jpeglib.h (55479B)
1 /* 2 * jpeglib.h 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1998, Thomas G. Lane. 6 * Modified 2002-2009 by Guido Vollbeding. 7 * Lossless JPEG Modifications: 8 * Copyright (C) 1999, Ken Murchison. 9 * libjpeg-turbo Modifications: 10 * Copyright (C) 2009-2011, 2013-2014, 2016-2017, 2020, 2022-2024, 11 D. R. Commander. 12 * Copyright (C) 2015, Google, Inc. 13 * For conditions of distribution and use, see the accompanying README.ijg 14 * file. 15 * 16 * This file defines the application interface for the JPEG library. 17 * Most applications using the library need only include this file, 18 * and perhaps jerror.h if they want to know the exact error codes. 19 */ 20 21 /* NOTE: This header file does not include stdio.h, despite the fact that it 22 * uses FILE and size_t. That is by design, since the libjpeg API predates the 23 * widespread adoption of ANSI/ISO C. Referring to libjpeg.txt, it is a 24 * documented requirement that calling programs "include system headers that 25 * define at least the typedefs FILE and size_t" before including jpeglib.h. 26 * Technically speaking, changing that requirement by including stdio.h here 27 * would break backward API compatibility. Please do not file bug reports, 28 * feature requests, or pull requests regarding this. 29 */ 30 31 #ifndef JPEGLIB_H 32 #define JPEGLIB_H 33 34 /* 35 * First we include the configuration files that record how this 36 * installation of the JPEG library is set up. jconfig.h can be 37 * generated automatically for many systems. jmorecfg.h contains 38 * manual configuration options that most people need not worry about. 39 */ 40 41 #ifndef JCONFIG_INCLUDED /* in case jinclude.h already did */ 42 #include "jconfig.h" /* widely used configuration options */ 43 #endif 44 #include "jmorecfg.h" /* seldom changed options */ 45 46 47 #ifdef __cplusplus 48 #ifndef DONT_USE_EXTERN_C 49 extern "C" { 50 #endif 51 #endif 52 53 54 /* Various constants determining the sizes of things. 55 * All of these are specified by the JPEG standard, so don't change them 56 * if you want to be compatible. 57 */ 58 59 /* NOTE: In lossless mode, an MCU contains one or more samples rather than one 60 * or more 8x8 DCT blocks, so the term "data unit" is used to generically 61 * describe a sample in lossless mode or an 8x8 DCT block in lossy mode. To 62 * preserve backward API/ABI compatibility, the field and macro names retain 63 * the "block" terminology. 64 */ 65 66 #define DCTSIZE 8 /* The basic DCT block is 8x8 samples */ 67 #define DCTSIZE2 64 /* DCTSIZE squared; # of elements in a block */ 68 #define NUM_QUANT_TBLS 4 /* Quantization tables are numbered 0..3 */ 69 #define NUM_HUFF_TBLS 4 /* Huffman tables are numbered 0..3 */ 70 #define NUM_ARITH_TBLS 16 /* Arith-coding tables are numbered 0..15 */ 71 #define MAX_COMPS_IN_SCAN 4 /* JPEG limit on # of components in one scan */ 72 #define MAX_SAMP_FACTOR 4 /* JPEG limit on sampling factors */ 73 /* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard; 74 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU. 75 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU 76 * to handle it. We even let you do this from the jconfig.h file. However, 77 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe 78 * sometimes emits noncompliant files doesn't mean you should too. 79 */ 80 #define C_MAX_BLOCKS_IN_MCU 10 /* compressor's limit on data units/MCU */ 81 #ifndef D_MAX_BLOCKS_IN_MCU 82 #define D_MAX_BLOCKS_IN_MCU 10 /* decompressor's limit on data units/MCU */ 83 #endif 84 85 86 /* Data structures for images (arrays of samples and of DCT coefficients). 