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| 1 /* | |
| 2 * jdcolor.c | |
| 3 * | |
| 4 * Copyright (C) 1991-1997, 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 output colorspace conversion routines. | |
| 9 */ | |
| 10 | |
| 11 #define JPEG_INTERNALS | |
| 12 #include "jinclude.h" | |
| 13 #include "jpeglib.h" | |
| 14 | |
| 15 | |
| 16 /* Private subobject */ | |
| 17 | |
| 18 typedef struct { | |
| 19 struct jpeg_color_deconverter pub; /* public fields */ | |
| 20 | |
| 21 /* Private state for YCC->RGB conversion */ | |
| 22 int * Cr_r_tab; /* => table for Cr to R conversion */ | |
| 23 int * Cb_b_tab; /* => table for Cb to B conversion */ | |
| 24 INT32 * Cr_g_tab; /* => table for Cr to G conversion */ | |
| 25 INT32 * Cb_g_tab; /* => table for Cb to G conversion */ | |
| 26 } my_color_deconverter; | |
| 27 | |
| 28 typedef my_color_deconverter * my_cconvert_ptr; | |
| 29 | |
| 30 | |
| 31 /**************** YCbCr -> RGB conversion: most common case **************/ | |
| 32 | |
| 33 /* | |
| 34 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are | |
| 35 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5. | |
| 36 * The conversion equations to be implemented are therefore | |
| 37 * R = Y + 1.40200 * Cr | |
| 38 * G = Y - 0.34414 * Cb - 0.71414 * Cr | |
| 39 * B = Y + 1.77200 * Cb | |
| 40 * where Cb and Cr represent the incoming values less CENTERJSAMPLE. | |
| 41 * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.) | |
| 42 * | |
| 43 * To avoid floating-point arithmetic, we represent the fractional constants | |
| 44 * as integers scaled up by 2^16 (about 4 digits precision); we have to divide | |
| 45 * the products by 2^16, with appropriate rounding, to get the correct answer. | |
| 46 * Notice that Y, being an integral input, does not contribute any fraction | |
| 47 * so it need not participate in the rounding. | |
| 48 * | |
| 49 * For even more speed, we avoid doing any multiplications in the inner loop | |
| 50 * by precalculating the constants times Cb and Cr for all possible values. | |
| 51 * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table); | |
| 52 * for 12-bit samples it is still acceptable. It's not very reasonable for | |
| 53 * 16-bit samples, but if you want lossless storage you shouldn't be changing | |
| 54 * colorspace anyway. | |
| 55 * The Cr=>R and Cb=>B values can be rounded to integers in advance; the | |
| 56 * values for the G calculation are left scaled up, since we must add them | |
| 57 * together before rounding. | |
| 58 */ | |
| 59 | |
| 60 #define SCALEBITS 16 /* speediest right-shift on some machines */ | |
| 61 #define ONE_HALF ((INT32) 1 << (SCALEBITS-1)) | |
| 62 #define FIX(x) ((INT32) ((x) * (1L<<SCALEBITS) + 0.5)) | |
| 63 | |
| 64 | |
| 65 /* | |
| 66 * Initialize tables for YCC->RGB colorspace conversion. | |
| 67 */ | |
| 68 | |
| 69 LOCAL(void) | |
| 70 build_ycc_rgb_table (j_decompress_ptr cinfo) | |
| 71 { | |
| 72 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; | |
| 73 int i; | |
| 74 INT32 x; | |
| 75 SHIFT_TEMPS | |
| 76 | |
| 77 cconvert->Cr_r_tab = (int *) | |
| 78 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 79 (MAXJSAMPLE+1) * SIZEOF(int)); | |
