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annotate libs/libjpeg/jcparam.c @ 0:b2f14e535253

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author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 01 Feb 2014 19:58:19 +0200
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nuclear@0 1 /*
nuclear@0 2 * jcparam.c
nuclear@0 3 *
nuclear@0 4 * Copyright (C) 1991-1998, Thomas G. Lane.
nuclear@0 5 * This file is part of the Independent JPEG Group's software.
nuclear@0 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@0 7 *
nuclear@0 8 * This file contains optional default-setting code for the JPEG compressor.
nuclear@0 9 * Applications do not have to use this file, but those that don't use it
nuclear@0 10 * must know a lot more about the innards of the JPEG code.
nuclear@0 11 */
nuclear@0 12
nuclear@0 13 #define JPEG_INTERNALS
nuclear@0 14 #include "jinclude.h"
nuclear@0 15 #include "jpeglib.h"
nuclear@0 16
nuclear@0 17
nuclear@0 18 /*
nuclear@0 19 * Quantization table setup routines
nuclear@0 20 */
nuclear@0 21
nuclear@0 22 GLOBAL(void)
nuclear@0 23 jpeg_add_quant_table (j_compress_ptr cinfo, int which_tbl,
nuclear@0 24 const unsigned int *basic_table,
nuclear@0 25 int scale_factor, boolean force_baseline)
nuclear@0 26 /* Define a quantization table equal to the basic_table times
nuclear@0 27 * a scale factor (given as a percentage).
nuclear@0 28 * If force_baseline is TRUE, the computed quantization table entries
nuclear@0 29 * are limited to 1..255 for JPEG baseline compatibility.
nuclear@0 30 */
nuclear@0 31 {
nuclear@0 32 JQUANT_TBL ** qtblptr;
nuclear@0 33 int i;
nuclear@0 34 long temp;
nuclear@0 35
nuclear@0 36 /* Safety check to ensure start_compress not called yet. */
nuclear@0 37 if (cinfo->global_state != CSTATE_START)
nuclear@0 38 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@0 39
nuclear@0 40 if (which_tbl < 0 || which_tbl >= NUM_QUANT_TBLS)
nuclear@0 41 ERREXIT1(cinfo, JERR_DQT_INDEX, which_tbl);
nuclear@0 42
nuclear@0 43 qtblptr = & cinfo->quant_tbl_ptrs[which_tbl];
nuclear@0 44
nuclear@0 45 if (*qtblptr == NULL)
nuclear@0 46 *qtblptr = jpeg_alloc_quant_table((j_common_ptr) cinfo);
nuclear@0 47
nuclear@0 48 for (i = 0; i < DCTSIZE2; i++) {
nuclear@0 49 temp = ((long) basic_table[i] * scale_factor + 50L) / 100L;
nuclear@0 50 /* limit the values to the valid range */
nuclear@0 51 if (temp <= 0L) temp = 1L;
nuclear@0 52 if (temp > 32767L) temp = 32767L; /* max quantizer needed for 12 bits */
nuclear@0 53 if (force_baseline && temp > 255L)
nuclear@0 54 temp = 255L; /* limit to baseline range if requested */
nuclear@0 55 (*qtblptr)->quantval[i] = (UINT16) temp;
nuclear@0 56 }
nuclear@0 57
nuclear@0 58 /* Initialize sent_table FALSE so table will be written to JPEG file. */
nuclear@0 59 (*qtblptr)->sent_table = FALSE;
nuclear@0 60 }
nuclear@0 61
nuclear@0 62
nuclear@0 63 GLOBAL(void)
nuclear@0 64 jpeg_set_linear_quality (j_compress_ptr cinfo, int scale_factor,
nuclear@0 65 boolean force_baseline)
nuclear@0 66 /* Set or change the 'quality' (quantization) setting, using default tables
nuclear@0 67 * and a straight percentage-scaling quality scale. In most cases it's better
nuclear@0 68 * to use jpeg_set_quality (below); this entry point is provided for
nuclear@0 69 * applications that insist on a linear percentage scaling.
nuclear@0 70 */
nuclear@0 71 {
nuclear@0 72 /* These are the sample quantization tables given in JPEG spec section K.1.
nuclear@0 73 * The spec says that the values given produce "good" quality, and
nuclear@0 74 * when divided by 2, "very good" quality.
