Re: [Lcms-user] Apply profile with PCS = cmsSigXYZData, Color Space = cmsSigGrayData

[Noel C. <NCa...@Pr...>]

Hi Aaron,

 

What do you mean by "applies the ICC profile"?  Are you trying to convert the image to be displayed accurately on a monitor?

 

If so, wouldn't you want the output type to be RGB and use the monitor's profile as the output profile?

 

Perhaps I'm not understanding at all what you're trying to accomplish.

 

-Noel

 

 

From: Aaron Boxer [mailto:bo...@gm...] 
Sent: Mon, February 20, 2017 1:04 AM
To: lcm...@li...
Subject: [Lcms-user] Apply profile with PCS = cmsSigXYZData, Color Space = cmsSigGrayData

 

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