1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 // This file is available under and governed by the GNU General Public
26 // License version 2 only, as published by the Free Software Foundation.
27 // However, the following notice accompanied the original version of this
28 // file:
29 //
30 //---------------------------------------------------------------------------------
31 //
32 // Little Color Management System
33 // Copyright (c) 1998-2013 Marti Maria Saguer
34 //
35 // Permission is hereby granted, free of charge, to any person obtaining
36 // a copy of this software and associated documentation files (the "Software"),
37 // to deal in the Software without restriction, including without limitation
38 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
39 // and/or sell copies of the Software, and to permit persons to whom the Software
40 // is furnished to do so, subject to the following conditions:
41 //
42 // The above copyright notice and this permission notice shall be included in
43 // all copies or substantial portions of the Software.
44 //
45 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
46 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO
47 // THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
48 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
49 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
50 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
51 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
52 //
53 //---------------------------------------------------------------------------------
54 //
55 #include "lcms2_internal.h"
56
57 // Tone curves are powerful constructs that can contain curves specified in diverse ways.
58 // The curve is stored in segments, where each segment can be sampled or specified by parameters.
59 // a 16.bit simplification of the *whole* curve is kept for optimization purposes. For float operation,
60 // each segment is evaluated separately. Plug-ins may be used to define new parametric schemes,
61 // each plug-in may define up to MAX_TYPES_IN_LCMS_PLUGIN functions types. For defining a function,
62 // the plug-in should provide the type id, how many parameters each type has, and a pointer to
63 // a procedure that evaluates the function. In the case of reverse evaluation, the evaluator will
64 // be called with the type id as a negative value, and a sampled version of the reversed curve
65 // will be built.
66
67 // ----------------------------------------------------------------- Implementation
68 // Maxim number of nodes
69 #define MAX_NODES_IN_CURVE 4097
70 #define MINUS_INF (-1E22F)
71 #define PLUS_INF (+1E22F)
72
73 // The list of supported parametric curves
74 typedef struct _cmsParametricCurvesCollection_st {
75
76 int nFunctions; // Number of supported functions in this chunk
77 int FunctionTypes[MAX_TYPES_IN_LCMS_PLUGIN]; // The identification types
78 int ParameterCount[MAX_TYPES_IN_LCMS_PLUGIN]; // Number of parameters for each function
79 cmsParametricCurveEvaluator Evaluator; // The evaluator
80
81 struct _cmsParametricCurvesCollection_st* Next; // Next in list
82
83 } _cmsParametricCurvesCollection;
84
85 // This is the default (built-in) evaluator
86 static cmsFloat64Number DefaultEvalParametricFn(cmsInt32Number Type, const cmsFloat64Number Params[], cmsFloat64Number R);
87
88 // The built-in list
89 static _cmsParametricCurvesCollection DefaultCurves = {
90 9, // # of curve types
91 { 1, 2, 3, 4, 5, 6, 7, 8, 108 }, // Parametric curve ID
92 { 1, 3, 4, 5, 7, 4, 5, 5, 1 }, // Parameters by type
93 DefaultEvalParametricFn, // Evaluator
94 NULL // Next in chain
95 };
96
97 // Duplicates the zone of memory used by the plug-in in the new context
98 static
99 void DupPluginCurvesList(struct _cmsContext_struct* ctx,
100 const struct _cmsContext_struct* src)
101 {
102 _cmsCurvesPluginChunkType newHead = { NULL };
103 _cmsParametricCurvesCollection* entry;
104 _cmsParametricCurvesCollection* Anterior = NULL;
105 _cmsCurvesPluginChunkType* head = (_cmsCurvesPluginChunkType*) src->chunks[CurvesPlugin];
106
107 _cmsAssert(head != NULL);
108
109 // Walk the list copying all nodes
110 for (entry = head->ParametricCurves;
111 entry != NULL;
112 entry = entry ->Next) {
113
114 _cmsParametricCurvesCollection *newEntry = ( _cmsParametricCurvesCollection *) _cmsSubAllocDup(ctx ->MemPool, entry, sizeof(_cmsParametricCurvesCollection));
115
116 if (newEntry == NULL)
117 return;
118
119 // We want to keep the linked list order, so this is a little bit tricky
120 newEntry -> Next = NULL;
121 if (Anterior)
122 Anterior -> Next = newEntry;
123
124 Anterior = newEntry;
125
126 if (newHead.ParametricCurves == NULL)
127 newHead.ParametricCurves = newEntry;
128 }
129
130 ctx ->chunks[CurvesPlugin] = _cmsSubAllocDup(ctx->MemPool, &newHead, sizeof(_cmsCurvesPluginChunkType));
131 }
132
133 // The allocator have to follow the chain
134 void _cmsAllocCurvesPluginChunk(struct _cmsContext_struct* ctx,
135 const struct _cmsContext_struct* src)
136 {
137 _cmsAssert(ctx != NULL);
138
