Hi,
>Thanks, Marti. Is the white point and transfer function not already
specified in the profile? Pardon my ignorance,
>not that familiar with colour transforms.
No worries, if you use a real profile, yes, it is included in the
profile. If you use a built-in profile, that is a template to generate
profiles, so you need parameters.
Try this:
// A gamma-2.2 gray space
static
cmsHPROFILE Create_Gray22(void)
{
cmsHPROFILE hProfile;
cmsToneCurve* Curve = cmsBuildGamma(DbgThread(), 2.2);
if (Curve == NULL) return NULL;
hProfile = cmsCreateGrayProfileTHR(DbgThread(), cmsD50_xyY(), Curve);
cmsFreeToneCurve(Curve);
return hProfile;
}
Regards
Marti
On 20/02/2017 17:33, Aaron Boxer wrote:
Thanks, Marti. Is the white point and transfer function not already
specified in the profile? Pardon my ignorance,
not that familiar with colour transforms.
On Mon, Feb 20, 2017 at 11:28 AM, Martí Maria
<marti.ma...@littlecms.com <mailto:marti.ma...@littlecms.com>> wrote:
Hi,
You need to specify white point and transfer function to
cmsCreateGrayProfile(), see manual page 28
Regards
Marti
On 20/02/2017 7:04, Aaron Boxer wrote:
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
<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
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