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);
}
static
int BlackPointUsingPerceptualBlack(LPcmsCIEXYZ BlackPoint,
cmsHPROFILE hProfile,
DWORD dwFlags)
{
cmsHTRANSFORM hPercLab2CMYK, hRelColCMYK2Lab;
cmsHPROFILE hLab;
cmsCIELab LabIn, LabOut;
WORD CMYK[MAXCHANNELS];
cmsCIEXYZ BlackXYZ, MediaWhite;
if (!cmsIsIntentSupported(hProfile, INTENT_PERCEPTUAL, LCMS_USED_AS_INPUT)) {
BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0;
return 0;
}
hLab = cmsCreateLabProfile(NULL);
hPercLab2CMYK = cmsCreateTransform(hLab, TYPE_Lab_DBL,
hProfile, TYPE_CMYK_16,
INTENT_PERCEPTUAL, cmsFLAGS_NOTPRECALC);
hRelColCMYK2Lab = cmsCreateTransform(hProfile, TYPE_CMYK_16,
hLab, TYPE_Lab_DBL,
INTENT_RELATIVE_COLORIMETRIC, cmsFLAGS_NOTPRECALC);
LabIn.L = LabIn.a = LabIn.b = 0;
cmsDoTransform(hPercLab2CMYK, &LabIn, CMYK, 1);
cmsDoTransform(hRelColCMYK2Lab, CMYK, &LabOut, 1);
if (LabOut.L > 50) LabOut.L = 50;
LabOut.a = LabOut.b = 0;
cmsDeleteTransform(hPercLab2CMYK);
cmsDeleteTransform(hRelColCMYK2Lab);
cmsCloseProfile(hLab);
cmsLab2XYZ(NULL, &BlackXYZ, &LabOut);
if (!(dwFlags & LCMS_BPFLAGS_D50_ADAPTED)){
cmsTakeMediaWhitePoint(&MediaWhite, hProfile);
cmsAdaptToIlluminant(BlackPoint, cmsD50_XYZ(), &MediaWhite, &BlackXYZ);
}
else
*BlackPoint = BlackXYZ;
return 1;
}
static
cmsHPROFILE CreateNamedColorDevicelink(cmsHTRANSFORM xform)
{
_LPcmsTRANSFORM v = (_LPcmsTRANSFORM) xform;
cmsHPROFILE hICC;
cmsCIEXYZ WhitePoint;
int i, nColors;
size_t Size;
LPcmsNAMEDCOLORLIST nc2;
hICC = _cmsCreateProfilePlaceholder();
if (hICC == NULL) return NULL;
cmsSetRenderingIntent(hICC, v -> Intent);
cmsSetDeviceClass(hICC, icSigNamedColorClass);
cmsSetColorSpace(hICC, v ->ExitColorSpace);
cmsSetPCS(hICC, cmsGetPCS(v ->InputProfile));
cmsTakeMediaWhitePoint(&WhitePoint, v ->InputProfile);
cmsAddTag(hICC, icSigMediaWhitePointTag, &WhitePoint);
cmsAddTag(hICC, icSigDeviceMfgDescTag, (LPVOID) "LittleCMS");
cmsAddTag(hICC, icSigProfileDescriptionTag, (LPVOID) "Named color Device link");
cmsAddTag(hICC, icSigDeviceModelDescTag, (LPVOID) "Named color Device link");
nColors = cmsNamedColorCount(xform);
nc2 = cmsAllocNamedColorList(nColors);
Size = sizeof(cmsNAMEDCOLORLIST) + (sizeof(cmsNAMEDCOLOR) * (nColors-1));
CopyMemory(nc2, v->NamedColorList, Size);
nc2 ->ColorantCount = _cmsChannelsOf(v ->ExitColorSpace);
for (i=0; i < nColors; i++) {
cmsDoTransform(xform, &i, nc2 ->List[i].DeviceColorant, 1);
}
cmsAddTag(hICC, icSigNamedColor2Tag, (void*) nc2);
cmsFreeNamedColorList(nc2);
return hICC;
}
// Get Perceptual black of v4 profiles.
static
int GetV4PerceptualBlack(LPcmsCIEXYZ BlackPoint, cmsHPROFILE hProfile, DWORD dwFlags)
{
if (dwFlags & LCMS_BPFLAGS_D50_ADAPTED) {
BlackPoint->X = PERCEPTUAL_BLACK_X;
BlackPoint->Y = PERCEPTUAL_BLACK_Y;
BlackPoint->Z = PERCEPTUAL_BLACK_Z;
}
else {
cmsCIEXYZ D50BlackPoint, MediaWhite;
cmsTakeMediaWhitePoint(&MediaWhite, hProfile);
D50BlackPoint.X = PERCEPTUAL_BLACK_X;
D50BlackPoint.Y = PERCEPTUAL_BLACK_Y;
D50BlackPoint.Z = PERCEPTUAL_BLACK_Z;
cmsAdaptToIlluminant(BlackPoint, cmsD50_XYZ(), &MediaWhite, &D50BlackPoint);
}
return 1;
}
static
int BlackPointAsDarkerColorant(cmsHPROFILE hInput,
int Intent,
LPcmsCIEXYZ BlackPoint,
DWORD dwFlags)
{
WORD *Black, *White;
cmsHTRANSFORM xform;
icColorSpaceSignature Space;
int nChannels;
DWORD dwFormat;
cmsHPROFILE hLab;
cmsCIELab Lab;
cmsCIEXYZ BlackXYZ, MediaWhite;
// If the profile does not support input direction, assume Black point 0
if (!cmsIsIntentSupported(hInput, Intent, LCMS_USED_AS_INPUT)) {
BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0;
return 0;
}
// Try to get black by using black colorant
Space = cmsGetColorSpace(hInput);
if (!_cmsEndPointsBySpace(Space, &White, &Black, &nChannels)) {
BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0;
return 0;
}
dwFormat = CHANNELS_SH(nChannels)|BYTES_SH(2);
hLab = cmsCreateLabProfile(NULL);
xform = cmsCreateTransform(hInput, dwFormat,
hLab, TYPE_Lab_DBL, Intent, cmsFLAGS_NOTPRECALC);
cmsDoTransform(xform, Black, &Lab, 1);
// Force it to be neutral, clip to max. L* of 50
Lab.a = Lab.b = 0;
if (Lab.L > 50) Lab.L = 50;
cmsCloseProfile(hLab);
cmsDeleteTransform(xform);
cmsLab2XYZ(NULL, &BlackXYZ, &Lab);
if (Intent == INTENT_ABSOLUTE_COLORIMETRIC) {
*BlackPoint = BlackXYZ;
}
else {
if (!(dwFlags & LCMS_BPFLAGS_D50_ADAPTED)) {
cmsTakeMediaWhitePoint(&MediaWhite, hInput);
cmsAdaptToIlluminant(BlackPoint, cmsD50_XYZ(), &MediaWhite, &BlackXYZ);
}
else
*BlackPoint = BlackXYZ;
}
return 1;
}