nuclear@0 75 */
nuclear@0 76 static const unsigned int std_luminance_quant_tbl[DCTSIZE2] = {
nuclear@0 77 16, 11, 10, 16, 24, 40, 51, 61,
nuclear@0 78 12, 12, 14, 19, 26, 58, 60, 55,
nuclear@0 79 14, 13, 16, 24, 40, 57, 69, 56,
nuclear@0 80 14, 17, 22, 29, 51, 87, 80, 62,
nuclear@0 81 18, 22, 37, 56, 68, 109, 103, 77,
nuclear@0 82 24, 35, 55, 64, 81, 104, 113, 92,
nuclear@0 83 49, 64, 78, 87, 103, 121, 120, 101,
nuclear@0 84 72, 92, 95, 98, 112, 100, 103, 99
nuclear@0 85 };
nuclear@0 86 static const unsigned int std_chrominance_quant_tbl[DCTSIZE2] = {
nuclear@0 87 17, 18, 24, 47, 99, 99, 99, 99,
nuclear@0 88 18, 21, 26, 66, 99, 99, 99, 99,
nuclear@0 89 24, 26, 56, 99, 99, 99, 99, 99,
nuclear@0 90 47, 66, 99, 99, 99, 99, 99, 99,
nuclear@0 91 99, 99, 99, 99, 99, 99, 99, 99,
nuclear@0 92 99, 99, 99, 99, 99, 99, 99, 99,
nuclear@0 93 99, 99, 99, 99, 99, 99, 99, 99,
nuclear@0 94 99, 99, 99, 99, 99, 99, 99, 99
nuclear@0 95 };
nuclear@0 96
nuclear@0 97 /* Set up two quantization tables using the specified scaling */
nuclear@0 98 jpeg_add_quant_table(cinfo, 0, std_luminance_quant_tbl,
nuclear@0 99 scale_factor, force_baseline);
nuclear@0 100 jpeg_add_quant_table(cinfo, 1, std_chrominance_quant_tbl,
nuclear@0 101 scale_factor, force_baseline);
nuclear@0 102 }
nuclear@0 103
nuclear@0 104
nuclear@0 105 GLOBAL(int)
nuclear@0 106 jpeg_quality_scaling (int quality)
nuclear@0 107 /* Convert a user-specified quality rating to a percentage scaling factor
nuclear@0 108 * for an underlying quantization table, using our recommended scaling curve.
nuclear@0 109 * The input 'quality' factor should be 0 (terrible) to 100 (very good).
nuclear@0 110 */
nuclear@0 111 {
nuclear@0 112 /* Safety limit on quality factor. Convert 0 to 1 to avoid zero divide. */
nuclear@0 113 if (quality <= 0) quality = 1;
nuclear@0 114 if (quality > 100) quality = 100;
nuclear@0 115
nuclear@0 116 /* The basic table is used as-is (scaling 100) for a quality of 50.
nuclear@0 117 * Qualities 50..100 are converted to scaling percentage 200 - 2*Q;
nuclear@0 118 * note that at Q=100 the scaling is 0, which will cause jpeg_add_quant_table
nuclear@0 119 * to make all the table entries 1 (hence, minimum quantization loss).
nuclear@0 120 * Qualities 1..50 are converted to scaling percentage 5000/Q.
nuclear@0 121 */
nuclear@0 122 if (quality < 50)
nuclear@0 123 quality = 5000 / quality;
nuclear@0 124 else
nuclear@0 125 quality = 200 - quality*2;
nuclear@0 126
nuclear@0 127 return quality;
nuclear@0 128 }
nuclear@0 129
nuclear@0 130
nuclear@0 131 GLOBAL(void)
nuclear@0 132 jpeg_set_quality (j_compress_ptr cinfo, int quality, boolean force_baseline)
nuclear@0 133 /* Set or change the 'quality' (quantization) setting, using default tables.
nuclear@0 134 * This is the standard quality-adjusting entry point for typical user
nuclear@0 135 * interfaces; only those who want detailed control over quantization tables
nuclear@0 136 * would use the preceding three routines directly.
