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| 1 // qcms |
| 2 // Copyright (C) 2009 Mozilla Foundation |
| 3 // |
| 4 // Permission is hereby granted, free of charge, to any person obtaining |
| 5 // a copy of this software and associated documentation files (the "Software"), |
| 6 // to deal in the Software without restriction, including without limitation |
| 7 // the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| 8 // and/or sell copies of the Software, and to permit persons to whom the Softwar
e |
| 9 // is furnished to do so, subject to the following conditions: |
| 10 // |
| 11 // The above copyright notice and this permission notice shall be included in |
| 12 // all copies or substantial portions of the Software. |
| 13 // |
| 14 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 15 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO |
| 16 // THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| 17 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
| 18 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
| 19 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
| 20 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
| 21 |
| 22 #define _ISOC99_SOURCE /* for INFINITY */ |
| 23 |
| 24 #include <math.h> |
| 25 #include <assert.h> |
| 26 #include <string.h> //memcpy |
| 27 #include "qcmsint.h" |
| 28 #include "transform_util.h" |
| 29 #include "matrix.h" |
| 30 |
| 31 #if !defined(INFINITY) |
| 32 #define INFINITY HUGE_VAL |
| 33 #endif |
| 34 |
| 35 #define PARAMETRIC_CURVE_TYPE 0x70617261 //'para' |
| 36 |
| 37 /* value must be a value between 0 and 1 */ |
| 38 //XXX: is the above a good restriction to have? |
| 39 // the output range of this function is 0..1 |
| 40 float lut_interp_linear(double input_value, uint16_t *table, size_t length) |
| 41 { |
| 42 int upper, lower; |
| 43 float value; |
| 44 input_value = input_value * (length - 1); // scale to length of the arra
y |
| 45 upper = ceil(input_value); |
| 46 lower = floor(input_value); |
| 47 //XXX: can we be more performant here? |
| 48 value = table[upper]*(1. - (upper - input_value)) + table[lower]*(upper
- input_value); |
| 49 /* scale the value */ |
| 50 return value * (1.f/65535.f); |
| 51 } |
| 52 |
| 53 /* same as above but takes and returns a uint16_t value representing a range fro
m 0..1 */ |
| 54 uint16_t lut_interp_linear16(uint16_t input_value, uint16_t *table, size_t lengt
h) |
| 55 { |
| 56 /* Start scaling input_value to the length of the array: 65535*(length-1
). |
| 57 * We'll divide out the 65535 next */ |
| 58 uintptr_t value = (input_value * (length - 1)); |
| 59 uint32_t upper = (value + 65534) / 65535; /* equivalent to ceil(value/65
535) */ |
| 60 uint32_t lower = value / 65535; /* equivalent to floor(value/6
5535) */ |
| 61 /* interp is the distance from upper to value scaled to 0..65535 */ |
| 62 uint32_t interp = value % 65535; |
| 63 |
| 64 value = (table[upper]*(interp) + table[lower]*(65535 - interp))/65535; /
/ 0..65535*65535 |
| 65 |
| 66 return value; |
| 67 } |
| 68 |
| 69 /* same as above but takes an input_value from 0..PRECACHE_OUTPUT_MAX |
| 70 * and returns a uint8_t value representing a range from 0..1 */ |
| 71 static |