139 if (src != NULL) {
140
141 // Copy all linked list
142 DupPluginCurvesList(ctx, src);
143 }
144 else {
145 static _cmsCurvesPluginChunkType CurvesPluginChunk = { NULL };
146 ctx ->chunks[CurvesPlugin] = _cmsSubAllocDup(ctx ->MemPool, &CurvesPluginChunk, sizeof(_cmsCurvesPluginChunkType));
147 }
148 }
149
150
151 // The linked list head
152 _cmsCurvesPluginChunkType _cmsCurvesPluginChunk = { NULL };
153
154 // As a way to install new parametric curves
155 cmsBool _cmsRegisterParametricCurvesPlugin(cmsContext ContextID, cmsPluginBase* Data)
156 {
157 _cmsCurvesPluginChunkType* ctx = ( _cmsCurvesPluginChunkType*) _cmsContextGetClientChunk(ContextID, CurvesPlugin);
158 cmsPluginParametricCurves* Plugin = (cmsPluginParametricCurves*) Data;
159 _cmsParametricCurvesCollection* fl;
160
161 if (Data == NULL) {
162
163 ctx -> ParametricCurves = NULL;
164 return TRUE;
165 }
166
167 fl = (_cmsParametricCurvesCollection*) _cmsPluginMalloc(ContextID, sizeof(_cmsParametricCurvesCollection));
168 if (fl == NULL) return FALSE;
169
170 // Copy the parameters
171 fl ->Evaluator = Plugin ->Evaluator;
172 fl ->nFunctions = Plugin ->nFunctions;
173
174 // Make sure no mem overwrites
175 if (fl ->nFunctions > MAX_TYPES_IN_LCMS_PLUGIN)
176 fl ->nFunctions = MAX_TYPES_IN_LCMS_PLUGIN;
177
178 // Copy the data
179 memmove(fl->FunctionTypes, Plugin ->FunctionTypes, fl->nFunctions * sizeof(cmsUInt32Number));
180 memmove(fl->ParameterCount, Plugin ->ParameterCount, fl->nFunctions * sizeof(cmsUInt32Number));
181
182 // Keep linked list
183 fl ->Next = ctx->ParametricCurves;
184 ctx->ParametricCurves = fl;
185
186 // All is ok
187 return TRUE;
188 }
189
190
191 // Search in type list, return position or -1 if not found
192 static
193 int IsInSet(int Type, _cmsParametricCurvesCollection* c)
194 {
195 int i;
196
197 for (i=0; i < c ->nFunctions; i++)
198 if (abs(Type) == c ->FunctionTypes[i]) return i;
199
200 return -1;
201 }
202
203
204 // Search for the collection which contains a specific type
205 static
206 _cmsParametricCurvesCollection *GetParametricCurveByType(cmsContext ContextID, int Type, int* index)
207 {
208 _cmsParametricCurvesCollection* c;
209 int Position;
210 _cmsCurvesPluginChunkType* ctx = ( _cmsCurvesPluginChunkType*) _cmsContextGetClientChunk(ContextID, CurvesPlugin);
211
212 for (c = ctx->ParametricCurves; c != NULL; c = c ->Next) {
213
214 Position = IsInSet(Type, c);
215
216 if (Position != -1) {
217 if (index != NULL)
218 *index = Position;
219 return c;
220 }
221 }
222 // If none found, revert for defaults
223 for (c = &DefaultCurves; c != NULL; c = c ->Next) {
224
225 Position = IsInSet(Type, c);
226
227 if (Position != -1) {
228 if (index != NULL)
229 *index = Position;
230 return c;
231 }
232 }
233
234 return NULL;
235 }
236
237 // Low level allocate, which takes care of memory details. nEntries may be zero, and in this case
238 // no optimation curve is computed. nSegments may also be zero in the inverse case, where only the
239 // optimization curve is given. Both features simultaneously is an error
240 static
241 cmsToneCurve* AllocateToneCurveStruct(cmsContext ContextID, cmsInt32Number nEntries,
242 cmsInt32Number nSegments, const cmsCurveSegment* Segments,
243 const cmsUInt16Number* Values)
244 {
245 cmsToneCurve* p;
246 int i;
247
248 // We allow huge tables, which are then restricted for smoothing operations
249 if (nEntries > 65530 || nEntries < 0) {
250 cmsSignalError(ContextID, cmsERROR_RANGE, "Couldn't create tone curve of more than 65530 entries");
251 return NULL;
252 }
253
254 if (nEntries <= 0 && nSegments <= 0) {
255 cmsSignalError(ContextID, cmsERROR_RANGE, "Couldn't create tone curve with zero segments and no table");
256 return NULL;
257 }
258
259 // Allocate all required pointers, etc.
260 p = (cmsToneCurve*) _cmsMallocZero(ContextID, sizeof(cmsToneCurve));
261 if (!p) return NULL;
262
263 // In this case, there are no segments
264 if (nSegments <= 0) {
265 p ->Segments = NULL;
266 p ->Evals = NULL;
267 }
268 else {
269 p ->Segments = (cmsCurveSegment*) _cmsCalloc(ContextID, nSegments, sizeof(cmsCurveSegment));
270 if (p ->Segments == NULL) goto Error;
271
272 p ->Evals = (cmsParametricCurveEvaluator*) _cmsCalloc(ContextID, nSegments, sizeof(cmsParametricCurveEvaluator));
273 if (p ->Evals == NULL) goto Error;
274 }
275
276 p -> nSegments = nSegments;
277
278 // This 16-bit table contains a limited precision representation of the whole curve and is kept for
279 // increasing xput on certain operations.
280 if (nEntries <= 0) {
281 p ->Table16 = NULL;
282 }
283 else {
284 p ->Table16 = (cmsUInt16Number*) _cmsCalloc(ContextID, nEntries, sizeof(cmsUInt16Number));
285 if (p ->Table16 == NULL) goto Error;
286 }
287
288 p -> nEntries = nEntries;
289
290 // Initialize members if requested
291 if (Values != NULL && (nEntries > 0)) {
292
293 for (i=0; i < nEntries; i++)
294 p ->Table16[i] = Values[i];
295 }
296
297 // Initialize the segments stuff. The evaluator for each segment is located and a pointer to it
298 // is placed in advance to maximize performance.
