1 //---------------------------------------------------------------------------------
3 // Little Color Management System
4 // Copyright (c) 1998-2013 Marti Maria Saguer
6 // Permission is hereby granted, free of charge, to any person obtaining
7 // a copy of this software and associated documentation files (the "Software"),
8 // to deal in the Software without restriction, including without limitation
9 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 // and/or sell copies of the Software, and to permit persons to whom the Software
11 // is furnished to do so, subject to the following conditions:
13 // The above copyright notice and this permission notice shall be included in
14 // all copies or substantial portions of the Software.
16 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
18 // THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
22 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 //---------------------------------------------------------------------------------
27 #include "lcms2_internal.h"
29 // Tone curves are powerful constructs that can contain curves specified in diverse ways.
30 // The curve is stored in segments, where each segment can be sampled or specified by parameters.
31 // a 16.bit simplification of the *whole* curve is kept for optimization purposes. For float operation,
32 // each segment is evaluated separately. Plug-ins may be used to define new parametric schemes,
33 // each plug-in may define up to MAX_TYPES_IN_LCMS_PLUGIN functions types. For defining a function,
34 // the plug-in should provide the type id, how many parameters each type has, and a pointer to
35 // a procedure that evaluates the function. In the case of reverse evaluation, the evaluator will
36 // be called with the type id as a negative value, and a sampled version of the reversed curve
39 // ----------------------------------------------------------------- Implementation
40 // Maxim number of nodes
41 #define MAX_NODES_IN_CURVE 4097
42 #define MINUS_INF (-1E22F)
43 #define PLUS_INF (+1E22F)
45 // The list of supported parametric curves
46 typedef struct _cmsParametricCurvesCollection_st {
48 int nFunctions; // Number of supported functions in this chunk
49 int FunctionTypes[MAX_TYPES_IN_LCMS_PLUGIN]; // The identification types
50 int ParameterCount[MAX_TYPES_IN_LCMS_PLUGIN]; // Number of parameters for each function
51 cmsParametricCurveEvaluator Evaluator; // The evaluator
53 struct _cmsParametricCurvesCollection_st* Next; // Next in list
55 } _cmsParametricCurvesCollection;
57 // This is the default (built-in) evaluator
58 static cmsFloat64Number DefaultEvalParametricFn(cmsInt32Number Type, const cmsFloat64Number Params[], cmsFloat64Number R);
61 static _cmsParametricCurvesCollection DefaultCurves = {
62 9, // # of curve types
63 { 1, 2, 3, 4, 5, 6, 7, 8, 108 }, // Parametric curve ID
64 { 1, 3, 4, 5, 7, 4, 5, 5, 1 }, // Parameters by type
65 DefaultEvalParametricFn, // Evaluator
69 // Duplicates the zone of memory used by the plug-in in the new context
71 void DupPluginCurvesList(struct _cmsContext_struct* ctx,
72 const struct _cmsContext_struct* src)
74 _cmsCurvesPluginChunkType newHead = { NULL };
75 _cmsParametricCurvesCollection* entry;
76 _cmsParametricCurvesCollection* Anterior = NULL;
77 _cmsCurvesPluginChunkType* head = (_cmsCurvesPluginChunkType*) src->chunks[CurvesPlugin];
79 _cmsAssert(head != NULL);
81 // Walk the list copying all nodes
82 for (entry = head->ParametricCurves;
84 entry = entry ->Next) {
86 _cmsParametricCurvesCollection *newEntry = ( _cmsParametricCurvesCollection *) _cmsSubAllocDup(ctx ->MemPool, entry, sizeof(_cmsParametricCurvesCollection));
91 // We want to keep the linked list order, so this is a little bit tricky
92 newEntry -> Next = NULL;
94 Anterior -> Next = newEntry;
98 if (newHead.ParametricCurves == NULL)
99 newHead.ParametricCurves = newEntry;
102 ctx ->chunks[CurvesPlugin] = _cmsSubAllocDup(ctx->MemPool, &newHead, sizeof(_cmsCurvesPluginChunkType));
105 // The allocator have to follow the chain
106 void _cmsAllocCurvesPluginChunk(struct _cmsContext_struct* ctx,
107 const struct _cmsContext_struct* src)
109 _cmsAssert(ctx != NULL);
113 // Copy all linked list