| 72 uint8_t lut_interp_linear_precache_output(uint32_t input_value, uint16_t *table,
size_t length) |
| 73 { |
| 74 /* Start scaling input_value to the length of the array: PRECACHE_OUTPUT
_MAX*(length-1). |
| 75 * We'll divide out the PRECACHE_OUTPUT_MAX next */ |
| 76 uintptr_t value = (input_value * (length - 1)); |
| 77 |
| 78 /* equivalent to ceil(value/PRECACHE_OUTPUT_MAX) */ |
| 79 uint32_t upper = (value + PRECACHE_OUTPUT_MAX-1) / PRECACHE_OUTPUT_MAX; |
| 80 /* equivalent to floor(value/PRECACHE_OUTPUT_MAX) */ |
| 81 uint32_t lower = value / PRECACHE_OUTPUT_MAX; |
| 82 /* interp is the distance from upper to value scaled to 0..PRECACHE_OUTP
UT_MAX */ |
| 83 uint32_t interp = value % PRECACHE_OUTPUT_MAX; |
| 84 |
| 85 /* the table values range from 0..65535 */ |
| 86 value = (table[upper]*(interp) + table[lower]*(PRECACHE_OUTPUT_MAX - int
erp)); // 0..(65535*PRECACHE_OUTPUT_MAX) |
| 87 |
| 88 /* round and scale */ |
| 89 value += (PRECACHE_OUTPUT_MAX*65535/255)/2; |
| 90 value /= (PRECACHE_OUTPUT_MAX*65535/255); // scale to 0..255 |
| 91 return value; |
| 92 } |
| 93 |
| 94 /* value must be a value between 0 and 1 */ |
| 95 //XXX: is the above a good restriction to have? |
| 96 float lut_interp_linear_float(float value, float *table, size_t length) |
| 97 { |
| 98 int upper, lower; |
| 99 value = value * (length - 1); |
| 100 upper = ceil(value); |
| 101 lower = floor(value); |
| 102 //XXX: can we be more performant here? |
| 103 value = table[upper]*(1. - (upper - value)) + table[lower]*(upper - valu
e); |
| 104 /* scale the value */ |
| 105 return value; |
| 106 } |
| 107 |
| 108 #if 0 |
| 109 /* if we use a different representation i.e. one that goes from 0 to 0x1000 we c
an be more efficient |
| 110 * because we can avoid the divisions and use a shifting instead */ |
| 111 /* same as above but takes and returns a uint16_t value representing a range fro
m 0..1 */ |
| 112 uint16_t lut_interp_linear16(uint16_t input_value, uint16_t *table, int length) |
| 113 { |
| 114 uint32_t value = (input_value * (length - 1)); |
| 115 uint32_t upper = (value + 4095) / 4096; /* equivalent to ceil(value/4096
) */ |
| 116 uint32_t lower = value / 4096; /* equivalent to floor(value/40
96) */ |
| 117 uint32_t interp = value % 4096; |
| 118 |
| 119 value = (table[upper]*(interp) + table[lower]*(4096 - interp))/4096; //
0..4096*4096 |
| 120 |
| 121 return value; |
| 122 } |
| 123 #endif |
| 124 |
| 125 void compute_curve_gamma_table_type1(float gamma_table[256], uint16_t gamma) |
| 126 { |
| 127 unsigned int i; |
| 128 float gamma_float = u8Fixed8Number_to_float(gamma); |
| 129 for (i = 0; i < 256; i++) { |
| 130 // 0..1^(0..255 + 255/256) will always be between 0 and 1 |
| 131 gamma_table[i] = pow(i/255., gamma_float); |
| 132 } |
| 133 } |
| 134 |
| 135 void compute_curve_gamma_table_type2(float gamma_table[256], uint16_t *table, si
ze_t length) |
| 136 { |
| 137 unsigned int i; |
| 138 for (i = 0; i < 256; i++) { |
| 139 gamma_table[i] = lut_interp_linear(i/255., table, length); |
| 140 } |
| 141 } |
| 142 |
| 143 void compute_curve_gamma_table_type_parametric(float gamma_table[256], float par
ameter[7], int count) |
| 144 { |
| 145 size_t X; |
| 146 float interval; |
| 147 float a, b, c, e, f; |
| 148 float y = parameter[0]; |
