//---------------------------------------------------------------------------------

//

//  Little Color Management System

//  Copyright (c) 1998-2026 Marti Maria Saguer

//

// Permission is hereby granted, free of charge, to any person obtaining

// a copy of this software and associated documentation files (the "Software"),

// to deal in the Software without restriction, including without limitation

// the rights to use, copy, modify, merge, publish, distribute, sublicense,

// and/or sell copies of the Software, and to permit persons to whom the Software

// is furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in

// all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO

// THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE

// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION

// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION

// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

//

//---------------------------------------------------------------------------------

//

#include "lcms2_internal.h"

// This is the default routine for ICC-style intents. A user may decide to override it by using a plugin.

// Supported intents are perceptual, relative colorimetric, saturation and ICC-absolute colorimetric

static

cmsPipeline* DefaultICCintents(cmsContext     ContextID,

                               cmsUInt32Number nProfiles,

                               cmsUInt32Number Intents[],

                               cmsHPROFILE     hProfiles[],

                               cmsBool         BPC[],

                               cmsFloat64Number AdaptationStates[],

                               cmsUInt32Number dwFlags);

//---------------------------------------------------------------------------------

// This is the entry for black-preserving K-only intents, which are non-ICC. Last profile have to be a output profile

// to do the trick (no devicelinks allowed at that position)

static

cmsPipeline*  BlackPreservingKOnlyIntents(cmsContext     ContextID,

                                          cmsUInt32Number nProfiles,

                                          cmsUInt32Number Intents[],

                                          cmsHPROFILE     hProfiles[],

                                          cmsBool         BPC[],

                                          cmsFloat64Number AdaptationStates[],

                                          cmsUInt32Number dwFlags);

//---------------------------------------------------------------------------------

// This is the entry for black-plane preserving, which are non-ICC. Again, Last profile have to be a output profile

// to do the trick (no devicelinks allowed at that position)

static

cmsPipeline*  BlackPreservingKPlaneIntents(cmsContext     ContextID,

                                           cmsUInt32Number nProfiles,

                                           cmsUInt32Number Intents[],

                                           cmsHPROFILE     hProfiles[],

                                           cmsBool         BPC[],

                                           cmsFloat64Number AdaptationStates[],

                                           cmsUInt32Number dwFlags);

//---------------------------------------------------------------------------------

// This is a structure holding implementations for all supported intents.

typedef struct _cms_intents_list {

    cmsUInt32Number Intent;

    char            Description[256];

    cmsIntentFn     Link;

    struct _cms_intents_list*  Next;

} cmsIntentsList;

// Built-in intents

static cmsIntentsList DefaultIntents[] = {

    { INTENT_PERCEPTUAL,                            "Perceptual",                                   DefaultICCintents,            &DefaultIntents[1] },

    { INTENT_RELATIVE_COLORIMETRIC,                 "Relative colorimetric",                        DefaultICCintents,            &DefaultIntents[2] },

    { INTENT_SATURATION,                            "Saturation",                                   DefaultICCintents,            &DefaultIntents[3] },

    { INTENT_ABSOLUTE_COLORIMETRIC,                 "Absolute colorimetric",                        DefaultICCintents,            &DefaultIntents[4] },

    { INTENT_PRESERVE_K_ONLY_PERCEPTUAL,            "Perceptual preserving black ink",              BlackPreservingKOnlyIntents,  &DefaultIntents[5] },

    { INTENT_PRESERVE_K_ONLY_RELATIVE_COLORIMETRIC, "Relative colorimetric preserving black ink",   BlackPreservingKOnlyIntents,  &DefaultIntents[6] },

    { INTENT_PRESERVE_K_ONLY_SATURATION,            "Saturation preserving black ink",              BlackPreservingKOnlyIntents,  &DefaultIntents[7] },

    { INTENT_PRESERVE_K_PLANE_PERCEPTUAL,           "Perceptual preserving black plane",            BlackPreservingKPlaneIntents, &DefaultIntents[8] },

    { INTENT_PRESERVE_K_PLANE_RELATIVE_COLORIMETRIC,"Relative colorimetric preserving black plane", BlackPreservingKPlaneIntents, &DefaultIntents[9] },

    { INTENT_PRESERVE_K_PLANE_SATURATION,           "Saturation preserving black plane",            BlackPreservingKPlaneIntents, NULL }

};

// A pointer to the beginning of the list

_cmsIntentsPluginChunkType _cmsIntentsPluginChunk = { NULL };

