C++ cmsPipelineAlloc函数代码示例

static
cmsPipeline* BuildGrayOutputPipeline(cmsHPROFILE hProfile)
{
    cmsToneCurve *GrayTRC, *RevGrayTRC;
    cmsPipeline* Lut;
    cmsContext ContextID = cmsGetProfileContextID(hProfile);

    GrayTRC = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigGrayTRCTag);
    if (GrayTRC == NULL) return NULL;

    RevGrayTRC = cmsReverseToneCurve(GrayTRC);
    if (RevGrayTRC == NULL) return NULL;

    Lut = cmsPipelineAlloc(ContextID, 3, 1);
    if (Lut == NULL) {
        cmsFreeToneCurve(RevGrayTRC);
        return NULL;
    }

    if (cmsGetPCS(hProfile) == cmsSigLabData) {

        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 1,  3, PickLstarMatrix, NULL));
    }
    else  {
        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 1,  3, PickYMatrix, NULL));
    }

    cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocToneCurves(ContextID, 1, &RevGrayTRC));
    cmsFreeToneCurve(RevGrayTRC);

    return Lut;
}

// This function does create the virtual output profile, with the necessary gamut mapping
static
cmsHPROFILE CreatePCS2ITU_ICC(void)
{
    cmsHPROFILE hProfile;
    cmsPipeline* BToA0;
    cmsStage* ColorMap;

    BToA0 = cmsPipelineAlloc(0, 3, 3);
    if (BToA0 == NULL) return NULL;

    ColorMap = cmsStageAllocCLut16bit(0, GRID_POINTS, 3, 3, NULL);
    if (ColorMap == NULL) return NULL;

    cmsPipelineInsertStage(BToA0, cmsAT_BEGIN, ColorMap);
    cmsStageSampleCLut16bit(ColorMap, PCS2ITU, NULL, 0);

    hProfile = cmsCreateProfilePlaceholder(0);
    if (hProfile == NULL) {
        cmsPipelineFree(BToA0);
        return NULL;
    }

    cmsWriteTag(hProfile, cmsSigBToA0Tag, BToA0);
    cmsSetColorSpace(hProfile, cmsSigLabData);
    cmsSetPCS(hProfile, cmsSigLabData);
    cmsSetDeviceClass(hProfile, cmsSigColorSpaceClass);

    cmsPipelineFree(BToA0);

    return hProfile;
}

static
cmsPipeline* BuildRGBOutputMatrixShaper(cmsHPROFILE hProfile)
{
    cmsPipeline* Lut;
    cmsToneCurve *Shapes[3], *InvShapes[3];
    cmsMAT3 Mat, Inv;
    int i, j;
    cmsContext ContextID = cmsGetProfileContextID(hProfile);

    if (!ReadICCMatrixRGB2XYZ(&Mat, hProfile))
        return NULL;

    if (!_cmsMAT3inverse(&Mat, &Inv))
        return NULL;

    // XYZ PCS in encoded in 1.15 format, and the matrix input should come in 0..0xffff range, so
    // we need to adjust the input by a << 1 to obtain a 1.16 fixed and then by a factor of
    // (0xffff/0x10000) to put data in 0..0xffff range. Total factor is (2.0*65535.0)/65536.0;

    for (i=0; i < 3; i++)
        for (j=0; j < 3; j++)
            Inv.v[i].n[j] *= OutpAdj;

    Shapes[0] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigRedTRCTag);
    Shapes[1] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigGreenTRCTag);
    Shapes[2] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigBlueTRCTag);

    if (!Shapes[0] || !Shapes[1] || !Shapes[2])
        return NULL;

    InvShapes[0] = cmsReverseToneCurve(Shapes[0]);
    InvShapes[1] = cmsReverseToneCurve(Shapes[1]);
    InvShapes[2] = cmsReverseToneCurve(Shapes[2]);

    if (!InvShapes[0] || !InvShapes[1] || !InvShapes[2]) {
        return NULL;
    }

    Lut = cmsPipelineAlloc(ContextID, 3, 3);
    if (Lut != NULL) {

        // Note that it is certainly possible a single profile would have a LUT based
        // tag for output working in lab and a matrix-shaper for the fallback cases.
        // This is not allowed by the spec, but this code is tolerant to those cases
        if (cmsGetPCS(hProfile) == cmsSigLabData) {

             cmsPipelineInsertStage(Lut, cmsAT_END, _cmsStageAllocLab2XYZ(ContextID));
        }

