jccolor.c revision 4a795dda3d916c591206d2c37d6b583098204108
1/* 2 * jccolor.c 3 * 4 * Copyright (C) 1991-1996, Thomas G. Lane. 5 * This file is part of the Independent JPEG Group's software. 6 * For conditions of distribution and use, see the accompanying README file. 7 * 8 * This file contains input colorspace conversion routines. 9 */ 10 11#define JPEG_INTERNALS 12#include "jinclude.h" 13#include "jpeglib.h" 14 15// this enables unrolling null_convert's loop, and reading/write ints for speed 16#define ENABLE_ANDROID_NULL_CONVERT 17 18/* Private subobject */ 19 20typedef struct { 21 struct jpeg_color_converter pub; /* public fields */ 22 23 /* Private state for RGB->YCC conversion */ 24 INT32 * rgb_ycc_tab; /* => table for RGB to YCbCr conversion */ 25} my_color_converter; 26 27typedef my_color_converter * my_cconvert_ptr; 28 29 30/**************** RGB -> YCbCr conversion: most common case **************/ 31 32/* 33 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are 34 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5. 35 * The conversion equations to be implemented are therefore 36 * Y = 0.29900 * R + 0.58700 * G + 0.11400 * B 37 * Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B + CENTERJSAMPLE 38 * Cr = 0.50000 * R - 0.41869 * G - 0.08131 * B + CENTERJSAMPLE 39 * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.) 40 * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2, 41 * rather than CENTERJSAMPLE, for Cb and Cr. This gave equal positive and 42 * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0) 43 * were not represented exactly. Now we sacrifice exact representation of 44 * maximum red and maximum blue in order to get exact grayscales. 45 * 46 * To avoid floating-point arithmetic, we represent the fractional constants 47 * as integers scaled up by 2^16 (about 4 digits precision); we have to divide 48 * the products by 2^16, with appropriate rounding, to get the correct answer. 49 * 50 * For even more speed, we avoid doing any multiplications in the inner loop 51 * by precalculating the constants times R,G,B for all possible values. 52 * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table); 53 * for 12-bit samples it is still acceptable. It's not very reasonable for 54 * 16-bit samples, but if you want lossless storage you shouldn't be changing 55 * colorspace anyway. 56 * The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included 57 * in the tables to save adding them separately in the inner loop. 58 */ 59 60#define SCALEBITS 16 /* speediest right-shift on some machines */ 61#define CBCR_OFFSET ((INT32) CENTERJSAMPLE << SCALEBITS) 62#define ONE_HALF ((INT32) 1 << (SCALEBITS-1)) 63#define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5)) 64 65/* We allocate one big table and divide it up into eight parts, instead of 66 * doing eight alloc_small requests. This lets us use a single table base 67 * address, which can be held in a register in the inner loops on many 68 * machines (more than can hold all eight addresses, anyway). 69 */ 70 71#define R_Y_OFF 0 /* offset to R => Y section */ 72#define G_Y_OFF (1*(MAXJSAMPLE+1)) /* offset to G => Y section */ 73#define B_Y_OFF (2*(MAXJSAMPLE+1)) /* etc. */ 74#define R_CB_OFF (3*(MAXJSAMPLE+1)) 75#define G_CB_OFF (4*(MAXJSAMPLE+1)) 76#define B_CB_OFF (5*(MAXJSAMPLE+1)) 77#define R_CR_OFF B_CB_OFF /* B=>Cb, R=>Cr are the same */ 78#define G_CR_OFF (6*(MAXJSAMPLE+1)) 79#define B_CR_OFF (7*(MAXJSAMPLE+1)) 80#define TABLE_SIZE (8*(MAXJSAMPLE+1)) 81 82 83/* 84 * Initialize for RGB->YCC colorspace conversion. 