULL), TYPE_Lab_DBL,
cmsCreateNULLProfile(), TYPE_GRAY_8, cmsCreate_sRGBProfile(),
INTENT_RELATIVE_COLORIMETRIC, INTENT_ABSOLUTE_COLORIMETRIC,
cmsFLAGS_GAMUTCHECK);
cmsCIELab Lab = { 50, -125, 125 };
cmsCIELab Lab2 = { 50, -10, 12 };
cmsUInt8Number gamut;
cmsDoTransform(xfrm, &Lab, &gamut, 1); // Gives the alarm != 0
cmsDoTransform(xfrm, &Lab2, &gamut, 1); // Gives 0
That should work as you expect.
Regards
Matri
Quoting Martin Florek <mflo...@gmail.com>:
> I would like to check if a Lab color is within an ICC profile's gamut.
> For this I create a proofing transform, but I get an error "Couldn't
> link the profiles". I create the transform like this:
>
> cmsCreateProofingTransform(cmsCreateLab4Profile(), TYPE_Lab_DBL,
> outProfile, TYPE_RGB_DBL, cmsCreateNULLProfile(),
> INTENT_RELATIVE_COLORIMETRIC, INTENT_ABSOLUTE_COLORIMETRIC,
> cmsFLAGS_GAMUTCHECK | cmsFLAG_SOFTPROOFING);
>
> When I create a normal transform from the custom Lab and the outProfile
> (loaded from an ICC profile file), the conversion works perfectly. I set
> the alarm codes to 0xffff before creating a proofing transform.
>
> What am I doing wrong? Another question about out of gamut values, is
> there a way to get unbounded results from a transform (or multi profile
> transform) so I could check if the colour is out of gamut when RGB
> values are smaller than zero and bigger than 1, without the need of a
> proofing profile? Thank you.
> Regards,
>
>
> Martin
>
> ------------------------------------------------------------------------------
> Shape the Mobile Experience: Free Subscription
> Software experts and developers: Be at the forefront of tech innovation.
> Intel(R) Software Adrenaline delivers strategic insight and game-changing
> conversations that shape the rapidly evolving mobile landscape. Sign up now.
> http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk
> _______________________________________________
> Lcms-user mailing list
> Lcms-user@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/lcms-user
------------------------------------------------------------------------------
Shape the Mobile Experience: Free Subscription
Software experts and developers: Be at the forefront of tech innovation.
Intel(R) Software Adrenaline delivers strategic insight and game-changing
conversations that shape the rapidly evolving mobile landscape. Sign up now.
http://pubads.g.doubleclick.net/gampad/clk?id=63431311&iu=/4140/ostg.clktrk
_______________________________________________
Lcms-user mailing list
Lcms-user@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/lcms-user
