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comparison: media/libjpeg/jcparam.c
media/libjpeg/jcparam.c
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| -1:000000000000 | 0:c9eebae145a1 |
|---|---|
| 1 /* | |
| 2 * jcparam.c | |
| 3 * | |
| 4 * This file was part of the Independent JPEG Group's software: | |
| 5 * Copyright (C) 1991-1998, Thomas G. Lane. | |
| 6 * Modified 2003-2008 by Guido Vollbeding. | |
| 7 * libjpeg-turbo Modifications: | |
| 8 * Copyright (C) 2009-2011, D. R. Commander. | |
| 9 * For conditions of distribution and use, see the accompanying README file. | |
| 10 * | |
| 11 * This file contains optional default-setting code for the JPEG compressor. | |
| 12 * Applications do not have to use this file, but those that don't use it | |
| 13 * must know a lot more about the innards of the JPEG code. | |
| 14 */ | |
| 15 | |
| 16 #define JPEG_INTERNALS | |
| 17 #include "jinclude.h" | |
| 18 #include "jpeglib.h" | |
| 19 #include "jstdhuff.c" | |
| 20 | |
| 21 | |
| 22 /* | |
| 23 * Quantization table setup routines | |
| 24 */ | |
| 25 | |
| 26 GLOBAL(void) | |
| 27 jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl, | |
| 28 const unsigned int *basic_table, | |
| 29 int scale_factor, boolean force_baseline) | |
| 30 /* Define a quantization table equal to the basic_table times | |
| 31 * a scale factor (given as a percentage). | |
| 32 * If force_baseline is TRUE, the computed quantization table entries | |
| 33 * are limited to 1..255 for JPEG baseline compatibility. | |
| 34 */ | |
| 35 { | |
| 36 JQUANT_TBL ** qtblptr; | |
| 37 int i; | |
| 38 long temp; | |
| 39 | |
| 40 /* Safety check to ensure start_compress not called yet. */ | |
| 41 if (cinfo->global_state != CSTATE_START) | |
| 42 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
| 43 | |
| 44 if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS) | |
| 45 ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl); | |
| 46 | |
| 47 qtblptr = & cinfo->quant_tbl_ptrs[which_tbl]; | |
| 48 | |
| 49 if (*qtblptr == NULL) | |
| 50 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo); | |
| 51 | |
| 52 for (i = 0; i < DCTSIZE2; i++) { | |
| 53 temp = ((long) basic_table[i] * scale_factor + 50L) / 100L; | |
| 54 /* limit the values to the valid range */ | |
| 55 if (temp <= 0L) temp = 1L; | |
| 56 if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */ | |
| 57 if (force_baseline && temp > 255L) | |
| 58 temp = 255L; /* limit to baseline range if requested */ | |
| 59 (*qtblptr)->quantval[i] = (UINT16) temp; | |
| 60 } | |
| 61 | |
| 62 /* Initialize sent_table FALSE so table will be written to JPEG file. */ | |
| 63 (*qtblptr)->sent_table = FALSE; | |
| 64 } | |
| 65 | |
| 66 | |
| 67 /* These are the sample quantization tables given in JPEG spec section K.1. | |
| 68 * The spec says that the values given produce "good" quality, and | |
| 69 * when divided by 2, "very good" quality. | |
| 70 */ | |
| 71 static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = { | |
| 72 16, 11, 10, 16, 24, 40, 51, 61, | |
| 73 12, 12, 14, 19, 26, 58, 60, 55, | |
| 74 14, 13, 16, 24, 40, 57, 69, 56, | |
| 75 14, 17, 22, 29, 51, 87, 80, 62, | |
| 76 18, 22, 37, 56, 68, 109, 103, 77, | |
| 77 24, 35, 55, 64, 81, 104, 113, 92, | |
| 78 49, 64, 78, 87, 103, 121, 120, 101, | |
| 79 72, 92, 95, 98, 112, 100, 103, 99 | |
| 80 }; | |
| 81 static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = { | |
| 82 17, 18, 24, 47, 99, 99, 99, 99, | |
| 83 18, 21, 26, 66, 99, 99, 99, 99, | |
| 84 24, 26, 56, 99, 99, 99, 99, 99, | |
| 85 47, 66, 99, 99, 99, 99, 99, 99, | |
| 86 99, 99, 99, 99, 99, 99, 99, 99, | |
| 87 99, 99, 99, 99, 99, 99, 99, 99, | |