299 if (Segments != NULL && (nSegments > 0)) {
300
301 _cmsParametricCurvesCollection *c;
302
303 p ->SegInterp = (cmsInterpParams**) _cmsCalloc(ContextID, nSegments, sizeof(cmsInterpParams*));
304 if (p ->SegInterp == NULL) goto Error;
305
306 for (i=0; i< nSegments; i++) {
307
308 // Type 0 is a special marker for table-based curves
309 if (Segments[i].Type == 0)
310 p ->SegInterp[i] = _cmsComputeInterpParams(ContextID, Segments[i].nGridPoints, 1, 1, NULL, CMS_LERP_FLAGS_FLOAT);
311
312 memmove(&p ->Segments[i], &Segments[i], sizeof(cmsCurveSegment));
313
314 if (Segments[i].Type == 0 && Segments[i].SampledPoints != NULL)
315 p ->Segments[i].SampledPoints = (cmsFloat32Number*) _cmsDupMem(ContextID, Segments[i].SampledPoints, sizeof(cmsFloat32Number) * Segments[i].nGridPoints);
316 else
317 p ->Segments[i].SampledPoints = NULL;
318
319
320 c = GetParametricCurveByType(ContextID, Segments[i].Type, NULL);
321 if (c != NULL)
322 p ->Evals[i] = c ->Evaluator;
323 }
324 }
325
326 p ->InterpParams = _cmsComputeInterpParams(ContextID, p ->nEntries, 1, 1, p->Table16, CMS_LERP_FLAGS_16BITS);
327 if (p->InterpParams != NULL)
328 return p;
329
330 Error:
331 if (p -> Segments) _cmsFree(ContextID, p ->Segments);
332 if (p -> Evals) _cmsFree(ContextID, p -> Evals);
333 if (p ->Table16) _cmsFree(ContextID, p ->Table16);
334 _cmsFree(ContextID, p);
335 return NULL;
336 }
337
338
339 // Parametric Fn using floating point
340 static
341 cmsFloat64Number DefaultEvalParametricFn(cmsInt32Number Type, const cmsFloat64Number Params[], cmsFloat64Number R)
342 {
343 cmsFloat64Number e, Val, disc;
344
345 switch (Type) {
346
347 // X = Y ^ Gamma
348 case 1:
349 if (R < 0) {
350
351 if (fabs(Params[0] - 1.0) < MATRIX_DET_TOLERANCE)
352 Val = R;
353 else
354 Val = 0;
355 }
356 else
357 Val = pow(R, Params[0]);
358 break;
359
360 // Type 1 Reversed: X = Y ^1/gamma
361 case -1:
362 if (R < 0) {
363
364 if (fabs(Params[0] - 1.0) < MATRIX_DET_TOLERANCE)
365 Val = R;
366 else
367 Val = 0;
368 }
369 else
370 Val = pow(R, 1/Params[0]);
371 break;
372
373 // CIE 122-1966
374 // Y = (aX + b)^Gamma | X >= -b/a
375 // Y = 0 | else
376 case 2:
377 disc = -Params[2] / Params[1];
378
379 if (R >= disc ) {
380
381 e = Params[1]*R + Params[2];
382
383 if (e > 0)
384 Val = pow(e, Params[0]);
385 else
386 Val = 0;
387 }
388 else
389 Val = 0;
390 break;
391
392 // Type 2 Reversed
393 // X = (Y ^1/g - b) / a
394 case -2:
395 if (R < 0)
396 Val = 0;
397 else
398 Val = (pow(R, 1.0/Params[0]) - Params[2]) / Params[1];
399
400 if (Val < 0)
401 Val = 0;
402 break;
403
404
405 // IEC 61966-3
406 // Y = (aX + b)^Gamma | X <= -b/a
407 // Y = c | else
408 case 3:
409 disc = -Params[2] / Params[1];
410 if (disc < 0)
411 disc = 0;
412
413 if (R >= disc) {
414
415 e = Params[1]*R + Params[2];
416
417 if (e > 0)
418 Val = pow(e, Params[0]) + Params[3];
419 else
420 Val = 0;
421 }
422 else
423 Val = Params[3];
424 break;
425
426
427 // Type 3 reversed
428 // X=((Y-c)^1/g - b)/a | (Y>=c)
429 // X=-b/a | (Y<c)
430 case -3:
431 if (R >= Params[3]) {
432
433 e = R - Params[3];
434
435 if (e > 0)
436 Val = (pow(e, 1/Params[0]) - Params[2]) / Params[1];
437 else
438 Val = 0;
439 }
440 else {
441 Val = -Params[2] / Params[1];
442 }
443 break;
444
445
446 // IEC 61966-2.1 (sRGB)
447 // Y = (aX + b)^Gamma | X >= d
448 // Y = cX | X < d
449 case 4:
450 if (R >= Params[4]) {
451
452 e = Params[1]*R + Params[2];
453
454 if (e > 0)
455 Val = pow(e, Params[0]);
456 else
457 Val = 0;
458 }
459 else
460 Val = R * Params[3];
461 break;
462
463 // Type 4 reversed
464 // X=((Y^1/g-b)/a) | Y >= (ad+b)^g
465 // X=Y/c | Y< (ad+b)^g
466 case -4:
467 e = Params[1] * Params[4] + Params[2];
468 if (e < 0)
469 disc = 0;
470 else
471 disc = pow(e, Params[0]);
472
473 if (R >= disc) {
474
475 Val = (pow(R, 1.0/Params[0]) - Params[2]) / Params[1];
476 }
477 else {
478 Val = R / Params[3];
479 }
480 break;
481
482
483 // Y = (aX + b)^Gamma + e | X >= d
484 // Y = cX + f | X < d
485 case 5:
486 if (R >= Params[4]) {
487
488 e = Params[1]*R + Params[2];
489
490 if (e > 0)
491 Val = pow(e, Params[0]) + Params[5];
492 else
493 Val = Params[5];
494 }
495 else
496 Val = R*Params[3] + Params[6];
497 break;
498
499
500 // Reversed type 5
501 // X=((Y-e)1/g-b)/a | Y >=(ad+b)^g+e), cd+f
502 // X=(Y-f)/c | else
503 case -5:
504
505 disc = Params[3] * Params[4] + Params[6];
506 if (R >= disc) {
507
508 e = R - Params[5];
509 if (e < 0)
510 Val = 0;
511 else
512 Val = (pow(e, 1.0/Params[0]) - Params[2]) / Params[1];
513 }
514 else {
515 Val = (R - Params[6]) / Params[3];