| 149 if (count == 0) { |
| 150 a = 1; |
| 151 b = 0; |
| 152 c = 0; |
| 153 e = 0; |
| 154 f = 0; |
| 155 interval = -INFINITY; |
| 156 } else if(count == 1) { |
| 157 a = parameter[1]; |
| 158 b = parameter[2]; |
| 159 c = 0; |
| 160 e = 0; |
| 161 f = 0; |
| 162 interval = -1 * parameter[2] / parameter[1]; |
| 163 } else if(count == 2) { |
| 164 a = parameter[1]; |
| 165 b = parameter[2]; |
| 166 c = 0; |
| 167 e = parameter[3]; |
| 168 f = parameter[3]; |
| 169 interval = -1 * parameter[2] / parameter[1]; |
| 170 } else if(count == 3) { |
| 171 a = parameter[1]; |
| 172 b = parameter[2]; |
| 173 c = parameter[3]; |
| 174 e = -c; |
| 175 f = 0; |
| 176 interval = parameter[4]; |
| 177 } else if(count == 4) { |
| 178 a = parameter[1]; |
| 179 b = parameter[2]; |
| 180 c = parameter[3]; |
| 181 e = parameter[5] - c; |
| 182 f = parameter[6]; |
| 183 interval = parameter[4]; |
| 184 } else { |
| 185 assert(0 && "invalid parametric function type."); |
| 186 a = 1; |
| 187 b = 0; |
| 188 c = 0; |
| 189 e = 0; |
| 190 f = 0; |
| 191 interval = -INFINITY; |
| 192 } |
| 193 for (X = 0; X < 256; X++) { |
| 194 float x = X / 255.0; |
| 195 if (x >= interval) { |
| 196 // XXX The equations are not exactly as definied in the
spec but are |
| 197 // algebraic equivilent. |
| 198 // TODO Should division by 255 be for the whole expressi
on. |
| 199 gamma_table[X] = clamp_float(pow(a * x + b, y) + c + e); |
| 200 } else { |
| 201 gamma_table[X] = clamp_float(c * x + f); |
| 202 } |
| 203 } |
| 204 } |
| 205 |
| 206 void compute_curve_gamma_table_type0(float gamma_table[256]) |
| 207 { |
| 208 unsigned int i; |
| 209 for (i = 0; i < 256; i++) { |
| 210 gamma_table[i] = i/255.; |
| 211 } |
| 212 } |
| 213 |
| 214 float clamp_float(float a) |
| 215 { |
| 216 /* One would naturally write this function as the following: |
| 217 if (a > 1.) |
| 218 return 1.; |
| 219 else if (a < 0) |
| 220 return 0; |
| 221 else |
| 222 return a; |
| 223 |
| 224 However, that version will let NaNs pass through which is undesirable |
| 225 for most consumers. |
| 226 */ |
| 227 |
| 228 if (a > 1.) |
| 229 return 1.; |
| 230 else if (a >= 0) |
| 231 return a; |
| 232 else // a < 0 or a is NaN |
| 233 return 0; |
| 234 } |
| 235 |
| 236 unsigned char clamp_u8(float v) |
| 237 { |
| 238 if (v > 255.) |
| 239 return 255; |
| 240 else if (v < 0) |
| 241 return 0; |
| 242 else |
| 243 return floor(v+.5); |
| 244 } |
| 245 |
| 246 float u8Fixed8Number_to_float(uint16_t x) |
| 247 { |
| 248 // 0x0000 = 0. |
| 249 // 0x0100 = 1. |
| 250 // 0xffff = 255 + 255/256 |
| 251 return x/256.; |
| 252 } |
| 253 |
| 254 /* The SSE2 code uses min & max which let NaNs pass through. |
| 255 We want to try to prevent that here by ensuring that |
| 256 gamma table is within expected values. */ |
| 257 void validate_gamma_table(float gamma_table[256]) |
| 258 { |
| 259 int i; |
| 260 for (i = 0; i < 256; i++) { |
| 261 // Note: we check that the gamma is not in range |
| 262 // instead of out of range so that we catch NaNs |
| 263 if (!(gamma_table[i] >= 0.f && gamma_table[i] <= 1.f)) { |
| 264 gamma_table[i] = 0.f; |
| 265 } |
| 266 } |
| 267 } |
| 268 |
| 269 float *build_input_gamma_table(struct curveType *TRC) |
| 270 { |
| 271 float *gamma_table; |
| 272 |