114 DupPluginCurvesList(ctx, src);
117 static _cmsCurvesPluginChunkType CurvesPluginChunk = { NULL };
118 ctx ->chunks[CurvesPlugin] = _cmsSubAllocDup(ctx ->MemPool, &CurvesPluginChunk, sizeof(_cmsCurvesPluginChunkType));
123 // The linked list head
124 _cmsCurvesPluginChunkType _cmsCurvesPluginChunk = { NULL };
126 // As a way to install new parametric curves
127 cmsBool _cmsRegisterParametricCurvesPlugin(cmsContext ContextID, cmsPluginBase* Data)
129 _cmsCurvesPluginChunkType* ctx = ( _cmsCurvesPluginChunkType*) _cmsContextGetClientChunk(ContextID, CurvesPlugin);
130 cmsPluginParametricCurves* Plugin = (cmsPluginParametricCurves*) Data;
131 _cmsParametricCurvesCollection* fl;
135 ctx -> ParametricCurves = NULL;
139 fl = (_cmsParametricCurvesCollection*) _cmsPluginMalloc(ContextID, sizeof(_cmsParametricCurvesCollection));
140 if (fl == NULL) return FALSE;
142 // Copy the parameters
143 fl ->Evaluator = Plugin ->Evaluator;
144 fl ->nFunctions = Plugin ->nFunctions;
146 // Make sure no mem overwrites
147 if (fl ->nFunctions > MAX_TYPES_IN_LCMS_PLUGIN)
148 fl ->nFunctions = MAX_TYPES_IN_LCMS_PLUGIN;
151 memmove(fl->FunctionTypes, Plugin ->FunctionTypes, fl->nFunctions * sizeof(cmsUInt32Number));
152 memmove(fl->ParameterCount, Plugin ->ParameterCount, fl->nFunctions * sizeof(cmsUInt32Number));
155 fl ->Next = ctx->ParametricCurves;
156 ctx->ParametricCurves = fl;
163 // Search in type list, return position or -1 if not found
165 int IsInSet(int Type, _cmsParametricCurvesCollection* c)
169 for (i=0; i < c ->nFunctions; i++)
170 if (abs(Type) == c ->FunctionTypes[i]) return i;
176 // Search for the collection which contains a specific type
178 _cmsParametricCurvesCollection *GetParametricCurveByType(cmsContext ContextID, int Type, int* index)
180 _cmsParametricCurvesCollection* c;
182 _cmsCurvesPluginChunkType* ctx = ( _cmsCurvesPluginChunkType*) _cmsContextGetClientChunk(ContextID, CurvesPlugin);
184 for (c = ctx->ParametricCurves; c != NULL; c = c ->Next) {
186 Position = IsInSet(Type, c);
188 if (Position != -1) {
194 // If none found, revert for defaults
195 for (c = &DefaultCurves; c != NULL; c = c ->Next) {
197 Position = IsInSet(Type, c);
199 if (Position != -1) {
209 // Low level allocate, which takes care of memory details. nEntries may be zero, and in this case
210 // no optimation curve is computed. nSegments may also be zero in the inverse case, where only the
211 // optimization curve is given. Both features simultaneously is an error
213 cmsToneCurve* AllocateToneCurveStruct(cmsContext ContextID, cmsInt32Number nEntries,
214 cmsInt32Number nSegments, const cmsCurveSegment* Segments,
215 const cmsUInt16Number* Values)
220 // We allow huge tables, which are then restricted for smoothing operations
221 if (nEntries > 65530 || nEntries < 0) {
222 cmsSignalError(ContextID, cmsERROR_RANGE, "Couldn't create tone curve of more than 65530 entries");
226 if (nEntries <= 0 && nSegments <= 0) {
227 cmsSignalError(ContextID, cmsERROR_RANGE, "Couldn't create tone curve with zero segments and no table");
231 // Allocate all required pointers, etc.
232 p = (cmsToneCurve*) _cmsMallocZero(ContextID, sizeof(cmsToneCurve));
235 // In this case, there are no segments
236 if (nSegments <= 0) {
241 p ->Segments = (cmsCurveSegment*) _cmsCalloc(ContextID, nSegments, sizeof(cmsCurveSegment));
242 if (p ->Segments == NULL) goto Error;
244 p ->Evals = (cmsParametricCurveEvaluator*) _cmsCalloc(ContextID, nSegments, sizeof(cmsParametricCurveEvaluator));
245 if (p ->Evals == NULL) goto Error;
248 p -> nSegments = nSegments;
250 // This 16-bit table contains a limited precision representation of the whole curve and is kept for
251 // increasing xput on certain operations.
256 p ->Table16 = (cmsUInt16Number*) _cmsCalloc(ContextID, nEntries, sizeof(cmsUInt16Number));
257 if (p ->Table16 == NULL) goto Error;
260 p -> nEntries = nEntries;
262 // Initialize members if requested
263 if (Values != NULL && (nEntries > 0)) {
265 for (i=0; i < nEntries; i++)
266 p ->Table16[i] = Values[i];
269 // Initialize the segments stuff. The evaluator for each segment is located and a pointer to it
270 // is placed in advance to maximize performance.