| 88 99, 99, 99, 99, 99, 99, 99, 99, | |
| 89 99, 99, 99, 99, 99, 99, 99, 99 | |
| 90 }; | |
| 91 | |
| 92 | |
| 93 #if JPEG_LIB_VERSION >= 70 | |
| 94 GLOBAL(void) | |
| 95 jpeg_default_qtables (j_compress_ptr cinfo, boolean force_baseline) | |
| 96 /* Set or change the 'quality' (quantization) setting, using default tables | |
| 97 * and straight percentage-scaling quality scales. | |
| 98 * This entry point allows different scalings for luminance and chrominance. | |
| 99 */ | |
| 100 { | |
| 101 /* Set up two quantization tables using the specified scaling */ | |
| 102 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, | |
| 103 cinfo->q_scale_factor[0], force_baseline); | |
| 104 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, | |
| 105 cinfo->q_scale_factor[1], force_baseline); | |
| 106 } | |
| 107 #endif | |
| 108 | |
| 109 | |
| 110 GLOBAL(void) | |
| 111 jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor, | |
| 112 boolean force_baseline) | |
| 113 /* Set or change the 'quality' (quantization) setting, using default tables | |
| 114 * and a straight percentage-scaling quality scale. In most cases it's better | |
| 115 * to use jpeg_set_quality (below); this entry point is provided for | |
| 116 * applications that insist on a linear percentage scaling. | |
| 117 */ | |
| 118 { | |
| 119 /* Set up two quantization tables using the specified scaling */ | |
| 120 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, | |
| 121 scale_factor, force_baseline); | |
| 122 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, | |
| 123 scale_factor, force_baseline); | |
| 124 } | |
| 125 | |
| 126 | |
| 127 GLOBAL(int) | |
| 128 jpeg_quality_scaling (int quality) | |
| 129 /* Convert a user-specified quality rating to a percentage scaling factor | |
| 130 * for an underlying quantization table, using our recommended scaling curve. | |
| 131 * The input 'quality' factor should be 0 (terrible) to 100 (very good). | |
| 132 */ | |
| 133 { | |
| 134 /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */ | |
| 135 if (quality <= 0) quality = 1; | |
| 136 if (quality > 100) quality = 100; | |
| 137 | |
| 138 /* The basic table is used as-is (scaling 100) for a quality of 50. | |
| 139 * Qualities 50..100 are converted to scaling percentage 200 - 2*Q; | |
| 140 * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table | |
| 141 * to make all the table entries 1 (hence, minimum quantization loss). | |
| 142 * Qualities 1..50 are converted to scaling percentage 5000/Q. | |
| 143 */ | |
| 144 if (quality < 50) | |
| 145 quality = 5000 / quality; | |
| 146 else | |
| 147 quality = 200 - quality*2; | |
| 148 | |
| 149 return quality; | |
| 150 } | |
| 151 | |
| 152 | |
| 153 GLOBAL(void) | |
| 154 jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline) | |
| 155 /* Set or change the 'quality' (quantization) setting, using default tables. | |
| 156 * This is the standard quality-adjusting entry point for typical user | |
| 157 * interfaces; only those who want detailed control over quantization tables | |
| 158 * would use the preceding three routines directly. | |
| 159 */ | |
| 160 { | |
| 161 /* Convert user 0-100 rating to percentage scaling */ | |
| 162 quality = jpeg_quality_scaling(quality); | |
| 163 | |
| 164 /* Set up standard quality tables */ | |
| 165 jpeg_set_linear_quality(cinfo, quality, force_baseline); | |
| 166 } | |
| 167 | |
| 168 | |
| 169 /* | |
| 170 * Default parameter setup for compression. | |
| 171 * | |
| 172 * Applications that don't choose to use this routine must do their | |
| 173 * own setup of all these parameters. Alternately, you can call this | |