        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, (cmsFloat64Number*) &Inv, NULL));
        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocToneCurves(ContextID, 3, InvShapes));
    }

    cmsFreeToneCurveTriple(InvShapes);
    return Lut;
}

static
cmsPipeline* BuildRGBOutputMatrixShaper(cmsHPROFILE hProfile)
{
    cmsPipeline* Lut;
    cmsToneCurve *Shapes[3], *InvShapes[3];
    cmsMAT3 Mat, Inv;
    int i, j;
    cmsContext ContextID = cmsGetProfileContextID(hProfile);

    if (!ReadICCMatrixRGB2XYZ(&Mat, hProfile))
        return NULL;

    if (!_cmsMAT3inverse(&Mat, &Inv))
        return NULL;

    // XYZ PCS in encoded in 1.15 format, and the matrix input should come in 0..0xffff range, so
    // we need to adjust the input by a << 1 to obtain a 1.16 fixed and then by a factor of 
    // (0xffff/0x10000) to put data in 0..0xffff range. Total factor is (2.0*65535.0)/65536.0;

    for (i=0; i < 3; i++)
        for (j=0; j < 3; j++)
            Inv.v[i].n[j] *= OutpAdj;

    Shapes[0] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigRedTRCTag);        
    Shapes[1] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigGreenTRCTag);
    Shapes[2] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigBlueTRCTag);

    if (!Shapes[0] || !Shapes[1] || !Shapes[2])
        return NULL;

    InvShapes[0] = cmsReverseToneCurve(Shapes[0]);
    InvShapes[1] = cmsReverseToneCurve(Shapes[1]);
    InvShapes[2] = cmsReverseToneCurve(Shapes[2]);

    if (!InvShapes[0] || !InvShapes[1] || !InvShapes[2]) {      
        return NULL;
    }

    Lut = cmsPipelineAlloc(ContextID, 3, 3);
    if (Lut != NULL) {

        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, (cmsFloat64Number*) &Inv, NULL));
        cmsStage* mpe = cmsStageAllocToneCurves(ContextID, 3, InvShapes);
        if (mpe)
          cmsPipelineInsertStage(Lut, cmsAT_END, mpe);
        else  {
          cmsPipelineFree(Lut);
          Lut = NULL;
        }
    }

    cmsFreeToneCurveTriple(InvShapes);
    return Lut;
}

// Gray input pipeline
static
cmsPipeline* BuildGrayInputMatrixPipeline(cmsHPROFILE hProfile)
{
    cmsToneCurve *GrayTRC;
    cmsPipeline* Lut;
    cmsContext ContextID = cmsGetProfileContextID(hProfile);

    GrayTRC = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigGrayTRCTag);
    if (GrayTRC == NULL) return NULL;

    Lut = cmsPipelineAlloc(ContextID, 1, 3);
    if (Lut == NULL)
        goto Error;

    if (cmsGetPCS(hProfile) == cmsSigLabData) {

        // In this case we implement the profile as an  identity matrix plus 3 tone curves
        cmsUInt16Number Zero[2] = { 0x8080, 0x8080 };
        cmsToneCurve* EmptyTab;
        cmsToneCurve* LabCurves[3];

        EmptyTab = cmsBuildTabulatedToneCurve16(ContextID, 2, Zero);

        if (EmptyTab == NULL)
            goto Error;

        LabCurves[0] = GrayTRC;
        LabCurves[1] = EmptyTab;
        LabCurves[2] = EmptyTab;

        if (!cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 3,  1, OneToThreeInputMatrix, NULL)) ||
            !cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocToneCurves(ContextID, 3, LabCurves))) {
                cmsFreeToneCurve(EmptyTab);
                goto Error;
        }

        cmsFreeToneCurve(EmptyTab);

    }
    else  {

        if (!cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocToneCurves(ContextID, 1, &GrayTRC)) ||
            !cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 3,  1, GrayInputMatrix, NULL)))
            goto Error;
    }

    return Lut;

