int cmsDetectBlackPoint(LPcmsCIEXYZ BlackPoint, cmsHPROFILE hProfile, int Intent, DWORD dwFlags)
{
// v4 + perceptual & saturation intents does have its own black point
if ((cmsGetProfileICCversion(hProfile) >= 0x4000000) &&
(Intent == INTENT_PERCEPTUAL || Intent == INTENT_SATURATION)) {
return GetV4PerceptualBlack(BlackPoint, hProfile, dwFlags);
}
#ifdef HONOR_BLACK_POINT_TAG
// v2, v4 rel/abs colorimetric
if (cmsIsTag(hProfile, icSigMediaBlackPointTag) &&
Intent == INTENT_RELATIVE_COLORIMETRIC) {
cmsCIEXYZ BlackXYZ, UntrustedBlackPoint, TrustedBlackPoint, MediaWhite;
cmsCIELab Lab;
// If black point is specified, then use it,
cmsTakeMediaBlackPoint(&BlackXYZ, hProfile);
cmsTakeMediaWhitePoint(&MediaWhite, hProfile);
// Black point is absolute XYZ, so adapt to D50 to get PCS value
cmsAdaptToIlluminant(&UntrustedBlackPoint, &MediaWhite, cmsD50_XYZ(), &BlackXYZ);
// Force a=b=0 to get rid of any chroma
cmsXYZ2Lab(NULL, &Lab, &UntrustedBlackPoint);
Lab.a = Lab.b = 0;
if (Lab.L > 50) Lab.L = 50; // Clip to L* <= 50
cmsLab2XYZ(NULL, &TrustedBlackPoint, &Lab);
// Return BP as D50 relative or absolute XYZ (depends on flags)
if (!(dwFlags & LCMS_BPFLAGS_D50_ADAPTED))
cmsAdaptToIlluminant(BlackPoint, cmsD50_XYZ(), &MediaWhite, &TrustedBlackPoint);
else
*BlackPoint = TrustedBlackPoint;
}
#endif
// If output profile, discount ink-limiting
if (Intent == INTENT_RELATIVE_COLORIMETRIC &&
(cmsGetDeviceClass(hProfile) == icSigOutputClass) &&
(cmsGetColorSpace(hProfile) == icSigCmykData))
return BlackPointUsingPerceptualBlack(BlackPoint, hProfile, dwFlags);
// Nope, compute BP using current intent.
return BlackPointAsDarkerColorant(hProfile, Intent, BlackPoint, dwFlags);
}
cmsBool CMSEXPORT cmsDetectBlackPoint(cmsCIEXYZ* BlackPoint, cmsHPROFILE hProfile, cmsUInt32Number Intent, cmsUInt32Number dwFlags)
{
// Zero for black point
if (cmsGetDeviceClass(hProfile) == cmsSigLinkClass) {
BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0;
return FALSE;
}
// v4 + perceptual & saturation intents does have its own black point, and it is
// well specified enough to use it. Black point tag is deprecated in V4.
if ((cmsGetEncodedICCversion(hProfile) >= 0x4000000) &&
(Intent == INTENT_PERCEPTUAL || Intent == INTENT_SATURATION)) {
// Matrix shaper share MRC & perceptual intents
if (cmsIsMatrixShaper(hProfile))
return BlackPointAsDarkerColorant(hProfile, INTENT_RELATIVE_COLORIMETRIC, BlackPoint, 0);
// Get Perceptual black out of v4 profiles. That is fixed for perceptual & saturation intents
BlackPoint -> X = cmsPERCEPTUAL_BLACK_X;
BlackPoint -> Y = cmsPERCEPTUAL_BLACK_Y;
BlackPoint -> Z = cmsPERCEPTUAL_BLACK_Z;
return TRUE;
}
#ifdef CMS_USE_PROFILE_BLACK_POINT_TAG
// v2, v4 rel/abs colorimetric
if (cmsIsTag(hProfile, cmsSigMediaBlackPointTag) &&
Intent == INTENT_RELATIVE_COLORIMETRIC) {
cmsCIEXYZ *BlackPtr, BlackXYZ, UntrustedBlackPoint, TrustedBlackPoint, MediaWhite;
cmsCIELab Lab;
// If black point is specified, then use it,
BlackPtr = cmsReadTag(hProfile, cmsSigMediaBlackPointTag);
if (BlackPtr != NULL) {
BlackXYZ = *BlackPtr;
_cmsReadMediaWhitePoint(&MediaWhite, hProfile);
// Black point is absolute XYZ, so adapt to D50 to get PCS value
cmsAdaptToIlluminant(&UntrustedBlackPoint, &MediaWhite, cmsD50_XYZ(), &BlackXYZ);
// Force a=b=0 to get rid of any chroma
cmsXYZ2Lab(NULL, &Lab, &UntrustedBlackPoint);
Lab.a = Lab.b = 0;
if (Lab.L > 50) Lab.L = 50; // Clip to L* <= 50
cmsLab2XYZ(NULL, &TrustedBlackPoint, &Lab);
if (BlackPoint != NULL)
*BlackPoint = TrustedBlackPoint;
return TRUE;
}
}
#endif
// That is about v2 profiles.
// If output profile, discount ink-limiting and that's all
if (Intent == INTENT_RELATIVE_COLORIMETRIC &&
(cmsGetDeviceClass(hProfile) == cmsSigOutputClass) &&
(cmsGetColorSpace(hProfile) == cmsSigCmykData))
return BlackPointUsingPerceptualBlack(BlackPoint, hProfile);
// Nope, compute BP using current intent.
return BlackPointAsDarkerColorant(hProfile, Intent, BlackPoint, dwFlags);
}