516 }
517 break;
518
519
520 // Types 6,7,8 comes from segmented curves as described in ICCSpecRevision_02_11_06_Float.pdf
521 // Type 6 is basically identical to type 5 without d
522
523 // Y = (a * X + b) ^ Gamma + c
524 case 6:
525 e = Params[1]*R + Params[2];
526
527 if (e < 0)
528 Val = Params[3];
529 else
530 Val = pow(e, Params[0]) + Params[3];
531 break;
532
533 // ((Y - c) ^1/Gamma - b) / a
534 case -6:
535 e = R - Params[3];
536 if (e < 0)
537 Val = 0;
538 else
539 Val = (pow(e, 1.0/Params[0]) - Params[2]) / Params[1];
540 break;
541
542
543 // Y = a * log (b * X^Gamma + c) + d
544 case 7:
545
546 e = Params[2] * pow(R, Params[0]) + Params[3];
547 if (e <= 0)
548 Val = Params[4];
549 else
550 Val = Params[1]*log10(e) + Params[4];
551 break;
552
553 // (Y - d) / a = log(b * X ^Gamma + c)
554 // pow(10, (Y-d) / a) = b * X ^Gamma + c
555 // pow((pow(10, (Y-d) / a) - c) / b, 1/g) = X
556 case -7:
557 Val = pow((pow(10.0, (R-Params[4]) / Params[1]) - Params[3]) / Params[2], 1.0 / Params[0]);
558 break;
559
560
561 //Y = a * b^(c*X+d) + e
562 case 8:
563 Val = (Params[0] * pow(Params[1], Params[2] * R + Params[3]) + Params[4]);
564 break;
565
566
567 // Y = (log((y-e) / a) / log(b) - d ) / c
568 // a=0, b=1, c=2, d=3, e=4,
569 case -8:
570
571 disc = R - Params[4];
572 if (disc < 0) Val = 0;
573 else
574 Val = (log(disc / Params[0]) / log(Params[1]) - Params[3]) / Params[2];
575 break;
576
577 // S-Shaped: (1 - (1-x)^1/g)^1/g
578 case 108:
579 Val = pow(1.0 - pow(1 - R, 1/Params[0]), 1/Params[0]);
580 break;
581
582 // y = (1 - (1-x)^1/g)^1/g
583 // y^g = (1 - (1-x)^1/g)
584 // 1 - y^g = (1-x)^1/g
585 // (1 - y^g)^g = 1 - x
586 // 1 - (1 - y^g)^g
587 case -108:
588 Val = 1 - pow(1 - pow(R, Params[0]), Params[0]);
589 break;
590
591 default:
592 // Unsupported parametric curve. Should never reach here
593 return 0;
594 }
595
596 return Val;
597 }
598
599 // Evaluate a segmented funtion for a single value. Return -1 if no valid segment found .
600 // If fn type is 0, perform an interpolation on the table
601 static
602 cmsFloat64Number EvalSegmentedFn(const cmsToneCurve *g, cmsFloat64Number R)
603 {
604 int i;
605
606 for (i = g ->nSegments-1; i >= 0 ; --i) {
607
608 // Check for domain
609 if ((R > g ->Segments[i].x0) && (R <= g ->Segments[i].x1)) {
610
611 // Type == 0 means segment is sampled
612 if (g ->Segments[i].Type == 0) {
613
614 cmsFloat32Number R1 = (cmsFloat32Number) (R - g ->Segments[i].x0) / (g ->Segments[i].x1 - g ->Segments[i].x0);
615 cmsFloat32Number Out;
616
617 // Setup the table (TODO: clean that)
618 g ->SegInterp[i]-> Table = g ->Segments[i].SampledPoints;
619
620 g ->SegInterp[i] -> Interpolation.LerpFloat(&R1, &Out, g ->SegInterp[i]);
621
622 return Out;
623 }
624 else
625 return g ->Evals[i](g->Segments[i].Type, g ->Segments[i].Params, R);
626 }
627 }
628
629 return MINUS_INF;
630 }
631
632 // Access to estimated low-res table
633 cmsUInt32Number CMSEXPORT cmsGetToneCurveEstimatedTableEntries(const cmsToneCurve* t)
634 {
635 _cmsAssert(t != NULL);
636 return t ->nEntries;
637 }
638
639 const cmsUInt16Number* CMSEXPORT cmsGetToneCurveEstimatedTable(const cmsToneCurve* t)
640 {
641 _cmsAssert(t != NULL);
642 return t ->Table16;
643 }
644
645
646 // Create an empty gamma curve, by using tables. This specifies only the limited-precision part, and leaves the
647 // floating point description empty.
648 cmsToneCurve* CMSEXPORT cmsBuildTabulatedToneCurve16(cmsContext ContextID, cmsInt32Number nEntries, const cmsUInt16Number Values[])
649 {
650 return AllocateToneCurveStruct(ContextID, nEntries, 0, NULL, Values);
651 }
652
653 static
654 int EntriesByGamma(cmsFloat64Number Gamma)
655 {
656 if (fabs(Gamma - 1.0) < 0.001) return 2;
657 return 4096;
658 }
659
660
661 // Create a segmented gamma, fill the table
662 cmsToneCurve* CMSEXPORT cmsBuildSegmentedToneCurve(cmsContext ContextID,
663 cmsInt32Number nSegments, const cmsCurveSegment Segments[])
664 {
665 int i;
666 cmsFloat64Number R, Val;
667 cmsToneCurve* g;
668 int nGridPoints = 4096;
669
670 _cmsAssert(Segments != NULL);
671
672 // Optimizatin for identity curves.
673 if (nSegments == 1 && Segments[0].Type == 1) {
674
675 nGridPoints = EntriesByGamma(Segments[0].Params[0]);
676 }
677
678 g = AllocateToneCurveStruct(ContextID, nGridPoints, nSegments, Segments, NULL);
679 if (g == NULL) return NULL;
680
681 // Once we have the floating point version, we can approximate a 16 bit table of 4096 entries
682 // for performance reasons. This table would normally not be used except on 8/16 bits transforms.