// Duplicates the zone of memory used by the plug-in in the new context

static

void DupPluginIntentsList(struct _cmsContext_struct* ctx,

                                               const struct _cmsContext_struct* src)

{

   _cmsIntentsPluginChunkType newHead = { NULL };

   cmsIntentsList*  entry;

   cmsIntentsList*  Anterior = NULL;

   _cmsIntentsPluginChunkType* head = (_cmsIntentsPluginChunkType*) src->chunks[IntentPlugin];

    // Walk the list copying all nodes

   for (entry = head->Intents;

        entry != NULL;

        entry = entry ->Next) {

            cmsIntentsList *newEntry = ( cmsIntentsList *) _cmsSubAllocDup(ctx ->MemPool, entry, sizeof(cmsIntentsList));

            if (newEntry == NULL)

                return;

            // We want to keep the linked list order, so this is a little bit tricky

            newEntry -> Next = NULL;

            if (Anterior)

                Anterior -> Next = newEntry;

            Anterior = newEntry;

            if (newHead.Intents == NULL)

                newHead.Intents = newEntry;

    }

  ctx ->chunks[IntentPlugin] = _cmsSubAllocDup(ctx->MemPool, &newHead, sizeof(_cmsIntentsPluginChunkType));

}

void  _cmsAllocIntentsPluginChunk(struct _cmsContext_struct* ctx,

                                         const struct _cmsContext_struct* src)

{

    if (src != NULL) {

        // Copy all linked list

        DupPluginIntentsList(ctx, src);

    }

    else {

        static _cmsIntentsPluginChunkType IntentsPluginChunkType = { NULL };

        ctx ->chunks[IntentPlugin] = _cmsSubAllocDup(ctx ->MemPool, &IntentsPluginChunkType, sizeof(_cmsIntentsPluginChunkType));

    }

}

// Search the list for a suitable intent. Returns NULL if not found

static

cmsIntentsList* SearchIntent(cmsContext ContextID, cmsUInt32Number Intent)

{

    _cmsIntentsPluginChunkType* ctx = ( _cmsIntentsPluginChunkType*) _cmsContextGetClientChunk(ContextID, IntentPlugin);

    cmsIntentsList* pt;

    for (pt = ctx -> Intents; pt != NULL; pt = pt -> Next)

        if (pt ->Intent == Intent) return pt;

    for (pt = DefaultIntents; pt != NULL; pt = pt -> Next)

        if (pt ->Intent == Intent) return pt;

    return NULL;

}

// Black point compensation. Implemented as a linear scaling in XYZ. Black points

// should come relative to the white point. Fills an matrix/offset element m

// which is organized as a 4x4 matrix.

static

void ComputeBlackPointCompensation(cmsContext ContextID, const cmsCIEXYZ* BlackPointIn,

                                   const cmsCIEXYZ* BlackPointOut,

                                   cmsMAT3* m, cmsVEC3* off)

{

  cmsFloat64Number ax, ay, az, bx, by, bz, tx, ty, tz;

   // Now we need to compute a matrix plus an offset m and of such of

   // [m]*bpin + off = bpout

   // [m]*D50  + off = D50

   //

   // This is a linear scaling in the form ax+b, where

   // a = (bpout - D50) / (bpin - D50)

   // b = - D50* (bpout - bpin) / (bpin - D50)

   tx = BlackPointIn->X - cmsD50_XYZ(ContextID)->X;

   ty = BlackPointIn->Y - cmsD50_XYZ(ContextID)->Y;

   tz = BlackPointIn->Z - cmsD50_XYZ(ContextID)->Z;

   ax = (BlackPointOut->X - cmsD50_XYZ(ContextID)->X) / tx;

   ay = (BlackPointOut->Y - cmsD50_XYZ(ContextID)->Y) / ty;

   az = (BlackPointOut->Z - cmsD50_XYZ(ContextID)->Z) / tz;

   bx = - cmsD50_XYZ(ContextID)-> X * (BlackPointOut->X - BlackPointIn->X) / tx;

   by = - cmsD50_XYZ(ContextID)-> Y * (BlackPointOut->Y - BlackPointIn->Y) / ty;

   bz = - cmsD50_XYZ(ContextID)-> Z * (BlackPointOut->Z - BlackPointIn->Z) / tz;

   _cmsVEC3init(ContextID, &m ->v[0], ax, 0,  0);