nuclear@0 137 */
nuclear@0 138 {
nuclear@0 139 /* Convert user 0-100 rating to percentage scaling */
nuclear@0 140 quality = jpeg_quality_scaling(quality);
nuclear@0 141
nuclear@0 142 /* Set up standard quality tables */
nuclear@0 143 jpeg_set_linear_quality(cinfo, quality, force_baseline);
nuclear@0 144 }
nuclear@0 145
nuclear@0 146
nuclear@0 147 /*
nuclear@0 148 * Huffman table setup routines
nuclear@0 149 */
nuclear@0 150
nuclear@0 151 LOCAL(void)
nuclear@0 152 add_huff_table (j_compress_ptr cinfo,
nuclear@0 153 JHUFF_TBL **htblptr, const UINT8 *bits, const UINT8 *val)
nuclear@0 154 /* Define a Huffman table */
nuclear@0 155 {
nuclear@0 156 int nsymbols, len;
nuclear@0 157
nuclear@0 158 if (*htblptr == NULL)
nuclear@0 159 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
nuclear@0 160
nuclear@0 161 /* Copy the number-of-symbols-of-each-code-length counts */
nuclear@0 162 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
nuclear@0 163
nuclear@0 164 /* Validate the counts. We do this here mainly so we can copy the right
nuclear@0 165 * number of symbols from the val[] array, without risking marching off
nuclear@0 166 * the end of memory. jchuff.c will do a more thorough test later.
nuclear@0 167 */
nuclear@0 168 nsymbols = 0;
nuclear@0 169 for (len = 1; len <= 16; len++)
nuclear@0 170 nsymbols += bits[len];
nuclear@0 171 if (nsymbols < 1 || nsymbols > 256)
nuclear@0 172 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
nuclear@0 173
nuclear@0 174 MEMCOPY((*htblptr)->huffval, val, nsymbols * SIZEOF(UINT8));
nuclear@0 175
nuclear@0 176 /* Initialize sent_table FALSE so table will be written to JPEG file. */
nuclear@0 177 (*htblptr)->sent_table = FALSE;
nuclear@0 178 }
nuclear@0 179
nuclear@0 180
nuclear@0 181 LOCAL(void)
nuclear@0 182 std_huff_tables (j_compress_ptr cinfo)
nuclear@0 183 /* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
nuclear@0 184 /* IMPORTANT: these are only valid for 8-bit data precision! */
nuclear@0 185 {
nuclear@0 186 static const UINT8 bits_dc_luminance[17] =
nuclear@0 187 { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
nuclear@0 188 static const UINT8 val_dc_luminance[] =
nuclear@0 189 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
nuclear@0 190
nuclear@0 191 static const UINT8 bits_dc_chrominance[17] =
nuclear@0 192 { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
nuclear@0 193 static const UINT8 val_dc_chrominance[] =
nuclear@0 194 { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
nuclear@0 195
nuclear@0 196 static const UINT8 bits_ac_luminance[17] =
nuclear@0 197 { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
nuclear@0 198 static const UINT8 val_ac_luminance[] =
nuclear@0 199 { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
nuclear@0 200 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
nuclear@0 201 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
nuclear@0 202 0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
nuclear@0 203 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
nuclear@0 204 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
nuclear@0 205 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
nuclear@0 206 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
nuclear@0 207 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
nuclear@0 208 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
nuclear@0 209 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
nuclear@0 210 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
nuclear@0 211 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
nuclear@0 212 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
nuclear@0 213 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
nuclear@0 214 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
nuclear@0 215 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
nuclear@0 216 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
nuclear@0 217 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
nuclear@0 218 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
nuclear@0 219 0xf9, 0xfa };
nuclear@0 220
nuclear@0 221 static const UINT8 bits_ac_chrominance[17] =
nuclear@0 222 { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
nuclear@0 223 static const UINT8 val_ac_chrominance[] =
nuclear@0 224 { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
nuclear@0 225 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
nuclear@0 226 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
nuclear@0 227 0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
nuclear@0 228 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
nuclear@0 229 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
nuclear@0 230 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
nuclear@0 231 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
nuclear@0 232 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
nuclear@0 233 0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
nuclear@0 234 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
nuclear@0 235 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
nuclear@0 236 0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
nuclear@0 237 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
nuclear@0 238 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
nuclear@0 239 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
nuclear@0 240 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
nuclear@0 241 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
nuclear@0 242 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
nuclear@0 243 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
nuclear@0 244 0xf9, 0xfa };
nuclear@0 245
nuclear@0 246 add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[0],
nuclear@0 247 bits_dc_luminance, val_dc_luminance);
nuclear@0 248 add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[0],
nuclear@0 249 bits_ac_luminance, val_ac_luminance);
nuclear@0 250 add_huff_table(cinfo, &cinfo->dc_huff_tbl_ptrs[1],
nuclear@0 251 bits_dc_chrominance, val_dc_chrominance);
nuclear@0 252 add_huff_table(cinfo, &cinfo->ac_huff_tbl_ptrs[1],
nuclear@0 253 bits_ac_chrominance, val_ac_chrominance);
nuclear@0 254 }
nuclear@0 255
nuclear@0 256
nuclear@0 257 /*
nuclear@0 258 * Default parameter setup for compression.