271 if (Segments != NULL && (nSegments > 0)) {
273 _cmsParametricCurvesCollection *c;
275 p ->SegInterp = (cmsInterpParams**) _cmsCalloc(ContextID, nSegments, sizeof(cmsInterpParams*));
276 if (p ->SegInterp == NULL) goto Error;
278 for (i=0; i< nSegments; i++) {
280 // Type 0 is a special marker for table-based curves
281 if (Segments[i].Type == 0)
282 p ->SegInterp[i] = _cmsComputeInterpParams(ContextID, Segments[i].nGridPoints, 1, 1, NULL, CMS_LERP_FLAGS_FLOAT);
284 memmove(&p ->Segments[i], &Segments[i], sizeof(cmsCurveSegment));
286 if (Segments[i].Type == 0 && Segments[i].SampledPoints != NULL)
287 p ->Segments[i].SampledPoints = (cmsFloat32Number*) _cmsDupMem(ContextID, Segments[i].SampledPoints, sizeof(cmsFloat32Number) * Segments[i].nGridPoints);
289 p ->Segments[i].SampledPoints = NULL;
292 c = GetParametricCurveByType(ContextID, Segments[i].Type, NULL);
294 p ->Evals[i] = c ->Evaluator;
298 p ->InterpParams = _cmsComputeInterpParams(ContextID, p ->nEntries, 1, 1, p->Table16, CMS_LERP_FLAGS_16BITS);
299 if (p->InterpParams != NULL)
303 if (p -> Segments) _cmsFree(ContextID, p ->Segments);
304 if (p -> Evals) _cmsFree(ContextID, p -> Evals);
305 if (p ->Table16) _cmsFree(ContextID, p ->Table16);
306 _cmsFree(ContextID, p);
311 // Parametric Fn using floating point
313 cmsFloat64Number DefaultEvalParametricFn(cmsInt32Number Type, const cmsFloat64Number Params[], cmsFloat64Number R)
315 cmsFloat64Number e, Val, disc;
323 if (fabs(Params[0] - 1.0) < MATRIX_DET_TOLERANCE)
329 Val = pow(R, Params[0]);
332 // Type 1 Reversed: X = Y ^1/gamma
336 if (fabs(Params[0] - 1.0) < MATRIX_DET_TOLERANCE)
342 Val = pow(R, 1/Params[0]);
346 // Y = (aX + b)^Gamma | X >= -b/a
349 disc = -Params[2] / Params[1];
353 e = Params[1]*R + Params[2];
356 Val = pow(e, Params[0]);
365 // X = (Y ^1/g - b) / a
370 Val = (pow(R, 1.0/Params[0]) - Params[2]) / Params[1];
378 // Y = (aX + b)^Gamma | X <= -b/a
381 disc = -Params[2] / Params[1];
387 e = Params[1]*R + Params[2];
390 Val = pow(e, Params[0]) + Params[3];
400 // X=((Y-c)^1/g - b)/a | (Y>=c)
403 if (R >= Params[3]) {
408 Val = (pow(e, 1/Params[0]) - Params[2]) / Params[1];
413 Val = -Params[2] / Params[1];
418 // IEC 61966-2.1 (sRGB)
419 // Y = (aX + b)^Gamma | X >= d
422 if (R >= Params[4]) {
424 e = Params[1]*R + Params[2];
427 Val = pow(e, Params[0]);
436 // X=((Y^1/g-b)/a) | Y >= (ad+b)^g
437 // X=Y/c | Y< (ad+b)^g
439 e = Params[1] * Params[4] + Params[2];
443 disc = pow(e, Params[0]);
447 Val = (pow(R, 1.0/Params[0]) - Params[2]) / Params[1];
455 // Y = (aX + b)^Gamma + e | X >= d
456 // Y = cX + f | X < d
458 if (R >= Params[4]) {
460 e = Params[1]*R + Params[2];
463 Val = pow(e, Params[0]) + Params[5];
468 Val = R*Params[3] + Params[6];
473 // X=((Y-e)1/g-b)/a | Y >=(ad+b)^g+e), cd+f
477 disc = Params[3] * Params[4] + Params[6];
484 Val = (pow(e, 1.0/Params[0]) - Params[2]) / Params[1];
487 Val = (R - Params[6]) / Params[3];
492 // Types 6,7,8 comes from segmented curves as described in ICCSpecRevision_02_11_06_Float.pdf
493 // Type 6 is basically identical to type 5 without d
495 // Y = (a * X + b) ^ Gamma + c
497 e = Params[1]*R + Params[2];
502 Val = pow(e, Params[0]) + Params[3];
505 // ((Y - c) ^1/Gamma - b) / a
511 Val = (pow(e, 1.0/Params[0]) - Params[2]) / Params[1];
515 // Y = a * log (b * X^Gamma + c) + d
518 e = Params[2] * pow(R, Params[0]) + Params[3];
522 Val = Params[1]*log10(e) + Params[4];
525 // (Y - d) / a = log(b * X ^Gamma + c)
526 // pow(10, (Y-d) / a) = b * X ^Gamma + c
527 // pow((pow(10, (Y-d) / a) - c) / b, 1/g) = X
529 Val = pow((pow(10.0, (R-Params[4]) / Params[1]) - Params[3]) / Params[2], 1.0 / Params[0]);
533 //Y = a * b^(c*X+d) + e
535 Val = (Params[0] * pow(Params[1], Params[2] * R + Params[3]) + Params[4]);
539 // Y = (log((y-e) / a) / log(b) - d ) / c
540 // a=0, b=1, c=2, d=3, e=4,
543 disc = R - Params[4];
544 if (disc < 0) Val = 0;
546 Val = (log(disc / Params[0]) / log(Params[1]) - Params[3]) / Params[2];
549 // S-Shaped: (1 - (1-x)^1/g)^1/g
551 Val = pow(1.0 - pow(1 - R, 1/Params[0]), 1/Params[0]);
554 // y = (1 - (1-x)^1/g)^1/g
555 // y^g = (1 - (1-x)^1/g)
556 // 1 - y^g = (1-x)^1/g
557 // (1 - y^g)^g = 1 - x
560 Val = 1 - pow(1 - pow(R, Params[0]), Params[0]);
564 // Unsupported parametric curve. Should never reach here
571 // Evaluate a segmented funtion for a single value. Return -1 if no valid segment found .
