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Add opt-in iccMAX support for Hybrid Printer Profiles with Reflectance #593

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109 changes: 109 additions & 0 deletions include/lcms2.h
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Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,19 @@
// Uncomment to get rid of the tables for "half" float support
// #define CMS_NO_HALF_SUPPORT 1

// Uncomment to enable reading iccMAX (ICC.2) spectral data embedded in ICC.1
// profiles. Off by default: it widens the set of profiles, tags and processing
// elements the parser accepts.
// #define CMS_USE_ICCMAX_SPECTRAL 1

// iccMAX support cannot be built without half float support: ICC.2 encodes the
// header's spectralRange as float16Number (ICC.2:2023 4.2.8), so with the tables
// gone a spectral PCS cannot be read or written at all, float16ArrayType is
// unavailable, and the spectral white point tag cannot be parsed.
#if defined(CMS_USE_ICCMAX_SPECTRAL) && defined(CMS_NO_HALF_SUPPORT)
# error "CMS_USE_ICCMAX_SPECTRAL requires half float support: ICC.2 encodes spectralRange as float16Number, so CMS_NO_HALF_SUPPORT and CMS_USE_ICCMAX_SPECTRAL are mutually exclusive. Undefine one of them."
#endif

// Uncomment to get rid of pthreads/windows dependency
// #define CMS_NO_PTHREADS 1

Expand Down Expand Up @@ -345,6 +358,13 @@ typedef enum {
cmsSigViewingConditionsType = 0x76696577, // 'view'
cmsSigXYZType = 0x58595A20, // 'XYZ '
cmsSigMHC2Type = 0x4D484332 // 'MHC2'
#ifdef CMS_USE_ICCMAX_SPECTRAL
,
cmsSigEmbeddedProfileType = 0x49434370, // 'ICCp', holds an embedded ICC.2 profile
cmsSigFloat16ArrayType = 0x666C3136, // 'fl16', ICC.2 10.2.9 float16ArrayType
cmsSigFloat32ArrayType = 0x666C3332, // 'fl32', ICC.2 10.2.10 float32ArrayType
cmsSigSpectralViewingConditionsType = 0x7376636E // 'svcn', ICC.2 10.2.22
#endif


} cmsTagTypeSignature;
Expand Down Expand Up @@ -424,6 +444,12 @@ typedef enum {
cmsSigcicpTag = 0x63696370, // 'cicp'
cmsSigArgyllArtsTag = 0x61727473, // 'arts'
cmsSigMHC2Tag = 0x4D484332 // 'MHC2'
#ifdef CMS_USE_ICCMAX_SPECTRAL
,
cmsSigEmbeddedV5ProfileTag = 0x49434335, // 'ICC5', an embedded ICC.2 profile
cmsSigSpectralWhitePointTag = 0x73777074, // 'swpt', ICC.2 9.2.112
cmsSigSpectralViewingConditionsTag = 0x7376636E // 'svcn', ICC.2 9.2.111
#endif

} cmsTagSignature;

Expand Down Expand Up @@ -552,6 +578,9 @@ typedef enum {
cmsSigCurveSetElemType = 0x63767374, //'cvst'
cmsSigMatrixElemType = 0x6D617466, //'matf'
cmsSigCLutElemType = 0x636C7574, //'clut'
#ifdef CMS_USE_ICCMAX_SPECTRAL
cmsSigExtCLutElemType = 0x78636C74, //'xclt' (ICC.2 extendedCLUTElement)
#endif

cmsSigBAcsElemType = 0x62414353, // 'bACS'
cmsSigEAcsElemType = 0x65414353, // 'eACS'
Expand Down Expand Up @@ -581,6 +610,10 @@ typedef enum {
cmsSigFormulaCurveSeg = 0x70617266, // 'parf'
cmsSigSampledCurveSeg = 0x73616D66, // 'samf'
cmsSigSegmentedCurve = 0x63757266 // 'curf'
#ifdef CMS_USE_ICCMAX_SPECTRAL
,
cmsSigSingleSampledCurve = 0x736E6766 // 'sngf' (ICC.2 singleSampledCurve)
#endif