nuclear@0 259 *
nuclear@0 260 * Applications that don't choose to use this routine must do their
nuclear@0 261 * own setup of all these parameters. Alternately, you can call this
nuclear@0 262 * to establish defaults and then alter parameters selectively. This
nuclear@0 263 * is the recommended approach since, if we add any new parameters,
nuclear@0 264 * your code will still work (they'll be set to reasonable defaults).
nuclear@0 265 */
nuclear@0 266
nuclear@0 267 GLOBAL(void)
nuclear@0 268 jpeg_set_defaults (j_compress_ptr cinfo)
nuclear@0 269 {
nuclear@0 270 int i;
nuclear@0 271
nuclear@0 272 /* Safety check to ensure start_compress not called yet. */
nuclear@0 273 if (cinfo->global_state != CSTATE_START)
nuclear@0 274 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@0 275
nuclear@0 276 /* Allocate comp_info array large enough for maximum component count.
nuclear@0 277 * Array is made permanent in case application wants to compress
nuclear@0 278 * multiple images at same param settings.
nuclear@0 279 */
nuclear@0 280 if (cinfo->comp_info == NULL)
nuclear@0 281 cinfo->comp_info = (jpeg_component_info *)
nuclear@0 282 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
nuclear@0 283 MAX_COMPONENTS * SIZEOF(jpeg_component_info));
nuclear@0 284
nuclear@0 285 /* Initialize everything not dependent on the color space */
nuclear@0 286
nuclear@0 287 cinfo->data_precision = BITS_IN_JSAMPLE;
nuclear@0 288 /* Set up two quantization tables using default quality of 75 */
nuclear@0 289 jpeg_set_quality(cinfo, 75, TRUE);
nuclear@0 290 /* Set up two Huffman tables */
nuclear@0 291 std_huff_tables(cinfo);
nuclear@0 292
nuclear@0 293 /* Initialize default arithmetic coding conditioning */
nuclear@0 294 for (i = 0; i < NUM_ARITH_TBLS; i++) {
nuclear@0 295 cinfo->arith_dc_L[i] = 0;
nuclear@0 296 cinfo->arith_dc_U[i] = 1;
nuclear@0 297 cinfo->arith_ac_K[i] = 5;
nuclear@0 298 }
nuclear@0 299
nuclear@0 300 /* Default is no multiple-scan output */
nuclear@0 301 cinfo->scan_info = NULL;
nuclear@0 302 cinfo->num_scans = 0;
nuclear@0 303
nuclear@0 304 /* Expect normal source image, not raw downsampled data */
nuclear@0 305 cinfo->raw_data_in = FALSE;
nuclear@0 306
nuclear@0 307 /* Use Huffman coding, not arithmetic coding, by default */
nuclear@0 308 cinfo->arith_code = FALSE;
nuclear@0 309
nuclear@0 310 /* By default, don't do extra passes to optimize entropy coding */
nuclear@0 311 cinfo->optimize_coding = FALSE;
nuclear@0 312 /* The standard Huffman tables are only valid for 8-bit data precision.
nuclear@0 313 * If the precision is higher, force optimization on so that usable
nuclear@0 314 * tables will be computed. This test can be removed if default tables
nuclear@0 315 * are supplied that are valid for the desired precision.