85 */ 86 87METHODDEF(void) 88rgb_ycc_start (j_compress_ptr cinfo) 89{ 90 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 91 INT32 * rgb_ycc_tab; 92 INT32 i; 93 94 /* Allocate and fill in the conversion tables. */ 95 cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *) 96 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 97 (TABLE_SIZE * SIZEOF(INT32))); 98 99 for (i = 0; i <= MAXJSAMPLE; i++) { 100 rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i; 101 rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i; 102 rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i + ONE_HALF; 103 rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i; 104 rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i; 105 /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr. 106 * This ensures that the maximum output will round to MAXJSAMPLE 107 * not MAXJSAMPLE+1, and thus that we don't have to range-limit. 108 */ 109 rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1; 110/* B=>Cb and R=>Cr tables are the same 111 rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i + CBCR_OFFSET + ONE_HALF-1; 112*/ 113 rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i; 114 rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i; 115 } 116} 117 118 119/* 120 * Convert some rows of samples to the JPEG colorspace. 121 * 122 * Note that we change from the application's interleaved-pixel format 123 * to our internal noninterleaved, one-plane-per-component format. 124 * The input buffer is therefore three times as wide as the output buffer. 125 * 126 * A starting row offset is provided only for the output buffer. The caller 127 * can easily adjust the passed input_buf value to accommodate any row 128 * offset required on that side. 129 */ 130 131METHODDEF(void) 132rgb_ycc_convert (j_compress_ptr cinfo, 133 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 134 JDIMENSION output_row, int num_rows) 135{ 136 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 137 register int r, g, b; 138 register INT32 * ctab = cconvert->rgb_ycc_tab; 139 register JSAMPROW inptr; 140 register JSAMPROW outptr0, outptr1, outptr2; 141 register JDIMENSION col; 142 JDIMENSION num_cols = cinfo->image_width; 143 144 while (--num_rows >= 0) { 145 inptr = *input_buf++; 146 outptr0 = output_buf[0][output_row]; 147 outptr1 = output_buf[1][output_row]; 148 outptr2 = output_buf[2][output_row]; 149 output_row++; 150 for (col = 0; col < num_cols; col++) { 151 r = GETJSAMPLE(inptr[RGB_RED]); 152 g = GETJSAMPLE(inptr[RGB_GREEN]); 153 b = GETJSAMPLE(inptr[RGB_BLUE]); 154 inptr += RGB_PIXELSIZE; 155 /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations 156 * must be too; we do not need an explicit range-limiting operation. 157 * Hence the value being shifted is never negative, and we don't 158 * need the general RIGHT_SHIFT macro. 159 */ 160 /* Y */ 161 outptr0[col] = (JSAMPLE) 162 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) 163 >> SCALEBITS); 164 /* Cb */ 165 outptr1[col] = (JSAMPLE) 166 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF]) 167 >> SCALEBITS); 168 /* Cr */ 169 outptr2[col] = (JSAMPLE) 170 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF]) 171 >> SCALEBITS); 172 } 173 } 174} 175 176#ifdef ANDROID_RGB 177/* Converts RGB565 row into YCbCr */ 178METHODDEF(void) 179rgb565_ycc_convert (j_compress_ptr cinfo, 180 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 181 JDIMENSION output_row, int num_rows) 182{ 183 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 184 register int r, g, b; 185 register INT32 * ctab = cconvert->rgb_ycc_tab; 186 register unsigned short* inptr; 187 register JSAMPROW outptr0, outptr1, outptr2; 188 register JDIMENSION col; 189 JDIMENSION num_cols = cinfo->image_width; 190 191 while (--num_rows >= 0) { 192 inptr = (unsigned short*)(*input_buf++); 193 outptr0 = output_buf[0][output_row]; 194 outptr1 = output_buf[1][output_row]; 195 outptr2 = output_buf[2][output_row]; 196 output_row++; 197 for (col = 0; col < num_cols; col++) { 198 register const unsigned short color = inptr[col]; 199 r = ((color & 0xf800) >> 8) | ((color & 0xf800) >> 14); 200 g = ((color & 0x7e0) >> 3) | ((color & 0x7e0) >> 9); 201 b = ((color & 0x1f) << 3) | ((color & 0x1f) >> 2); 202 /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations 203 * must be too; we do not need an explicit range-limiting operation. 