| 80 cconvert->Cb_b_tab = (int *) | |
| 81 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 82 (MAXJSAMPLE+1) * SIZEOF(int)); | |
| 83 cconvert->Cr_g_tab = (INT32 *) | |
| 84 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 85 (MAXJSAMPLE+1) * SIZEOF(INT32)); | |
| 86 cconvert->Cb_g_tab = (INT32 *) | |
| 87 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 88 (MAXJSAMPLE+1) * SIZEOF(INT32)); | |
| 89 | |
| 90 for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) { | |
| 91 /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */ | |
| 92 /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */ | |
| 93 /* Cr=>R value is nearest int to 1.40200 * x */ | |
| 94 cconvert->Cr_r_tab[i] = (int) | |
| 95 RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS); | |
| 96 /* Cb=>B value is nearest int to 1.77200 * x */ | |
| 97 cconvert->Cb_b_tab[i] = (int) | |
| 98 RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS); | |
| 99 /* Cr=>G value is scaled-up -0.71414 * x */ | |
| 100 cconvert->Cr_g_tab[i] = (- FIX(0.71414)) * x; | |
| 101 /* Cb=>G value is scaled-up -0.34414 * x */ | |
| 102 /* We also add in ONE_HALF so that need not do it in inner loop */ | |
| 103 cconvert->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF; | |
| 104 } | |
| 105 } | |
| 106 | |
| 107 | |
| 108 /* | |
| 109 * Convert some rows of samples to the output colorspace. | |
| 110 * | |
| 111 * Note that we change from noninterleaved, one-plane-per-component format | |
| 112 * to interleaved-pixel format. The output buffer is therefore three times | |
| 113 * as wide as the input buffer. | |
| 114 * A starting row offset is provided only for the input buffer. The caller | |
| 115 * can easily adjust the passed output_buf value to accommodate any row | |
| 116 * offset required on that side. | |
| 117 */ | |
| 118 | |
| 119 METHODDEF(void) | |
| 120 ycc_rgb_convert (j_decompress_ptr cinfo, | |
| 121 JSAMPIMAGE input_buf, JDIMENSION input_row, | |
| 122 JSAMPARRAY output_buf, int num_rows) | |
| 123 { | |
| 124 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; | |
| 125 register int y, cb, cr; | |
| 126 register JSAMPROW outptr; | |
| 127 register JSAMPROW inptr0, inptr1, inptr2; | |
| 128 register JDIMENSION col; | |
| 129 JDIMENSION num_cols = cinfo->output_width; | |
| 130 /* copy these pointers into registers if possible */ | |
| 131 register JSAMPLE * range_limit = cinfo->sample_range_limit; | |
| 132 register int * Crrtab = cconvert->Cr_r_tab; | |
| 133 register int * Cbbtab = cconvert->Cb_b_tab; | |
| 134 register INT32 * Crgtab = cconvert->Cr_g_tab; | |
| 135 register INT32 * Cbgtab = cconvert->Cb_g_tab; | |
| 136 SHIFT_TEMPS | |
| 137 | |
| 138 while (--num_rows >= 0) { | |
| 139 inptr0 = input_buf[0][input_row]; | |
| 140 inptr1 = input_buf[1][input_row]; | |
| 141 inptr2 = input_buf[2][input_row]; | |
| 142 input_row++; | |
| 143 outptr = *output_buf++; | |
| 144 for (col = 0; col < num_cols; col++) { | |
| 145 y = GETJSAMPLE(inptr0[col]); | |
| 146 cb = GETJSAMPLE(inptr1[col]); | |
| 147 cr = GETJSAMPLE(inptr2[col]); | |
| 148 /* Range-limiting is essential due to noise introduced by DCT losses. */ | |