   _cmsVEC3init(ContextID, &m ->v[1], 0, ay,  0);

   _cmsVEC3init(ContextID, &m ->v[2], 0,  0,  az);

   _cmsVEC3init(ContextID, off, bx, by, bz);

}

// Approximate a blackbody illuminant based on CHAD information

static

cmsFloat64Number CHAD2Temp(cmsContext ContextID, const cmsMAT3* Chad)

{

    // Convert D50 across inverse CHAD to get the absolute white point

    cmsVEC3 d, s;

    cmsCIEXYZ Dest;

    cmsCIExyY DestChromaticity;

    cmsFloat64Number TempK;

    cmsMAT3 m1, m2;

    m1 = *Chad;

    if (!_cmsMAT3inverse(ContextID, &m1, &m2)) return FALSE;

    s.n[VX] = cmsD50_XYZ(ContextID) -> X;

    s.n[VY] = cmsD50_XYZ(ContextID) -> Y;

    s.n[VZ] = cmsD50_XYZ(ContextID) -> Z;

    _cmsMAT3eval(ContextID, &d, &m2, &s);

    Dest.X = d.n[VX];

    Dest.Y = d.n[VY];

    Dest.Z = d.n[VZ];

    cmsXYZ2xyY(ContextID, &DestChromaticity, &Dest);

    if (!cmsTempFromWhitePoint(ContextID, &TempK, &DestChromaticity))

        return -1.0;

    return TempK;

}

// Compute a CHAD based on a given temperature

static

void Temp2CHAD(cmsContext ContextID, cmsMAT3* Chad, cmsFloat64Number Temp)

{

    cmsCIEXYZ White;

    cmsCIExyY ChromaticityOfWhite;

    cmsWhitePointFromTemp(ContextID, &ChromaticityOfWhite, Temp);

    cmsxyY2XYZ(ContextID,&White, &ChromaticityOfWhite);

    _cmsAdaptationMatrix(ContextID, Chad, NULL, &White, cmsD50_XYZ(ContextID));

}

// Join scalings to obtain relative input to absolute and then to relative output.

// Result is stored in a 3x3 matrix

static

cmsBool  ComputeAbsoluteIntent(cmsContext ContextID, cmsFloat64Number AdaptationState,

                               const cmsCIEXYZ* WhitePointIn,

                               const cmsMAT3* ChromaticAdaptationMatrixIn,

                               const cmsCIEXYZ* WhitePointOut,

                               const cmsMAT3* ChromaticAdaptationMatrixOut,

                               cmsMAT3* m)

{

    cmsMAT3 Scale, m1, m2, m3, m4;

    // TODO: Follow Marc Mahy's recommendation to check if CHAD is same by using M1*M2 == M2*M1. If so, do nothing.

    // TODO: Add support for ArgyllArts tag

    // Adaptation state

    if (AdaptationState == 1.0) {

        // Observer is fully adapted. Keep chromatic adaptation.

        // That is the standard V4 behaviour

        _cmsVEC3init(ContextID, &m->v[0], WhitePointIn->X / WhitePointOut->X, 0, 0);

        _cmsVEC3init(ContextID, &m->v[1], 0, WhitePointIn->Y / WhitePointOut->Y, 0);

        _cmsVEC3init(ContextID, &m->v[2], 0, 0, WhitePointIn->Z / WhitePointOut->Z);

    }

    else  {

        // Incomplete adaptation. This is an advanced feature.

        _cmsVEC3init(ContextID, &Scale.v[0], WhitePointIn->X / WhitePointOut->X, 0, 0);

        _cmsVEC3init(ContextID, &Scale.v[1], 0,  WhitePointIn->Y / WhitePointOut->Y, 0);

        _cmsVEC3init(ContextID, &Scale.v[2], 0, 0,  WhitePointIn->Z / WhitePointOut->Z);

        if (AdaptationState == 0.0) {

            m1 = *ChromaticAdaptationMatrixOut;

            _cmsMAT3per(ContextID, &m2, &m1, &Scale);

            // m2 holds CHAD from output white to D50 times abs. col. scaling

            // Observer is not adapted, undo the chromatic adaptation

            _cmsMAT3per(ContextID, m, &m2, ChromaticAdaptationMatrixOut);

            m3 = *ChromaticAdaptationMatrixIn;

            if (!_cmsMAT3inverse(ContextID, &m3, &m4)) return FALSE;

            _cmsMAT3per(ContextID, m, &m2, &m4);