204 * Hence the value being shifted is never negative, and we don't 205 * need the general RIGHT_SHIFT macro. 206 */ 207 /* Y */ 208 outptr0[col] = (JSAMPLE) 209 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) 210 >> SCALEBITS); 211 /* Cb */ 212 outptr1[col] = (JSAMPLE) 213 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF]) 214 >> SCALEBITS); 215 /* Cr */ 216 outptr2[col] = (JSAMPLE) 217 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF]) 218 >> SCALEBITS); 219 } 220 } 221} 222#endif /* ANDROID_RGB */ 223 224/**************** Cases other than RGB -> YCbCr **************/ 225 226 227/* 228 * Convert some rows of samples to the JPEG colorspace. 229 * This version handles RGB->grayscale conversion, which is the same 230 * as the RGB->Y portion of RGB->YCbCr. 231 * We assume rgb_ycc_start has been called (we only use the Y tables). 232 */ 233 234METHODDEF(void) 235rgb_gray_convert (j_compress_ptr cinfo, 236 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 237 JDIMENSION output_row, int num_rows) 238{ 239 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 240 register int r, g, b; 241 register INT32 * ctab = cconvert->rgb_ycc_tab; 242 register JSAMPROW inptr; 243 register JSAMPROW outptr; 244 register JDIMENSION col; 245 JDIMENSION num_cols = cinfo->image_width; 246 247 while (--num_rows >= 0) { 248 inptr = *input_buf++; 249 outptr = output_buf[0][output_row]; 250 output_row++; 251 for (col = 0; col < num_cols; col++) { 252 r = GETJSAMPLE(inptr[RGB_RED]); 253 g = GETJSAMPLE(inptr[RGB_GREEN]); 254 b = GETJSAMPLE(inptr[RGB_BLUE]); 255 inptr += RGB_PIXELSIZE; 256 /* Y */ 257 outptr[col] = (JSAMPLE) 258 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) 259 >> SCALEBITS); 260 } 261 } 262} 263 264 265/* 266 * Convert some rows of samples to the JPEG colorspace. 267 * This version handles Adobe-style CMYK->YCCK conversion, 268 * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same 269 * conversion as above, while passing K (black) unchanged. 270 * We assume rgb_ycc_start has been called. 271 */ 272 273METHODDEF(void) 274cmyk_ycck_convert (j_compress_ptr cinfo, 275 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 276 JDIMENSION output_row, int num_rows) 277{ 278 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; 279 register int r, g, b; 280 register INT32 * ctab = cconvert->rgb_ycc_tab; 281 register JSAMPROW inptr; 282 register JSAMPROW outptr0, outptr1, outptr2, outptr3; 283 register JDIMENSION col; 284 JDIMENSION num_cols = cinfo->image_width; 285 286 while (--num_rows >= 0) { 287 inptr = *input_buf++; 288 outptr0 = output_buf[0][output_row]; 289 outptr1 = output_buf[1][output_row]; 290 outptr2 = output_buf[2][output_row]; 291 outptr3 = output_buf[3][output_row]; 292 output_row++; 293 for (col = 0; col < num_cols; col++) { 294 r = MAXJSAMPLE - GETJSAMPLE(inptr[0]); 295 g = MAXJSAMPLE - GETJSAMPLE(inptr[1]); 296 b = MAXJSAMPLE - GETJSAMPLE(inptr[2]); 297 /* K passes through as-is */ 298 outptr3[col] = inptr[3]; /* don't need GETJSAMPLE here */ 299 inptr += 4; 300 /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations 301 * must be too; we do not need an explicit range-limiting operation. 302 * Hence the value being shifted is never negative, and we don't 303 * need the general RIGHT_SHIFT macro. 304 */ 305 /* Y */ 306 outptr0[col] = (JSAMPLE) 307 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF]) 308 >> SCALEBITS); 309 /* Cb */ 310 outptr1[col] = (JSAMPLE) 311 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF]) 312 >> SCALEBITS); 313 /* Cr */ 314 outptr2[col] = (JSAMPLE) 315 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF]) 316 >> SCALEBITS); 317 } 318 } 319} 320 321 322/* 323 * Convert some rows of samples to the JPEG colorspace. 324 * This version handles grayscale output with no conversion. 