I used wrong encoding in previous post, sorry about that. Repost the prevous message:
I am studying icc profile & cms, and have read part of lcms 1.17 source code, but there're something confuse me. In the function Rel2RelStepAbsCoefs() in Cmscnvrt.c, as my understanding, this funcion will generate the transform matrix for converting relative colorimetric to absolute colorimetric. And before using the white points to construct the scaling matrix, the function apply chromatic adaptaion on them. Here is my question, in icc profile 4.2 spec, section 9.2.25 describe the mediaWhitePointTag as: " This tag, which is used for generating ICC-absolute colorimetric intent, specifies the XYZ tristimulus values of the media white point. If the media is measured under an illumination source which has a chromaticity other than D50, the measured values must be adjusted to D50 using the chromaticAdaptationTag matrix before recording in the tag. ... " The spec says that the media white point recorded in profile has already been adapted to D50, but why the Rel2RelStepAbsCoefs() function adapted the white point again? Do I have a misunderstanding about the code? ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Lcms-user mailing list Lcms-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lcms-user