| 273 if (!TRC) return NULL; |
| 274 gamma_table = malloc(sizeof(float)*256); |
| 275 if (gamma_table) { |
| 276 if (TRC->type == PARAMETRIC_CURVE_TYPE) { |
| 277 compute_curve_gamma_table_type_parametric(gamma_table, T
RC->parameter, TRC->count); |
| 278 } else { |
| 279 if (TRC->count == 0) { |
| 280 compute_curve_gamma_table_type0(gamma_table); |
| 281 } else if (TRC->count == 1) { |
| 282 compute_curve_gamma_table_type1(gamma_table, TRC
->data[0]); |
| 283 } else { |
| 284 compute_curve_gamma_table_type2(gamma_table, TRC
->data, TRC->count); |
| 285 } |
| 286 } |
| 287 } |
| 288 |
| 289 validate_gamma_table(gamma_table); |
| 290 |
| 291 return gamma_table; |
| 292 } |
| 293 |
| 294 struct matrix build_colorant_matrix(qcms_profile *p) |
| 295 { |
| 296 struct matrix result; |
| 297 result.m[0][0] = s15Fixed16Number_to_float(p->redColorant.X); |
| 298 result.m[0][1] = s15Fixed16Number_to_float(p->greenColorant.X); |
| 299 result.m[0][2] = s15Fixed16Number_to_float(p->blueColorant.X); |
| 300 result.m[1][0] = s15Fixed16Number_to_float(p->redColorant.Y); |
| 301 result.m[1][1] = s15Fixed16Number_to_float(p->greenColorant.Y); |
| 302 result.m[1][2] = s15Fixed16Number_to_float(p->blueColorant.Y); |
| 303 result.m[2][0] = s15Fixed16Number_to_float(p->redColorant.Z); |
| 304 result.m[2][1] = s15Fixed16Number_to_float(p->greenColorant.Z); |
| 305 result.m[2][2] = s15Fixed16Number_to_float(p->blueColorant.Z); |
| 306 result.invalid = false; |
| 307 return result; |
| 308 } |
| 309 |
| 310 /* The following code is copied nearly directly from lcms. |
| 311 * I think it could be much better. For example, Argyll seems to have better cod
e in |
| 312 * icmTable_lookup_bwd and icmTable_setup_bwd. However, for now this is a quick
way |
| 313 * to a working solution and allows for easy comparing with lcms. */ |
| 314 uint16_fract_t lut_inverse_interp16(uint16_t Value, uint16_t LutTable[], int len
gth, int NumZeroes, int NumPoles) |
| 315 { |
| 316 int l = 1; |
| 317 int r = 0x10000; |
| 318 int x = 0, res; // 'int' Give spacing for negative values |
| 319 int cell0, cell1; |
| 320 double val2; |
| 321 double y0, y1, x0, x1; |
| 322 double a, b, f; |
| 323 |
| 324 // July/27 2001 - Expanded to handle degenerated curves with an arbitrar
y |
| 325 // number of elements containing 0 at the beginning of the table (Zeroes
) |
| 326 // and another arbitrary number of poles (FFFFh) at the end. |
| 327 |
| 328 // There are no zeros at the beginning and we are trying to find a zero,
so |
| 329 // return anything. It seems zero would be the less destructive choice |
| 330 /* I'm not sure that this makes sense, but oh well... */ |
| 331 if (NumZeroes == 0 && Value == 0) |
| 332 return 0; |
| 333 |
| 334 // Does the curve belong to this case? |
| 335 if (NumZeroes > 1 || NumPoles > 1) |
| 336 { |
| 337 int a, b, sample; |
| 338 |
| 339 // Identify if value fall downto 0 or FFFF zone |
| 340 if (Value == 0) return 0; |
| 341 // if (Value == 0xFFFF) return 0xFFFF; |
| 342 sample = (length-1) * ((double) Value * (1./65535.)); |
| 343 if (LutTable[sample] == 0xffff) |
| 344 return 0xffff; |
| 345 |
| 346 // else restrict to valid zone |
| 347 |
| 348 a = ((NumZeroes-1) * 0xFFFF) / (length-1); |
| 349 b = ((length-1 - NumPoles) * 0xFFFF) / (length-1); |