325 * The source can be either plain grayscale or YCbCr (since Y == gray). 326 */ 327 328METHODDEF(void) 329grayscale_convert (j_compress_ptr cinfo, 330 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 331 JDIMENSION output_row, int num_rows) 332{ 333 register JSAMPROW inptr; 334 register JSAMPROW outptr; 335 register JDIMENSION col; 336 JDIMENSION num_cols = cinfo->image_width; 337 int instride = cinfo->input_components; 338 339 while (--num_rows >= 0) { 340 inptr = *input_buf++; 341 outptr = output_buf[0][output_row]; 342 output_row++; 343 for (col = 0; col < num_cols; col++) { 344 outptr[col] = inptr[0]; /* don't need GETJSAMPLE() here */ 345 inptr += instride; 346 } 347 } 348} 349 350#ifdef ENABLE_ANDROID_NULL_CONVERT 351 352typedef unsigned long UINT32; 353 354#define B0(n) ((n) & 0xFF) 355#define B1(n) (((n) >> 8) & 0xFF) 356#define B2(n) (((n) >> 16) & 0xFF) 357#define B3(n) ((n) >> 24) 358 359#define PACK(a, b, c, d) ((a) | ((b) << 8) | ((c) << 16) | ((d) << 24)) 360 361static int ptr_is_quad(const void* p) 362{ 363 return (((const char*)p - (const char*)0) & 3) == 0; 364} 365 366static void copyquads(const UINT32 in[], UINT32 out0[], UINT32 out1[], UINT32 out2[], int col4) 367{ 368 do { 369 UINT32 src0 = *in++; 370 UINT32 src1 = *in++; 371 UINT32 src2 = *in++; 372 // LEndian 373 *out0++ = PACK(B0(src0), B3(src0), B2(src1), B1(src2)); 374 *out1++ = PACK(B1(src0), B0(src1), B3(src1), B2(src2)); 375 *out2++ = PACK(B2(src0), B1(src1), B0(src2), B3(src2)); 376 } while (--col4 != 0); 377} 378 379#endif 380 381/* 382 * Convert some rows of samples to the JPEG colorspace. 383 * This version handles multi-component colorspaces without conversion. 384 * We assume input_components == num_components. 385 */ 386 387METHODDEF(void) 388null_convert (j_compress_ptr cinfo, 389 JSAMPARRAY input_buf, JSAMPIMAGE output_buf, 390 JDIMENSION output_row, int num_rows) 391{ 392 register JSAMPROW inptr; 393 register JSAMPROW outptr; 394 register JDIMENSION col; 395 register int ci; 396 int nc = cinfo->num_components; 397 JDIMENSION num_cols = cinfo->image_width; 398 399#ifdef ENABLE_ANDROID_NULL_CONVERT 400 if (1 == num_rows && 3 == nc && num_cols > 0) { 401 JSAMPROW inptr = *input_buf; 402 JSAMPROW outptr0 = output_buf[0][output_row]; 403 JSAMPROW outptr1 = output_buf[1][output_row]; 404 JSAMPROW outptr2 = output_buf[2][output_row]; 405 406 int col = num_cols; 407 int col4 = col >> 2; 408 if (col4 > 0 && ptr_is_quad(inptr) && ptr_is_quad(outptr0) && 409 ptr_is_quad(outptr1) && ptr_is_quad(outptr2)) { 410 411 const UINT32* in = (const UINT32*)inptr; 412 UINT32* out0 = (UINT32*)outptr0; 413 UINT32* out1 = (UINT32*)outptr1; 414 UINT32* out2 = (UINT32*)outptr2; 415 copyquads(in, out0, out1, out2, col4); 416 col &= 3; 417 if (0 == col) 418 return; 419 col4 <<= 2; 420 inptr += col4 * 3; /* we read this 3 times per in copyquads */ 421 outptr0 += col4; 422 outptr1 += col4; 423 outptr2 += col4; 424 /* fall through to while-loop */ 425 } 426 do { 427 *outptr0++ = *inptr++; 428 *outptr1++ = *inptr++; 429 *outptr2++ = *inptr++; 430 } while (--col != 0); 431 return; 432 } 433SLOW: 434#endif 435 while (--num_rows >= 0) { 436 /* It seems fastest to make a separate pass for each component. */ 437 for (ci = 0; ci < nc; ci++) { 438 inptr = *input_buf; 439 outptr = output_buf[ci][output_row]; 440 for (col = 0; col < num_cols; col++) { 441 outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */ 442 inptr += nc; 443 } 444 } 445 input_buf++; 446 output_row++; 447 } 448} 449 450 451/* 452 * Empty method for start_pass. 453 */ 454 455METHODDEF(void) 456null_method (j_compress_ptr cinfo) 457{ 458 /* no work needed */ 459} 460 461 462/* 463 * Module initialization routine for input colorspace conversion. 