1 #if !defined(_FX_JPEG_TURBO_) 2 /* 3 * jcparam.c 4 * 5 * Copyright (C) 1991-1998, Thomas G. Lane. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains optional default-setting code for the JPEG compressor. 10 * Applications do not have to use this file, but those that don't use it 11 * must know a lot more about the innards of the JPEG code. 12 */ 13 14 #define JPEG_INTERNALS 15 #include "jinclude.h" 16 #include "jpeglib.h" 17 18 19 /* 20 * Quantization table setup routines 21 */ 22 23 GLOBAL(void) 24 jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl, 25 const unsigned int *basic_table, 26 int scale_factor, boolean force_baseline) 27 /* Define a quantization table equal to the basic_table times 28 * a scale factor (given as a percentage). 29 * If force_baseline is TRUE, the computed quantization table entries 30 * are limited to 1..255 for JPEG baseline compatibility. 31 */ 32 { 33 JQUANT_TBL ** qtblptr; 34 int i; 35 long temp; 36 37 /* Safety check to ensure start_compress not called yet. */ 38 if (cinfo->global_state != CSTATE_START) 39 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 40 41 if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS) 42 ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl); 43 44 qtblptr = & cinfo->quant_tbl_ptrs[which_tbl]; 45 46 if (*qtblptr == NULL) 47 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo); 48 49 for (i = 0; i < DCTSIZE2; i++) { 50 temp = ((long) basic_table[i] * scale_factor + 50L) / 100L; 51 /* limit the values to the valid range */ 52 if (temp <= 0L) temp = 1L; 53 if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */ 54 if (force_baseline && temp > 255L) 55 temp = 255L; /* limit to baseline range if requested */ 56 (*qtblptr)->quantval[i] = (UINT16) temp; 57 } 58 59 /* Initialize sent_table FALSE so table will be written to JPEG file. */ 60 (*qtblptr)->sent_table = FALSE; 61 } 62 63 64 GLOBAL(void) 65 jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor, 66 boolean force_baseline) 67 /* Set or change the 'quality' (quantization) setting, using default tables 68 * and a straight percentage-scaling quality scale. In most cases it's better 69 * to use jpeg_set_quality (below); this entry point is provided for 70 * applications that insist on a linear percentage scaling. 71 */ 72 { 73 /* These are the sample quantization tables given in JPEG spec section K.1. 74 * The spec says that the values given produce "good" quality, and 75 * when divided by 2, "very good" quality. 76 */ 77 static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = { 78 16, 11, 10, 16, 24, 40, 51, 61, 79 12, 12, 14, 19, 26, 58, 60, 55, 80 14, 13, 16, 24, 40, 57, 69, 56, 81 14, 17, 22, 29, 51, 87, 80, 62, 82 18, 22, 37, 56, 68, 109, 103, 77, 83 24, 35, 55, 64, 81, 104, 113, 92, 84 49, 64, 78, 87, 103, 121, 120, 101, 85 72, 92, 95, 98, 112, 100, 103, 99 86 }; 87 static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = { 88 17, 18, 24, 47, 99, 99, 99, 99, 89 18, 21, 26, 66, 99, 99, 99, 99, 90 24, 26, 56, 99, 99, 99, 99, 99, 91 47, 66, 99, 99, 99, 99, 99, 99, 92 99, 99, 99, 99, 99, 99, 99, 99, 93 99, 99, 99, 99, 99, 99, 99, 99, 94 99, 99, 99, 99, 99, 99, 99, 99, 95 99, 99, 99, 99, 99, 99, 99, 99 96 }; 97 98 /* Set up two quantization tables using the specified scaling */ 99 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl, 100 scale_factor, force_baseline); 101 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, 102 scale_factor, force_baseline); 103 } 104 105 106 GLOBAL(int) 107 jpeg_quality_scaling (int quality) 108 /* Convert a user-specified quality rating to a percentage scaling factor 109 * for an underlying quantization table, using our recommended scaling curve. 110 * The input 'quality' factor should be 0 (terrible) to 100 (very good). 111 */ 112 { 113 /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */ 114 if (quality <= 0) quality = 1; 115 if (quality > 100) quality = 100; 116 117 /* The basic table is used as-is (scaling 100) for a quality of 50. 118 * Qualities 50..100 are converted to scaling percentage 200 - 2*Q; 119 * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table 120 * to make all the table entries 1 (hence, minimum quantization loss). 121 * Qualities 1..50 are converted to scaling percentage 5000/Q. 122 */ 123 if (quality < 50) 124 quality = 5000 / quality; 125 else 126 quality = 200 - quality*2; 127 128 return quality; 129 } 130 131 132 GLOBAL(void) 133 jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline) 134 /* Set or change the 'quality' (quantization) setting, using default tables. 