} cmsCurveSegSignature;

Expand Down Expand Up @@ -1564,6 +1597,82 @@ CMSAPI void CMSEXPORT cmsSetHeaderRenderingIntent(cmsHPROFILE hProf
CMSAPI cmsColorSpaceSignature
CMSEXPORT cmsGetPCS(cmsHPROFILE hProfile);
CMSAPI void CMSEXPORT cmsSetPCS(cmsHPROFILE hProfile, cmsColorSpaceSignature pcs);

#ifdef CMS_USE_ICCMAX_SPECTRAL
// An array of spectral values, as carried by the ICC.2 float16ArrayType and
// float32ArrayType tag types. The count lives here rather than in a tag
// descriptor, because ICC.2 derives it from the tag size.
typedef struct {
cmsContext ContextID;
cmsUInt32Number nValues;
cmsFloat32Number* Values;

// Both fl16 and fl32 are read; the tag is always written back as fl32,
// because fl32 is lossless from fl16 and Little-CMS does not preserve
// tag encodings.

} cmsFloatArray;

CMSAPI cmsFloatArray* CMSEXPORT cmsAllocFloatArray(cmsContext ContextID, cmsUInt32Number nValues);
CMSAPI void CMSEXPORT cmsFreeFloatArray(cmsFloatArray* v);

// Observer and illuminant for a spectrally-based PCS (ICC.2:2023 Table 69). The
// observer step count N and the illuminant step count M are independent of each
// other and of the spectral PCS channel count -- nothing here may assume they agree.
typedef struct {
cmsContext ContextID;

cmsUInt32Number ObserverType; // Table 70: 0 custom, 1 CIE 1931, 2 CIE 1964
cmsFloat32Number ObserverStart; // nm
cmsFloat32Number ObserverEnd; // nm
cmsUInt16Number ObserverSteps; // N
cmsFloat32Number* Observer; // 3N values: all X, then all Y, then all Z

cmsUInt32Number IlluminantType; // Table 71: 1 D50, 2 D65, 9 black body by CCT, ...
cmsFloat32Number CCT; // only meaningful for types 9 and 0Ah
cmsFloat32Number IlluminantStart; // nm
cmsFloat32Number IlluminantEnd; // nm
cmsUInt16Number IlluminantSteps; // M
cmsFloat32Number* Illuminant; // M values

cmsCIEXYZ IlluminantXYZ; // un-normalised, Y in cd/m2
cmsCIEXYZ SurroundXYZ; // un-normalised

} cmsSpectralViewingConditions;

CMSAPI cmsSpectralViewingConditions*
CMSEXPORT cmsAllocSpectralViewingConditions(cmsContext ContextID,
cmsUInt16Number ObserverSteps,
cmsUInt16Number IlluminantSteps);
CMSAPI void CMSEXPORT cmsFreeSpectralViewingConditions(cmsSpectralViewingConditions* v);

// Read or write spectralWhitePointTag in any of the three encodings ICC.2 9.2.112
// permits, including uInt16ArrayType, which has no registered type handler because
// its 1/65535 scaling belongs to this tag rather than to the generic ui16 signature.
// These dispatch on the tag's own type signature. On success the caller owns *Out
// and releases it with cmsFreeFloatArray.
CMSAPI cmsBool CMSEXPORT cmsReadSpectralWhitePoint(cmsHPROFILE hProfile,
cmsFloatArray** Out);
CMSAPI cmsBool CMSEXPORT cmsWriteSpectralWhitePoint(cmsHPROFILE hProfile,
const cmsFloatArray* In,
cmsTagTypeSignature AsType);
#endif