nuclear@0 316 */
nuclear@0 317 if (cinfo->data_precision > 8)
nuclear@0 318 cinfo->optimize_coding = TRUE;
nuclear@0 319
nuclear@0 320 /* By default, use the simpler non-cosited sampling alignment */
nuclear@0 321 cinfo->CCIR601_sampling = FALSE;
nuclear@0 322
nuclear@0 323 /* No input smoothing */
nuclear@0 324 cinfo->smoothing_factor = 0;
nuclear@0 325
nuclear@0 326 /* DCT algorithm preference */
nuclear@0 327 cinfo->dct_method = JDCT_DEFAULT;
nuclear@0 328
nuclear@0 329 /* No restart markers */
nuclear@0 330 cinfo->restart_interval = 0;
nuclear@0 331 cinfo->restart_in_rows = 0;
nuclear@0 332
nuclear@0 333 /* Fill in default JFIF marker parameters. Note that whether the marker
nuclear@0 334 * will actually be written is determined by jpeg_set_colorspace.
nuclear@0 335 *
nuclear@0 336 * By default, the library emits JFIF version code 1.01.
nuclear@0 337 * An application that wants to emit JFIF 1.02 extension markers should set
nuclear@0 338 * JFIF_minor_version to 2. We could probably get away with just defaulting
nuclear@0 339 * to 1.02, but there may still be some decoders in use that will complain
nuclear@0 340 * about that; saying 1.01 should minimize compatibility problems.
nuclear@0 341 */
nuclear@0 342 cinfo->JFIF_major_version = 1; /* Default JFIF version = 1.01 */
nuclear@0 343 cinfo->JFIF_minor_version = 1;
nuclear@0 344 cinfo->density_unit = 0; /* Pixel size is unknown by default */
nuclear@0 345 cinfo->X_density = 1; /* Pixel aspect ratio is square by default */
nuclear@0 346 cinfo->Y_density = 1;
nuclear@0 347
nuclear@0 348 /* Choose JPEG colorspace based on input space, set defaults accordingly */
nuclear@0 349
nuclear@0 350 jpeg_default_colorspace(cinfo);
nuclear@0 351 }
nuclear@0 352
nuclear@0 353
nuclear@0 354 /*
nuclear@0 355 * Select an appropriate JPEG colorspace for in_color_space.
nuclear@0 356 */
nuclear@0 357
nuclear@0 358 GLOBAL(void)
nuclear@0 359 jpeg_default_colorspace (j_compress_ptr cinfo)
nuclear@0 360 {
nuclear@0 361 switch (cinfo->in_color_space) {
nuclear@0 362 case JCS_GRAYSCALE:
nuclear@0 363 jpeg_set_colorspace(cinfo, JCS_GRAYSCALE);
nuclear@0 364 break;
nuclear@0 365 case JCS_RGB:
nuclear@0 366 jpeg_set_colorspace(cinfo, JCS_YCbCr);
nuclear@0 367 break;
nuclear@0 368 case JCS_YCbCr:
nuclear@0 369 jpeg_set_colorspace(cinfo, JCS_YCbCr);
nuclear@0 370 break;
nuclear@0 371 case JCS_CMYK:
nuclear@0 372 jpeg_set_colorspace(cinfo, JCS_CMYK); /* By default, no translation */
nuclear@0 373 break;
nuclear@0 374 case JCS_YCCK:
nuclear@0 375 jpeg_set_colorspace(cinfo, JCS_YCCK);
nuclear@0 376 break;
nuclear@0 377 case JCS_UNKNOWN:
nuclear@0 378 jpeg_set_colorspace(cinfo, JCS_UNKNOWN);
nuclear@0 379 break;
nuclear@0 380 default:
nuclear@0 381 ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
nuclear@0 382 }
nuclear@0 383 }
nuclear@0 384
nuclear@0 385
nuclear@0 386 /*
nuclear@0 387 * Set the JPEG colorspace, and choose colorspace-dependent default values.
nuclear@0 388 */
nuclear@0 389
nuclear@0 390 GLOBAL(void)
nuclear@0 391 jpeg_set_colorspace (j_compress_ptr cinfo, J_COLOR_SPACE colorspace)
nuclear@0 392 {
nuclear@0 393 jpeg_component_info * compptr;
nuclear@0 394 int ci;
nuclear@0 395
nuclear@0 396 #define SET_COMP(index,id,hsamp,vsamp,quant,dctbl,actbl) \
nuclear@0 397 (compptr = &cinfo->comp_info[index], \
nuclear@0 398 compptr->component_id = (id), \
nuclear@0 399 compptr->h_samp_factor = (hsamp), \
nuclear@0 400 compptr->v_samp_factor = (vsamp), \
nuclear@0 401 compptr->quant_tbl_no = (quant), \
nuclear@0 402 compptr->dc_tbl_no = (dctbl), \
nuclear@0 403 compptr->ac_tbl_no = (actbl) )
nuclear@0 404
nuclear@0 405 /* Safety check to ensure start_compress not called yet. */
nuclear@0 406 if (cinfo->global_state != CSTATE_START)
nuclear@0 407 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@0 408
nuclear@0 409 /* For all colorspaces, we use Q and Huff tables 0 for luminance components,
nuclear@0 410 * tables 1 for chrominance components.