Error:
    cmsFreeToneCurve(GrayTRC);
    cmsPipelineFree(Lut);
    return NULL;
}

cmsHPROFILE CMSEXPORT cmsCreateLinearizationDeviceLinkTHR(cmsContext ContextID,
                                                          cmsColorSpaceSignature ColorSpace,
                                                          cmsToneCurve* const TransferFunctions[])
{
    cmsHPROFILE hICC;
    cmsPipeline* Pipeline;
    cmsStage* Lin;
    int nChannels;

    hICC = cmsCreateProfilePlaceholder(ContextID);
    if (!hICC)                          
        return NULL;

    cmsSetProfileVersion(hICC, 4.3);

    cmsSetDeviceClass(hICC,      cmsSigLinkClass);
    cmsSetColorSpace(hICC,       ColorSpace);
    cmsSetPCS(hICC,              ColorSpace);

    cmsSetHeaderRenderingIntent(hICC,  INTENT_PERCEPTUAL); 

    // Set up channels
    nChannels = cmsChannelsOf(ColorSpace);

    // Creates a Pipeline with prelinearization step only
    Pipeline = cmsPipelineAlloc(ContextID, nChannels, nChannels);
    if (Pipeline == NULL) goto Error;


    // Copy tables to Pipeline
    Lin = cmsStageAllocToneCurves(ContextID, nChannels, TransferFunctions);
    if (Lin == NULL) goto Error;

    cmsPipelineInsertStage(Pipeline, cmsAT_BEGIN, Lin);

    // Create tags       
    if (!SetTextTags(hICC, L"Linearization built-in")) goto Error;    
    if (!cmsWriteTag(hICC, cmsSigAToB0Tag, (void*) Pipeline)) goto Error;       
    if (!SetSeqDescTag(hICC, "Linearization built-in")) goto Error;

    // Pipeline is already on virtual profile
    cmsPipelineFree(Pipeline);

    // Ok, done
    return hICC;

Error:
    if (hICC)
        cmsCloseProfile(hICC);


    return NULL;
}

// RGB Matrix shaper
static
cmsPipeline* BuildRGBInputMatrixShaper(cmsHPROFILE hProfile)
{
    cmsPipeline* Lut;
    cmsMAT3 Mat;
    cmsToneCurve *Shapes[3];
    cmsContext ContextID = cmsGetProfileContextID(hProfile);
    int i, j;

    if (!ReadICCMatrixRGB2XYZ(&Mat, hProfile)) return NULL;

    // XYZ PCS in encoded in 1.15 format, and the matrix output comes in 0..0xffff range, so
    // we need to adjust the output by a factor of (0x10000/0xffff) to put data in
    // a 1.16 range, and then a >> 1 to obtain 1.15. The total factor is (65536.0)/(65535.0*2)

    for (i=0; i < 3; i++)
        for (j=0; j < 3; j++)
            Mat.v[i].n[j] *= InpAdj;


    Shapes[0] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigRedTRCTag);
    Shapes[1] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigGreenTRCTag);
    Shapes[2] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigBlueTRCTag);

    if (!Shapes[0] || !Shapes[1] || !Shapes[2])
        return NULL;

    Lut = cmsPipelineAlloc(ContextID, 3, 3);
    if (Lut != NULL) {

        if (!cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocToneCurves(ContextID, 3, Shapes)) ||
            !cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, (cmsFloat64Number*) &Mat, NULL)))
            goto Error;

        // Note that it is certainly possible a single profile would have a LUT based
        // tag for output working in lab and a matrix-shaper for the fallback cases. 
        // This is not allowed by the spec, but this code is tolerant to those cases    
        if (cmsGetPCS(hProfile) == cmsSigLabData) {

            if (!cmsPipelineInsertStage(Lut, cmsAT_END, _cmsStageAllocXYZ2Lab(ContextID)))
                goto Error;
        }

    }

    return Lut;

Error:
    cmsPipelineFree(Lut);
    return NULL;
}

// Creates a fake NULL profile. This profile return 1 channel as always 0.
// Is useful only for gamut checking tricks
cmsHPROFILE CMSEXPORT cmsCreateNULLProfileTHR(cmsContext ContextID)
{
    cmsHPROFILE hProfile;
    cmsPipeline* LUT = NULL;
    cmsStage* PostLin;
    cmsToneCurve* EmptyTab;
    cmsUInt16Number Zero[2] = { 0, 0 };

    hProfile = cmsCreateProfilePlaceholder(ContextID);
    if (!hProfile)                          // can't allocate
        return NULL;

    cmsSetProfileVersion(hProfile, 4.3);

    if (!SetTextTags(hProfile, L"NULL profile built-in")) goto Error;



    cmsSetDeviceClass(hProfile, cmsSigOutputClass);
    cmsSetColorSpace(hProfile,  cmsSigGrayData);
    cmsSetPCS(hProfile,         cmsSigLabData);