#ifdef CMS_USE_ICCMAX_SPECTRAL
// Spectral PCS, from the ICC.2 (iccMAX) header. Zero when the profile does not
// declare one, which is the case for every ICC.1 profile.
CMSAPI cmsUInt32Number CMSEXPORT cmsGetSpectralPCS(cmsHPROFILE hProfile);
CMSAPI cmsBool CMSEXPORT cmsSetSpectralPCS(cmsHPROFILE hProfile, cmsUInt32Number SpectralPCS);
CMSAPI cmsUInt16Number CMSEXPORT cmsGetSpectralPCSChannels(cmsHPROFILE hProfile);
CMSAPI cmsBool CMSEXPORT cmsGetSpectralPCSRange(cmsHPROFILE hProfile,
cmsFloat32Number* Start,
cmsFloat32Number* End,
cmsUInt16Number* Steps);
CMSAPI cmsBool CMSEXPORT cmsSetSpectralPCSRange(cmsHPROFILE hProfile,
cmsFloat32Number Start,
cmsFloat32Number End,
cmsUInt16Number Steps);
#endif
CMSAPI cmsColorSpaceSignature
CMSEXPORT cmsGetColorSpace(cmsHPROFILE hProfile);
CMSAPI void CMSEXPORT cmsSetColorSpace(cmsHPROFILE hProfile, cmsColorSpaceSignature sig);
Expand Down
127 changes: 125 additions & 2 deletions src/cmsgamma.c
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Original file line number Diff line number Diff line change
Expand Up @@ -54,14 +54,39 @@ typedef struct _cmsParametricCurvesCollection_st {

} _cmsParametricCurvesCollection;

#ifdef CMS_USE_ICCMAX_SPECTRAL

// Exponentiation guarded against a non-positive base, which pow() would turn into
// NaN for a fractional exponent. Mirrors clipPow in the iccMAX reference
// implementation, and is used for every power in the ICC.2 formula segment types,
// including each X^gamma: a segmented curve's outer segments extend to +/-infinity,
// so a negative X is reachable.
static
cmsFloat64Number clipPow(cmsFloat64Number v, cmsFloat64Number g)
{
if (v <= 0) return 0.0;

return pow(v, g);
}

#endif

// This is the default (built-in) evaluator
static cmsFloat64Number DefaultEvalParametricFn(cmsInt32Number Type, const cmsFloat64Number Params[], cmsFloat64Number R);

// The built-in list
// The built-in list. The iccMAX types 9..13 are appended rather than inserted in
// numeric order: IsInSet returns a positional index that callers use against
// ParameterCount[], so existing positions must not shift.
static _cmsParametricCurvesCollection DefaultCurves = {
#ifdef CMS_USE_ICCMAX_SPECTRAL
15, // # of curve types
{ 1, 2, 3, 4, 5, 6, 7, 8, 108, 109, 9, 10, 11, 12, 13 }, // Parametric curve ID
{ 1, 3, 4, 5, 7, 4, 5, 5, 1, 1, 5, 5, 6, 7, 6 }, // Parameters by type
#else
10, // # of curve types
{ 1, 2, 3, 4, 5, 6, 7, 8, 108, 109 }, // Parametric curve ID
{ 1, 3, 4, 5, 7, 4, 5, 5, 1, 1 }, // Parameters by type
#endif
DefaultEvalParametricFn, // Evaluator
NULL // Next in chain
};
Expand Down Expand Up @@ -228,6 +253,30 @@ cmsToneCurve* AllocateToneCurveStruct(cmsContext ContextID, cmsUInt32Number nEnt
return NULL;
}

#ifdef CMS_USE_ICCMAX_SPECTRAL
// IsInSet matches on abs(Type), so a negative type is accepted whenever the
// positive one is registered, on the understanding that the evaluator implements
// the analytic inverse. For the ICC.2 formula segment types 9..13 it deliberately
// does not, so a curve built with -9..-13 would evaluate to 0 everywhere. Reject
// it here -- the common path for both cmsBuildParametricToneCurve and
// cmsBuildSegmentedToneCurve -- rather than hand back a silently useless curve.
if (Segments != NULL) {

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

if (Segments[i].Type <= -9 && Segments[i].Type >= -13) {

cmsSignalError(ContextID, cmsERROR_RANGE,
"Parametric curve type %d has no analytic inverse in Little-CMS: the ICC.2 "
"formula segment types 9 to 13 are forward-only. Build the forward curve with "
"type %d and reverse it numerically with cmsReverseToneCurveEx.",
Segments[i].Type, -Segments[i].Type);
return NULL;
}
}
}
#endif // CMS_USE_ICCMAX_SPECTRAL