135 * This is the standard quality-adjusting entry point for typical user 136 * interfaces; only those who want detailed control over quantization tables 137 * would use the preceding three routines directly. 138 */ 139 { 140 /* Convert user 0-100 rating to percentage scaling */ 141 quality = jpeg_quality_scaling(quality); 142 143 /* Set up standard quality tables */ 144 jpeg_set_linear_quality(cinfo, quality, force_baseline); 145 } 146 147 148 /* 149 * Huffman table setup routines 150 */ 151 152 LOCAL(void) 153 add_huff_table (j_compress_ptr cinfo, 154 JHUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val) 155 /* Define a Huffman table */ 156 { 157 int nsymbols, len; 158 159 if (*htblptr == NULL) 160 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 161 162 /* Copy the number-of-symbols-of-each-code-length counts */ 163 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 164 165 /* Validate the counts. We do this here mainly so we can copy the right 166 * number of symbols from the val[] array, without risking marching off 167 * the end of memory. jchuff.c will do a more thorough test later. 168 */ 169 nsymbols = 0; 170 for (len = 1; len <= 16; len++) 171 nsymbols += bits[len]; 172 if (nsymbols < 1 || nsymbols > 256) 173 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 174 175 MEMCOPY((*htblptr)->huffval, val, nsymbols * SIZEOF(UINT8)); 176 177 /* Initialize sent_table FALSE so table will be written to JPEG file. */ 178 (*htblptr)->sent_table = FALSE; 179 } 180 181 182 LOCAL(void) 183 std_huff_tables (j_compress_ptr cinfo) 184 /* Set up the standard Huffman tables (cf. JPEG standard section K.3) */ 185 /* IMPORTANT: these are only valid for 8-bit data precision! */ 186 { 187 static const UINT8 bits_dc_luminance[17] = 188 { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 }; 189 static const UINT8 val_dc_luminance[] = 190 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }; 191 192 static const UINT8 bits_dc_chrominance[17] = 193 { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 }; 194 static const UINT8 val_dc_chrominance[] = 195 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }; 196 197 static const UINT8 bits_ac_luminance[17] = 198 { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d }; 199 static const UINT8 val_ac_luminance[] = 200 { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 201 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 202 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 203 0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 204 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 205 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28, 206 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 207 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 208 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 209 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 210 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 211 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 212 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 213 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 214 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 215 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 216 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 217 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2, 218 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 219 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 220 0xf9, 0xfa }; 221 222 static const UINT8 bits_ac_chrominance[17] = 223 { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 }; 224 static const UINT8 val_ac_chrominance[] = 225 { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 226 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 227 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 228 0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 229 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 230 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26, 231 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 232 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 233 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 234 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 235 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 236 