    // An empty LUTs is all we need
    LUT = cmsPipelineAlloc(ContextID, 1, 1);
    if (LUT == NULL) goto Error;

    EmptyTab = cmsBuildTabulatedToneCurve16(ContextID, 2, Zero);
    PostLin = cmsStageAllocToneCurves(ContextID, 1, &EmptyTab);
    cmsFreeToneCurve(EmptyTab);

    if (!cmsPipelineInsertStage(LUT, cmsAT_END, PostLin))
        goto Error;

    if (!cmsWriteTag(hProfile, cmsSigBToA0Tag, (void*) LUT)) goto Error;
    if (!cmsWriteTag(hProfile, cmsSigMediaWhitePointTag, cmsD50_XYZ())) goto Error;

    cmsPipelineFree(LUT);
    return hProfile;

Error:

    if (LUT != NULL)
        cmsPipelineFree(LUT);

    if (hProfile != NULL)
        cmsCloseProfile(hProfile);

    return NULL;
}

// Creates a fake XYZ identity
cmsHPROFILE CMSEXPORT cmsCreateXYZProfileTHR(cmsContext ContextID)
{
    cmsHPROFILE hProfile;
    cmsPipeline* LUT = NULL;

    hProfile = cmsCreateRGBProfileTHR(ContextID, cmsD50_xyY(), NULL, NULL);
    if (hProfile == NULL) return NULL;

    cmsSetProfileVersion(hProfile, 4.3);

    cmsSetDeviceClass(hProfile, cmsSigAbstractClass);
    cmsSetColorSpace(hProfile,  cmsSigXYZData);
    cmsSetPCS(hProfile,         cmsSigXYZData);

    if (!SetTextTags(hProfile, L"XYZ identity built-in")) goto Error;

    // An identity LUT is all we need
    LUT = cmsPipelineAlloc(ContextID, 3, 3);
    if (LUT == NULL) goto Error;

    if (!cmsPipelineInsertStage(LUT, cmsAT_BEGIN, _cmsStageAllocIdentityCurves(ContextID, 3)))
        goto Error;

    if (!cmsWriteTag(hProfile, cmsSigAToB0Tag, LUT)) goto Error;
    cmsPipelineFree(LUT);

    return hProfile;

Error:

    if (LUT != NULL)
        cmsPipelineFree(LUT);

    if (hProfile != NULL)
        cmsCloseProfile(hProfile);

    return NULL;
}

// Creates a fake Lab identity.
cmsHPROFILE CMSEXPORT cmsCreateLab2ProfileTHR(cmsContext ContextID, const cmsCIExyY* WhitePoint)
{
    cmsHPROFILE hProfile;
    cmsPipeline* LUT = NULL;

    hProfile = cmsCreateRGBProfileTHR(ContextID, WhitePoint == NULL ? cmsD50_xyY() : WhitePoint, NULL, NULL);
    if (hProfile == NULL) return NULL;

    cmsSetProfileVersion(hProfile, 2.1);

    cmsSetDeviceClass(hProfile, cmsSigAbstractClass);
    cmsSetColorSpace(hProfile,  cmsSigLabData);
    cmsSetPCS(hProfile,         cmsSigLabData);

    if (!SetTextTags(hProfile, L"Lab identity built-in")) return NULL;

    // An identity LUT is all we need
    LUT = cmsPipelineAlloc(ContextID, 3, 3);
    if (LUT == NULL) goto Error;

    if (!cmsPipelineInsertStage(LUT, cmsAT_BEGIN, _cmsStageAllocIdentityCLut(ContextID, 3)))
        goto Error;

    if (!cmsWriteTag(hProfile, cmsSigAToB0Tag, LUT)) goto Error;
    cmsPipelineFree(LUT);

    return hProfile;