| 350 |
| 351 l = a - 1; |
| 352 r = b + 1; |
| 353 |
| 354 // Ensure a valid binary search range |
| 355 |
| 356 if (l < 1) |
| 357 l = 1; |
| 358 if (r > 0x10000) |
| 359 r = 0x10000; |
| 360 |
| 361 // If the search range is inverted due to degeneracy, |
| 362 // deem LutTable non-invertible in this search range. |
| 363 // Refer to https://bugzil.la/1132467 |
| 364 |
| 365 if (r <= l) |
| 366 return 0; |
| 367 } |
| 368 |
| 369 // For input 0, return that to maintain black level. Note the binary sea
rch |
| 370 // does not. For example, it inverts the standard sRGB gamma curve to 7
at |
| 371 // the origin, causing a black level error. |
| 372 |
| 373 if (Value == 0 && NumZeroes) { |
| 374 return 0; |
| 375 } |
| 376 |
| 377 // Seems not a degenerated case... apply binary search |
| 378 |
| 379 while (r > l) { |
| 380 |
| 381 x = (l + r) / 2; |
| 382 |
| 383 res = (int) lut_interp_linear16((uint16_fract_t) (x-1), LutTable
, length); |
| 384 |
| 385 if (res == Value) { |
| 386 |
| 387 // Found exact match. |
| 388 |
| 389 return (uint16_fract_t) (x - 1); |
| 390 } |
| 391 |
| 392 if (res > Value) r = x - 1; |
| 393 else l = x + 1; |
| 394 } |
| 395 |
| 396 // Not found, should we interpolate? |
| 397 |
| 398 // Get surrounding nodes |
| 399 |
| 400 assert(x >= 1); |
| 401 |
| 402 val2 = (length-1) * ((double) (x - 1) / 65535.0); |
| 403 |
| 404 cell0 = (int) floor(val2); |
| 405 cell1 = (int) ceil(val2); |
| 406 |
| 407 assert(cell0 >= 0); |
| 408 assert(cell1 >= 0); |
| 409 assert(cell0 < length); |
| 410 assert(cell1 < length); |
| 411 |
| 412 if (cell0 == cell1) return (uint16_fract_t) x; |
| 413 |
| 414 y0 = LutTable[cell0] ; |
| 415 x0 = (65535.0 * cell0) / (length-1); |
| 416 |
| 417 y1 = LutTable[cell1] ; |
| 418 x1 = (65535.0 * cell1) / (length-1); |
| 419 |
| 420 a = (y1 - y0) / (x1 - x0); |
| 421 b = y0 - a * x0; |
| 422 |
| 423 if (fabs(a) < 0.01) return (uint16_fract_t) x; |
| 424 |
| 425 f = ((Value - b) / a); |
| 426 |
| 427 if (f < 0.0) return (uint16_fract_t) 0; |
| 428 if (f >= 65535.0) return (uint16_fract_t) 0xFFFF; |
| 429 |
| 430 return (uint16_fract_t) floor(f + 0.5); |
| 431 } |
| 432 |
| 433 // December/16 2015 - Moved this code out of lut_inverse_interp16 |
| 434 // in order to save computation in invert_lut loop. |
| 435 static void count_zeroes_and_poles(uint16_t *LutTable, int length, int *NumZeroe
s, int *NumPoles) |
| 436 { |
| 437 int z = 0, p = 0; |
| 438 |
| 439 while (LutTable[z] == 0 && z < length - 1) |
| 440 z++; |
| 441 *NumZeroes = z; |
| 442 |
| 443 while (LutTable[length - 1 - p] == 0xFFFF && p < length - 1) |
| 444 p++; |
| 445 *NumPoles = p; |
| 446 } |
| 447 |
| 448 /* |
| 449 The number of entries needed to invert a lookup table should not |
| 450 necessarily be the same as the original number of entries. This is |
| 451 especially true of lookup tables that have a small number of entries. |
| 452 |
| 453 For example: |
| 454 Using a table like: |
| 455 {0, 3104, 14263, 34802, 65535} |
| 456 invert_lut will produce an inverse of: |
| 457 {3, 34459, 47529, 56801, 65535} |
| 458 which has an maximum error of about 9855 (pixel difference of ~38.346) |
| 459 |
| 460 For now, we punt the decision of output size to the caller. */ |