87 */ 88 89 typedef JSAMPLE *JSAMPROW; /* ptr to one image row of pixel samples. */ 90 typedef JSAMPROW *JSAMPARRAY; /* ptr to some rows (a 2-D sample array) */ 91 typedef JSAMPARRAY *JSAMPIMAGE; /* a 3-D sample array: top index is color */ 92 93 typedef J12SAMPLE *J12SAMPROW; /* ptr to one image row of 12-bit pixel 94 samples. */ 95 typedef J12SAMPROW *J12SAMPARRAY; /* ptr to some 12-bit sample rows (a 2-D 96 12-bit sample array) */ 97 typedef J12SAMPARRAY *J12SAMPIMAGE; /* a 3-D 12-bit sample array: top index is 98 color */ 99 100 typedef J16SAMPLE *J16SAMPROW; /* ptr to one image row of 16-bit pixel 101 samples. */ 102 typedef J16SAMPROW *J16SAMPARRAY; /* ptr to some 16-bit sample rows (a 2-D 103 16-bit sample array) */ 104 typedef J16SAMPARRAY *J16SAMPIMAGE; /* a 3-D 16-bit sample array: top index is 105 color */ 106 107 typedef JCOEF JBLOCK[DCTSIZE2]; /* one block of coefficients */ 108 typedef JBLOCK *JBLOCKROW; /* pointer to one row of coefficient blocks */ 109 typedef JBLOCKROW *JBLOCKARRAY; /* a 2-D array of coefficient blocks */ 110 typedef JBLOCKARRAY *JBLOCKIMAGE; /* a 3-D array of coefficient blocks */ 111 112 typedef JCOEF *JCOEFPTR; /* useful in a couple of places */ 113 114 115 /* Types for JPEG compression parameters and working tables. */ 116 117 118 /* DCT coefficient quantization tables. */ 119 120 typedef struct { 121 /* This array gives the coefficient quantizers in natural array order 122 * (not the zigzag order in which they are stored in a JPEG DQT marker). 123 * CAUTION: IJG versions prior to v6a kept this array in zigzag order. 124 */ 125 UINT16 quantval[DCTSIZE2]; /* quantization step for each coefficient */ 126 /* This field is used only during compression. It's initialized FALSE when 127 * the table is created, and set TRUE when it's been output to the file. 128 * You could suppress output of a table by setting this to TRUE. 129 * (See jpeg_suppress_tables for an example.) 130 */ 131 boolean sent_table; /* TRUE when table has been output */ 132 } JQUANT_TBL; 133 134 135 /* Huffman coding tables. */ 136 137 typedef struct { 138 /* These two fields directly represent the contents of a JPEG DHT marker */ 139 UINT8 bits[17]; /* bits[k] = # of symbols with codes of */ 140 /* length k bits; bits[0] is unused */ 141 UINT8 huffval[256]; /* The symbols, in order of incr code length */ 142 /* This field is used only during compression. It's initialized FALSE when 143 * the table is created, and set TRUE when it's been output to the file. 144 * You could suppress output of a table by setting this to TRUE. 145 * (See jpeg_suppress_tables for an example.) 146 */ 147 boolean sent_table; /* TRUE when table has been output */ 148 } JHUFF_TBL; 149 150 151 /* Basic info about one component (color channel). */ 152 153 typedef struct { 154 /* These values are fixed over the whole image. */ 155 /* For compression, they must be supplied by parameter setup; */ 156 /* for decompression, they are read from the SOF marker. */ 157 int component_id; /* identifier for this component (0..255) */ 158 int component_index; /* its index in SOF or cinfo->comp_info[] */ 159 int h_samp_factor; /* horizontal sampling factor (1..4) */ 160 int v_samp_factor; /* vertical sampling factor (1..4) */ 161 int quant_tbl_no; /* quantization table selector (0..3) */ 162 /* These values may vary between scans. */ 163 /* For compression, they must be supplied by parameter setup; */ 164 /* for decompression, they are read from the SOS marker. */ 165 /* The decompressor output side may not use these variables. */ 166 int dc_tbl_no; /* DC entropy table selector (0..3) */ 167 int ac_tbl_no; /* AC entropy table selector (0..3) */ 168 169 /* Remaining fields should be treated as private by applications. */ 170 171 /* These values are computed during compression or decompression startup: */ 172 /* Component's size in data units. 173 * In lossy mode, any dummy blocks added to complete an MCU are not counted; 174 * therefore these values do not depend on whether a scan is interleaved or 175 * not. In lossless mode, these are always equal to the image width and 176 * height. 177 */ 178 JDIMENSION width_in_blocks; 179 JDIMENSION height_in_blocks; 180 /* Size of a data unit in samples. Always DCTSIZE for lossy compression. 