Hi, Casper, one of the Krita hackers asked me to ask the about following:
--- After having used lcms to do some lightness transformation using the following code I've come across a problem. My code tries to convert from a working colorspace to lab and back. But whil in lab it modifies the L* channel with the use of a transfer table. The trouble is that white pixels are not touched. Even if I set the transform / gamme table to all zero the white pixels remain white. Am I doing something wrong or is there a bug in lcms: LPGAMMATABLE transferFunctions[3]; transferFunctions[0] = cmsBuildGamma(256, 1.0); transferFunctions[1] = cmsBuildGamma(256, 1.0); transferFunctions[2] = cmsBuildGamma(256, 1.0); for(int i =0; i < 256; i++) transferFunctions[0]->GammaTable[i] = transferValues[i]; profiles[1] = cmsCreateLinearizationDeviceLink(icSigLabData, transferFunctions); cmsSetDeviceClass(profiles[1], icSigAbstractClass); profiles[0] = m_profile->profile(); profiles[2] = m_profile->profile(); transform = cmsCreateMultiprofileTransform(adj->profiles, 3, m_cmType, m_cmType, INTENT_PERCEPTUAL, 0); cmsDoTransform(transform, src, dst, nPixels); --- Any idea? -- Boudewijn Rempt http://www.valdyas.org/fading/index.cgi
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