        } else {

            cmsMAT3 MixedCHAD;

            cmsFloat64Number TempSrc, TempDest, Temp;

            m1 = *ChromaticAdaptationMatrixIn;

            if (!_cmsMAT3inverse(ContextID, &m1, &m2)) return FALSE;

            _cmsMAT3per(ContextID, &m3, &m2, &Scale);

            // m3 holds CHAD from input white to D50 times abs. col. scaling

            TempSrc  = CHAD2Temp(ContextID, ChromaticAdaptationMatrixIn);

            TempDest = CHAD2Temp(ContextID, ChromaticAdaptationMatrixOut);

            if (TempSrc < 0.0 || TempDest < 0.0) return FALSE; // Something went wrong

            if (_cmsMAT3isIdentity(ContextID, &Scale) && fabs(TempSrc - TempDest) < 0.01) {

                _cmsMAT3identity(ContextID, m);

                return TRUE;

            }

            Temp = (1.0 - AdaptationState) * TempDest + AdaptationState * TempSrc;

            // Get a CHAD from whatever output temperature to D50. This replaces output CHAD

            Temp2CHAD(ContextID, &MixedCHAD, Temp);

            _cmsMAT3per(ContextID, m, &m3, &MixedCHAD);

        }

    }

    return TRUE;

}

// Just to see if m matrix should be applied

static

cmsBool IsEmptyLayer(cmsContext ContextID, cmsMAT3* m, cmsVEC3* off)

{

    cmsFloat64Number diff = 0;

    cmsMAT3 Ident;

    int i;

    if (m == NULL && off == NULL) return TRUE;  // NULL is allowed as an empty layer

    if (m == NULL && off != NULL) return FALSE; // This is an internal error

    _cmsMAT3identity(ContextID, &Ident);

    for (i=0; i < 3*3; i++)

        diff += fabs(((cmsFloat64Number*)m)[i] - ((cmsFloat64Number*)&Ident)[i]);

    for (i=0; i < 3; i++)

        diff += fabs(((cmsFloat64Number*)off)[i]);

    return (diff < 0.002);

}

// Compute the conversion layer

static

cmsBool ComputeConversion(cmsContext ContextID,

                          cmsUInt32Number i,

                          cmsHPROFILE hProfiles[],

                          cmsUInt32Number Intent,

                          cmsBool BPC,

                          cmsFloat64Number AdaptationState,

                          cmsMAT3* m, cmsVEC3* off)

{

    int k;

    // m  and off are set to identity and this is detected latter on

    _cmsMAT3identity(ContextID, m);

    _cmsVEC3init(ContextID, off, 0, 0, 0);

    // If intent is abs. colorimetric,

    if (Intent == INTENT_ABSOLUTE_COLORIMETRIC) {

        cmsCIEXYZ WhitePointIn, WhitePointOut;

        cmsMAT3 ChromaticAdaptationMatrixIn, ChromaticAdaptationMatrixOut;

        if (!_cmsReadMediaWhitePoint(ContextID, &WhitePointIn, hProfiles[i - 1])) return FALSE;

        if (!_cmsReadCHAD(ContextID, &ChromaticAdaptationMatrixIn, hProfiles[i - 1])) return FALSE;

        if (!_cmsReadMediaWhitePoint(ContextID, &WhitePointOut, hProfiles[i])) return FALSE;

        if (!_cmsReadCHAD(ContextID, &ChromaticAdaptationMatrixOut, hProfiles[i])) return FALSE;

        if (!ComputeAbsoluteIntent(ContextID, AdaptationState,

                                  &WhitePointIn,  &ChromaticAdaptationMatrixIn,

                                  &WhitePointOut, &ChromaticAdaptationMatrixOut, m)) return FALSE;

    }

    else {

        // Rest of intents may apply BPC.

        if (BPC) {

            cmsCIEXYZ BlackPointIn = { 0, 0, 0}, BlackPointOut = { 0, 0, 0 };

            cmsDetectBlackPoint(ContextID, &BlackPointIn,  hProfiles[i-1], Intent, 0);

            cmsDetectDestinationBlackPoint(ContextID, &BlackPointOut, hProfiles[i], Intent, 0);

            // If black points are equal, then do nothing

            if (BlackPointIn.X != BlackPointOut.X ||

                BlackPointIn.Y != BlackPointOut.Y ||

                BlackPointIn.Z != BlackPointOut.Z)

                    ComputeBlackPointCompensation(ContextID, &BlackPointIn, &BlackPointOut, m, off);

        }

    }

    // Offset should be adjusted because the encoding. We encode XYZ normalized to 0..1.0,

    // to do that, we divide by MAX_ENCODEABLE_XZY. The conversion stage goes XYZ -> XYZ so

    // we have first to convert from encoded to XYZ and then convert back to encoded.

