1 ////////////////////////////////////////////////////////////////////////////// 2 // 3 // Copyright (c) 2004, Industrial Light & Magic, a division of Lucasfilm 4 // Entertainment Company Ltd. Portions contributed and copyright held by 5 // others as indicated. All rights reserved. 6 // 7 // Redistribution and use in source and binary forms, with or without 8 // modification, are permitted provided that the following conditions are 9 // met: 10 // 11 // * Redistributions of source code must retain the above 12 // copyright notice, this list of conditions and the following 13 // disclaimer. 14 // 15 // * Redistributions in binary form must reproduce the above 16 // copyright notice, this list of conditions and the following 17 // disclaimer in the documentation and/or other materials provided with 18 // the distribution. 19 // 20 // * Neither the name of Industrial Light & Magic nor the names of 21 // any other contributors to this software may be used to endorse or 22 // promote products derived from this software without specific prior 23 // written permission. 24 // 25 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS 26 // IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 27 // THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 // PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 29 // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 30 // EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 31 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 32 // PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 33 // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 34 // NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 35 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 // 37 ////////////////////////////////////////////////////////////////////////////// 38 39 //----------------------------------------------------------------------------- 40 // 41 // Conversion between RGBA and YCA data. 42 // 43 //----------------------------------------------------------------------------- 44 45 #include <ImfRgbaYca.h> 46 #include <assert.h> 47 #include <algorithm> 48 49 using namespace Imath; 50 using namespace std; 51 52 namespace Imf { 53 namespace RgbaYca { 54 55 56 V3f 57 computeYw (const Chromaticities &cr) 58 { 59 M44f m = RGBtoXYZ (cr, 1); 60 return V3f (m[0][1], m[1][1], m[2][1]) / (m[0][1] + m[1][1] + m[2][1]); 61 } 62 63 64 void 65 RGBAtoYCA (const V3f &yw, 66 int n, 67 bool aIsValid, 68 const Rgba rgbaIn[/*n*/], 69 Rgba ycaOut[/*n*/]) 70 { 71 for (int i = 0; i < n; ++i) 72 { 73 Rgba in = rgbaIn[i]; 74 Rgba &out = ycaOut[i]; 75 76 // 77 // Conversion to YCA and subsequent chroma subsampling 78 // work only if R, G and B are finite and non-negative. 79 // 80 81 if (!in.r.isFinite() || in.r < 0) 82 in.r = 0; 83 84 if (!in.g.isFinite() || in.g < 0) 85 in.g = 0; 86 87 if (!in.b.isFinite() || in.b < 0) 88 in.b = 0; 89 90 if (in.r == in.g && in.g == in.b) 91 { 92 // 93 // Special case -- R, G and B are equal. To avoid rounding 94 // errors, we explicitly set the output luminance channel 95 // to G, and the chroma channels to 0. 