| 174 * to establish defaults and then alter parameters selectively. This | |
| 175 * is the recommended approach since, if we add any new parameters, | |
| 176 * your code will still work (they'll be set to reasonable defaults). | |
| 177 */ | |
| 178 | |
| 179 GLOBAL(void) | |
| 180 jpeg_set_defaults (j_compress_ptr cinfo) | |
| 181 { | |
| 182 int i; | |
| 183 | |
| 184 /* Safety check to ensure start_compress not called yet. */ | |
| 185 if (cinfo->global_state != CSTATE_START) | |
| 186 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
| 187 | |
| 188 /* Allocate comp_info array large enough for maximum component count. | |
| 189 * Array is made permanent in case application wants to compress | |
| 190 * multiple images at same param settings. | |
| 191 */ | |
| 192 if (cinfo->comp_info == NULL) | |
| 193 cinfo->comp_info = (jpeg_component_info *) | |
| 194 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, | |
| 195 MAX_COMPONENTS * SIZEOF(jpeg_component_info)); | |
| 196 | |
| 197 /* Initialize everything not dependent on the color space */ | |
| 198 | |
| 199 #if JPEG_LIB_VERSION >= 70 | |
| 200 cinfo->scale_num = 1; /* 1:1 scaling */ | |
| 201 cinfo->scale_denom = 1; | |
| 202 #endif | |
| 203 cinfo->data_precision = BITS_IN_JSAMPLE; | |
| 204 /* Set up two quantization tables using default quality of 75 */ | |
| 205 jpeg_set_quality(cinfo, 75, TRUE); | |
| 206 /* Set up two Huffman tables */ | |
| 207 std_huff_tables((j_common_ptr) cinfo); | |
| 208 | |
| 209 /* Initialize default arithmetic coding conditioning */ | |
| 210 for (i = 0; i < NUM_ARITH_TBLS; i++) { | |
| 211 cinfo->arith_dc_L[i] = 0; | |
| 212 cinfo->arith_dc_U[i] = 1; | |
| 213 cinfo->arith_ac_K[i] = 5; | |
| 214 } | |
| 215 | |
| 216 /* Default is no multiple-scan output */ | |
| 217 cinfo->scan_info = NULL; | |
| 218 cinfo->num_scans = 0; | |
| 219 | |
| 220 /* Expect normal source image, not raw downsampled data */ | |
| 221 cinfo->raw_data_in = FALSE; | |
| 222 | |
| 223 /* Use Huffman coding, not arithmetic coding, by default */ | |
| 224 cinfo->arith_code = FALSE; | |
| 225 | |
| 226 /* By default, don't do extra passes to optimize entropy coding */ | |
| 227 cinfo->optimize_coding = FALSE; | |
| 228 /* The standard Huffman tables are only valid for 8-bit data precision. | |
| 229 * If the precision is higher, force optimization on so that usable | |
| 230 * tables will be computed. This test can be removed if default tables | |
| 231 * are supplied that are valid for the desired precision. | |
| 232 */ | |
| 233 if (cinfo->data_precision > 8) | |
| 234 cinfo->optimize_coding = TRUE; | |
| 235 | |
| 236 /* By default, use the simpler non-cosited sampling alignment */ | |
| 237 cinfo->CCIR601_sampling = FALSE; | |
| 238 | |
| 239 #if JPEG_LIB_VERSION >= 70 | |
| 240 /* By default, apply fancy downsampling */ | |
| 241 cinfo->do_fancy_downsampling = TRUE; | |
| 242 #endif | |
| 243 | |
| 244 /* No input smoothing */ | |
| 245 cinfo->smoothing_factor = 0; | |
| 246 | |
| 247 /* DCT algorithm preference */ | |
| 248 cinfo->dct_method = JDCT_DEFAULT; | |
| 249 | |
| 250 /* No restart markers */ | |
| 251 cinfo->restart_interval = 0; | |
| 252 cinfo->restart_in_rows = 0; | |
| 253 | |
| 254 /* Fill in default JFIF marker parameters. Note that whether the marker | |
| 255 * will actually be written is determined by jpeg_set_colorspace. | |
| 256 * | |
| 257 * By default, the library emits JFIF version code 1.01. | |
| 258 * An application that wants to emit JFIF 1.02 extension markers should set | |
| 259 * JFIF_minor_version to 2. We could probably get away with just defaulting | |
| 260 * to 1.02, but there may still be some decoders in use that will complain | |