    // y = Mx + Off

    // x = x'c

    // y = M x'c + Off

    // y = y'c; y' = y / c

    // y' = (Mx'c + Off) /c = Mx' + (Off / c)

    for (k=0; k < 3; k++) {

        off ->n[k] /= MAX_ENCODEABLE_XYZ;

    }

    return TRUE;

}

// Add a conversion stage if needed. If a matrix/offset m is given, it applies to XYZ space

static

cmsBool AddConversion(cmsContext ContextID, cmsPipeline* Result, cmsColorSpaceSignature InPCS, cmsColorSpaceSignature OutPCS, cmsMAT3* m, cmsVEC3* off)

{

    cmsFloat64Number* m_as_dbl = (cmsFloat64Number*) m;

    cmsFloat64Number* off_as_dbl = (cmsFloat64Number*) off;

    // Handle PCS mismatches. A specialized stage is added to the LUT in such case

    switch (InPCS) {

    case cmsSigXYZData: // Input profile operates in XYZ

        switch (OutPCS) {

        case cmsSigXYZData:  // XYZ -> XYZ

            if (!IsEmptyLayer(ContextID, m, off) &&

                !cmsPipelineInsertStage(ContextID, Result, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, m_as_dbl, off_as_dbl)))

                return FALSE;

            break;

        case cmsSigLabData:  // XYZ -> Lab

            if (!IsEmptyLayer(ContextID, m, off) &&

                !cmsPipelineInsertStage(ContextID, Result, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, m_as_dbl, off_as_dbl)))

                return FALSE;

            if (!cmsPipelineInsertStage(ContextID, Result, cmsAT_END, _cmsStageAllocXYZ2Lab(ContextID)))

                return FALSE;

            break;

        default:

            return FALSE;   // Colorspace mismatch

        }

        break;

    case cmsSigLabData: // Input profile operates in Lab

        switch (OutPCS) {

        case cmsSigXYZData:  // Lab -> XYZ

            if (!cmsPipelineInsertStage(ContextID, Result, cmsAT_END, _cmsStageAllocLab2XYZ(ContextID)))

                return FALSE;

            if (!IsEmptyLayer(ContextID, m, off) &&

                !cmsPipelineInsertStage(ContextID, Result, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, m_as_dbl, off_as_dbl)))

                return FALSE;

            break;

        case cmsSigLabData:  // Lab -> Lab

            if (!IsEmptyLayer(ContextID, m, off)) {

                if (!cmsPipelineInsertStage(ContextID, Result, cmsAT_END, _cmsStageAllocLab2XYZ(ContextID)) ||

                    !cmsPipelineInsertStage(ContextID, Result, cmsAT_END, cmsStageAllocMatrix(ContextID, 3, 3, m_as_dbl, off_as_dbl)) ||

                    !cmsPipelineInsertStage(ContextID, Result, cmsAT_END, _cmsStageAllocXYZ2Lab(ContextID)))

                    return FALSE;

            }

            break;

        default:

            return FALSE;  // Mismatch

        }

        break;

        // On colorspaces other than PCS, check for same space

    default:

        if (InPCS != OutPCS) return FALSE;

        break;

    }

    return TRUE;

}

// Is a given space compatible with another?

static

cmsBool ColorSpaceIsCompatible(cmsColorSpaceSignature a, cmsColorSpaceSignature b)

{

    // If they are same, they are compatible.

    if (a == b) return TRUE;

    // Check for MCH4 substitution of CMYK

    if ((a == cmsSig4colorData) && (b == cmsSigCmykData)) return TRUE;

    if ((a == cmsSigCmykData) && (b == cmsSig4colorData)) return TRUE;

    // Check for XYZ/Lab. Those spaces are interchangeable as they can be computed one from other.

    if ((a == cmsSigXYZData) && (b == cmsSigLabData)) return TRUE;

    if ((a == cmsSigLabData) && (b == cmsSigXYZData)) return TRUE;

    return FALSE;

}

// 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 = cmsSigLabData, 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(ContextID, hProfiles[0]);