683 for (i=0; i < nGridPoints; i++) {
684
685 R = (cmsFloat64Number) i / (nGridPoints-1);
686
687 Val = EvalSegmentedFn(g, R);
688
689 // Round and saturate
690 g ->Table16[i] = _cmsQuickSaturateWord(Val * 65535.0);
691 }
692
693 return g;
694 }
695
696 // Use a segmented curve to store the floating point table
697 cmsToneCurve* CMSEXPORT cmsBuildTabulatedToneCurveFloat(cmsContext ContextID, cmsUInt32Number nEntries, const cmsFloat32Number values[])
698 {
699 cmsCurveSegment Seg[3];
700
701 // A segmented tone curve should have function segments in the first and last positions
702 // Initialize segmented curve part up to 0 to constant value = samples[0]
703 Seg[0].x0 = MINUS_INF;
704 Seg[0].x1 = 0;
705 Seg[0].Type = 6;
706
707 Seg[0].Params[0] = 1;
708 Seg[0].Params[1] = 0;
709 Seg[0].Params[2] = 0;
710 Seg[0].Params[3] = values[0];
711 Seg[0].Params[4] = 0;
712
713 // From zero to 1
714 Seg[1].x0 = 0;
715 Seg[1].x1 = 1.0;
716 Seg[1].Type = 0;
717
718 Seg[1].nGridPoints = nEntries;
719 Seg[1].SampledPoints = (cmsFloat32Number*) values;
720
721 // Final segment is constant = lastsample
722 Seg[2].x0 = 1.0;
723 Seg[2].x1 = PLUS_INF;
724 Seg[2].Type = 6;
725
726 Seg[2].Params[0] = 1;
727 Seg[2].Params[1] = 0;
728 Seg[2].Params[2] = 0;
729 Seg[2].Params[3] = values[nEntries-1];
730 Seg[2].Params[4] = 0;
731
732
733 return cmsBuildSegmentedToneCurve(ContextID, 3, Seg);
734 }
735
736 // Parametric curves
737 //
738 // Parameters goes as: Curve, a, b, c, d, e, f
739 // Type is the ICC type +1
740 // if type is negative, then the curve is analyticaly inverted
741 cmsToneCurve* CMSEXPORT cmsBuildParametricToneCurve(cmsContext ContextID, cmsInt32Number Type, const cmsFloat64Number Params[])
742 {
743 cmsCurveSegment Seg0;
744 int Pos = 0;
745 cmsUInt32Number size;
746 _cmsParametricCurvesCollection* c = GetParametricCurveByType(ContextID, Type, &Pos);
747
748 _cmsAssert(Params != NULL);
749
750 if (c == NULL) {
751 cmsSignalError(ContextID, cmsERROR_UNKNOWN_EXTENSION, "Invalid parametric curve type %d", Type);
752 return NULL;
753 }
754
755 memset(&Seg0, 0, sizeof(Seg0));
756
757 Seg0.x0 = MINUS_INF;
758 Seg0.x1 = PLUS_INF;
759 Seg0.Type = Type;
760
761 size = c->ParameterCount[Pos] * sizeof(cmsFloat64Number);
762 memmove(Seg0.Params, Params, size);
763
764 return cmsBuildSegmentedToneCurve(ContextID, 1, &Seg0);
765 }
766
767
768
769 // Build a gamma table based on gamma constant
770 cmsToneCurve* CMSEXPORT cmsBuildGamma(cmsContext ContextID, cmsFloat64Number Gamma)
771 {
772 return cmsBuildParametricToneCurve(ContextID, 1, &Gamma);
773 }
774
775
776 // Free all memory taken by the gamma curve
777 void CMSEXPORT cmsFreeToneCurve(cmsToneCurve* Curve)
778 {
779 cmsContext ContextID;
780
781 if (Curve == NULL) return;
782
783 ContextID = Curve ->InterpParams->ContextID;
784
785 _cmsFreeInterpParams(Curve ->InterpParams);
786
787 if (Curve -> Table16)
788 _cmsFree(ContextID, Curve ->Table16);
789
790 if (Curve ->Segments) {
791
792 cmsUInt32Number i;
793
794 for (i=0; i < Curve ->nSegments; i++) {
795
796 if (Curve ->Segments[i].SampledPoints) {
797 _cmsFree(ContextID, Curve ->Segments[i].SampledPoints);
798 }
799
800 if (Curve ->SegInterp[i] != 0)
801 _cmsFreeInterpParams(Curve->SegInterp[i]);
802 }
803
804 _cmsFree(ContextID, Curve ->Segments);
805 _cmsFree(ContextID, Curve ->SegInterp);
806 }
807
808 if (Curve -> Evals)
809 _cmsFree(ContextID, Curve -> Evals);
810
811 if (Curve) _cmsFree(ContextID, Curve);
812 }
813
814 // Utility function, free 3 gamma tables
815 void CMSEXPORT cmsFreeToneCurveTriple(cmsToneCurve* Curve[3])
816 {
817
818 _cmsAssert(Curve != NULL);
819
820 if (Curve[0] != NULL) cmsFreeToneCurve(Curve[0]);
821 if (Curve[1] != NULL) cmsFreeToneCurve(Curve[1]);
822 if (Curve[2] != NULL) cmsFreeToneCurve(Curve[2]);
823
824 Curve[0] = Curve[1] = Curve[2] = NULL;
825 }
826
827
828 // Duplicate a gamma table
829 cmsToneCurve* CMSEXPORT cmsDupToneCurve(const cmsToneCurve* In)
830 {
831 if (In == NULL) return NULL;
832
833 return AllocateToneCurveStruct(In ->InterpParams ->ContextID, In ->nEntries, In ->nSegments, In ->Segments, In ->Table16);
834 }
835
836 // Joins two curves for X and Y. Curves should be monotonic.