| 261 * about that; saying 1.01 should minimize compatibility problems. | |
| 262 */ | |
| 263 cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */ | |
| 264 cinfo->JFIF_minor_version = 1; | |
| 265 cinfo->density_unit = 0; /* Pixel size is unknown by default */ | |
| 266 cinfo->X_density = 1; /* Pixel aspect ratio is square by default */ | |
| 267 cinfo->Y_density = 1; | |
| 268 | |
| 269 /* Choose JPEG colorspace based on input space, set defaults accordingly */ | |
| 270 | |
| 271 jpeg_default_colorspace(cinfo); | |
| 272 } | |
| 273 | |
| 274 | |
| 275 /* | |
| 276 * Select an appropriate JPEG colorspace for in_color_space. | |
| 277 */ | |
| 278 | |
| 279 GLOBAL(void) | |
| 280 jpeg_default_colorspace (j_compress_ptr cinfo) | |
| 281 { | |
| 282 switch (cinfo->in_color_space) { | |
| 283 case JCS_GRAYSCALE: | |
| 284 jpeg_set_colorspace(cinfo, JCS_GRAYSCALE); | |
| 285 break; | |
| 286 case JCS_RGB: | |
| 287 case JCS_EXT_RGB: | |
| 288 case JCS_EXT_RGBX: | |
| 289 case JCS_EXT_BGR: | |
| 290 case JCS_EXT_BGRX: | |
| 291 case JCS_EXT_XBGR: | |
| 292 case JCS_EXT_XRGB: | |
| 293 case JCS_EXT_RGBA: | |
| 294 case JCS_EXT_BGRA: | |
| 295 case JCS_EXT_ABGR: | |
| 296 case JCS_EXT_ARGB: | |
| 297 jpeg_set_colorspace(cinfo, JCS_YCbCr); | |
| 298 break; | |
| 299 case JCS_YCbCr: | |
| 300 jpeg_set_colorspace(cinfo, JCS_YCbCr); | |
| 301 break; | |
| 302 case JCS_CMYK: | |
| 303 jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */ | |
| 304 break; | |
| 305 case JCS_YCCK: | |
| 306 jpeg_set_colorspace(cinfo, JCS_YCCK); | |
| 307 break; | |
| 308 case JCS_UNKNOWN: | |
| 309 jpeg_set_colorspace(cinfo, JCS_UNKNOWN); | |
| 310 break; | |
| 311 default: | |
| 312 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); | |
| 313 } | |
| 314 } | |
| 315 | |
| 316 | |
| 317 /* | |
| 318 * Set the JPEG colorspace, and choose colorspace-dependent default values. | |
| 319 */ | |
| 320 | |
| 321 GLOBAL(void) | |
| 322 jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace) | |
| 323 { | |
| 324 jpeg_component_info * compptr; | |
| 325 int ci; | |
| 326 | |
| 327 #define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \ | |
| 328 (compptr = &cinfo->comp_info[index], \ | |
| 329 compptr->component_id = (id), \ | |
| 330 compptr->h_samp_factor = (hsamp), \ | |
| 331 compptr->v_samp_factor = (vsamp), \ | |
| 332 compptr->quant_tbl_no = (quant), \ | |
| 333 compptr->dc_tbl_no = (dctbl), \ | |
| 334 compptr->ac_tbl_no = (actbl) ) | |
| 335 | |
| 336 /* Safety check to ensure start_compress not called yet. */ | |
| 337 if (cinfo->global_state != CSTATE_START) | |
| 338 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
| 339 | |
| 340 /* For all colorspaces, we use Q and Huff tables 0 for luminance components, | |
| 341 * tables 1 for chrominance components. | |
| 342 */ | |
| 343 | |
| 344 cinfo->jpeg_color_space = colorspace; | |
| 345 | |
| 346 cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */ | |
| 347 cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */ | |
| 348 | |
| 349 switch (colorspace) { | |
| 350 case JCS_GRAYSCALE: | |
| 351 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ | |
| 352 cinfo->num_components = 1; | |
| 353 /* JFIF specifies component ID 1 */ | |
| 354 SET_COMP(0, 1, 1,1, 0, 0,0); | |
| 355 break; | |
| 356 case JCS_RGB: | |
| 357 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */ | |
| 358 cinfo->num_components = 3; | |
| 359 SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0); | |
| 360 SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0); | |
| 361 SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0); | |
| 362 break; | |
| 363 case JCS_YCbCr: | |
| 364 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ | |
| 365 cinfo->num_components = 3; | |
| 366 /* JFIF specifies component IDs 1,2,3 */ | |
| 367 /* We default to 2x2 subsamples of chrominance */ | |
| 368 SET_COMP(0, 1, 2,2, 0, 0,0); | |
| 369 SET_COMP(1, 2, 1,1, 1, 1,1); | |
| 370 SET_COMP(2, 3, 1,1, 1, 1,1); | |
| 371 break; | |
| 372 case JCS_CMYK: | |
| 373 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */ | |
| 374 cinfo->num_components = 4; | |
| 375 SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0); | |
| 376 SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0); | |
| 377 SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0); | |
| 378 SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0); | |
| 379 break; | |
| 380 case JCS_YCCK: | |
| 381 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */ | |
| 382 cinfo->num_components = 4; | |
| 383 SET_COMP(0, 1, 2,2, 0, 0,0); | |
| 384 SET_COMP(1, 2, 1,1, 1, 1,1); | |
| 385 SET_COMP(2, 3, 1,1, 1, 1,1); | |
| 386 SET_COMP(3, 4, 2,2, 0, 0,0); | |
| 387 break; | |
| 388 case JCS_UNKNOWN: | |
| 389 cinfo->num_components = cinfo->input_components; | |
| 390 if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS) | |
| 391 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, | |
| 392 MAX_COMPONENTS); | |
| 393 for (ci = 0; ci < cinfo->num_components; ci++) { | |
| 394 SET_COMP(ci, ci, 1,1, 0, 0,0); | |
| 395 } | |
| 396 break; | |
| 397 default: | |
| 398 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); | |
| 399 } | |
| 400 } | |
| 401 | |
| 402 | |
| 403 #ifdef C_PROGRESSIVE_SUPPORTED | |
| 404 | |
| 405 LOCAL(jpeg_scan_info *) | |
| 406 fill_a_scan (jpeg_scan_info * scanptr, int ci, | |
| 407 int Ss, int Se, int Ah, int Al) | |
| 408 /* Support routine: generate one scan for specified component */ | |
| 409 { | |
| 410 scanptr->comps_in_scan = 1; | |
| 411 scanptr->component_index[0] = ci; | |
| 412 scanptr->Ss = Ss; | |
| 413 scanptr->Se = Se; | |
| 414 scanptr->Ah = Ah; | |
| 415 scanptr->Al = Al; | |
| 416 scanptr++; | |
| 417 return scanptr; | |
| 418 } | |
| 419 | |
| 420 LOCAL(jpeg_scan_info *) | |
| 421 fill_scans (jpeg_scan_info * scanptr, int ncomps, | |
| 422 int Ss, int Se, int Ah, int Al) | |
| 423 /* Support routine: generate one scan for each component */ | |
| 424 { | |
| 425 int ci; | |
| 426 | |
| 427 for (ci = 0; ci < ncomps; ci++) { | |
| 428 scanptr->comps_in_scan = 1; | |
| 429 scanptr->component_index[0] = ci; | |
| 430 scanptr->Ss = Ss; | |
| 431 scanptr->Se = Se; | |
| 432 scanptr->Ah = Ah; | |
| 433 scanptr->Al = Al; | |
| 434 scanptr++; | |
| 435 } | |
| 436 return scanptr; | |
| 437 } | |
| 438 | |
| 439 LOCAL(jpeg_scan_info *) | |
| 440 fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al) | |
| 441 /* Support routine: generate interleaved DC scan if possible, else N scans */ | |
| 442 { | |
| 443 int ci; | |
| 444 | |
| 445 if (ncomps <= MAX_COMPS_IN_SCAN) { | |
| 446 /* Single interleaved DC scan */ | |
| 447 scanptr->comps_in_scan = ncomps; | |
| 448 for (ci = 0; ci < ncomps; ci++) | |
| 449 scanptr->component_index[ci] = ci; | |
| 450 scanptr->Ss = scanptr->Se = 0; | |
| 451 scanptr->Ah = Ah; | |
| 452 scanptr->Al = Al; | |
| 453 scanptr++; | |
| 454 } else { | |
| 455 /* Noninterleaved DC scan for each component */ | |
| 456 scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al); | |
| 457 } | |
| 458 return scanptr; | |
| 459 } | |
| 460 | |
| 461 | |
| 462 /* | |
| 463 * Create a recommended progressive-JPEG script. | |
| 464 * cinfo->num_components and cinfo->jpeg_color_space must be correct. | |
| 465 */ | |
| 466 | |
| 467 GLOBAL(void) | |
| 468 jpeg_simple_progression (j_compress_ptr cinfo) | |
| 469 { | |