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

        cmsBool  lIsDeviceLink, lIsInput;

        hProfile      = hProfiles[i];

        ClassSig      = cmsGetDeviceClass(ContextID, 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(ContextID, hProfile);

            ColorSpaceOut   = cmsGetPCS(ContextID, hProfile);

        }

        else {

            ColorSpaceIn    = cmsGetPCS(ContextID, hProfile);

            ColorSpaceOut   = cmsGetColorSpace(ContextID, 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(ContextID, hProfile, Intent);

            if (Lut == NULL) goto Error;

            // What about abstract profiles?

             if (ClassSig == cmsSigAbstractClass && i > 0) {

                if (!ComputeConversion(ContextID, i, hProfiles, Intent, BPC[i], AdaptationStates[i], &m, &off)) goto Error;

             }

             else {

                _cmsMAT3identity(ContextID, &m);

                _cmsVEC3init(ContextID, &off, 0, 0, 0);

             }

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

        }

        else {

            if (lIsInput) {

                // Input direction means non-pcs connection, so proceed like devicelinks

                Lut = _cmsReadInputLUT(ContextID, hProfile, Intent);

                if (Lut == NULL) goto Error;

            }

            else {

                // Output direction means PCS connection. Intent may apply here

                Lut = _cmsReadOutputLUT(ContextID, hProfile, Intent);

                if (Lut == NULL) goto Error;

                if (!ComputeConversion(ContextID, i, hProfiles, Intent, BPC[i], AdaptationStates[i], &m, &off)) goto Error;

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

            }

        }

        // Concatenate to the output LUT

        if (!cmsPipelineCat(ContextID, Result, Lut))

            goto Error;

        cmsPipelineFree(ContextID, Lut);

        Lut = NULL;

        // Update current space

        CurrentColorSpace = ColorSpaceOut;

    }

    // Check for non-negatives clip

    if (dwFlags & cmsFLAGS_NONEGATIVES) {

        if (ColorSpaceOut == cmsSigGrayData ||

            ColorSpaceOut == cmsSigRgbData ||

            ColorSpaceOut == cmsSigCmykData) {

            cmsStage* clip = _cmsStageClipNegatives(ContextID, cmsChannelsOfColorSpace(ContextID, ColorSpaceOut));

            if (clip == NULL) goto Error;

            if (!cmsPipelineInsertStage(ContextID, Result, cmsAT_END, clip))

                goto Error;

        }

    }

    if (cmsChannelsOfColorSpace(ContextID, ColorSpaceOut) != (cmsInt32Number) cmsPipelineOutputChannels(ContextID, Result))

        goto Error;

    return Result;

Error:

    if (Lut != NULL) cmsPipelineFree(ContextID, Lut);

    if (Result != NULL) cmsPipelineFree(ContextID, Result);

    return NULL;

    cmsUNUSED_PARAMETER(dwFlags);

}

// Wrapper for DLL calling convention

cmsPipeline*  CMSEXPORT _cmsDefaultICCintents(cmsContext     ContextID,

                                              cmsUInt32Number nProfiles,

                                              cmsUInt32Number TheIntents[],

                                              cmsHPROFILE     hProfiles[],

                                              cmsBool         BPC[],

                                              cmsFloat64Number AdaptationStates[],

                                              cmsUInt32Number dwFlags)

{

    return DefaultICCintents(ContextID, nProfiles, TheIntents, hProfiles, BPC, AdaptationStates, dwFlags);

}

// Black preserving intents ---------------------------------------------------------------------------------------------

// Translate black-preserving intents to ICC ones

static

cmsUInt32Number TranslateNonICCIntents(cmsUInt32Number Intent)

{

    switch (Intent) {

        case INTENT_PRESERVE_K_ONLY_PERCEPTUAL:

        case INTENT_PRESERVE_K_PLANE_PERCEPTUAL:

            return INTENT_PERCEPTUAL;

        case INTENT_PRESERVE_K_ONLY_RELATIVE_COLORIMETRIC:

        case INTENT_PRESERVE_K_PLANE_RELATIVE_COLORIMETRIC:

            return INTENT_RELATIVE_COLORIMETRIC;

        case INTENT_PRESERVE_K_ONLY_SATURATION:

        case INTENT_PRESERVE_K_PLANE_SATURATION:

            return INTENT_SATURATION;

        default: return Intent;

    }

}

// Sampler for Black-only preserving CMYK->CMYK transforms

typedef struct {

    cmsPipeline*    cmyk2cmyk;      // The original transform

    cmsToneCurve*   KTone;          // Black-to-black tone curve

} GrayOnlyParams;

// Preserve black only if that is the only ink used

static

int BlackPreservingGrayOnlySampler(cmsContext ContextID, CMSREGISTER const cmsUInt16Number In[], CMSREGISTER cmsUInt16Number Out[], CMSREGISTER void* Cargo)

{

    GrayOnlyParams* bp = (GrayOnlyParams*) Cargo;

    // If going across black only, keep black only

    if (In[0] == 0 && In[1] == 0 && In[2] == 0) {

        // TAC does not apply because it is black ink!