| 461 static uint16_t *invert_lut(uint16_t *table, int length, size_t out_length) |
| 462 { |
| 463 int NumZeroes; |
| 464 int NumPoles; |
| 465 int i; |
| 466 /* for now we invert the lut by creating a lut of size out_length |
| 467 * and attempting to lookup a value for each entry using lut_inverse_int
erp16 */ |
| 468 uint16_t *output = malloc(sizeof(uint16_t)*out_length); |
| 469 if (!output) |
| 470 return NULL; |
| 471 |
| 472 // December/16 2015 - Compute the input curve zero and pole extents outs
ide |
| 473 // the loop and pass them to lut_inverse_interp16. |
| 474 count_zeroes_and_poles(table, length, &NumZeroes, &NumPoles); |
| 475 |
| 476 for (i = 0; i < out_length; i++) { |
| 477 double x = ((double) i * 65535.) / (double) (out_length - 1); |
| 478 uint16_fract_t input = floor(x + .5); |
| 479 output[i] = lut_inverse_interp16(input, table, length, NumZeroes
, NumPoles); |
| 480 } |
| 481 |
| 482 return output; |
| 483 } |
| 484 |
| 485 static void compute_precache_pow(uint8_t *output, float gamma) |
| 486 { |
| 487 uint32_t v = 0; |
| 488 for (v = 0; v < PRECACHE_OUTPUT_SIZE; v++) { |
| 489 //XXX: don't do integer/float conversion... and round? |
| 490 output[v] = 255. * pow(v/(double)PRECACHE_OUTPUT_MAX, gamma); |
| 491 } |
| 492 } |
| 493 |
| 494 void compute_precache_lut(uint8_t *output, uint16_t *table, int length) |
| 495 { |
| 496 uint32_t v = 0; |
| 497 for (v = 0; v < PRECACHE_OUTPUT_SIZE; v++) { |
| 498 output[v] = lut_interp_linear_precache_output(v, table, length); |
| 499 } |
| 500 } |
| 501 |
| 502 void compute_precache_linear(uint8_t *output) |
| 503 { |
| 504 uint32_t v = 0; |
| 505 for (v = 0; v < PRECACHE_OUTPUT_SIZE; v++) { |
| 506 //XXX: round? |
| 507 output[v] = v / (PRECACHE_OUTPUT_SIZE/256); |
| 508 } |
| 509 } |
| 510 |
| 511 qcms_bool compute_precache(struct curveType *trc, uint8_t *output) |
| 512 { |
| 513 |
| 514 if (trc->type == PARAMETRIC_CURVE_TYPE) { |
| 515 float gamma_table[256]; |
| 516 uint16_t gamma_table_uint[256]; |
| 517 uint16_t i; |
| 518 uint16_t *inverted; |
| 519 int inverted_size = 256; |
| 520 |
| 521 compute_curve_gamma_table_type_parametric(gamma_table, t
rc->parameter, trc->count); |
| 522 for(i = 0; i < 256; i++) { |
| 523 gamma_table_uint[i] = (uint16_t)(gamma_table[i]
* 65535); |
| 524 } |
| 525 |
| 526 //XXX: the choice of a minimum of 256 here is not backed
by any theory, |
| 527 // measurement or data, howeve r it is what lcms use
s. |
| 528 // the maximum number we would need is 65535 because
that's the |
| 529 // accuracy used for computing the pre cache table |
| 530 if (inverted_size < 256) |
| 531 inverted_size = 256; |
| 532 |
| 533 inverted = invert_lut(gamma_table_uint, 256, inverted_si
ze); |
| 534 if (!inverted) |
| 535 return false; |
| 536 compute_precache_lut(output, inverted, inverted_size); |
| 537 free(inverted); |
| 538 } else { |
| 539 if (trc->count == 0) { |
| 540 compute_precache_linear(output); |
| 541 } else if (trc->count == 1) { |
| 542 compute_precache_pow(output, 1./u8Fixed8Number_to_float(
trc->data[0])); |
| 543 } else { |
| 544 uint16_t *inverted; |
| 545 int inverted_size = trc->count; |
| 546 //XXX: the choice of a minimum of 256 here is not backed
by any theory, |