Error:

    if (LUT != NULL)
        cmsPipelineFree(LUT);

    if (hProfile != NULL)
        cmsCloseProfile(hProfile);

    return NULL;
}

// RGB Matrix shaper
static
cmsPipeline* BuildRGBInputMatrixShaper(cmsHPROFILE hProfile)
{
    cmsPipeline* Lut;
    cmsMAT3 Mat;
    cmsToneCurve *Shapes[3];
    cmsContext ContextID = cmsGetProfileContextID(hProfile);
    int i, j;

    if (!ReadICCMatrixRGB2XYZ(&Mat, hProfile)) return NULL;

    // XYZ PCS in encoded in 1.15 format, and the matrix output comes in 0..0xffff range, so
    // we need to adjust the output by a factor of (0x10000/0xffff) to put data in 
    // a 1.16 range, and then a >> 1 to obtain 1.15. The total factor is (65536.0)/(65535.0*2)
    
    for (i=0; i < 3; i++)
        for (j=0; j < 3; j++)
            Mat.v[i].n[j] *= InpAdj;
    

    Shapes[0] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigRedTRCTag);        
    Shapes[1] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigGreenTRCTag);
    Shapes[2] = (cmsToneCurve *) cmsReadTag(hProfile, cmsSigBlueTRCTag);

    if (!Shapes[0] || !Shapes[1] || !Shapes[2])
        return NULL;

    Lut = cmsPipelineAlloc(ContextID, 3, 3);
    if (Lut != NULL) {

        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocToneCurves(ContextID, 3, Shapes));
        cmsPipelineInsertStage(Lut, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, (cmsFloat64Number*) &Mat, NULL));
    }

    return Lut;
}

// This is the entry for black-plane preserving, which are non-ICC
static
cmsPipeline* BlackPreservingKPlaneIntents(cmsContext     ContextID,
                                          cmsUInt32Number nProfiles,
                                          cmsUInt32Number TheIntents[],
                                          cmsHPROFILE     hProfiles[],
                                          cmsBool         BPC[],
                                          cmsFloat64Number AdaptationStates[],
                                          cmsUInt32Number dwFlags)
{
    PreserveKPlaneParams bp;
    cmsPipeline*    Result = NULL;
    cmsUInt32Number ICCIntents[256];
    cmsStage*         CLUT;
    cmsUInt32Number i, nGridPoints;
    cmsHPROFILE hLab;

    // Sanity check
    if (nProfiles < 1 || nProfiles > 255) return NULL;

    // Translate black-preserving intents to ICC ones
    for (i=0; i < nProfiles; i++)
        ICCIntents[i] = TranslateNonICCIntents(TheIntents[i]);

    // Check for non-cmyk profiles
    if (cmsGetColorSpace(hProfiles[0]) != cmsSigCmykData ||
        !(cmsGetColorSpace(hProfiles[nProfiles-1]) == cmsSigCmykData ||
        cmsGetDeviceClass(hProfiles[nProfiles-1]) == cmsSigOutputClass))
           return  DefaultICCintents(ContextID, nProfiles, ICCIntents, hProfiles, BPC, AdaptationStates, dwFlags);

    // Allocate an empty LUT for holding the result
    Result = cmsPipelineAlloc(ContextID, 4, 4);
    if (Result == NULL) return NULL;


    memset(&bp, 0, sizeof(bp));

    // We need the input LUT of the last profile, assuming this one is responsible of
    // black generation. This LUT will be seached in inverse order.
    bp.LabK2cmyk = _cmsReadInputLUT(hProfiles[nProfiles-1], INTENT_RELATIVE_COLORIMETRIC);
    if (bp.LabK2cmyk == NULL) goto Cleanup;

    // Get total area coverage (in 0..1 domain)
    bp.MaxTAC = cmsDetectTAC(hProfiles[nProfiles-1]) / 100.0;
    if (bp.MaxTAC <= 0) goto Cleanup;


    // Create a LUT holding normal ICC transform
    bp.cmyk2cmyk = DefaultICCintents(ContextID,
                                         nProfiles,
                                         ICCIntents,
                                         hProfiles,
                                         BPC,
                                         AdaptationStates,
                                         dwFlags);
    if (bp.cmyk2cmyk == NULL) goto Cleanup;

    // Now the tone curve
    bp.KTone = _cmsBuildKToneCurve(ContextID, 4096, nProfiles,
                                   ICCIntents,
                                   hProfiles,
                                   BPC,
                                   AdaptationStates,
                                   dwFlags);
    if (bp.KTone == NULL) goto Cleanup;