837 // We want to get
838 //
839 // y = Y^-1(X(t))
840 //
841 cmsToneCurve* CMSEXPORT cmsJoinToneCurve(cmsContext ContextID,
842 const cmsToneCurve* X,
843 const cmsToneCurve* Y, cmsUInt32Number nResultingPoints)
844 {
845 cmsToneCurve* out = NULL;
846 cmsToneCurve* Yreversed = NULL;
847 cmsFloat32Number t, x;
848 cmsFloat32Number* Res = NULL;
849 cmsUInt32Number i;
850
851
852 _cmsAssert(X != NULL);
853 _cmsAssert(Y != NULL);
854
855 Yreversed = cmsReverseToneCurveEx(nResultingPoints, Y);
856 if (Yreversed == NULL) goto Error;
857
858 Res = (cmsFloat32Number*) _cmsCalloc(ContextID, nResultingPoints, sizeof(cmsFloat32Number));
859 if (Res == NULL) goto Error;
860
861 //Iterate
862 for (i=0; i < nResultingPoints; i++) {
863
864 t = (cmsFloat32Number) i / (nResultingPoints-1);
865 x = cmsEvalToneCurveFloat(X, t);
866 Res[i] = cmsEvalToneCurveFloat(Yreversed, x);
867 }
868
869 // Allocate space for output
870 out = cmsBuildTabulatedToneCurveFloat(ContextID, nResultingPoints, Res);
871
872 Error:
873
874 if (Res != NULL) _cmsFree(ContextID, Res);
875 if (Yreversed != NULL) cmsFreeToneCurve(Yreversed);
876
877 return out;
878 }
879
880
881
882 // Get the surrounding nodes. This is tricky on non-monotonic tables
883 static
884 int GetInterval(cmsFloat64Number In, const cmsUInt16Number LutTable[], const struct _cms_interp_struc* p)
885 {
886 int i;
887 int y0, y1;
888
889 // A 1 point table is not allowed
890 if (p -> Domain[0] < 1) return -1;
891
892 // Let's see if ascending or descending.
893 if (LutTable[0] < LutTable[p ->Domain[0]]) {
894
895 // Table is overall ascending
896 for (i=p->Domain[0]-1; i >=0; --i) {
897
898 y0 = LutTable[i];
899 y1 = LutTable[i+1];
900
901 if (y0 <= y1) { // Increasing
902 if (In >= y0 && In <= y1) return i;
903 }
904 else
905 if (y1 < y0) { // Decreasing
906 if (In >= y1 && In <= y0) return i;
907 }
908 }
909 }
910 else {
911 // Table is overall descending
912 for (i=0; i < (int) p -> Domain[0]; i++) {
913
914 y0 = LutTable[i];
915 y1 = LutTable[i+1];
916
917 if (y0 <= y1) { // Increasing
918 if (In >= y0 && In <= y1) return i;
919 }
920 else
921 if (y1 < y0) { // Decreasing
922 if (In >= y1 && In <= y0) return i;
923 }
924 }
925 }
926
927 return -1;
928 }
929
930 // Reverse a gamma table
931 cmsToneCurve* CMSEXPORT cmsReverseToneCurveEx(cmsInt32Number nResultSamples, const cmsToneCurve* InCurve)
932 {
933 cmsToneCurve *out;
934 cmsFloat64Number a = 0, b = 0, y, x1, y1, x2, y2;
935 int i, j;
936 int Ascending;
937
938 _cmsAssert(InCurve != NULL);
939
940 // Try to reverse it analytically whatever possible
941
942 if (InCurve ->nSegments == 1 && InCurve ->Segments[0].Type > 0 &&
943 /* InCurve -> Segments[0].Type <= 5 */
944 GetParametricCurveByType(InCurve ->InterpParams->ContextID, InCurve ->Segments[0].Type, NULL) != NULL) {
945
946 return cmsBuildParametricToneCurve(InCurve ->InterpParams->ContextID,
947 -(InCurve -> Segments[0].Type),
948 InCurve -> Segments[0].Params);
949 }
950
951 // Nope, reverse the table.
952 out = cmsBuildTabulatedToneCurve16(InCurve ->InterpParams->ContextID, nResultSamples, NULL);
953 if (out == NULL)
954 return NULL;
955
956 // We want to know if this is an ascending or descending table
957 Ascending = !cmsIsToneCurveDescending(InCurve);
958
959 // Iterate across Y axis
960 for (i=0; i < nResultSamples; i++) {
961
962 y = (cmsFloat64Number) i * 65535.0 / (nResultSamples - 1);
963
964 // Find interval in which y is within.
965 j = GetInterval(y, InCurve->Table16, InCurve->InterpParams);
966 if (j >= 0) {
967
968
969 // Get limits of interval
970 x1 = InCurve ->Table16[j];
971 x2 = InCurve ->Table16[j+1];
972
973 y1 = (cmsFloat64Number) (j * 65535.0) / (InCurve ->nEntries - 1);
974 y2 = (cmsFloat64Number) ((j+1) * 65535.0 ) / (InCurve ->nEntries - 1);
975
976 // If collapsed, then use any
977 if (x1 == x2) {
978
979 out ->Table16[i] = _cmsQuickSaturateWord(Ascending ? y2 : y1);
980 continue;
981
982 } else {
983
984 // Interpolate
985 a = (y2 - y1) / (x2 - x1);
986 b = y2 - a * x2;
987 }
988 }
989
990 out ->Table16[i] = _cmsQuickSaturateWord(a* y + b);
991 }
992
993
994 return out;
995 }
996
997 // Reverse a gamma table
998 cmsToneCurve* CMSEXPORT cmsReverseToneCurve(const cmsToneCurve* InGamma)
999 {
1000 _cmsAssert(InGamma != NULL);
1001
1002 return cmsReverseToneCurveEx(4096, InGamma);
1003 }
1004
1005 // From: Eilers, P.H.C. (1994) Smoothing and interpolation with finite
1006 // differences. in: Graphic Gems IV, Heckbert, P.S. (ed.), Academic press.
1007 //
1008 // Smoothing and interpolation with second differences.
1009 //
1010 // Input: weights (w), data (y): vector from 1 to m.
1011 // Input: smoothing parameter (lambda), length (m).