96 // 97 // The special cases here and in YCAtoRGBA() ensure that 98 // converting black-and white images from RGBA to YCA and 99 // back is lossless. 100 // 101 102 out.r = 0; 103 out.g = in.g; 104 out.b = 0; 105 } 106 else 107 { 108 out.g = in.r * yw.x + in.g * yw.y + in.b * yw.z; 109 110 float Y = out.g; 111 112 if (abs (in.r - Y) < HALF_MAX * Y) 113 out.r = (in.r - Y) / Y; 114 else 115 out.r = 0; 116 117 if (abs (in.b - Y) < HALF_MAX * Y) 118 out.b = (in.b - Y) / Y; 119 else 120 out.b = 0; 121 } 122 123 if (aIsValid) 124 out.a = in.a; 125 else 126 out.a = 1; 127 } 128 } 129 130 131 void 132 decimateChromaHoriz (int n, 133 const Rgba ycaIn[/*n+N-1*/], 134 Rgba ycaOut[/*n*/]) 135 { 136 #ifdef DEBUG 137 assert (ycaIn != ycaOut); 138 #endif 139 140 int begin = N2; 141 int end = begin + n; 142 143 for (int i = begin, j = 0; i < end; ++i, ++j) 144 { 145 if ((j & 1) == 0) 146 { 147 ycaOut[j].r = ycaIn[i - 13].r * 0.001064f + 148 ycaIn[i - 11].r * -0.003771f + 149 ycaIn[i - 9].r * 0.009801f + 150 ycaIn[i - 7].r * -0.021586f + 151 ycaIn[i - 5].r * 0.043978f + 152 ycaIn[i - 3].r * -0.093067f + 153 ycaIn[i - 1].r * 0.313659f + 154 ycaIn[i ].r * 0.499846f + 155 ycaIn[i + 1].r * 0.313659f + 156 ycaIn[i + 3].r * -0.093067f + 157 ycaIn[i + 5].r * 0.043978f + 158 ycaIn[i + 7].r * -0.021586f + 159 ycaIn[i + 9].r * 0.009801f + 160 ycaIn[i + 11].r * -0.003771f + 161 ycaIn[i + 13].r * 0.001064f; 162 163 ycaOut[j].b = ycaIn[i - 13].b * 0.001064f + 164 ycaIn[i - 11].b * -0.003771f + 165 ycaIn[i - 9].b * 0.009801f + 166 ycaIn[i - 7].b * -0.021586f + 167 ycaIn[i - 5].b * 0.043978f + 168 ycaIn[i - 3].b * -0.093067f + 169 ycaIn[i - 1].b * 0.313659f + 170 ycaIn[i ].b * 0.499846f + 171 ycaIn[i + 1].b * 0.313659f + 172 ycaIn[i + 3].b * -0.093067f + 173 ycaIn[i + 5].b * 0.043978f + 174 ycaIn[i + 7].b * -0.021586f + 175 ycaIn[i + 9].b * 0.009801f + 176 ycaIn[i + 11].b * -0.003771f + 177 ycaIn[i + 13].b * 0.001064f; 178 } 179 180 ycaOut[j].g = ycaIn[i].g; 181 ycaOut[j].a = ycaIn[i].a; 182 } 183 } 184 185 186 void 187 decimateChromaVert (int n, 188 const Rgba * const ycaIn[N], 189 Rgba ycaOut[/*n*/]) 190 { 191 for (int i = 0; i < n; ++i) 192 { 193 if ((i & 1) == 0) 194 { 195 ycaOut[i].r = ycaIn[ 0][i].r * 0.001064f + 196 ycaIn[ 2][i].r * -0.003771f + 197 ycaIn[ 4][i].r * 0.009801f + 198 ycaIn[ 6][i].r * -0.021586f + 199 ycaIn[ 8][i].r * 0.043978f + 200 ycaIn[10][i].r * -0.093067f + 201 ycaIn[12][i].r * 0.313659f + 202 ycaIn[13][i].r * 0.499846f + 203 ycaIn[14][i].r * 0.313659f + 204 ycaIn[16][i].r * -0.093067f + 205 ycaIn[18][i].r * 0.043978f + 206 ycaIn[20][i].r * -0.021586f + 207 ycaIn[22][i].r * 0.009801f + 208 ycaIn[24][i].r * -0.003771f + 209 ycaIn[26][i].r * 0.001064f; 210 211 ycaOut[i].b = ycaIn[ 0][i].b * 0.001064f + 212 ycaIn[ 2][i].b * -0.003771f + 213 ycaIn[ 4][i].b * 0.009801f + 214 ycaIn[ 6][i].b * -0.021586f + 215 ycaIn[ 8][i].b * 0.043978f + 216 ycaIn[10][i].b * -0.093067f + 217 ycaIn[12][i].b * 0.313659f + 218 ycaIn[13][i].b * 0.499846f + 219 ycaIn[14][i].b * 0.313659f + 220 ycaIn[16][i].b * -0.093067f + 221 ycaIn[18][i].b * 0.043978f + 222 