// Allocate all required pointers, etc.
p = (cmsToneCurve*) _cmsMallocZero(ContextID, sizeof(cmsToneCurve));
if (!p) return NULL;
Expand Down Expand Up @@ -685,6 +734,70 @@ cmsFloat64Number DefaultEvalParametricFn(cmsInt32Number Type, const cmsFloat64Nu
break;


#ifdef CMS_USE_ICCMAX_SPECTRAL

// ICC.2 formulaCurveSegment function types 0003h..0007h, which ICC.1 does not
// define. Parameter order follows ICC.2:2023 Table 111; note that omega precedes
// gamma in types 12 and 13. Degenerate cases return a finite value rather than
// NaN or an infinity, matching how types 6 and 7 above behave: a NaN reaching a
// CLUT index is far worse than a clamped number. The analytic inverses (-9..-13)
// are deliberately not implemented -- curve reversal in lcms is numerical, so no
// profile path needs them, and a caller asking for a negative type here falls
// through to the default arm and receives 0.

// Y = a * (b * X + c)^g + d : g a b c d
case 9:
Val = Params[1] * clipPow(Params[2] * R + Params[3], Params[0]) + Params[4];
break;

// Y = a * ln(d * X^g - b) + c : g a b c d
case 10:
e = Params[4] * clipPow(R, Params[0]) - Params[2];
if (e <= 0)
Val = Params[3];
else
Val = Params[1] * log(e) + Params[3];
break;

// Y = e * exp((d * X^g - c) / a) + b : g a b c d e
case 11:
if (fabs(Params[1]) < MATRIX_DET_TOLERANCE)
Val = Params[2];
else
Val = Params[5] * exp((Params[4] * clipPow(R, Params[0]) - Params[3]) / Params[1]) + Params[2];
break;

// Y = d * (max(e * X^g - a, 0) / (b - c * X^g))^w : w g a b c d e
case 12:
{
cmsFloat64Number u = clipPow(R, Params[1]);
cmsFloat64Number den = Params[3] - Params[4] * u;
cmsFloat64Number num = Params[6] * u - Params[2];

if (num < 0) num = 0;

if (fabs(den) < MATRIX_DET_TOLERANCE)
Val = 0;
else
Val = Params[5] * clipPow(num / den, Params[0]);
}
break;

// Y = d * ((a + b * X^g) / (1 + c * X^g))^w : w g a b c d
case 13:
{
cmsFloat64Number u = clipPow(R, Params[1]);
cmsFloat64Number den = 1.0 + Params[4] * u;

if (fabs(den) < MATRIX_DET_TOLERANCE)
Val = 0;
else
Val = Params[5] * clipPow((Params[2] + Params[3] * u) / den, Params[0]);
}
break;

#endif

// S-Shaped: (1 - (1-x)^1/g)^1/g
case 108:
if (fabs(Params[0]) < MATRIX_DET_TOLERANCE)
Expand Down Expand Up @@ -967,9 +1080,19 @@ void CMSEXPORT cmsFreeToneCurveTriple(cmsToneCurve* Curve[3])
// Duplicate a gamma table
cmsToneCurve* CMSEXPORT cmsDupToneCurve(const cmsToneCurve* In)
{
cmsToneCurve* Out;

if (In == NULL) return NULL;

return AllocateToneCurveStruct(In ->InterpParams ->ContextID, In ->nEntries, In ->nSegments, In ->Segments, In ->Table16);
Out = AllocateToneCurveStruct(In ->InterpParams ->ContextID, In ->nEntries, In ->nSegments, In ->Segments, In ->Table16);

#ifdef CMS_USE_ICCMAX_SPECTRAL
// Carry the encoding across, so a duplicated curve is still written back in the
// form it arrived in. AllocateToneCurveStruct does not know about it.
if (Out != NULL) Out ->CurveType = In ->CurveType;
#endif

return Out;
}

// Joins two curves for X and Y. Curves should be monotonic.
Expand Down
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