1012 // Output: smoothed vector (z): vector from 1 to m.
1013
1014 static
1015 cmsBool smooth2(cmsContext ContextID, cmsFloat32Number w[], cmsFloat32Number y[], cmsFloat32Number z[], cmsFloat32Number lambda, int m)
1016 {
1017 int i, i1, i2;
1018 cmsFloat32Number *c, *d, *e;
1019 cmsBool st;
1020
1021
1022 c = (cmsFloat32Number*) _cmsCalloc(ContextID, MAX_NODES_IN_CURVE, sizeof(cmsFloat32Number));
1023 d = (cmsFloat32Number*) _cmsCalloc(ContextID, MAX_NODES_IN_CURVE, sizeof(cmsFloat32Number));
1024 e = (cmsFloat32Number*) _cmsCalloc(ContextID, MAX_NODES_IN_CURVE, sizeof(cmsFloat32Number));
1025
1026 if (c != NULL && d != NULL && e != NULL) {
1027
1028
1029 d[1] = w[1] + lambda;
1030 c[1] = -2 * lambda / d[1];
1031 e[1] = lambda /d[1];
1032 z[1] = w[1] * y[1];
1033 d[2] = w[2] + 5 * lambda - d[1] * c[1] * c[1];
1034 c[2] = (-4 * lambda - d[1] * c[1] * e[1]) / d[2];
1035 e[2] = lambda / d[2];
1036 z[2] = w[2] * y[2] - c[1] * z[1];
1037
1038 for (i = 3; i < m - 1; i++) {
1039 i1 = i - 1; i2 = i - 2;
1040 d[i]= w[i] + 6 * lambda - c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
1041 c[i] = (-4 * lambda -d[i1] * c[i1] * e[i1])/ d[i];
1042 e[i] = lambda / d[i];
1043 z[i] = w[i] * y[i] - c[i1] * z[i1] - e[i2] * z[i2];
1044 }
1045
1046 i1 = m - 2; i2 = m - 3;
1047
1048 d[m - 1] = w[m - 1] + 5 * lambda -c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
1049 c[m - 1] = (-2 * lambda - d[i1] * c[i1] * e[i1]) / d[m - 1];
1050 z[m - 1] = w[m - 1] * y[m - 1] - c[i1] * z[i1] - e[i2] * z[i2];
1051 i1 = m - 1; i2 = m - 2;
1052
1053 d[m] = w[m] + lambda - c[i1] * c[i1] * d[i1] - e[i2] * e[i2] * d[i2];
1054 z[m] = (w[m] * y[m] - c[i1] * z[i1] - e[i2] * z[i2]) / d[m];
1055 z[m - 1] = z[m - 1] / d[m - 1] - c[m - 1] * z[m];
1056
1057 for (i = m - 2; 1<= i; i--)
1058 z[i] = z[i] / d[i] - c[i] * z[i + 1] - e[i] * z[i + 2];
1059
1060 st = TRUE;
1061 }
1062 else st = FALSE;
1063
1064 if (c != NULL) _cmsFree(ContextID, c);
1065 if (d != NULL) _cmsFree(ContextID, d);
1066 if (e != NULL) _cmsFree(ContextID, e);
1067
1068 return st;
1069 }
1070
1071 // Smooths a curve sampled at regular intervals.
1072 cmsBool CMSEXPORT cmsSmoothToneCurve(cmsToneCurve* Tab, cmsFloat64Number lambda)
1073 {
1074 cmsFloat32Number w[MAX_NODES_IN_CURVE], y[MAX_NODES_IN_CURVE], z[MAX_NODES_IN_CURVE];
1075 int i, nItems, Zeros, Poles;
1076
1077 if (Tab == NULL) return FALSE;
1078
1079 if (cmsIsToneCurveLinear(Tab)) return TRUE; // Nothing to do
1080
1081 nItems = Tab -> nEntries;
1082
1083 if (nItems >= MAX_NODES_IN_CURVE) {
1084 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: too many points.");
1085 return FALSE;
1086 }
1087
1088 memset(w, 0, nItems * sizeof(cmsFloat32Number));
1089 memset(y, 0, nItems * sizeof(cmsFloat32Number));
1090 memset(z, 0, nItems * sizeof(cmsFloat32Number));
1091
1092 for (i=0; i < nItems; i++)
1093 {
1094 y[i+1] = (cmsFloat32Number) Tab -> Table16[i];
1095 w[i+1] = 1.0;
1096 }
1097
1098 if (!smooth2(Tab ->InterpParams->ContextID, w, y, z, (cmsFloat32Number) lambda, nItems)) return FALSE;
1099
1100 // Do some reality - checking...
1101 Zeros = Poles = 0;
1102 for (i=nItems; i > 1; --i) {
1103
1104 if (z[i] == 0.) Zeros++;
1105 if (z[i] >= 65535.) Poles++;
1106 if (z[i] < z[i-1]) {
1107 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: Non-Monotonic.");
1108 return FALSE;
1109 }
1110 }
1111
1112 if (Zeros > (nItems / 3)) {
1113 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: Degenerated, mostly zeros.");
1114 return FALSE;
1115 }
1116 if (Poles > (nItems / 3)) {
1117 cmsSignalError(Tab ->InterpParams->ContextID, cmsERROR_RANGE, "cmsSmoothToneCurve: Degenerated, mostly poles.");
1118 return FALSE;
1119 }
1120
1121 // Seems ok
1122 for (i=0; i < nItems; i++) {
1123
1124 // Clamp to cmsUInt16Number
1125 Tab -> Table16[i] = _cmsQuickSaturateWord(z[i+1]);
1126 }
1127
1128 return TRUE;
1129 }
1130
1131 // Is a table linear? Do not use parametric since we cannot guarantee some weird parameters resulting
1132 // in a linear table. This way assures it is linear in 12 bits, which should be enought in most cases.