572 // If fn type is 0, perform an interpolation on the table
574 cmsFloat64Number EvalSegmentedFn(const cmsToneCurve *g, cmsFloat64Number R)
578 for (i = g ->nSegments-1; i >= 0 ; --i) {
581 if ((R > g ->Segments[i].x0) && (R <= g ->Segments[i].x1)) {
583 // Type == 0 means segment is sampled
584 if (g ->Segments[i].Type == 0) {
586 cmsFloat32Number R1 = (cmsFloat32Number) (R - g ->Segments[i].x0) / (g ->Segments[i].x1 - g ->Segments[i].x0);
587 cmsFloat32Number Out;
589 // Setup the table (TODO: clean that)
590 g ->SegInterp[i]-> Table = g ->Segments[i].SampledPoints;
592 g ->SegInterp[i] -> Interpolation.LerpFloat(&R1, &Out, g ->SegInterp[i]);
597 return g ->Evals[i](g->Segments[i].Type, g ->Segments[i].Params, R);
604 // Access to estimated low-res table
605 cmsUInt32Number CMSEXPORT cmsGetToneCurveEstimatedTableEntries(const cmsToneCurve* t)
607 _cmsAssert(t != NULL);
611 const cmsUInt16Number* CMSEXPORT cmsGetToneCurveEstimatedTable(const cmsToneCurve* t)
613 _cmsAssert(t != NULL);
618 // Create an empty gamma curve, by using tables. This specifies only the limited-precision part, and leaves the
619 // floating point description empty.
620 cmsToneCurve* CMSEXPORT cmsBuildTabulatedToneCurve16(cmsContext ContextID, cmsInt32Number nEntries, const cmsUInt16Number Values[])
622 return AllocateToneCurveStruct(ContextID, nEntries, 0, NULL, Values);
626 int EntriesByGamma(cmsFloat64Number Gamma)
628 if (fabs(Gamma - 1.0) < 0.001) return 2;
633 // Create a segmented gamma, fill the table
634 cmsToneCurve* CMSEXPORT cmsBuildSegmentedToneCurve(cmsContext ContextID,
635 cmsInt32Number nSegments, const cmsCurveSegment Segments[])
638 cmsFloat64Number R, Val;
640 int nGridPoints = 4096;
642 _cmsAssert(Segments != NULL);
644 // Optimizatin for identity curves.
645 if (nSegments == 1 && Segments[0].Type == 1) {
647 nGridPoints = EntriesByGamma(Segments[0].Params[0]);
650 g = AllocateToneCurveStruct(ContextID, nGridPoints, nSegments, Segments, NULL);
651 if (g == NULL) return NULL;
653 // Once we have the floating point version, we can approximate a 16 bit table of 4096 entries
654 // for performance reasons. This table would normally not be used except on 8/16 bits transforms.