| 470 int ncomps = cinfo->num_components; | |
| 471 int nscans; | |
| 472 jpeg_scan_info * scanptr; | |
| 473 | |
| 474 /* Safety check to ensure start_compress not called yet. */ | |
| 475 if (cinfo->global_state != CSTATE_START) | |
| 476 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); | |
| 477 | |
| 478 /* Figure space needed for script. Calculation must match code below! */ | |
| 479 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { | |
| 480 /* Custom script for YCbCr color images. */ | |
| 481 nscans = 10; | |
| 482 } else { | |
| 483 /* All-purpose script for other color spaces. */ | |
| 484 if (ncomps > MAX_COMPS_IN_SCAN) | |
| 485 nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */ | |
| 486 else | |
| 487 nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */ | |
| 488 } | |
| 489 | |
| 490 /* Allocate space for script. | |
| 491 * We need to put it in the permanent pool in case the application performs | |
| 492 * multiple compressions without changing the settings. To avoid a memory | |
| 493 * leak if jpeg_simple_progression is called repeatedly for the same JPEG | |
| 494 * object, we try to re-use previously allocated space, and we allocate | |
| 495 * enough space to handle YCbCr even if initially asked for grayscale. | |
| 496 */ | |
| 497 if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) { | |
| 498 cinfo->script_space_size = MAX(nscans, 10); | |
| 499 cinfo->script_space = (jpeg_scan_info *) | |
| 500 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, | |
| 501 cinfo->script_space_size * SIZEOF(jpeg_scan_info)); | |
| 502 } | |
| 503 scanptr = cinfo->script_space; | |
| 504 cinfo->scan_info = scanptr; | |
| 505 cinfo->num_scans = nscans; | |
| 506 | |
| 507 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { | |
| 508 /* Custom script for YCbCr color images. */ | |
| 509 /* Initial DC scan */ | |
| 510 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); | |
| 511 /* Initial AC scan: get some luma data out in a hurry */ | |
| 512 scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2); | |
| 513 /* Chroma data is too small to be worth expending many scans on */ | |
| 514 scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1); | |
| 515 scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1); | |
| 516 /* Complete spectral selection for luma AC */ | |
| 517 scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2); | |
| 518 /* Refine next bit of luma AC */ | |
| 519 scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1); | |
| 520 /* Finish DC successive approximation */ | |
| 521 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); | |
| 522 /* Finish AC successive approximation */ | |
| 523 scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0); | |
| 524 scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0); | |
| 525 /* Luma bottom bit comes last since it's usually largest scan */ | |
| 526 scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0); | |
| 527 } else { | |
| 528 /* All-purpose script for other color spaces. */ | |
| 529 /* Successive approximation first pass */ | |
| 530 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); | |
| 531 scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2); | |
| 532 scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2); | |
| 533 /* Successive approximation second pass */ | |
| 534 scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1); | |
| 535 /* Successive approximation final pass */ | |
| 536 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); | |
| 537 scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0); | |
| 538 } | |
| 539 } | |
| 540 | |
| 541 #endif /* C_PROGRESSIVE_SUPPORTED */ |