ycaIn[20][i].b * -0.021586f + 223 ycaIn[22][i].b * 0.009801f + 224 ycaIn[24][i].b * -0.003771f + 225 ycaIn[26][i].b * 0.001064f; 226 } 227 228 ycaOut[i].g = ycaIn[13][i].g; 229 ycaOut[i].a = ycaIn[13][i].a; 230 } 231 } 232 233 234 void 235 roundYCA (int n, 236 unsigned int roundY, 237 unsigned int roundC, 238 const Rgba ycaIn[/*n*/], 239 Rgba ycaOut[/*n*/]) 240 { 241 for (int i = 0; i < n; ++i) 242 { 243 ycaOut[i].g = ycaIn[i].g.round (roundY); 244 ycaOut[i].a = ycaIn[i].a; 245 246 if ((i & 1) == 0) 247 { 248 ycaOut[i].r = ycaIn[i].r.round (roundC); 249 ycaOut[i].b = ycaIn[i].b.round (roundC); 250 } 251 } 252 } 253 254 255 void 256 reconstructChromaHoriz (int n, 257 const Rgba ycaIn[/*n+N-1*/], 258 Rgba ycaOut[/*n*/]) 259 { 260 #ifdef DEBUG 261 assert (ycaIn != ycaOut); 262 #endif 263 264 int begin = N2; 265 int end = begin + n; 266 267 for (int i = begin, j = 0; i < end; ++i, ++j) 268 { 269 if (j & 1) 270 { 271 ycaOut[j].r = ycaIn[i - 13].r * 0.002128f + 272 ycaIn[i - 11].r * -0.007540f + 273 ycaIn[i - 9].r * 0.019597f + 274 ycaIn[i - 7].r * -0.043159f + 275 ycaIn[i - 5].r * 0.087929f + 276 ycaIn[i - 3].r * -0.186077f + 277 ycaIn[i - 1].r * 0.627123f + 278 ycaIn[i + 1].r * 0.627123f + 279 ycaIn[i + 3].r * -0.186077f + 280 ycaIn[i + 5].r * 0.087929f + 281 ycaIn[i + 7].r * -0.043159f + 282 ycaIn[i + 9].r * 0.019597f + 283 ycaIn[i + 11].r * -0.007540f + 284 ycaIn[i + 13].r * 0.002128f; 285 286 ycaOut[j].b = ycaIn[i - 13].b * 0.002128f + 287 ycaIn[i - 11].b * -0.007540f + 288 ycaIn[i - 9].b * 0.019597f + 289 ycaIn[i - 7].b * -0.043159f + 290 ycaIn[i - 5].b * 0.087929f + 291 ycaIn[i - 3].b * -0.186077f + 292 ycaIn[i - 1].b * 0.627123f + 293 ycaIn[i + 1].b * 0.627123f + 294 ycaIn[i + 3].b * -0.186077f + 295 ycaIn[i + 5].b * 0.087929f + 296 ycaIn[i + 7].b * -0.043159f + 297 ycaIn[i + 9].b * 0.019597f + 298 ycaIn[i + 11].b * -0.007540f + 299 ycaIn[i + 13].b * 0.002128f; 300 } 301 else 302 { 303 ycaOut[j].r = ycaIn[i].r; 304 ycaOut[j].b = ycaIn[i].b; 305 } 306 307 ycaOut[j].g = ycaIn[i].g; 308 ycaOut[j].a = ycaIn[i].a; 309 } 310 } 311 312 313 void 314 reconstructChromaVert (int n, 315 const Rgba * const ycaIn[N], 316 Rgba ycaOut[/*n*/]) 317 { 318 for (int i = 0; i < n; ++i) 319 { 320 ycaOut[i].r = ycaIn[ 0][i].r * 0.002128f + 321 ycaIn[ 2][i].r * -0.007540f + 322 ycaIn[ 4][i].r * 0.019597f + 323 ycaIn[ 6][i].r * -0.043159f + 324 ycaIn[ 8][i].r * 0.087929f + 325 ycaIn[10][i].r * -0.186077f + 326 ycaIn[12][i].r * 0.627123f + 327 ycaIn[14][i].r * 0.627123f + 328 ycaIn[16][i].r * -0.186077f + 329 ycaIn[18][i].r * 0.087929f + 330 ycaIn[20][i].r * -0.043159f + 331 ycaIn[22][i].r * 0.019597f + 332 ycaIn[24][i].r * -0.007540f + 333 ycaIn[26][i].r * 0.002128f; 334 335 ycaOut[i].b = ycaIn[ 0][i].b * 0.002128f + 336 ycaIn[ 2][i].b * -0.007540f + 337 ycaIn[ 4][i].b * 0.019597f + 338 ycaIn[ 6][i].b * -0.043159f + 339 ycaIn[ 8][i].b * 0.087929f + 340 ycaIn[10][i].b * -0.186077f + 341 ycaIn[12][i].b * 0.627123f + 342 ycaIn[14][i].b * 0.627123f + 343 ycaIn[16][i].b * -0.186077f + 344 ycaIn[18][i].b * 0.087929f + 345 ycaIn[20][i].b * -0.043159f + 346 ycaIn[22][i].b * 0.019597f + 347 ycaIn[24][i].b * -0.007540f + 348 ycaIn[26][i].b * 0.002128f; 349 350 ycaOut[i].g = ycaIn[13][i].g; 351 ycaOut[i].a = ycaIn[13][i].a; 352 } 353 } 354 355 356 void 357 YCAtoRGBA (const Imath::V3f &yw, 358 int n, 359 const Rgba ycaIn[/*n*/], 360 Rgba rgbaOut[/*n*/]) 361 { 362 for (int i = 0; i < n; ++i) 363 { 364 const Rgba &in = ycaIn[i]; 365 Rgba &out = rgbaOut[i]; 366 367 if (in.r == 0 && in.b == 0) 368 { 369 // 370 // Special case -- both chroma channels are 0. To avoid 371 // rounding errors, we explicitly set the output R, G and B 372 // channels equal to the input luminance. 373 // 374 // The special cases here and in RGBAtoYCA() ensure that 375 // converting black-and white images from RGBA to YCA and 376 // back is lossless. 377 // 378 379 out.r = in.g; 380 out.g = in.g; 381 out.b = in.g; 382 out.a = in.a; 383 } 384 else 385 { 386 float Y = in.g; 387 float r = (in.r + 1) * Y; 388 float b = (in.b + 1) * Y; 389 float g = (Y - r * yw.x - b * yw.z) / yw.y; 390 391 out.r = r; 392 out.g = g; 393 out.b = b; 394 out.a = in.a; 395 } 396 } 397 } 398 399 400 namespace { 401 402 inline float 403 saturation (const Rgba &in) 404 { 405 float rgbMax = max (in.r, max (in.g, in.b)); 406 float rgbMin = min (in.r, min (in.g, in.b)); 407 408 if (rgbMax > 0) 409 return 1 - rgbMin / rgbMax; 410 else 411 return 0; 412 } 413 414 415 void 416 desaturate (const Rgba &in, float f, const V3f &yw, Rgba &out) 417 { 418 float rgbMax = max (in.r, max (in.g, in.b)); 419 420 out.r = max (float (rgbMax - (rgbMax - in.r) * f), 0.0f); 421 out.g = max (float (rgbMax - (rgbMax - in.g) * f), 0.0f); 422 out.b = max (float (rgbMax - (rgbMax - in.b) * f), 0.0f); 423 out.a = in.a; 424 425 float Yin = in.r * yw.x + in.g * yw.y + in.b * yw.z; 426 float Yout = out.r * yw.x + out.g * yw.y + out.b * yw.z; 427 428 if (Yout > 0) 429 { 430 out.r *= Yin / Yout; 431 out.g *= Yin / Yout; 432 out.b *= Yin / Yout; 433 } 434 } 435 436 } // namespace 437 438 439 void 440 fixSaturation (const Imath::V3f &yw, 441 int n, 442 const Rgba * const rgbaIn[3], 443 Rgba rgbaOut[/*n*/]) 444 { 445 float neighborA2 = saturation (rgbaIn[0][0]); 446 float neighborA1 = neighborA2; 447 448 float neighborB2 = saturation (rgbaIn[2][0]); 449 float neighborB1 = neighborB2; 450 451 for (int i = 0; i < n; ++i) 452 { 453 float neighborA0 = neighborA1; 454 neighborA1 = neighborA2; 455 456 float neighborB0 = neighborB1; 457 neighborB1 = neighborB2; 458 459 if (i < n - 1) 460 { 461 neighborA2 = saturation (rgbaIn[0][i + 1]); 462 neighborB2 = saturation (rgbaIn[2][i + 1]); 463 } 464 465 // 466 // A0 A1 A2 467 // rgbaOut[i] 468 // B0 B1 B2 469 // 470 471 float sMean = min (1.0f, 0.25f * (neighborA0 + neighborA2 + 472 neighborB0 + neighborB2)); 473 474 const Rgba &in = rgbaIn[1][i]; 475 Rgba &out = rgbaOut[i]; 476 477 float s = saturation (in); 478 479 if (s > sMean) 480 { 481 float sMax = min (1.0f, 1 - (1 - sMean) * 0.25f); 482 483 if (s > sMax) 484 { 485 desaturate (in, sMax / s, yw, out); 486 continue; 487 } 488 } 489 490 out = in; 491 } 492 } 493 494 } // namespace RgbaYca 495 } // namespace Imf 496