655 for (i=0; i < nGridPoints; i++) {
657 R = (cmsFloat64Number) i / (nGridPoints-1);
659 Val = EvalSegmentedFn(g, R);
661 // Round and saturate
662 g ->Table16[i] = _cmsQuickSaturateWord(Val * 65535.0);
668 // Use a segmented curve to store the floating point table
669 cmsToneCurve* CMSEXPORT cmsBuildTabulatedToneCurveFloat(cmsContext ContextID, cmsUInt32Number nEntries, const cmsFloat32Number values[])
671 cmsCurveSegment Seg[3];
673 // A segmented tone curve should have function segments in the first and last positions
674 // Initialize segmented curve part up to 0 to constant value = samples[0]
675 Seg[0].x0 = MINUS_INF;
679 Seg[0].Params[0] = 1;
680 Seg[0].Params[1] = 0;
681 Seg[0].Params[2] = 0;
682 Seg[0].Params[3] = values[0];
683 Seg[0].Params[4] = 0;
690 Seg[1].nGridPoints = nEntries;
691 Seg[1].SampledPoints = (cmsFloat32Number*) values;
693 // Final segment is constant = lastsample
695 Seg[2].x1 = PLUS_INF;
698 Seg[2].Params[0] = 1;
699 Seg[2].Params[1] = 0;
700 Seg[2].Params[2] = 0;
701 Seg[2].Params[3] = values[nEntries-1];
702 Seg[2].Params[4] = 0;
705 return cmsBuildSegmentedToneCurve(ContextID, 3, Seg);
710 // Parameters goes as: Curve, a, b, c, d, e, f
711 // Type is the ICC type +1
712 // if type is negative, then the curve is analyticaly inverted
713 cmsToneCurve* CMSEXPORT cmsBuildParametricToneCurve(cmsContext ContextID, cmsInt32Number Type, const cmsFloat64Number Params[])
715 cmsCurveSegment Seg0;
717 cmsUInt32Number size;
718 _cmsParametricCurvesCollection* c = GetParametricCurveByType(ContextID, Type, &Pos);
720 _cmsAssert(Params != NULL);
723 cmsSignalError(ContextID, cmsERROR_UNKNOWN_EXTENSION, "Invalid parametric curve type %d", Type);
727 memset(&Seg0, 0, sizeof(Seg0));
733 size = c->ParameterCount[Pos] * sizeof(cmsFloat64Number);
734 memmove(Seg0.Params, Params, size);
736 return cmsBuildSegmentedToneCurve(ContextID, 1, &Seg0);
741 // Build a gamma table based on gamma constant
742 cmsToneCurve* CMSEXPORT cmsBuildGamma(cmsContext ContextID, cmsFloat64Number Gamma)
744 return cmsBuildParametricToneCurve(ContextID, 1, &Gamma);
748 // Free all memory taken by the gamma curve
749 void CMSEXPORT cmsFreeToneCurve(cmsToneCurve* Curve)
751 cmsContext ContextID;
753 // added by Xiaochuan Liu
754 // Curve->InterpParams may be null
755 if (Curve == NULL || Curve->InterpParams == NULL) return;
757 ContextID = Curve ->InterpParams->ContextID;
759 _cmsFreeInterpParams(Curve ->InterpParams);
760 Curve ->InterpParams = NULL;
762 if (Curve -> Table16)
764 _cmsFree(ContextID, Curve ->Table16);
765 Curve ->Table16 = NULL;
768 if (Curve ->Segments) {
772 for (i=0; i < Curve ->nSegments; i++) {
774 if (Curve ->Segments[i].SampledPoints) {
775 _cmsFree(ContextID, Curve ->Segments[i].SampledPoints);
776 Curve ->Segments[i].SampledPoints = NULL;
779 if (Curve ->SegInterp[i] != 0)
781 _cmsFreeInterpParams(Curve->SegInterp[i]);
782 Curve->SegInterp[i] = NULL;
786 _cmsFree(ContextID, Curve ->Segments);
787 Curve ->Segments = NULL;
788 _cmsFree(ContextID, Curve ->SegInterp);
789 Curve ->SegInterp = NULL;
794 _cmsFree(ContextID, Curve -> Evals);
795 Curve -> Evals = NULL;
800 _cmsFree(ContextID, Curve);
805 // Utility function, free 3 gamma tables
806 void CMSEXPORT cmsFreeToneCurveTriple(cmsToneCurve* Curve[3])
809 _cmsAssert(Curve != NULL);
811 if (Curve[0] != NULL) cmsFreeToneCurve(Curve[0]);
812 if (Curve[1] != NULL) cmsFreeToneCurve(Curve[1]);
813 if (Curve[2] != NULL) cmsFreeToneCurve(Curve[2]);
815 Curve[0] = Curve[1] = Curve[2] = NULL;
819 // Duplicate a gamma table
820 cmsToneCurve* CMSEXPORT cmsDupToneCurve(const cmsToneCurve* In)
823 // fix openpdf bug(mantis id:0055683, google id:360198)
824 // the function CurveSetElemTypeFree in cmslut.c also needs to check pointer
825 if (In == NULL || In ->InterpParams == NULL || In ->Segments == NULL || In ->Table16 == NULL) return NULL;
827 return AllocateToneCurveStruct(In ->InterpParams ->ContextID, In ->nEntries, In ->nSegments, In ->Segments, In ->Table16);
830 // Joins two curves for X and Y. Curves should be monotonic.