| 149 outptr[RGB_RED] = range_limit[y + Crrtab[cr]]; | |
| 150 outptr[RGB_GREEN] = range_limit[y + | |
| 151 ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], | |
| 152 SCALEBITS))]; | |
| 153 outptr[RGB_BLUE] = range_limit[y + Cbbtab[cb]]; | |
| 154 outptr += RGB_PIXELSIZE; | |
| 155 } | |
| 156 } | |
| 157 } | |
| 158 | |
| 159 | |
| 160 /**************** Cases other than YCbCr -> RGB **************/ | |
| 161 | |
| 162 | |
| 163 /* | |
| 164 * Color conversion for no colorspace change: just copy the data, | |
| 165 * converting from separate-planes to interleaved representation. | |
| 166 */ | |
| 167 | |
| 168 METHODDEF(void) | |
| 169 null_convert (j_decompress_ptr cinfo, | |
| 170 JSAMPIMAGE input_buf, JDIMENSION input_row, | |
| 171 JSAMPARRAY output_buf, int num_rows) | |
| 172 { | |
| 173 register JSAMPROW inptr, outptr; | |
| 174 register JDIMENSION count; | |
| 175 register int num_components = cinfo->num_components; | |
| 176 JDIMENSION num_cols = cinfo->output_width; | |
| 177 int ci; | |
| 178 | |
| 179 while (--num_rows >= 0) { | |
| 180 for (ci = 0; ci < num_components; ci++) { | |
| 181 inptr = input_buf[ci][input_row]; | |
| 182 outptr = output_buf[0] + ci; | |
| 183 for (count = num_cols; count > 0; count--) { | |
| 184 *outptr = *inptr++; /* needn't bother with GETJSAMPLE() here */ | |
| 185 outptr += num_components; | |
| 186 } | |
| 187 } | |
| 188 input_row++; | |
| 189 output_buf++; | |
| 190 } | |
| 191 } | |
| 192 | |
| 193 | |
| 194 /* | |
| 195 * Color conversion for grayscale: just copy the data. | |
| 196 * This also works for YCbCr -> grayscale conversion, in which | |
| 197 * we just copy the Y (luminance) component and ignore chrominance. | |
| 198 */ | |
| 199 | |
| 200 METHODDEF(void) | |
| 201 grayscale_convert (j_decompress_ptr cinfo, | |
| 202 JSAMPIMAGE input_buf, JDIMENSION input_row, | |
| 203 JSAMPARRAY output_buf, int num_rows) | |
| 204 { | |
| 205 jcopy_sample_rows(input_buf[0], (int) input_row, output_buf, 0, | |
| 206 num_rows, cinfo->output_width); | |
| 207 } | |
| 208 | |
| 209 | |
| 210 /* | |
| 211 * Convert grayscale to RGB: just duplicate the graylevel three times. | |
| 212 * This is provided to support applications that don't want to cope | |
| 213 * with grayscale as a separate case. | |
| 214 */ | |
| 215 | |
| 216 METHODDEF(void) | |
| 217 gray_rgb_convert (j_decompress_ptr cinfo, | |
| 218 JSAMPIMAGE input_buf, JDIMENSION input_row, | |
| 219 JSAMPARRAY output_buf, int num_rows) | |
| 220 { | |
| 221 register JSAMPROW inptr, outptr; | |
| 222 register JDIMENSION col; | |
| 223 JDIMENSION num_cols = cinfo->output_width; | |
| 224 | |
| 225 while (--num_rows >= 0) { | |
| 226 inptr = input_buf[0][input_row++]; | |
| 227 outptr = *output_buf++; | |
| 228 for (col = 0; col < num_cols; col++) { | |
| 229 /* We can dispense with GETJSAMPLE() here */ | |
| 230 outptr[RGB_RED] = outptr[RGB_GREEN] = outptr[RGB_BLUE] = inptr[col]; | |
| 231 outptr += RGB_PIXELSIZE; | |
| 232 } | |
| 233 } | |
| 234 } | |
| 235 | |
| 236 | |
| 237 /* | |
| 238 * Adobe-style YCCK->CMYK conversion. | |
| 239 * We convert YCbCr to R=1-C, G=1-M, and B=1-Y using the same | |
