1ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov//--------------------------------------------------------------------------------- 2ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// 3ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Little Color Management System 4d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann// Copyright (c) 1998-2016 Marti Maria Saguer 5ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// 6ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Permission is hereby granted, free of charge, to any person obtaining 7ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// a copy of this software and associated documentation files (the "Software"), 8ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// to deal in the Software without restriction, including without limitation 9ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// the rights to use, copy, modify, merge, publish, distribute, sublicense, 10ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// and/or sell copies of the Software, and to permit persons to whom the Software 11ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// is furnished to do so, subject to the following conditions: 12ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// 13ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// The above copyright notice and this permission notice shall be included in 14ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// all copies or substantial portions of the Software. 15ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// 16ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO 18ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 19ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 20ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 21ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 22ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// 24ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov//--------------------------------------------------------------------------------- 25ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// 26ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 27ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#include "lcms2_internal.h" 28ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 29ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 30ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define cmsmin(a, b) (((a) < (b)) ? (a) : (b)) 31ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#define cmsmax(a, b) (((a) > (b)) ? (a) : (b)) 32ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 33ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// This file contains routines for resampling and LUT optimization, black point detection 34ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// and black preservation. 35ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 36ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Black point detection ------------------------------------------------------------------------- 37ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 38ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 39ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// PCS -> PCS round trip transform, always uses relative intent on the device -> pcs 40ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganovstatic 41ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovcmsHTRANSFORM CreateRoundtripXForm(cmsHPROFILE hProfile, cmsUInt32Number nIntent) 42ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 43ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsContext ContextID = cmsGetProfileContextID(hProfile); 44ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHPROFILE hLab = cmsCreateLab4ProfileTHR(ContextID, NULL); 45ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHTRANSFORM xform; 46ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsBool BPC[4] = { FALSE, FALSE, FALSE, FALSE }; 47ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number States[4] = { 1.0, 1.0, 1.0, 1.0 }; 48ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHPROFILE hProfiles[4]; 49ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUInt32Number Intents[4]; 50ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 51ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hProfiles[0] = hLab; hProfiles[1] = hProfile; hProfiles[2] = hProfile; hProfiles[3] = hLab; 52ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Intents[0] = INTENT_RELATIVE_COLORIMETRIC; Intents[1] = nIntent; Intents[2] = INTENT_RELATIVE_COLORIMETRIC; Intents[3] = INTENT_RELATIVE_COLORIMETRIC; 53ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 54ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov xform = cmsCreateExtendedTransform(ContextID, 4, hProfiles, BPC, Intents, 55ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov States, NULL, 0, TYPE_Lab_DBL, TYPE_Lab_DBL, cmsFLAGS_NOCACHE|cmsFLAGS_NOOPTIMIZE); 56ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 57ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCloseProfile(hLab); 58ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return xform; 59ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 60ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 61ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Use darker colorants to obtain black point. This works in the relative colorimetric intent and 62ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// assumes more ink results in darker colors. No ink limit is assumed. 63ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganovstatic 64ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovcmsBool BlackPointAsDarkerColorant(cmsHPROFILE hInput, 65ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUInt32Number Intent, 66ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIEXYZ* BlackPoint, 67ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUInt32Number dwFlags) 68ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 69ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUInt16Number *Black; 70ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHTRANSFORM xform; 71ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsColorSpaceSignature Space; 72ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUInt32Number nChannels; 73ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUInt32Number dwFormat; 74ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHPROFILE hLab; 75ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIELab Lab; 76ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIEXYZ BlackXYZ; 77ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsContext ContextID = cmsGetProfileContextID(hInput); 78ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 79ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // If the profile does not support input direction, assume Black point 0 80ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (!cmsIsIntentSupported(hInput, Intent, LCMS_USED_AS_INPUT)) { 81ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 82ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 83ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 84ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 85ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 86ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Create a formatter which has n channels and floating point 87ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov dwFormat = cmsFormatterForColorspaceOfProfile(hInput, 2, FALSE); 88ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 89ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Try to get black by using black colorant 90ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Space = cmsGetColorSpace(hInput); 91ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 92ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // This function returns darker colorant in 16 bits for several spaces 93ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (!_cmsEndPointsBySpace(Space, NULL, &Black, &nChannels)) { 94ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 95ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 96ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 97ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 98ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 99ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (nChannels != T_CHANNELS(dwFormat)) { 100ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 101ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 102ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 103ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 104ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Lab will be used as the output space, but lab2 will avoid recursion 105ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hLab = cmsCreateLab2ProfileTHR(ContextID, NULL); 106ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (hLab == NULL) { 107ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 108ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 109ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 110ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 111ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Create the transform 112ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov xform = cmsCreateTransformTHR(ContextID, hInput, dwFormat, 113ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hLab, TYPE_Lab_DBL, Intent, cmsFLAGS_NOOPTIMIZE|cmsFLAGS_NOCACHE); 114ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCloseProfile(hLab); 115ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 116ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (xform == NULL) { 117ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 118ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Something went wrong. Get rid of open resources and return zero as black 119ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 120ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 121ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 122ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 123ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Convert black to Lab 124ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDoTransform(xform, Black, &Lab, 1); 125ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 126ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Force it to be neutral, clip to max. L* of 50 127ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.a = Lab.b = 0; 128ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Lab.L > 50) Lab.L = 50; 129ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 130ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Free the resources 131ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDeleteTransform(xform); 132ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 133ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Convert from Lab (which is now clipped) to XYZ. 134ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsLab2XYZ(NULL, &BlackXYZ, &Lab); 135ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 136ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (BlackPoint != NULL) 137ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov *BlackPoint = BlackXYZ; 138ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 139ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 140ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 141ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsUNUSED_PARAMETER(dwFlags); 142ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 143ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 144ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Get a black point of output CMYK profile, discounting any ink-limiting embedded 145ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// in the profile. For doing that, we use perceptual intent in input direction: 146ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Lab (0, 0, 0) -> [Perceptual] Profile -> CMYK -> [Rel. colorimetric] Profile -> Lab 147ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganovstatic 148ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovcmsBool BlackPointUsingPerceptualBlack(cmsCIEXYZ* BlackPoint, cmsHPROFILE hProfile) 149ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 150ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHTRANSFORM hRoundTrip; 151ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIELab LabIn, LabOut; 152ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIEXYZ BlackXYZ; 153ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 154ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Is the intent supported by the profile? 155ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (!cmsIsIntentSupported(hProfile, INTENT_PERCEPTUAL, LCMS_USED_AS_INPUT)) { 156ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 157ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 158ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 159ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 160ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 161ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hRoundTrip = CreateRoundtripXForm(hProfile, INTENT_PERCEPTUAL); 162ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (hRoundTrip == NULL) { 163ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 164ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 165ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 166ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 167ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov LabIn.L = LabIn.a = LabIn.b = 0; 168ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDoTransform(hRoundTrip, &LabIn, &LabOut, 1); 169ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 170ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Clip Lab to reasonable limits 171ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (LabOut.L > 50) LabOut.L = 50; 172ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov LabOut.a = LabOut.b = 0; 173ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 174ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDeleteTransform(hRoundTrip); 175ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 176ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Convert it to XYZ 177ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsLab2XYZ(NULL, &BlackXYZ, &LabOut); 178ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 179ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (BlackPoint != NULL) 180ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov *BlackPoint = BlackXYZ; 181ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 182ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 183ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 184ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 185ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// This function shouldn't exist at all -- there is such quantity of broken 186ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// profiles on black point tag, that we must somehow fix chromaticity to 187ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// avoid huge tint when doing Black point compensation. This function does 188ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// just that. There is a special flag for using black point tag, but turned 189ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// off by default because it is bogus on most profiles. The detection algorithm 190ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// involves to turn BP to neutral and to use only L component. 191ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovcmsBool CMSEXPORT cmsDetectBlackPoint(cmsCIEXYZ* BlackPoint, cmsHPROFILE hProfile, cmsUInt32Number Intent, cmsUInt32Number dwFlags) 192ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 193ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsProfileClassSignature devClass; 194ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 195ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Make sure the device class is adequate 196ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov devClass = cmsGetDeviceClass(hProfile); 197ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (devClass == cmsSigLinkClass || 198ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov devClass == cmsSigAbstractClass || 199ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov devClass == cmsSigNamedColorClass) { 200ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 201ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 202ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 203ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 204ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Make sure intent is adequate 205ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Intent != INTENT_PERCEPTUAL && 206ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Intent != INTENT_RELATIVE_COLORIMETRIC && 207ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Intent != INTENT_SATURATION) { 208ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 209ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 210ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 211ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 212ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // v4 + perceptual & saturation intents does have its own black point, and it is 213ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // well specified enough to use it. Black point tag is deprecated in V4. 214ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if ((cmsGetEncodedICCversion(hProfile) >= 0x4000000) && 215ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (Intent == INTENT_PERCEPTUAL || Intent == INTENT_SATURATION)) { 216ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 217ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Matrix shaper share MRC & perceptual intents 218ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (cmsIsMatrixShaper(hProfile)) 219ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return BlackPointAsDarkerColorant(hProfile, INTENT_RELATIVE_COLORIMETRIC, BlackPoint, 0); 220ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 221ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Get Perceptual black out of v4 profiles. That is fixed for perceptual & saturation intents 222ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = cmsPERCEPTUAL_BLACK_X; 223ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> Y = cmsPERCEPTUAL_BLACK_Y; 224ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> Z = cmsPERCEPTUAL_BLACK_Z; 225ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 226ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 227ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 228ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 229ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 230ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#ifdef CMS_USE_PROFILE_BLACK_POINT_TAG 231ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 232ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // v2, v4 rel/abs colorimetric 233ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (cmsIsTag(hProfile, cmsSigMediaBlackPointTag) && 234ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Intent == INTENT_RELATIVE_COLORIMETRIC) { 235ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 236ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIEXYZ *BlackPtr, BlackXYZ, UntrustedBlackPoint, TrustedBlackPoint, MediaWhite; 237ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIELab Lab; 238ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 239ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // If black point is specified, then use it, 240ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 241ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPtr = cmsReadTag(hProfile, cmsSigMediaBlackPointTag); 242ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (BlackPtr != NULL) { 243ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 244ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackXYZ = *BlackPtr; 245ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov _cmsReadMediaWhitePoint(&MediaWhite, hProfile); 246ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 247ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Black point is absolute XYZ, so adapt to D50 to get PCS value 248ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsAdaptToIlluminant(&UntrustedBlackPoint, &MediaWhite, cmsD50_XYZ(), &BlackXYZ); 249ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 250ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Force a=b=0 to get rid of any chroma 251ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsXYZ2Lab(NULL, &Lab, &UntrustedBlackPoint); 252ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.a = Lab.b = 0; 253ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Lab.L > 50) Lab.L = 50; // Clip to L* <= 50 254ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsLab2XYZ(NULL, &TrustedBlackPoint, &Lab); 255ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 256ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (BlackPoint != NULL) 257ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov *BlackPoint = TrustedBlackPoint; 258ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 259ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 260ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 261ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 262ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov#endif 263ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 264ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // That is about v2 profiles. 265ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 266ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // If output profile, discount ink-limiting and that's all 267ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Intent == INTENT_RELATIVE_COLORIMETRIC && 268ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (cmsGetDeviceClass(hProfile) == cmsSigOutputClass) && 269ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (cmsGetColorSpace(hProfile) == cmsSigCmykData)) 270ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return BlackPointUsingPerceptualBlack(BlackPoint, hProfile); 271ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 272ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Nope, compute BP using current intent. 273ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return BlackPointAsDarkerColorant(hProfile, Intent, BlackPoint, dwFlags); 274ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 275ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 276ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 277ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 278ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// --------------------------------------------------------------------------------------------------------- 279ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 280ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Least Squares Fit of a Quadratic Curve to Data 281ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// http://www.personal.psu.edu/jhm/f90/lectures/lsq2.html 282ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 283ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganovstatic 284ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovcmsFloat64Number RootOfLeastSquaresFitQuadraticCurve(int n, cmsFloat64Number x[], cmsFloat64Number y[]) 285ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 286ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov double sum_x = 0, sum_x2 = 0, sum_x3 = 0, sum_x4 = 0; 287ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov double sum_y = 0, sum_yx = 0, sum_yx2 = 0; 288ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov double d, a, b, c; 289ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov int i; 290ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsMAT3 m; 291ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsVEC3 v, res; 292ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 293ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (n < 4) return 0; 294ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 295ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (i=0; i < n; i++) { 296ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 297ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov double xn = x[i]; 298ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov double yn = y[i]; 299ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 300ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_x += xn; 301ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_x2 += xn*xn; 302ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_x3 += xn*xn*xn; 303ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_x4 += xn*xn*xn*xn; 304ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 305ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_y += yn; 306ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_yx += yn*xn; 307ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov sum_yx2 += yn*xn*xn; 308ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 309ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 310ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov _cmsVEC3init(&m.v[0], n, sum_x, sum_x2); 311ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov _cmsVEC3init(&m.v[1], sum_x, sum_x2, sum_x3); 312ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov _cmsVEC3init(&m.v[2], sum_x2, sum_x3, sum_x4); 313ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 314ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov _cmsVEC3init(&v, sum_y, sum_yx, sum_yx2); 315ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 316ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (!_cmsMAT3solve(&res, &m, &v)) return 0; 317ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 318ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 319ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov a = res.n[2]; 320ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov b = res.n[1]; 321ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov c = res.n[0]; 322ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 323ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (fabs(a) < 1.0E-10) { 324ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 325ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return cmsmin(0, cmsmax(50, -c/b )); 326ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 327ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov else { 328ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 329ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov d = b*b - 4.0 * a * c; 330ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (d <= 0) { 331ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return 0; 332ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 333ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov else { 334ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 335ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov double rt = (-b + sqrt(d)) / (2.0 * a); 336ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 337ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return cmsmax(0, cmsmin(50, rt)); 338ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 339ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 340ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 341ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 342ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 343ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 344ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 345ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// Calculates the black point of a destination profile. 346ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov// This algorithm comes from the Adobe paper disclosing its black point compensation method. 347ee451cb395940862dad63c85adfe8f2fd55e864cSvet GanovcmsBool CMSEXPORT cmsDetectDestinationBlackPoint(cmsCIEXYZ* BlackPoint, cmsHPROFILE hProfile, cmsUInt32Number Intent, cmsUInt32Number dwFlags) 348ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov{ 349ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsColorSpaceSignature ColorSpace; 350ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsHTRANSFORM hRoundTrip = NULL; 351ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIELab InitialLab, destLab, Lab; 352ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number inRamp[256], outRamp[256]; 353ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number MinL, MaxL; 354ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsBool NearlyStraightMidrange = TRUE; 355ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number yRamp[256]; 356ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number x[256], y[256]; 357ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number lo, hi; 358ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov int n, l; 359ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsProfileClassSignature devClass; 360ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 361ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Make sure the device class is adequate 362ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov devClass = cmsGetDeviceClass(hProfile); 363ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (devClass == cmsSigLinkClass || 364ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov devClass == cmsSigAbstractClass || 365ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov devClass == cmsSigNamedColorClass) { 366ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 367ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 368ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 369ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 370ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Make sure intent is adequate 371ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Intent != INTENT_PERCEPTUAL && 372ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Intent != INTENT_RELATIVE_COLORIMETRIC && 373ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Intent != INTENT_SATURATION) { 374ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 375ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 376ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 377ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 378ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 379ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // v4 + perceptual & saturation intents does have its own black point, and it is 380ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // well specified enough to use it. Black point tag is deprecated in V4. 381ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if ((cmsGetEncodedICCversion(hProfile) >= 0x4000000) && 382ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (Intent == INTENT_PERCEPTUAL || Intent == INTENT_SATURATION)) { 383ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 384ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Matrix shaper share MRC & perceptual intents 385ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (cmsIsMatrixShaper(hProfile)) 386ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return BlackPointAsDarkerColorant(hProfile, INTENT_RELATIVE_COLORIMETRIC, BlackPoint, 0); 387ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 388ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Get Perceptual black out of v4 profiles. That is fixed for perceptual & saturation intents 389ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = cmsPERCEPTUAL_BLACK_X; 390ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> Y = cmsPERCEPTUAL_BLACK_Y; 391ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> Z = cmsPERCEPTUAL_BLACK_Z; 392ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 393ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 394ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 395ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 396ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Check if the profile is lut based and gray, rgb or cmyk (7.2 in Adobe's document) 397ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov ColorSpace = cmsGetColorSpace(hProfile); 398ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (!cmsIsCLUT(hProfile, Intent, LCMS_USED_AS_OUTPUT ) || 399ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (ColorSpace != cmsSigGrayData && 400ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov ColorSpace != cmsSigRgbData && 401ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov ColorSpace != cmsSigCmykData)) { 402ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 403ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // In this case, handle as input case 404ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return cmsDetectBlackPoint(BlackPoint, hProfile, Intent, dwFlags); 405ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 406ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 407ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // It is one of the valid cases!, use Adobe algorithm 408ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 409ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 410ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Set a first guess, that should work on good profiles. 411ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Intent == INTENT_RELATIVE_COLORIMETRIC) { 412ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 413ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsCIEXYZ IniXYZ; 414ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 415ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // calculate initial Lab as source black point 416ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (!cmsDetectBlackPoint(&IniXYZ, hProfile, Intent, dwFlags)) { 417ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 418ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 419ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 420ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // convert the XYZ to lab 421ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsXYZ2Lab(NULL, &InitialLab, &IniXYZ); 422ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 423ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } else { 424ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 425ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // set the initial Lab to zero, that should be the black point for perceptual and saturation 426ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov InitialLab.L = 0; 427ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov InitialLab.a = 0; 428ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov InitialLab.b = 0; 429ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 430ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 431ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 432ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Step 