835 cmsToneCurve* CMSEXPORT cmsJoinToneCurve(cmsContext ContextID,
836 const cmsToneCurve* X,
837 const cmsToneCurve* Y, cmsUInt32Number nResultingPoints)
839 cmsToneCurve* out = NULL;
840 cmsToneCurve* Yreversed = NULL;
841 cmsFloat32Number t, x;
842 cmsFloat32Number* Res = NULL;
846 _cmsAssert(X != NULL);
847 _cmsAssert(Y != NULL);
849 Yreversed = cmsReverseToneCurveEx(nResultingPoints, Y);
850 if (Yreversed == NULL) goto Error;
852 Res = (cmsFloat32Number*) _cmsCalloc(ContextID, nResultingPoints, sizeof(cmsFloat32Number));
853 if (Res == NULL) goto Error;
856 for (i=0; i < nResultingPoints; i++) {
858 t = (cmsFloat32Number) i / (nResultingPoints-1);
859 x = cmsEvalToneCurveFloat(X, t);
860 Res[i] = cmsEvalToneCurveFloat(Yreversed, x);
863 // Allocate space for output
864 out = cmsBuildTabulatedToneCurveFloat(ContextID, nResultingPoints, Res);
868 if (Res != NULL) _cmsFree(ContextID, Res);
869 if (Yreversed != NULL) cmsFreeToneCurve(Yreversed);
876 // Get the surrounding nodes. This is tricky on non-monotonic tables
878 int GetInterval(cmsFloat64Number In, const cmsUInt16Number LutTable[], const struct _cms_interp_struc* p)
883 // A 1 point table is not allowed
884 if (p -> Domain[0] < 1) return -1;
886 // Let's see if ascending or descending.
887 if (LutTable[0] < LutTable[p ->Domain[0]]) {
889 // Table is overall ascending
890 for (i=p->Domain[0]-1; i >=0; --i) {
895 if (y0 <= y1) { // Increasing
896 if (In >= y0 && In <= y1) return i;
899 if (y1 < y0) { // Decreasing
900 if (In >= y1 && In <= y0) return i;
905 // Table is overall descending
906 for (i=0; i < (int) p -> Domain[0]; i++) {
911 if (y0 <= y1) { // Increasing
912 if (In >= y0 && In <= y1) return i;
915 if (y1 < y0) { // Decreasing
916 if (In >= y1 && In <= y0) return i;
924 // Reverse a gamma table
925 cmsToneCurve* CMSEXPORT cmsReverseToneCurveEx(cmsInt32Number nResultSamples, const cmsToneCurve* InCurve)
928 cmsFloat64Number a = 0, b = 0, y, x1, y1, x2, y2;
932 _cmsAssert(InCurve != NULL);
934 // Try to reverse it analytically whatever possible
936 if (InCurve ->nSegments == 1 && InCurve ->Segments[0].Type > 0 &&
937 /* InCurve -> Segments[0].Type <= 5 */
938 GetParametricCurveByType(InCurve ->InterpParams->ContextID, InCurve ->Segments[0].Type, NULL) != NULL) {
940 return cmsBuildParametricToneCurve(InCurve ->InterpParams->ContextID,
941 -(InCurve -> Segments[0].Type),
942 InCurve -> Segments[0].Params);
945 // Nope, reverse the table.
946 out = cmsBuildTabulatedToneCurve16(InCurve ->InterpParams->ContextID, nResultSamples, NULL);
950 // We want to know if this is an ascending or descending table
951 Ascending = !cmsIsToneCurveDescending(InCurve);
953 // Iterate across Y axis
954 for (i=0; i < nResultSamples; i++) {
956 y = (cmsFloat64Number) i * 65535.0 / (nResultSamples - 1);
958 // Find interval in which y is within.
959 j = GetInterval(y, InCurve->Table16, InCurve->InterpParams);
963 // Get limits of interval
964 x1 = InCurve ->Table16[j];
965 x2 = InCurve ->Table16[j+1];
967 y1 = (cmsFloat64Number) (j * 65535.0) / (InCurve ->nEntries - 1);
968 y2 = (cmsFloat64Number) ((j+1) * 65535.0 ) / (InCurve ->nEntries - 1);
970 // If collapsed, then use any
973 out ->Table16[i] = _cmsQuickSaturateWord(Ascending ? y2 : y1);
979 a = (y2 - y1) / (x2 - x1);
984 out ->Table16[i] = _cmsQuickSaturateWord(a* y + b);
991 // Reverse a gamma table
992 cmsToneCurve* CMSEXPORT cmsReverseToneCurve(const cmsToneCurve* InGamma)
994 _cmsAssert(InGamma != NULL);
996 return cmsReverseToneCurveEx(4096, InGamma);
999 // From: Eilers, P.H.C. (1994) Smoothing and interpolation with finite
1000 // differences. in: Graphic Gems IV, Heckbert, P.S. (ed.), Academic press.
1002 // Smoothing and interpolation with second differences.
1004 // Input: weights (w), data (y): vector from 1 to m.