    // To measure the output, Last profile to Lab
    hLab = cmsCreateLab4ProfileTHR(ContextID, NULL);
    bp.hProofOutput = cmsCreateTransformTHR(ContextID, hProfiles[nProfiles-1],
                                         CHANNELS_SH(4)|BYTES_SH(2), hLab, TYPE_Lab_DBL,
                                         INTENT_RELATIVE_COLORIMETRIC,
                                         cmsFLAGS_NOCACHE|cmsFLAGS_NOOPTIMIZE);
    if ( bp.hProofOutput == NULL) goto Cleanup;

    // Same as anterior, but lab in the 0..1 range
    bp.cmyk2Lab = cmsCreateTransformTHR(ContextID, hProfiles[nProfiles-1],
                                         FLOAT_SH(1)|CHANNELS_SH(4)|BYTES_SH(4), hLab,
                                         FLOAT_SH(1)|CHANNELS_SH(3)|BYTES_SH(4),
                                         INTENT_RELATIVE_COLORIMETRIC,
                                         cmsFLAGS_NOCACHE|cmsFLAGS_NOOPTIMIZE);
    if (bp.cmyk2Lab == NULL) goto Cleanup;
    cmsCloseProfile(hLab);

    // Error estimation (for debug only)
    bp.MaxError = 0;

    // How many gridpoints are we going to use?
    nGridPoints = _cmsReasonableGridpointsByColorspace(cmsSigCmykData, dwFlags);


    CLUT = cmsStageAllocCLut16bit(ContextID, nGridPoints, 4, 4, NULL);
    if (CLUT == NULL) goto Cleanup;

    if (!cmsPipelineInsertStage(Result, cmsAT_BEGIN, CLUT))
        goto Cleanup;

    cmsStageSampleCLut16bit(CLUT, BlackPreservingSampler, (void*) &bp, 0);

Cleanup:

//.........这里部分代码省略.........

//.........这里部分代码省略.........
        cmsSignalError(ContextID, cmsERROR_RANGE, "Wrong position of PCS. 1..255 expected, %d found.", nGamutPCSposition);
        return NULL;
    }

    hLab = cmsCreateLab4ProfileTHR(ContextID, NULL);
    if (hLab == NULL) return NULL;


    // The figure of merit. On matrix-shaper profiles, should be almost zero as
    // the conversion is pretty exact. On LUT based profiles, different resolutions
    // of input and output CLUT may result in differences.

    if (cmsIsMatrixShaper(hGamut)) {

        Chain.Thereshold = 1.0;
    }
    else {
        Chain.Thereshold = ERR_THERESHOLD;
    }


    // Create a copy of parameters
    for (i=0; i < nGamutPCSposition; i++) {
        ProfileList[i]    = hProfiles[i];
        BPCList[i]        = BPC[i];
        AdaptationList[i] = AdaptationStates[i];
        IntentList[i]     = Intents[i];
    }

    // Fill Lab identity
    ProfileList[nGamutPCSposition] = hLab;
    BPCList[nGamutPCSposition] = 0;
    AdaptationList[nGamutPCSposition] = 1.0;
    IntentList[nGamutPCSposition] = INTENT_RELATIVE_COLORIMETRIC;


    ColorSpace  = cmsGetColorSpace(hGamut);

    nChannels   = cmsChannelsOf(ColorSpace);
    nGridpoints = _cmsReasonableGridpointsByColorspace(ColorSpace, cmsFLAGS_HIGHRESPRECALC);
    dwFormat    = (CHANNELS_SH(nChannels)|BYTES_SH(2));

    // 16 bits to Lab double
    Chain.hInput = cmsCreateExtendedTransform(ContextID,
        nGamutPCSposition + 1,
        ProfileList,
        BPCList,
        IntentList,
        AdaptationList,
        NULL, 0,
        dwFormat, TYPE_Lab_DBL,
        cmsFLAGS_NOCACHE);


    // Does create the forward step. Lab double to device
    dwFormat    = (CHANNELS_SH(nChannels)|BYTES_SH(2));
    Chain.hForward = cmsCreateTransformTHR(ContextID,
        hLab, TYPE_Lab_DBL,
        hGamut, dwFormat,
        INTENT_RELATIVE_COLORIMETRIC,
        cmsFLAGS_NOCACHE);

    // Does create the backwards step
    Chain.hReverse = cmsCreateTransformTHR(ContextID, hGamut, dwFormat,
        hLab, TYPE_Lab_DBL,
        INTENT_RELATIVE_COLORIMETRIC,
        cmsFLAGS_NOCACHE);


    // All ok?
    if (Chain.hInput && Chain.hForward && Chain.hReverse) {

        // Go on, try to compute gamut LUT from PCS. This consist on a single channel containing
        // dE when doing a transform back and forth on the colorimetric intent.