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 237 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 238 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 239 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 240 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 241 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 242 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 243 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 244 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 245 0xf9, 0xfa }; 246 247 add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0], 248 bits_dc_luminance, val_dc_luminance); 249 add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0], 250 bits_ac_luminance, val_ac_luminance); 251 add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1], 252 bits_dc_chrominance, val_dc_chrominance); 253 add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1], 254 bits_ac_chrominance, val_ac_chrominance); 255 } 256 257 258 /* 259 * Default parameter setup for compression. 260 * 261 * Applications that don't choose to use this routine must do their 262 * own setup of all these parameters. Alternately, you can call this 263 * to establish defaults and then alter parameters selectively. This 264 * is the recommended approach since, if we add any new parameters, 265 * your code will still work (they'll be set to reasonable defaults). 266 */ 267 268 GLOBAL(void) 269 jpeg_set_defaults (j_compress_ptr cinfo) 270 { 271 int i; 272 273 /* Safety check to ensure start_compress not called yet. */ 274 if (cinfo->global_state != CSTATE_START) 275 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 276 277 /* Allocate comp_info array large enough for maximum component count. 278 * Array is made permanent in case application wants to compress 279 * multiple images at same param settings. 280 */ 281 if (cinfo->comp_info == NULL) 282 cinfo->comp_info = (jpeg_component_info *) 283 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 284 MAX_COMPONENTS * SIZEOF(jpeg_component_info)); 285 286 /* Initialize everything not dependent on the color space */ 287 288 cinfo->data_precision = BITS_IN_JSAMPLE; 289 /* Set up two quantization tables using default quality of 75 */ 290 jpeg_set_quality(cinfo, 75, TRUE); 291 /* Set up two Huffman tables */ 292 std_huff_tables(cinfo); 293 294 /* Initialize default arithmetic coding conditioning */ 295 for (i = 0; i < NUM_ARITH_TBLS; i++) { 296 cinfo->arith_dc_L[i] = 0; 297 cinfo->arith_dc_U[i] = 1; 298 cinfo->arith_ac_K[i] = 5; 299 } 300 301 /* Default is no multiple-scan output */ 302 cinfo->scan_info = NULL; 303 cinfo->num_scans = 0; 304 305 /* Expect normal source image, not raw downsampled data */ 306 cinfo->raw_data_in = FALSE; 307 308 /* Use Huffman coding, not arithmetic coding, by default */ 309 cinfo->arith_code = FALSE; 310 311 /* By default, don't do extra passes to optimize entropy coding */ 312 cinfo->optimize_coding = FALSE; 313 /* The standard Huffman tables are only valid for 8-bit data precision. 314 * If the precision is higher, force optimization on so that usable 315 * tables will be computed. This test can be removed if default tables 316 * are supplied that are valid for the desired precision. 317 */ 318 if (cinfo->data_precision > 8) 319 cinfo->optimize_coding = TRUE; 320 321 /* By default, use the simpler non-cosited sampling alignment */ 322 cinfo->CCIR601_sampling = FALSE; 323 324 /* No input smoothing */ 325 cinfo->smoothing_factor = 0; 326 327 /* DCT algorithm preference */ 328 cinfo->dct_method = JDCT_DEFAULT; 329 330 /* No restart markers */ 331 cinfo->restart_interval = 0; 332 cinfo->restart_in_rows = 0; 333 334 /* Fill in default JFIF marker parameters. Note that whether the marker 335 * will actually be written is determined by jpeg_set_colorspace. 336 * 337 * By default, the library emits JFIF version code 1.01. 338 * An application that wants to emit JFIF 1.02 extension markers should set 339 * JFIF_minor_version to 2. We could probably get away with just defaulting 340 * to 1.02, but there may still be some decoders in use that will complain 341 * about that; saying 1.01 should minimize compatibility problems. 342 */ 343 cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */ 344 cinfo->JFIF_minor_version = 1; 345 cinfo->density_unit = 0; /* Pixel size is unknown by default */ 346 cinfo->X_density = 1; /* Pixel aspect ratio is square by default */ 347 cinfo->Y_density = 1; 348 349 /* Choose JPEG colorspace based on input space, set defaults accordingly */ 350 351 jpeg_default_colorspace(cinfo); 352 } 353 354 355 /* 356 * Select an appropriate JPEG colorspace for in_color_space. 