1005 // Input: smoothing parameter (lambda), length (m).
1006 // Output: smoothed vector (z): vector from 1 to m.
1009 cmsBool smooth2(cmsContext ContextID, cmsFloat32Number w[], cmsFloat32Number y[], cmsFloat32Number z[], cmsFloat32Number lambda, int m)
1012 cmsFloat32Number *c, *d, *e;
1016 c = (cmsFloat32Number*) _cmsCalloc(ContextID, MAX_NODES_IN_CURVE, sizeof(cmsFloat32Number));
1017 d = (cmsFloat32Number*) _cmsCalloc(ContextID, MAX_NODES_IN_CURVE, sizeof(cmsFloat32Number));
1018 e = (cmsFloat32Number*) _cmsCalloc(ContextID, MAX_NODES_IN_CURVE, sizeof(cmsFloat32Number));
1020 if (c != NULL && d != NULL && e != NULL) {
1023 d[1] = w[1] + lambda;
1024 c[1] = -2 * lambda / d[1];
1025 e[1] = lambda /d[1];
1027 d[2] = w[2] + 5 * lambda - d[1] * c[1] * c[1];
1028 c[2] = (-4 * lambda - d[1] * c[1] * e[1]) / d[2];
1029 e[2] = lambda / d[2];
1030 z[2] = w[2] * y[2] - c[1] * z[1];
1032 for (i = 3; i < m - 1; i++) {
1033 i1 = i - 1; i2 = i - 2;
1034 d[i]= w[i] + 6 * lambda - c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
1035 c[i] = (-4 * lambda -d[i1] * c[i1] * e[i1])/ d[i];
1036 e[i] = lambda / d[i];
1037 z[i] = w[i] * y[i] - c[i1] * z[i1] - e[i2] * z[i2];
1040 i1 = m - 2; i2 = m - 3;
1042 d[m - 1] = w[m - 1] + 5 * lambda -c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
1043 c[m - 1] = (-2 * lambda - d[i1] * c[i1] * e[i1]) / d[m - 1];
1044 z[m - 1] = w[m - 1] * y[m - 1] - c[i1] * z[i1] - e[i2] * z[i2];
1045 i1 = m - 1; i2 = m - 2;
1047 d[m] = w[m] + lambda - c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
1048 z[m] = (w[m] * y[m] - c[i1] * z[i1] - e[i2] * z[i2]) / d[m];
1049 z[m - 1] = z[m - 1] / d[m - 1] - c[m - 1] * z[m];
1051 for (i = m - 2; 1<= i; i--)
1052 z[i] = z[i] / d[i] - c[i] * z[i + 1] - e[i] * z[i + 2];
1058 if (c != NULL) _cmsFree(ContextID, c);
1059 if (d != NULL) _cmsFree(ContextID, d);
1060 if (e != NULL) _cmsFree(ContextID, e);
1065 // Smooths a curve sampled at regular intervals.
1066 cmsBool CMSEXPORT cmsSmoothToneCurve(cmsToneCurve* Tab, cmsFloat64Number lambda)
1068 cmsFloat32Number w[MAX_NODES_IN_CURVE], y[MAX_NODES_IN_CURVE], z[MAX_NODES_IN_CURVE];
1069 int i, nItems, Zeros, Poles;
1071 if (Tab == NULL) return FALSE;
1073 if (cmsIsToneCurveLinear(Tab)) return TRUE; // Nothing to do
1075 nItems = Tab -> nEntries;
1077 if (nItems >= MAX_NODES_IN_CURVE) {
1078 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: too many points.");
1082 memset(w, 0, nItems * sizeof(cmsFloat32Number));
1083 memset(y, 0, nItems * sizeof(cmsFloat32Number));
1084 memset(z, 0, nItems * sizeof(cmsFloat32Number));
1086 for (i=0; i < nItems; i++)
1088 y[i+1] = (cmsFloat32Number) Tab -> Table16[i];
1092 if (!smooth2(Tab ->InterpParams->ContextID, w, y, z, (cmsFloat32Number) lambda, nItems)) return FALSE;
1094 // Do some reality - checking...
1096 for (i=nItems; i > 1; --i) {
1098 if (z[i] == 0.) Zeros++;
1099 if (z[i] >= 65535.) Poles++;
1100 if (z[i] < z[i-1]) {
1101 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: Non-Monotonic.");
1106 if (Zeros > (nItems / 3)) {
1107 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: Degenerated, mostly zeros.");
1110 if (Poles > (nItems / 3)) {
1111 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: Degenerated, mostly poles.");
1116 for (i=0; i < nItems; i++) {
1118 // Clamp to cmsUInt16Number
1119 Tab -> Table16[i] = _cmsQuickSaturateWord(z[i+1]);
1125 // Is a table linear? Do not use parametric since we cannot guarantee some weird parameters resulting
1126 // in a linear table. This way assures it is linear in 12 bits, which should be enought in most cases.