| 240 * conversion as above, while passing K (black) unchanged. | |
| 241 * We assume build_ycc_rgb_table has been called. | |
| 242 */ | |
| 243 | |
| 244 METHODDEF(void) | |
| 245 ycck_cmyk_convert (j_decompress_ptr cinfo, | |
| 246 JSAMPIMAGE input_buf, JDIMENSION input_row, | |
| 247 JSAMPARRAY output_buf, int num_rows) | |
| 248 { | |
| 249 my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert; | |
| 250 register int y, cb, cr; | |
| 251 register JSAMPROW outptr; | |
| 252 register JSAMPROW inptr0, inptr1, inptr2, inptr3; | |
| 253 register JDIMENSION col; | |
| 254 JDIMENSION num_cols = cinfo->output_width; | |
| 255 /* copy these pointers into registers if possible */ | |
| 256 register JSAMPLE * range_limit = cinfo->sample_range_limit; | |
| 257 register int * Crrtab = cconvert->Cr_r_tab; | |
| 258 register int * Cbbtab = cconvert->Cb_b_tab; | |
| 259 register INT32 * Crgtab = cconvert->Cr_g_tab; | |
| 260 register INT32 * Cbgtab = cconvert->Cb_g_tab; | |
| 261 SHIFT_TEMPS | |
| 262 | |
| 263 while (--num_rows >= 0) { | |
| 264 inptr0 = input_buf[0][input_row]; | |
| 265 inptr1 = input_buf[1][input_row]; | |
| 266 inptr2 = input_buf[2][input_row]; | |
| 267 inptr3 = input_buf[3][input_row]; | |
| 268 input_row++; | |
| 269 outptr = *output_buf++; | |
| 270 for (col = 0; col < num_cols; col++) { | |
| 271 y = GETJSAMPLE(inptr0[col]); | |
| 272 cb = GETJSAMPLE(inptr1[col]); | |
| 273 cr = GETJSAMPLE(inptr2[col]); | |
| 274 /* Range-limiting is essential due to noise introduced by DCT losses. */ | |
| 275 outptr[0] = range_limit[MAXJSAMPLE - (y + Crrtab[cr])]; /* red */ | |
| 276 outptr[1] = range_limit[MAXJSAMPLE - (y + /* green */ | |
| 277 ((int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], | |
| 278 SCALEBITS)))]; | |
| 279 outptr[2] = range_limit[MAXJSAMPLE - (y + Cbbtab[cb])]; /* blue */ | |
| 280 /* K passes through unchanged */ | |
| 281 outptr[3] = inptr3[col]; /* don't need GETJSAMPLE here */ | |
| 282 outptr += 4; | |
| 283 } | |
| 284 } | |
| 285 } | |
| 286 | |
| 287 | |
| 288 /* | |
| 289 * Empty method for start_pass. | |
| 290 */ | |
| 291 | |
| 292 METHODDEF(void) | |
| 293 start_pass_dcolor (j_decompress_ptr cinfo) | |
| 294 { | |
| 295 /* no work needed */ | |
| 296 } | |
| 297 | |
| 298 | |
| 299 /* | |
| 300 * Module initialization routine for output colorspace conversion. | |
| 301 */ | |
| 302 | |
| 303 GLOBAL(void) | |
| 304 jinit_color_deconverter (j_decompress_ptr cinfo) | |
| 305 { | |
| 306 my_cconvert_ptr cconvert; | |
| 307 int ci; | |
| 308 | |
| 309 cconvert = (my_cconvert_ptr) | |
| 310 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
| 311 SIZEOF(my_color_deconverter)); | |
| 312 cinfo->cconvert = (struct jpeg_color_deconverter *) cconvert; | |
| 313 cconvert->pub.start_pass = start_pass_dcolor; | |
| 314 | |
| 315 /* Make sure num_components agrees with jpeg_color_space */ | |
| 316 switch (cinfo->jpeg_color_space) { | |
| 317 case JCS_GRAYSCALE: | |
| 318 if (cinfo->num_components != 1) | |
| 319 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); | |
| 320 break; | |
| 321 | |
| 322 case JCS_RGB: | |
| 323 case JCS_YCbCr: | |
| 324 if (cinfo->num_components != 3) | |