        Out[0] = Out[1] = Out[2] = 0;

        Out[3] = cmsEvalToneCurve16(ContextID, bp->KTone, In[3]);

        return TRUE;

    }

    // Keep normal transform for other colors

    bp ->cmyk2cmyk ->Eval16Fn(ContextID, In, Out, bp ->cmyk2cmyk->Data);

    return TRUE;

}

// Check whatever the profile is a CMYK->CMYK devicelink

static

cmsBool is_cmyk_devicelink(cmsContext ContextID, cmsHPROFILE hProfile)

{

    return cmsGetDeviceClass(ContextID, hProfile) == cmsSigLinkClass &&

            cmsGetColorSpace(ContextID, hProfile) == cmsSigCmykData;

}

// 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;

    cmsUInt32Number lastProfilePos;

    cmsUInt32Number preservationProfilesCount;

    cmsHPROFILE hLastProfile;

    // 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]);

    // Trim all CMYK devicelinks at the end

    lastProfilePos = nProfiles - 1;

    hLastProfile = hProfiles[lastProfilePos];

    // Skip CMYK->CMYK devicelinks on ending

    while (is_cmyk_devicelink(ContextID, hLastProfile))

    {

        if (lastProfilePos < 2)

            break;

        hLastProfile = hProfiles[--lastProfilePos];

    }

    preservationProfilesCount = lastProfilePos + 1;

    // Check for non-cmyk profiles

    if (cmsGetColorSpace(ContextID, hProfiles[0]) != cmsSigCmykData ||

        !(cmsGetColorSpace(ContextID, hLastProfile) == cmsSigCmykData ||

        cmsGetDeviceClass(ContextID, hLastProfile) == 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));

    // Create a LUT holding normal ICC transform

    bp.cmyk2cmyk = DefaultICCintents(ContextID,

        preservationProfilesCount,

        ICCIntents,

        hProfiles,

        BPC,

        AdaptationStates,

        dwFlags);

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

    // Now, compute the tone curve

    bp.KTone = _cmsBuildKToneCurve(ContextID,

        4096,

        preservationProfilesCount,

        ICCIntents,

        hProfiles,

        BPC,

        AdaptationStates,

        dwFlags);

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

    // How many gridpoints are we going to use?

    nGridPoints = _cmsReasonableGridpointsByColorspace(ContextID, 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(ContextID, Result, cmsAT_BEGIN, CLUT))

        goto Error;

    // Sample it. We cannot afford pre/post linearization this time.

    if (!cmsStageSampleCLut16bit(ContextID, CLUT, BlackPreservingGrayOnlySampler, (void*) &bp, 0))

        goto Error;

    // Insert possible devicelinks at the end

    for (i = lastProfilePos + 1; i < nProfiles; i++)

    {

        cmsPipeline* devlink = _cmsReadDevicelinkLUT(ContextID, hProfiles[i], ICCIntents[i]);

        if (devlink == NULL)

            goto Error;

        if (!cmsPipelineCat(ContextID, Result, devlink))

            goto Error;

    }

    // Get rid of xform and tone curve

    cmsPipelineFree(ContextID, bp.cmyk2cmyk);

    cmsFreeToneCurve(ContextID, bp.KTone);

    return Result;

Error:

    if (bp.cmyk2cmyk != NULL) cmsPipelineFree(ContextID, bp.cmyk2cmyk);

    if (bp.KTone != NULL)  cmsFreeToneCurve(ContextID, bp.KTone);

    if (Result != NULL) cmsPipelineFree(ContextID, Result);

    return NULL;