1127 cmsBool CMSEXPORT cmsIsToneCurveLinear(const cmsToneCurve* Curve)
1132 _cmsAssert(Curve != NULL);
1134 for (i=0; i < Curve ->nEntries; i++) {
1136 diff = abs((int) Curve->Table16[i] - (int) _cmsQuantizeVal(i, Curve ->nEntries));
1144 // Same, but for monotonicity
1145 cmsBool CMSEXPORT cmsIsToneCurveMonotonic(const cmsToneCurve* t)
1149 cmsBool lDescending;
1151 _cmsAssert(t != NULL);
1153 // Degenerated curves are monotonic? Ok, let's pass them
1155 if (n < 2) return TRUE;
1158 lDescending = cmsIsToneCurveDescending(t);
1162 last = t ->Table16[0];
1164 for (i = 1; i < n; i++) {
1166 if (t ->Table16[i] - last > 2) // We allow some ripple
1169 last = t ->Table16[i];
1175 last = t ->Table16[n-1];
1177 for (i = n-2; i >= 0; --i) {
1179 if (t ->Table16[i] - last > 2)
1182 last = t ->Table16[i];
1190 // Same, but for descending tables
1191 cmsBool CMSEXPORT cmsIsToneCurveDescending(const cmsToneCurve* t)
1193 _cmsAssert(t != NULL);
1195 return t ->Table16[0] > t ->Table16[t ->nEntries-1];
1199 // Another info fn: is out gamma table multisegment?
1200 cmsBool CMSEXPORT cmsIsToneCurveMultisegment(const cmsToneCurve* t)
1202 _cmsAssert(t != NULL);
1204 return t -> nSegments > 1;
1207 cmsInt32Number CMSEXPORT cmsGetToneCurveParametricType(const cmsToneCurve* t)
1209 _cmsAssert(t != NULL);
1211 if (t -> nSegments != 1) return 0;
1212 return t ->Segments[0].Type;
1215 // We need accuracy this time
1216 cmsFloat32Number CMSEXPORT cmsEvalToneCurveFloat(const cmsToneCurve* Curve, cmsFloat32Number v)
1218 _cmsAssert(Curve != NULL);
1220 // Check for 16 bits table. If so, this is a limited-precision tone curve
1221 if (Curve ->nSegments == 0) {
1223 cmsUInt16Number In, Out;
1225 In = (cmsUInt16Number) _cmsQuickSaturateWord(v * 65535.0);
1226 Out = cmsEvalToneCurve16(Curve, In);
1228 return (cmsFloat32Number) (Out / 65535.0);
1231 return (cmsFloat32Number) EvalSegmentedFn(Curve, v);
1234 // We need xput over here
1235 cmsUInt16Number CMSEXPORT cmsEvalToneCurve16(const cmsToneCurve* Curve, cmsUInt16Number v)
1237 cmsUInt16Number out;
1239 _cmsAssert(Curve != NULL);
1241 Curve ->InterpParams ->Interpolation.Lerp16(&v, &out, Curve ->InterpParams);
1246 // Least squares fitting.
1247 // A mathematical procedure for finding the best-fitting curve to a given set of points by
1248 // minimizing the sum of the squares of the offsets ("the residuals") of the points from the curve.
1249 // The sum of the squares of the offsets is used instead of the offset absolute values because
1250 // this allows the residuals to be treated as a continuous differentiable quantity.
1254 // R = (yi - (xi^g))
1255 // R2 = (yi - (xi^g))2
1256 // SUM R2 = SUM (yi - (xi^g))2
1258 // dR2/dg = -2 SUM x^g log(x)(y - x^g)
1259 // solving for dR2/dg = 0
1261 // g = 1/n * SUM(log(y) / log(x))
1263 cmsFloat64Number CMSEXPORT cmsEstimateGamma(const cmsToneCurve* t, cmsFloat64Number Precision)
1265 cmsFloat64Number gamma, sum, sum2;
1266 cmsFloat64Number n, x, y, Std;
1269 _cmsAssert(t != NULL);
1273 // Excluding endpoints
1274 for (i=1; i < (MAX_NODES_IN_CURVE-1); i++) {
1276 x = (cmsFloat64Number) i / (MAX_NODES_IN_CURVE-1);
1277 y = (cmsFloat64Number) cmsEvalToneCurveFloat(t, (cmsFloat32Number) x);
1279 // Avoid 7% on lower part to prevent
1280 // artifacts due to linear ramps
1282 if (y > 0. && y < 1. && x > 0.07) {
1284 gamma = log(y) / log(x);
1286 sum2 += gamma * gamma;
1291 // Take a look on SD to see if gamma isn't exponential at all
1292 Std = sqrt((n * sum2 - sum * sum) / (n*(n-1)));
1294 if (Std > Precision)
1297 return (sum / n); // The mean