nuclear@0 411 */
nuclear@0 412
nuclear@0 413 cinfo->jpeg_color_space = colorspace;
nuclear@0 414
nuclear@0 415 cinfo->write_JFIF_header = FALSE; /* No marker for non-JFIF colorspaces */
nuclear@0 416 cinfo->write_Adobe_marker = FALSE; /* write no Adobe marker by default */
nuclear@0 417
nuclear@0 418 switch (colorspace) {
nuclear@0 419 case JCS_GRAYSCALE:
nuclear@0 420 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
nuclear@0 421 cinfo->num_components = 1;
nuclear@0 422 /* JFIF specifies component ID 1 */
nuclear@0 423 SET_COMP(0, 1, 1,1, 0, 0,0);
nuclear@0 424 break;
nuclear@0 425 case JCS_RGB:
nuclear@0 426 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag RGB */
nuclear@0 427 cinfo->num_components = 3;
nuclear@0 428 SET_COMP(0, 0x52 /* 'R' */, 1,1, 0, 0,0);
nuclear@0 429 SET_COMP(1, 0x47 /* 'G' */, 1,1, 0, 0,0);
nuclear@0 430 SET_COMP(2, 0x42 /* 'B' */, 1,1, 0, 0,0);
nuclear@0 431 break;
nuclear@0 432 case JCS_YCbCr:
nuclear@0 433 cinfo->write_JFIF_header = TRUE; /* Write a JFIF marker */
nuclear@0 434 cinfo->num_components = 3;
nuclear@0 435 /* JFIF specifies component IDs 1,2,3 */
nuclear@0 436 /* We default to 2x2 subsamples of chrominance */
nuclear@0 437 SET_COMP(0, 1, 2,2, 0, 0,0);
nuclear@0 438 SET_COMP(1, 2, 1,1, 1, 1,1);
nuclear@0 439 SET_COMP(2, 3, 1,1, 1, 1,1);
nuclear@0 440 break;
nuclear@0 441 case JCS_CMYK:
nuclear@0 442 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag CMYK */
nuclear@0 443 cinfo->num_components = 4;
nuclear@0 444 SET_COMP(0, 0x43 /* 'C' */, 1,1, 0, 0,0);
nuclear@0 445 SET_COMP(1, 0x4D /* 'M' */, 1,1, 0, 0,0);
nuclear@0 446 SET_COMP(2, 0x59 /* 'Y' */, 1,1, 0, 0,0);
nuclear@0 447 SET_COMP(3, 0x4B /* 'K' */, 1,1, 0, 0,0);
nuclear@0 448 break;
nuclear@0 449 case JCS_YCCK:
nuclear@0 450 cinfo->write_Adobe_marker = TRUE; /* write Adobe marker to flag YCCK */
nuclear@0 451 cinfo->num_components = 4;
nuclear@0 452 SET_COMP(0, 1, 2,2, 0, 0,0);
nuclear@0 453 SET_COMP(1, 2, 1,1, 1, 1,1);
nuclear@0 454 SET_COMP(2, 3, 1,1, 1, 1,1);
nuclear@0 455 SET_COMP(3, 4, 2,2, 0, 0,0);
nuclear@0 456 break;
nuclear@0 457 case JCS_UNKNOWN:
nuclear@0 458 cinfo->num_components = cinfo->input_components;
nuclear@0 459 if (cinfo->num_components < 1 || cinfo->num_components > MAX_COMPONENTS)
nuclear@0 460 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components,
nuclear@0 461 MAX_COMPONENTS);
nuclear@0 462 for (ci = 0; ci < cinfo->num_components; ci++) {
nuclear@0 463 SET_COMP(ci, ci, 1,1, 0, 0,0);
nuclear@0 464 }
nuclear@0 465 break;
nuclear@0 466 default:
nuclear@0 467 ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
nuclear@0 468 }
nuclear@0 469 }
nuclear@0 470
nuclear@0 471
nuclear@0 472 #ifdef C_PROGRESSIVE_SUPPORTED
nuclear@0 473
nuclear@0 474 LOCAL(jpeg_scan_info *)
nuclear@0 475 fill_a_scan (jpeg_scan_info * scanptr, int ci,
nuclear@0 476 int Ss, int Se, int Ah, int Al)
nuclear@0 477 /* Support routine: generate one scan for specified component */
nuclear@0 478 {
nuclear@0 479 scanptr->comps_in_scan = 1;