357 */ 358 359 GLOBAL(void) 360 jpeg_default_colorspace (j_compress_ptr cinfo) 361 { 362 switch (cinfo->in_color_space) { 363 case JCS_GRAYSCALE: 364 jpeg_set_colorspace(cinfo, JCS_GRAYSCALE); 365 break; 366 case JCS_RGB: 367 jpeg_set_colorspace(cinfo, JCS_YCbCr); 368 break; 369 case JCS_YCbCr: 370 jpeg_set_colorspace(cinfo, JCS_YCbCr); 371 break; 372 case JCS_CMYK: 373 jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */ 374 break; 375 case JCS_YCCK: 376 jpeg_set_colorspace(cinfo, JCS_YCCK); 377 break; 378 case JCS_UNKNOWN: 379 jpeg_set_colorspace(cinfo, JCS_UNKNOWN); 380 break; 381 default: 382 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE); 383 } 384 } 385 386 387 /* 388 * Set the JPEG colorspace, and choose colorspace-dependent default values. 389 */ 390 391 GLOBAL(void) 392 jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace) 393 { 394 jpeg_component_info * compptr; 395 int ci; 396 397 #define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \ 398 (compptr = &cinfo->comp_info[index], \ 399 compptr->component_id = (id), \ 400 compptr->h_samp_factor = (hsamp), \ 401 compptr->v_samp_factor = (vsamp), \ 402 compptr->quant_tbl_no = (quant), \ 403 compptr->dc_tbl_no = (dctbl), \ 404 compptr->ac_tbl_no = (actbl) ) 405 406 /* Safety check to ensure start_compress not called yet. */ 407 if (cinfo->global_state != CSTATE_START) 408 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 409 410 /* For all colorspaces, we use Q and Huff tables 0 for luminance components, 411 * tables 1 for chrominance components. 412 */ 413 414 cinfo->jpeg_color_space = colorspace; 415 416 cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */ 417 cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */ 418 419 switch (colorspace) { 420 case JCS_GRAYSCALE: 421 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ 422 cinfo->num_components = 1; 423 /* JFIF specifies component ID 1 */ 424 SET_COMP(0, 1, 1,1, 0, 0,0); 425 break; 426 case JCS_RGB: 427 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */ 428 cinfo->num_components = 3; 429 SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0); 430 SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0); 431 SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0); 432 break; 433 case JCS_YCbCr: 434 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */ 435 cinfo->num_components = 3; 436 /* JFIF specifies component IDs 1,2,3 */ 437 /* We default to 2x2 subsamples of chrominance */ 438 SET_COMP(0, 1, 2,2, 0, 0,0); 439 SET_COMP(1, 2, 1,1, 1, 1,1); 440 SET_COMP(2, 3, 1,1, 1, 1,1); 441 break; 442 case JCS_CMYK: 443 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */ 444 cinfo->num_components = 4; 445 SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0); 446 SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0); 447 SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0); 448 SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0); 449 break; 450 case JCS_YCCK: 451 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */ 452 cinfo->num_components = 4; 453 SET_COMP(0, 1, 2,2, 0, 0,0); 454 SET_COMP(1, 2, 1,1, 1, 1,1); 455 SET_COMP(2, 3, 1,1, 1, 1,1); 456 SET_COMP(3, 4, 2,2, 0, 0,0); 457 break; 458 case JCS_UNKNOWN: 459 cinfo->num_components = cinfo->input_components; 460 if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS) 461 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 462 MAX_COMPONENTS); 463 for (ci = 0; ci < cinfo->num_components; ci++) { 464 SET_COMP(ci, ci, 1,1, 0, 0,0); 465 } 466 break; 467 default: 468 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE); 469 } 470 } 471 472 473 #ifdef C_PROGRESSIVE_SUPPORTED 474 475 LOCAL(jpeg_scan_info *) 476 fill_a_scan (jpeg_scan_info * scanptr, int ci, 477 int Ss, int Se, int Ah, int Al) 478 /* Support routine: generate one scan for specified component */ 479 { 480 scanptr->comps_in_scan = 1; 481 scanptr->component_index[0] = ci; 482 scanptr->Ss = Ss; 483 scanptr->Se = Se; 484 scanptr->Ah = Ah; 485 scanptr->Al = Al; 486 scanptr++; 487 return scanptr; 488 } 489 490 LOCAL(jpeg_scan_info *) 491 fill_scans (jpeg_scan_info * scanptr, int ncomps, 492 int Ss, int Se, int Ah, int Al) 493 /* Support routine: generate one scan for each component */ 