2 433ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // ====== 434ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 435ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Create a roundtrip. Define a Transform BT for all x in L*a*b* 436ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hRoundTrip = CreateRoundtripXForm(hProfile, Intent); 437ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (hRoundTrip == NULL) return FALSE; 438ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 439ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Compute ramps 440ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 441ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (l=0; l < 256; l++) { 442ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 443ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.L = (cmsFloat64Number) (l * 100.0) / 255.0; 444ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.a = cmsmin(50, cmsmax(-50, InitialLab.a)); 445ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.b = cmsmin(50, cmsmax(-50, InitialLab.b)); 446ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 447ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDoTransform(hRoundTrip, &Lab, &destLab, 1); 448ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 449ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov inRamp[l] = Lab.L; 450ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outRamp[l] = destLab.L; 451ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 452ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 453ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Make monotonic 454ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (l = 254; l > 0; --l) { 455ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov outRamp[l] = cmsmin(outRamp[l], outRamp[l+1]); 456ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 457ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 458ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Check 459ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (! (outRamp[0] < outRamp[255])) { 460ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 461ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDeleteTransform(hRoundTrip); 462ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 463ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 464ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 465ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 466ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 467ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Test for mid range straight (only on relative colorimetric) 468ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov NearlyStraightMidrange = TRUE; 469ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov MinL = outRamp[0]; MaxL = outRamp[255]; 470ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Intent == INTENT_RELATIVE_COLORIMETRIC) { 471ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 472ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (l=0; l < 256; l++) { 473ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 474ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (! ((inRamp[l] <= MinL + 0.2 * (MaxL - MinL) ) || 475ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov (fabs(inRamp[l] - outRamp[l]) < 4.0 ))) 476ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov NearlyStraightMidrange = FALSE; 477ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 478ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 479ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // If the mid range is straight (as determined above) then the 480ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // DestinationBlackPoint shall be the same as initialLab. 481ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Otherwise, the DestinationBlackPoint shall be determined 482ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // using curve fitting. 483ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (NearlyStraightMidrange) { 484ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 485ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsLab2XYZ(NULL, BlackPoint, &InitialLab); 486ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDeleteTransform(hRoundTrip); 487ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 488ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 489ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 490ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 491ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 492ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // curve fitting: The round-trip curve normally looks like a nearly constant section at the black point, 493d904c1ec7e8d1d86ed56f0dd252435d12cd345aePhilip P. Moltmann // with a corner and a nearly straight line to the white point. 494ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (l=0; l < 256; l++) { 495ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 496ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov yRamp[l] = (outRamp[l] - MinL) / (MaxL - MinL); 497ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 498ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 499ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // find the black point using the least squares error quadratic curve fitting 500ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Intent == INTENT_RELATIVE_COLORIMETRIC) { 501ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov lo = 0.1; 502ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hi = 0.5; 503ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 504ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov else { 505ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 506ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Perceptual and saturation 507ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov lo = 0.03; 508ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov hi = 0.25; 509ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 510ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 511ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // Capture shadow points for the fitting. 512ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov n = 0; 513ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov for (l=0; l < 256; l++) { 514ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 515ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsFloat64Number ff = yRamp[l]; 516ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 517ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (ff >= lo && ff < hi) { 518ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov x[n] = inRamp[l]; 519ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov y[n] = yRamp[l]; 520ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov n++; 521ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 522ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 523ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 524ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 525ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // No suitable points 526ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (n < 3 ) { 527ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDeleteTransform(hRoundTrip); 528ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov BlackPoint -> X = BlackPoint ->Y = BlackPoint -> Z = 0.0; 529ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return FALSE; 530ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 531ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 532ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 533ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov // fit and get the vertex of quadratic curve 534ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.L = RootOfLeastSquaresFitQuadraticCurve(n, x, y); 535ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 536ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov if (Lab.L < 0.0) { // clip to zero L* if the vertex is negative 537ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.L = 0; 538ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov } 539ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 540ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.a = InitialLab.a; 541ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov Lab.b = InitialLab.b; 542ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 543ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsLab2XYZ(NULL, BlackPoint, &Lab); 544ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov 545ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov cmsDeleteTransform(hRoundTrip); 546ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov return TRUE; 547ee451cb395940862dad63c85adfe8f2fd55e864cSvet Ganov} 548