nuclear@0 480 scanptr->component_index[0] = ci;
nuclear@0 481 scanptr->Ss = Ss;
nuclear@0 482 scanptr->Se = Se;
nuclear@0 483 scanptr->Ah = Ah;
nuclear@0 484 scanptr->Al = Al;
nuclear@0 485 scanptr++;
nuclear@0 486 return scanptr;
nuclear@0 487 }
nuclear@0 488
nuclear@0 489 LOCAL(jpeg_scan_info *)
nuclear@0 490 fill_scans (jpeg_scan_info * scanptr, int ncomps,
nuclear@0 491 int Ss, int Se, int Ah, int Al)
nuclear@0 492 /* Support routine: generate one scan for each component */
nuclear@0 493 {
nuclear@0 494 int ci;
nuclear@0 495
nuclear@0 496 for (ci = 0; ci < ncomps; ci++) {
nuclear@0 497 scanptr->comps_in_scan = 1;
nuclear@0 498 scanptr->component_index[0] = ci;
nuclear@0 499 scanptr->Ss = Ss;
nuclear@0 500 scanptr->Se = Se;
nuclear@0 501 scanptr->Ah = Ah;
nuclear@0 502 scanptr->Al = Al;
nuclear@0 503 scanptr++;
nuclear@0 504 }
nuclear@0 505 return scanptr;
nuclear@0 506 }
nuclear@0 507
nuclear@0 508 LOCAL(jpeg_scan_info *)
nuclear@0 509 fill_dc_scans (jpeg_scan_info * scanptr, int ncomps, int Ah, int Al)
nuclear@0 510 /* Support routine: generate interleaved DC scan if possible, else N scans */
nuclear@0 511 {
nuclear@0 512 int ci;
nuclear@0 513
nuclear@0 514 if (ncomps <= MAX_COMPS_IN_SCAN) {
nuclear@0 515 /* Single interleaved DC scan */
nuclear@0 516 scanptr->comps_in_scan = ncomps;
nuclear@0 517 for (ci = 0; ci < ncomps; ci++)
nuclear@0 518 scanptr->component_index[ci] = ci;
nuclear@0 519 scanptr->Ss = scanptr->Se = 0;
nuclear@0 520 scanptr->Ah = Ah;
nuclear@0 521 scanptr->Al = Al;
nuclear@0 522 scanptr++;
nuclear@0 523 } else {
nuclear@0 524 /* Noninterleaved DC scan for each component */
nuclear@0 525 scanptr = fill_scans(scanptr, ncomps, 0, 0, Ah, Al);
nuclear@0 526 }
nuclear@0 527 return scanptr;
nuclear@0 528 }
nuclear@0 529
nuclear@0 530
nuclear@0 531 /*
nuclear@0 532 * Create a recommended progressive-JPEG script.
nuclear@0 533 * cinfo->num_components and cinfo->jpeg_color_space must be correct.
nuclear@0 534 */
nuclear@0 535
nuclear@0 536 GLOBAL(void)
nuclear@0 537 jpeg_simple_progression (j_compress_ptr cinfo)
nuclear@0 538 {
nuclear@0 539 int ncomps = cinfo->num_components;
nuclear@0 540 int nscans;
nuclear@0 541 jpeg_scan_info * scanptr;
nuclear@0 542
nuclear@0 543 /* Safety check to ensure start_compress not called yet. */
nuclear@0 544 if (cinfo->global_state != CSTATE_START)
nuclear@0 545 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
nuclear@0 546
nuclear@0 547 /* Figure space needed for script. Calculation must match code below! */
nuclear@0 548 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
nuclear@0 549 /* Custom script for YCbCr color images. */
nuclear@0 550 nscans = 10;
nuclear@0 551 } else {
nuclear@0 552 /* All-purpose script for other color spaces. */
nuclear@0 553 if (ncomps > MAX_COMPS_IN_SCAN)
nuclear@0 554 nscans = 6 * ncomps; /* 2 DC + 4 AC scans per component */
nuclear@0 555 else
nuclear@0 556 nscans = 2 + 4 * ncomps; /* 2 DC scans; 4 AC scans per component */
nuclear@0 557 }
nuclear@0 558
nuclear@0 559 /* Allocate space for script.