494 { 495 int ci; 496 497 for (ci = 0; ci < ncomps; ci++) { 498 scanptr->comps_in_scan = 1; 499 scanptr->component_index[0] = ci; 500 scanptr->Ss = Ss; 501 scanptr->Se = Se; 502 scanptr->Ah = Ah; 503 scanptr->Al = Al; 504 scanptr++; 505 } 506 return scanptr; 507 } 508 509 LOCAL(jpeg_scan_info *) 510 fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al) 511 /* Support routine: generate interleaved DC scan if possible, else N scans */ 512 { 513 int ci; 514 515 if (ncomps <= MAX_COMPS_IN_SCAN) { 516 /* Single interleaved DC scan */ 517 scanptr->comps_in_scan = ncomps; 518 for (ci = 0; ci < ncomps; ci++) 519 scanptr->component_index[ci] = ci; 520 scanptr->Ss = scanptr->Se = 0; 521 scanptr->Ah = Ah; 522 scanptr->Al = Al; 523 scanptr++; 524 } else { 525 /* Noninterleaved DC scan for each component */ 526 scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al); 527 } 528 return scanptr; 529 } 530 531 532 /* 533 * Create a recommended progressive-JPEG script. 534 * cinfo->num_components and cinfo->jpeg_color_space must be correct. 535 */ 536 537 GLOBAL(void) 538 jpeg_simple_progression (j_compress_ptr cinfo) 539 { 540 int ncomps = cinfo->num_components; 541 int nscans; 542 jpeg_scan_info * scanptr; 543 544 /* Safety check to ensure start_compress not called yet. */ 545 if (cinfo->global_state != CSTATE_START) 546 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 547 548 /* Figure space needed for script. Calculation must match code below! */ 549 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { 550 /* Custom script for YCbCr color images. */ 551 nscans = 10; 552 } else { 553 /* All-purpose script for other color spaces. */ 554 if (ncomps > MAX_COMPS_IN_SCAN) 555 nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */ 556 else 557 nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */ 558 } 559 560 /* Allocate space for script. 561 * We need to put it in the permanent pool in case the application performs 562 * multiple compressions without changing the settings. To avoid a memory 563 * leak if jpeg_simple_progression is called repeatedly for the same JPEG 564 * object, we try to re-use previously allocated space, and we allocate 565 * enough space to handle YCbCr even if initially asked for grayscale. 566 */ 567 if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) { 568 cinfo->script_space_size = MAX(nscans, 10); 569 cinfo->script_space = (jpeg_scan_info *) 570 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 571 cinfo->script_space_size * SIZEOF(jpeg_scan_info)); 572 } 573 scanptr = cinfo->script_space; 574 cinfo->scan_info = scanptr; 575 cinfo->num_scans = nscans; 576 577 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) { 578 /* Custom script for YCbCr color images. */ 579 /* Initial DC scan */ 580 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); 581 /* Initial AC scan: get some luma data out in a hurry */ 582 scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2); 583 /* Chroma data is too small to be worth expending many scans on */ 584 scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1); 585 scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1); 586 /* Complete spectral selection for luma AC */ 587 scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2); 588 /* Refine next bit of luma AC */ 589 scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1); 590 /* Finish DC successive approximation */ 591 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); 592 /* Finish AC successive approximation */ 593 scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0); 594 scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0); 595 /* Luma bottom bit comes last since it's usually largest scan */ 596 scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0); 597 } else { 598 /* All-purpose script for other color spaces. */ 599 /* Successive approximation first pass */ 600 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1); 601 scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2); 602 scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2); 603 /* Successive approximation second pass */ 604 scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1); 605 /* Successive approximation final pass */ 606 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0); 607 scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0); 608 } 609 } 610 611 #endif /* C_PROGRESSIVE_SUPPORTED */ 612 613 #endif //_FX_JPEG_TURBO_ 614