        Gamut = cmsPipelineAlloc(ContextID, 3, 1);
        if (Gamut != NULL) {

            CLUT = cmsStageAllocCLut16bit(ContextID, nGridpoints, nChannels, 1, NULL);
            if (!cmsPipelineInsertStage(Gamut, cmsAT_BEGIN, CLUT)) {
                cmsPipelineFree(Gamut);
                Gamut = NULL;
            }
            else {
                cmsStageSampleCLut16bit(CLUT, GamutSampler, (void*) &Chain, 0);
            }
        }
    }
    else
        Gamut = NULL;   // Didn't work...

    // Free all needed stuff.
    if (Chain.hInput)   cmsDeleteTransform(Chain.hInput);
    if (Chain.hForward) cmsDeleteTransform(Chain.hForward);
    if (Chain.hReverse) cmsDeleteTransform(Chain.hReverse);
    if (hLab) cmsCloseProfile(hLab);

    // And return computed hull
    return Gamut;
}

// Default handler for ICC-style intents
static
cmsPipeline* DefaultICCintents(cmsContext       ContextID,
                               cmsUInt32Number  nProfiles,
                               cmsUInt32Number  TheIntents[],
                               cmsHPROFILE      hProfiles[],
                               cmsBool          BPC[],
                               cmsFloat64Number AdaptationStates[],
                               cmsUInt32Number  dwFlags)
{
    cmsPipeline* Lut = NULL;
    cmsPipeline* Result;
    cmsHPROFILE hProfile;
    cmsMAT3 m;
    cmsVEC3 off;
    cmsColorSpaceSignature ColorSpaceIn, ColorSpaceOut, CurrentColorSpace;
    cmsProfileClassSignature ClassSig;
    cmsUInt32Number  i, Intent;

    // For safety
    if (nProfiles == 0) return NULL;

    // Allocate an empty LUT for holding the result. 0 as channel count means 'undefined'
    Result = cmsPipelineAlloc(ContextID, 0, 0);
    if (Result == NULL) return NULL;

    CurrentColorSpace = cmsGetColorSpace(hProfiles[0]);

    for (i=0; i < nProfiles; i++) {

        cmsBool  lIsDeviceLink, lIsInput;

        hProfile      = hProfiles[i];
        ClassSig      = cmsGetDeviceClass(hProfile);
        lIsDeviceLink = (ClassSig == cmsSigLinkClass || ClassSig == cmsSigAbstractClass );

        // First profile is used as input unless devicelink or abstract
        if ((i == 0) && !lIsDeviceLink) {
            lIsInput = TRUE;
        }
        else {
          // Else use profile in the input direction if current space is not PCS
        lIsInput      = (CurrentColorSpace != cmsSigXYZData) &&
                        (CurrentColorSpace != cmsSigLabData);
        }

        Intent        = TheIntents[i];

        if (lIsInput || lIsDeviceLink) {

            ColorSpaceIn    = cmsGetColorSpace(hProfile);
            ColorSpaceOut   = cmsGetPCS(hProfile);
        }
        else {

            ColorSpaceIn    = cmsGetPCS(hProfile);
            ColorSpaceOut   = cmsGetColorSpace(hProfile);
        }

        if (!ColorSpaceIsCompatible(ColorSpaceIn, CurrentColorSpace)) {

            cmsSignalError(ContextID, cmsERROR_COLORSPACE_CHECK, "ColorSpace mismatch");
            goto Error;
        }

        // If devicelink is found, then no custom intent is allowed and we can
        // read the LUT to be applied. Settings don't apply here.
        if (lIsDeviceLink || ((ClassSig == cmsSigNamedColorClass) && (nProfiles == 1))) {