nuclear@0 560 * We need to put it in the permanent pool in case the application performs
nuclear@0 561 * multiple compressions without changing the settings. To avoid a memory
nuclear@0 562 * leak if jpeg_simple_progression is called repeatedly for the same JPEG
nuclear@0 563 * object, we try to re-use previously allocated space, and we allocate
nuclear@0 564 * enough space to handle YCbCr even if initially asked for grayscale.
nuclear@0 565 */
nuclear@0 566 if (cinfo->script_space == NULL || cinfo->script_space_size < nscans) {
nuclear@0 567 cinfo->script_space_size = MAX(nscans, 10);
nuclear@0 568 cinfo->script_space = (jpeg_scan_info *)
nuclear@0 569 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
nuclear@0 570 cinfo->script_space_size * SIZEOF(jpeg_scan_info));
nuclear@0 571 }
nuclear@0 572 scanptr = cinfo->script_space;
nuclear@0 573 cinfo->scan_info = scanptr;
nuclear@0 574 cinfo->num_scans = nscans;
nuclear@0 575
nuclear@0 576 if (ncomps == 3 && cinfo->jpeg_color_space == JCS_YCbCr) {
nuclear@0 577 /* Custom script for YCbCr color images. */
nuclear@0 578 /* Initial DC scan */
nuclear@0 579 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
nuclear@0 580 /* Initial AC scan: get some luma data out in a hurry */
nuclear@0 581 scanptr = fill_a_scan(scanptr, 0, 1, 5, 0, 2);
nuclear@0 582 /* Chroma data is too small to be worth expending many scans on */
nuclear@0 583 scanptr = fill_a_scan(scanptr, 2, 1, 63, 0, 1);
nuclear@0 584 scanptr = fill_a_scan(scanptr, 1, 1, 63, 0, 1);
nuclear@0 585 /* Complete spectral selection for luma AC */
nuclear@0 586 scanptr = fill_a_scan(scanptr, 0, 6, 63, 0, 2);
nuclear@0 587 /* Refine next bit of luma AC */
nuclear@0 588 scanptr = fill_a_scan(scanptr, 0, 1, 63, 2, 1);
nuclear@0 589 /* Finish DC successive approximation */
nuclear@0 590 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
nuclear@0 591 /* Finish AC successive approximation */
nuclear@0 592 scanptr = fill_a_scan(scanptr, 2, 1, 63, 1, 0);
nuclear@0 593 scanptr = fill_a_scan(scanptr, 1, 1, 63, 1, 0);
nuclear@0 594 /* Luma bottom bit comes last since it's usually largest scan */
nuclear@0 595 scanptr = fill_a_scan(scanptr, 0, 1, 63, 1, 0);
nuclear@0 596 } else {
nuclear@0 597 /* All-purpose script for other color spaces. */
nuclear@0 598 /* Successive approximation first pass */
nuclear@0 599 scanptr = fill_dc_scans(scanptr, ncomps, 0, 1);
nuclear@0 600 scanptr = fill_scans(scanptr, ncomps, 1, 5, 0, 2);
nuclear@0 601 scanptr = fill_scans(scanptr, ncomps, 6, 63, 0, 2);
nuclear@0 602 /* Successive approximation second pass */
nuclear@0 603 scanptr = fill_scans(scanptr, ncomps, 1, 63, 2, 1);
nuclear@0 604 /* Successive approximation final pass */
nuclear@0 605 scanptr = fill_dc_scans(scanptr, ncomps, 1, 0);
nuclear@0 606 scanptr = fill_scans(scanptr, ncomps, 1, 63, 1, 0);
nuclear@0 607 }
nuclear@0 608 }
nuclear@0 609
nuclear@0 610 #endif /* C_PROGRESSIVE_SUPPORTED */