}

// K Plane-preserving CMYK to CMYK ------------------------------------------------------------------------------------

typedef struct {

    cmsPipeline*     cmyk2cmyk;     // The original transform

    cmsHTRANSFORM    hProofOutput;  // Output CMYK to Lab (last profile)

    cmsHTRANSFORM    cmyk2Lab;      // The input chain

    cmsToneCurve*    KTone;         // Black-to-black tone curve

    cmsPipeline*     LabK2cmyk;     // The output profile

    cmsFloat64Number MaxError;

    cmsHTRANSFORM    hRoundTrip;

    cmsFloat64Number MaxTAC;

} PreserveKPlaneParams;

// The CLUT will be stored at 16 bits, but calculations are performed at cmsFloat32Number precision

static

int BlackPreservingSampler(cmsContext ContextID, CMSREGISTER const cmsUInt16Number In[], CMSREGISTER cmsUInt16Number Out[], CMSREGISTER void* Cargo)

{

    int i;

    cmsFloat32Number Inf[4], Outf[4];

    cmsFloat32Number LabK[4];

    cmsFloat64Number SumCMY, SumCMYK, Error, Ratio;

    cmsCIELab ColorimetricLab, BlackPreservingLab;

    PreserveKPlaneParams* bp = (PreserveKPlaneParams*) Cargo;

    // Convert from 16 bits to floating point

    for (i=0; i < 4; i++)

        Inf[i] = (cmsFloat32Number) (In[i] / 65535.0);

    // Get the K across Tone curve

    LabK[3] = cmsEvalToneCurveFloat(ContextID, bp ->KTone, Inf[3]);

    // If going across black only, keep black only

    if (In[0] == 0 && In[1] == 0 && In[2] == 0) {

        Out[0] = Out[1] = Out[2] = 0;

        Out[3] = _cmsQuickSaturateWord(LabK[3] * 65535.0);

        return TRUE;

    }

    // Try the original transform,

    cmsPipelineEvalFloat(ContextID, Inf, Outf, bp ->cmyk2cmyk);

    // Store a copy of the floating point result into 16-bit

    for (i=0; i < 4; i++)

            Out[i] = _cmsQuickSaturateWord(Outf[i] * 65535.0);

    // Maybe K is already ok (mostly on K=0)

    if (fabsf(Outf[3] - LabK[3]) < (3.0 / 65535.0)) {

        return TRUE;

    }

    // K differ, measure and keep Lab measurement for further usage

    // this is done in relative colorimetric intent

    cmsDoTransform(ContextID, bp->hProofOutput, Out, &ColorimetricLab, 1);

    // Is not black only and the transform doesn't keep black.

    // Obtain the Lab of output CMYK. After that we have Lab + K

    cmsDoTransform(ContextID, bp ->cmyk2Lab, Outf, LabK, 1);

    // Obtain the corresponding CMY using reverse interpolation

    // (K is fixed in LabK[3])

    if (!cmsPipelineEvalReverseFloat(ContextID, LabK, Outf, Outf, bp ->LabK2cmyk)) {

        // Cannot find a suitable value, so use colorimetric xform

        // which is already stored in Out[]

        return TRUE;

    }

    // Make sure to pass through K (which now is fixed)

    Outf[3] = LabK[3];

    // Apply TAC if needed

    SumCMY   = (cmsFloat64Number) Outf[0]  + Outf[1] + Outf[2];

    SumCMYK  = SumCMY + Outf[3];

    if (SumCMYK > bp ->MaxTAC) {

        Ratio = 1 - ((SumCMYK - bp->MaxTAC) / SumCMY);

        if (Ratio < 0)

            Ratio = 0;

    }

    else

       Ratio = 1.0;

    Out[0] = _cmsQuickSaturateWord(Outf[0] * Ratio * 65535.0);     // C

    Out[1] = _cmsQuickSaturateWord(Outf[1] * Ratio * 65535.0);     // M

    Out[2] = _cmsQuickSaturateWord(Outf[2] * Ratio * 65535.0);     // Y

    Out[3] = _cmsQuickSaturateWord(Outf[3] * 65535.0);

    // Estimate the error (this goes 16 bits to Lab DBL)

    cmsDoTransform(ContextID, bp->hProofOutput, Out, &BlackPreservingLab, 1);

    Error = cmsDeltaE(ContextID, &ColorimetricLab, &BlackPreservingLab);

    if (Error > bp -> MaxError)

        bp->MaxError = Error;

    return TRUE;

}

// 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;

    cmsUInt32Number lastProfilePos;

    cmsUInt32Number preservationProfilesCount;

    cmsHPROFILE hLastProfile;

    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]);