            // Get the involved LUT from the profile
            Lut = _cmsReadDevicelinkLUT(hProfile, Intent);
            if (Lut == NULL) goto Error;

            // What about abstract profiles?
             if (ClassSig == cmsSigAbstractClass && i > 0) {
                if (!ComputeConversion(i, hProfiles, Intent, BPC[i], AdaptationStates[i], &m, &off)) goto Error;
             }
             else {
                _cmsMAT3identity(&m);
                _cmsVEC3init(&off, 0, 0, 0);
             }


            if (!AddConversion(Result, CurrentColorSpace, ColorSpaceIn, &m, &off)) goto Error;

        }
        else {

            if (lIsInput) {
                // Input direction means non-pcs connection, so proceed like devicelinks
                Lut = _cmsReadInputLUT(hProfile, Intent);
                if (Lut == NULL) goto Error;
            }
            else {

                // Output direction means PCS connection. Intent may apply here
                Lut = _cmsReadOutputLUT(hProfile, Intent);
                if (Lut == NULL) goto Error;


//.........这里部分代码省略.........

// This is the entry for black-preserving K-only intents, which are non-ICC
static
cmsPipeline*  BlackPreservingKOnlyIntents(cmsContext     ContextID,
                                          cmsUInt32Number nProfiles,
                                          cmsUInt32Number TheIntents[],
                                          cmsHPROFILE     hProfiles[],
                                          cmsBool         BPC[],
                                          cmsFloat64Number AdaptationStates[],
                                          cmsUInt32Number dwFlags)
{
    GrayOnlyParams  bp;
    cmsPipeline*    Result;
    cmsUInt32Number ICCIntents[256];
    cmsStage*         CLUT;
    cmsUInt32Number i, nGridPoints;


    // Sanity check
    if (nProfiles < 1 || nProfiles > 255) return NULL;

    // Translate black-preserving intents to ICC ones
    for (i=0; i < nProfiles; i++)
        ICCIntents[i] = TranslateNonICCIntents(TheIntents[i]);

    // Check for non-cmyk profiles
    if (cmsGetColorSpace(hProfiles[0]) != cmsSigCmykData ||
        cmsGetColorSpace(hProfiles[nProfiles-1]) != cmsSigCmykData)
           return DefaultICCintents(ContextID, nProfiles, ICCIntents, hProfiles, BPC, AdaptationStates, dwFlags);

    memset(&bp, 0, sizeof(bp));

    // Allocate an empty LUT for holding the result
    Result = cmsPipelineAlloc(ContextID, 4, 4);
    if (Result == NULL) return NULL;

    // Create a LUT holding normal ICC transform
    bp.cmyk2cmyk = DefaultICCintents(ContextID,
        nProfiles,
        ICCIntents,
        hProfiles,
        BPC,
        AdaptationStates,
        dwFlags);

    if (bp.cmyk2cmyk == NULL) goto Error;

    // Now, compute the tone curve
    bp.KTone = _cmsBuildKToneCurve(ContextID,
        4096,
        nProfiles,
        ICCIntents,
        hProfiles,
        BPC,
        AdaptationStates,
        dwFlags);

    if (bp.KTone == NULL) goto Error;


    // How many gridpoints are we going to use?
    nGridPoints = _cmsReasonableGridpointsByColorspace(cmsSigCmykData, dwFlags);

    // Create the CLUT. 16 bits
    CLUT = cmsStageAllocCLut16bit(ContextID, nGridPoints, 4, 4, NULL);
    if (CLUT == NULL) goto Error;

    // This is the one and only MPE in this LUT
    if (!cmsPipelineInsertStage(Result, cmsAT_BEGIN, CLUT))
        goto Error;

    // Sample it. We cannot afford pre/post linearization this time.
    if (!cmsStageSampleCLut16bit(CLUT, BlackPreservingGrayOnlySampler, (void*) &bp, 0))
        goto Error;

    // Get rid of xform and tone curve
    cmsPipelineFree(bp.cmyk2cmyk);
    cmsFreeToneCurve(bp.KTone);

    return Result;

Error:

    if (bp.cmyk2cmyk != NULL) cmsPipelineFree(bp.cmyk2cmyk);
    if (bp.KTone != NULL)  cmsFreeToneCurve(bp.KTone);
    if (Result != NULL) cmsPipelineFree(Result);
    return NULL;

}