| 325 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); | |
| 326 break; | |
| 327 | |
| 328 case JCS_CMYK: | |
| 329 case JCS_YCCK: | |
| 330 if (cinfo->num_components != 4) | |
| 331 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); | |
| 332 break; | |
| 333 | |
| 334 default: /* JCS_UNKNOWN can be anything */ | |
| 335 if (cinfo->num_components < 1) | |
| 336 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); | |
| 337 break; | |
| 338 } | |
| 339 | |
| 340 /* Set out_color_components and conversion method based on requested space. | |
| 341 * Also clear the component_needed flags for any unused components, | |
| 342 * so that earlier pipeline stages can avoid useless computation. | |
| 343 */ | |
| 344 | |
| 345 switch (cinfo->out_color_space) { | |
| 346 case JCS_GRAYSCALE: | |
| 347 cinfo->out_color_components = 1; | |
| 348 if (cinfo->jpeg_color_space == JCS_GRAYSCALE || | |
| 349 cinfo->jpeg_color_space == JCS_YCbCr) { | |
| 350 cconvert->pub.color_convert = grayscale_convert; | |
| 351 /* For color->grayscale conversion, only the Y (0) component is needed */ | |
| 352 for (ci = 1; ci < cinfo->num_components; ci++) | |
| 353 cinfo->comp_info[ci].component_needed = FALSE; | |
| 354 } else | |
| 355 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); | |
| 356 break; | |
| 357 | |
| 358 case JCS_RGB: | |
| 359 cinfo->out_color_components = RGB_PIXELSIZE; | |
| 360 if (cinfo->jpeg_color_space == JCS_YCbCr) { | |
| 361 cconvert->pub.color_convert = ycc_rgb_convert; | |
| 362 build_ycc_rgb_table(cinfo); | |
| 363 } else if (cinfo->jpeg_color_space == JCS_GRAYSCALE) { | |
| 364 cconvert->pub.color_convert = gray_rgb_convert; | |
| 365 } else if (cinfo->jpeg_color_space == JCS_RGB && RGB_PIXELSIZE == 3) { | |
| 366 cconvert->pub.color_convert = null_convert; | |
| 367 } else | |
| 368 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); | |
| 369 break; | |
| 370 | |
| 371 case JCS_CMYK: | |
| 372 cinfo->out_color_components = 4; | |
| 373 if (cinfo->jpeg_color_space == JCS_YCCK) { | |
| 374 cconvert->pub.color_convert = ycck_cmyk_convert; | |
| 375 build_ycc_rgb_table(cinfo); | |
| 376 } else if (cinfo->jpeg_color_space == JCS_CMYK) { | |
| 377 cconvert->pub.color_convert = null_convert; | |
| 378 } else | |
| 379 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); | |
| 380 break; | |
| 381 | |
| 382 default: | |
| 383 /* Permit null conversion to same output space */ | |
| 384 if (cinfo->out_color_space == cinfo->jpeg_color_space) { | |
| 385 cinfo->out_color_components = cinfo->num_components; | |
| 386 cconvert->pub.color_convert = null_convert; | |
| 387 } else /* unsupported non-null conversion */ | |
| 388 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); | |
| 389 break; | |
| 390 } | |
| 391 | |
| 392 if (cinfo->quantize_colors) | |
| 393 cinfo->output_components = 1; /* single colormapped output component */ | |
| 394 else | |
| 395 cinfo->output_components = cinfo->out_color_components; | |
| 396 } | |
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Chromium Code Reviews
Issue 1705523002:
Remove libjpeg and libjpeg_turbo. (Closed)
Base URL: https://github.com/domokit/mojo.git@master