464 */ 465 466GLOBAL(void) 467jinit_color_converter (j_compress_ptr cinfo) 468{ 469 my_cconvert_ptr cconvert; 470 471 cconvert = (my_cconvert_ptr) 472 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 473 SIZEOF(my_color_converter)); 474 cinfo->cconvert = (struct jpeg_color_converter *) cconvert; 475 /* set start_pass to null method until we find out differently */ 476 cconvert->pub.start_pass = null_method; 477 478 /* Make sure input_components agrees with in_color_space */ 479 switch (cinfo->in_color_space) { 480 case JCS_GRAYSCALE: 481 if (cinfo->input_components != 1) 482 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 483 break; 484 485 case JCS_RGB: 486#if RGB_PIXELSIZE != 3 487 if (cinfo->input_components != RGB_PIXELSIZE) 488 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 489 break; 490#endif /* else share code with YCbCr */ 491 492 case JCS_YCbCr: 493 if (cinfo->input_components != 3) 494 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 495 break; 496 497 case JCS_CMYK: 498 case JCS_YCCK: 499 if (cinfo->input_components != 4) 500 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 501 break; 502 503#ifdef ANDROID_RGB 504 case JCS_RGB_565: 505 if (cinfo->input_components != 2) 506 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 507 break; 508#endif /* ANDROID_RGB */ 509 510 default: /* JCS_UNKNOWN can be anything */ 511 if (cinfo->input_components < 1) 512 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 513 break; 514 } 515 516 /* Check num_components, set conversion method based on requested space */ 517 switch (cinfo->jpeg_color_space) { 518 case JCS_GRAYSCALE: 519 if (cinfo->num_components != 1) 520 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 521 if (cinfo->in_color_space == JCS_GRAYSCALE) 522 cconvert->pub.color_convert = grayscale_convert; 523 else if (cinfo->in_color_space == JCS_RGB) { 524 cconvert->pub.start_pass = rgb_ycc_start; 525 cconvert->pub.color_convert = rgb_gray_convert; 526 } else if (cinfo->in_color_space == JCS_YCbCr) 527 cconvert->pub.color_convert = grayscale_convert; 528 else 529 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 530 break; 531 532 case JCS_RGB: 533 if (cinfo->num_components != 3) 534 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 535 if (cinfo->in_color_space == JCS_RGB && RGB_PIXELSIZE == 3) 536 cconvert->pub.color_convert = null_convert; 537 else 538 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 539 break; 540 541 case JCS_YCbCr: 542 if (cinfo->num_components != 3) 543 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 544 if (cinfo->in_color_space == JCS_RGB) { 545 cconvert->pub.start_pass = rgb_ycc_start; 546 cconvert->pub.color_convert = rgb_ycc_convert; 547 } else if (cinfo->in_color_space == JCS_YCbCr) { 548 cconvert->pub.color_convert = null_convert; 549 } 550#ifdef ANDROID_RGB 551 else if (cinfo->in_color_space == JCS_RGB_565) { 552 cconvert->pub.start_pass = rgb_ycc_start; 553 cconvert->pub.color_convert = rgb565_ycc_convert; 554 } 555#endif /* ANDROID_RGB */ 556 else 557 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 558 break; 559 560 case JCS_CMYK: 561 if (cinfo->num_components != 4) 562 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 563 if (cinfo->in_color_space == JCS_CMYK) 564 cconvert->pub.color_convert = null_convert; 565 else 566 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 567 break; 568 569 case JCS_YCCK: 570 if (cinfo->num_components != 4) 571 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 572 if (cinfo->in_color_space == JCS_CMYK) { 573 cconvert->pub.start_pass = rgb_ycc_start; 574 cconvert->pub.color_convert = cmyk_ycck_convert; 575 } else if (cinfo->in_color_space == JCS_YCCK) 576 cconvert->pub.color_convert = null_convert; 577 else 578 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 579 break; 580 581 default: /* allow null conversion of JCS_UNKNOWN */ 582 if (cinfo->jpeg_color_space != cinfo->in_color_space || 583 cinfo->num_components != cinfo->input_components) 584 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 585 cconvert->pub.color_convert = null_convert; 586 break; 587 } 588} 589