1133 cmsBool CMSEXPORT cmsIsToneCurveLinear(const cmsToneCurve* Curve)
1134 {
1135 cmsUInt32Number i;
1136 int diff;
1137
1138 _cmsAssert(Curve != NULL);
1139
1140 for (i=0; i < Curve ->nEntries; i++) {
1141
1142 diff = abs((int) Curve->Table16[i] - (int) _cmsQuantizeVal(i, Curve ->nEntries));
1143 if (diff > 0x0f)
1144 return FALSE;
1145 }
1146
1147 return TRUE;
1148 }
1149
1150 // Same, but for monotonicity
1151 cmsBool CMSEXPORT cmsIsToneCurveMonotonic(const cmsToneCurve* t)
1152 {
1153 int n;
1154 int i, last;
1155 cmsBool lDescending;
1156
1157 _cmsAssert(t != NULL);
1158
1159 // Degenerated curves are monotonic? Ok, let's pass them
1160 n = t ->nEntries;
1161 if (n < 2) return TRUE;
1162
1163 // Curve direction
1164 lDescending = cmsIsToneCurveDescending(t);
1165
1166 if (lDescending) {
1167
1168 last = t ->Table16[0];
1169
1170 for (i = 1; i < n; i++) {
1171
1172 if (t ->Table16[i] - last > 2) // We allow some ripple
1173 return FALSE;
1174 else
1175 last = t ->Table16[i];
1176
1177 }
1178 }
1179 else {
1180
1181 last = t ->Table16[n-1];
1182
1183 for (i = n-2; i >= 0; --i) {
1184
1185 if (t ->Table16[i] - last > 2)
1186 return FALSE;
1187 else
1188 last = t ->Table16[i];
1189
1190 }
1191 }
1192
1193 return TRUE;
1194 }
1195
1196 // Same, but for descending tables
1197 cmsBool CMSEXPORT cmsIsToneCurveDescending(const cmsToneCurve* t)
1198 {
1199 _cmsAssert(t != NULL);
1200
1201 return t ->Table16[0] > t ->Table16[t ->nEntries-1];
1202 }
1203
1204
1205 // Another info fn: is out gamma table multisegment?
1206 cmsBool CMSEXPORT cmsIsToneCurveMultisegment(const cmsToneCurve* t)
1207 {
1208 _cmsAssert(t != NULL);
1209
1210 return t -> nSegments > 1;
1211 }
1212
1213 cmsInt32Number CMSEXPORT cmsGetToneCurveParametricType(const cmsToneCurve* t)
1214 {
1215 _cmsAssert(t != NULL);
1216
1217 if (t -> nSegments != 1) return 0;
1218 return t ->Segments[0].Type;
1219 }
1220
1221 // We need accuracy this time
1222 cmsFloat32Number CMSEXPORT cmsEvalToneCurveFloat(const cmsToneCurve* Curve, cmsFloat32Number v)
1223 {
1224 _cmsAssert(Curve != NULL);
1225
1226 // Check for 16 bits table. If so, this is a limited-precision tone curve
1227 if (Curve ->nSegments == 0) {
1228
1229 cmsUInt16Number In, Out;
1230
1231 In = (cmsUInt16Number) _cmsQuickSaturateWord(v * 65535.0);
1232 Out = cmsEvalToneCurve16(Curve, In);
1233
1234 return (cmsFloat32Number) (Out / 65535.0);
1235 }
1236
1237 return (cmsFloat32Number) EvalSegmentedFn(Curve, v);
1238 }
1239
1240 // We need xput over here
1241 cmsUInt16Number CMSEXPORT cmsEvalToneCurve16(const cmsToneCurve* Curve, cmsUInt16Number v)
1242 {
1243 cmsUInt16Number out;
1244
1245 _cmsAssert(Curve != NULL);
1246
1247 Curve ->InterpParams ->Interpolation.Lerp16(&v, &out, Curve ->InterpParams);
1248 return out;
1249 }
1250
1251
1252 // Least squares fitting.
1253 // A mathematical procedure for finding the best-fitting curve to a given set of points by
1254 // minimizing the sum of the squares of the offsets ("the residuals") of the points from the curve.
1255 // The sum of the squares of the offsets is used instead of the offset absolute values because
1256 // this allows the residuals to be treated as a continuous differentiable quantity.
1257 //
1258 // y = f(x) = x ^ g
1259 //
1260 // R = (yi - (xi^g))
1261 // R2 = (yi - (xi^g))2
1262 // SUM R2 = SUM (yi - (xi^g))2
1263 //
1264 // dR2/dg = -2 SUM x^g log(x)(y - x^g)
1265 // solving for dR2/dg = 0
1266 //
1267 // g = 1/n * SUM(log(y) / log(x))
1268
1269 cmsFloat64Number CMSEXPORT cmsEstimateGamma(const cmsToneCurve* t, cmsFloat64Number Precision)
1270 {
1271 cmsFloat64Number gamma, sum, sum2;
1272 cmsFloat64Number n, x, y, Std;
1273 cmsUInt32Number i;
1274
1275 _cmsAssert(t != NULL);
1276
1277 sum = sum2 = n = 0;
1278
1279 // Excluding endpoints
1280 for (i=1; i < (MAX_NODES_IN_CURVE-1); i++) {
1281
1282 x = (cmsFloat64Number) i / (MAX_NODES_IN_CURVE-1);
1283 y = (cmsFloat64Number) cmsEvalToneCurveFloat(t, (cmsFloat32Number) x);
1284
1285 // Avoid 7% on lower part to prevent
1286 // artifacts due to linear ramps
1287
1288 if (y > 0. && y < 1. && x > 0.07) {
1289
1290 gamma = log(y) / log(x);
1291 sum += gamma;
1292 sum2 += gamma * gamma;
1293 n++;
1294 }
1295 }
1296
1297 // Take a look on SD to see if gamma isn't exponential at all
1298 Std = sqrt((n * sum2 - sum * sum) / (n*(n-1)));
1299
1300 if (Std > Precision)
1301 return -1.0;
1302
1303 return (sum / n); // The mean
1304 }