| 547 // measurement or data, howeve r it is what lcms use
s. |
| 548 // the maximum number we would need is 65535 because
that's the |
| 549 // accuracy used for computing the pre cache table |
| 550 if (inverted_size < 256) |
| 551 inverted_size = 256; |
| 552 |
| 553 inverted = invert_lut(trc->data, trc->count, inverted_si
ze); |
| 554 if (!inverted) |
| 555 return false; |
| 556 compute_precache_lut(output, inverted, inverted_size); |
| 557 free(inverted); |
| 558 } |
| 559 } |
| 560 return true; |
| 561 } |
| 562 |
| 563 |
| 564 static uint16_t *build_linear_table(int length) |
| 565 { |
| 566 int i; |
| 567 uint16_t *output = malloc(sizeof(uint16_t)*length); |
| 568 if (!output) |
| 569 return NULL; |
| 570 |
| 571 for (i = 0; i < length; i++) { |
| 572 double x = ((double) i * 65535.) / (double) (length - 1); |
| 573 uint16_fract_t input = floor(x + .5); |
| 574 output[i] = input; |
| 575 } |
| 576 return output; |
| 577 } |
| 578 |
| 579 static uint16_t *build_pow_table(float gamma, int length) |
| 580 { |
| 581 int i; |
| 582 uint16_t *output = malloc(sizeof(uint16_t)*length); |
| 583 if (!output) |
| 584 return NULL; |
| 585 |
| 586 for (i = 0; i < length; i++) { |
| 587 uint16_fract_t result; |
| 588 double x = ((double) i) / (double) (length - 1); |
| 589 x = pow(x, gamma); //XXX turn this conversion int
o a function |
| 590 result = floor(x*65535. + .5); |
| 591 output[i] = result; |
| 592 } |
| 593 return output; |
| 594 } |
| 595 |
| 596 void build_output_lut(struct curveType *trc, |
| 597 uint16_t **output_gamma_lut, size_t *output_gamma_lut_length) |
| 598 { |
| 599 if (trc->type == PARAMETRIC_CURVE_TYPE) { |
| 600 float gamma_table[256]; |
| 601 uint16_t gamma_table_uint[256]; |
| 602 uint16_t i; |
| 603 uint16_t *inverted; |
| 604 int inverted_size = 4096; |
| 605 |
| 606 compute_curve_gamma_table_type_parametric(gamma_table, trc->para
meter, trc->count); |
| 607 for(i = 0; i < 256; i++) { |
| 608 gamma_table_uint[i] = (uint16_t)(gamma_table[i] * 65535)
; |
| 609 } |
| 610 |
| 611 //XXX: the choice of a minimum of 256 here is not backed by any
theory, |
| 612 // measurement or data, however it is what lcms uses. |
| 613 // the maximum number we would need is 65535 because that's
the |
| 614 // accuracy used for computing the pre cache table |
| 615 inverted = invert_lut(gamma_table_uint, 256, inverted_size); |
| 616 if (!inverted) |
| 617 return; |
| 618 *output_gamma_lut = inverted; |
| 619 *output_gamma_lut_length = inverted_size; |
| 620 } else { |
| 621 if (trc->count == 0) { |
| 622 *output_gamma_lut = build_linear_table(4096); |
| 623 *output_gamma_lut_length = 4096; |
| 624 } else if (trc->count == 1) { |
| 625 float gamma = 1./u8Fixed8Number_to_float(trc->data[0]); |
| 626 *output_gamma_lut = build_pow_table(gamma, 4096); |
| 627 *output_gamma_lut_length = 4096; |
| 628 } else { |
| 629 //XXX: the choice of a minimum of 256 here is not backed
by any theory, |
| 630 // measurement or data, however it is what lcms uses
. |
| 631 *output_gamma_lut_length = trc->count; |
| 632 if (*output_gamma_lut_length < 256) |
| 633 *output_gamma_lut_length = 256; |
| 634 |
| 635 *output_gamma_lut = invert_lut(trc->data, trc->count, *o
utput_gamma_lut_length); |
| 636 } |
| 637 } |
| 638 |
| 639 } |
OLD | NEW |