181 * For lossy decompression this is the size of the output from one DCT block, 182 * reflecting any scaling we choose to apply during the IDCT step. 183 * Values from 1 to 16 are supported. Note that different components may 184 * receive different IDCT scalings. In lossless mode, this is always equal 185 * to 1. 186 */ 187 #if JPEG_LIB_VERSION >= 70 188 int DCT_h_scaled_size; 189 int DCT_v_scaled_size; 190 #else 191 int DCT_scaled_size; 192 #endif 193 /* The downsampled dimensions are the component's actual, unpadded number 194 * of samples at the main buffer (preprocessing/compression interface), thus 195 * downsampled_width = ceil(image_width * Hi/Hmax) 196 * and similarly for height. For lossy decompression, IDCT scaling is 197 * included, so 198 * downsampled_width = ceil(image_width * Hi/Hmax * DCT_[h_]scaled_size/DCTSIZE) 199 * In lossless mode, these are always equal to the image width and height. 200 */ 201 JDIMENSION downsampled_width; /* actual width in samples */ 202 JDIMENSION downsampled_height; /* actual height in samples */ 203 /* This flag is used only for decompression. In cases where some of the 204 * components will be ignored (eg grayscale output from YCbCr image), 205 * we can skip most computations for the unused components. 206 */ 207 boolean component_needed; /* do we need the value of this component? */ 208 209 /* These values are computed before starting a scan of the component. */ 210 /* The decompressor output side may not use these variables. */ 211 int MCU_width; /* number of data units per MCU, horizontally */ 212 int MCU_height; /* number of data units per MCU, vertically */ 213 int MCU_blocks; /* MCU_width * MCU_height */ 214 int MCU_sample_width; /* MCU width in samples, MCU_width*DCT_[h_]scaled_size */ 215 int last_col_width; /* # of non-dummy data units across in last MCU */ 216 int last_row_height; /* # of non-dummy data units down in last MCU */ 217 218 /* Saved quantization table for component; NULL if none yet saved. 219 * See jdinput.c comments about the need for this information. 220 * This field is currently used only for decompression. 221 */ 222 JQUANT_TBL *quant_table; 223 224 /* Private per-component storage for DCT or IDCT subsystem. */ 225 void *dct_table; 226 } jpeg_component_info; 227 228 229 /* The script for encoding a multiple-scan file is an array of these: */ 230 231 typedef struct { 232 int comps_in_scan; /* number of components encoded in this scan */ 233 int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */ 234 int Ss, Se; /* progressive JPEG spectral selection parms 235 (Ss is the predictor selection value in 236 lossless mode) */ 237 int Ah, Al; /* progressive JPEG successive approx. parms 238 (Al is the point transform value in lossless 239 mode) */ 240 } jpeg_scan_info; 241 242 /* The decompressor can save APPn and COM markers in a list of these: */ 243 244 typedef struct jpeg_marker_struct *jpeg_saved_marker_ptr; 245 246 struct jpeg_marker_struct { 247 jpeg_saved_marker_ptr next; /* next in list, or NULL */ 248 UINT8 marker; /* marker code: JPEG_COM, or JPEG_APP0+n */ 249 unsigned int original_length; /* # bytes of data in the file */ 250 unsigned int data_length; /* # bytes of data saved at data[] */ 251 JOCTET *data; /* the data contained in the marker */ 252 /* the marker length word is not counted in data_length or original_length */ 253 }; 254 255 /* Known color spaces. */ 256 257 #define JCS_EXTENSIONS 1 258 #define JCS_ALPHA_EXTENSIONS 1 259 260 typedef enum { 261 JCS_UNKNOWN, /* error/unspecified */ 262 JCS_GRAYSCALE, /* monochrome */ 263 JCS_RGB, /* red/green/blue as specified by the RGB_RED, 264 RGB_GREEN, RGB_BLUE, and RGB_PIXELSIZE macros */ 265 JCS_YCbCr, /* Y/Cb/Cr (also known as YUV) */ 266 JCS_CMYK, /* C/M/Y/K */ 267 JCS_YCCK, /* Y/Cb/Cr/K */ 268 JCS_EXT_RGB, /* red/green/blue */ 269 JCS_EXT_RGBX, /* red/green/blue/x */ 270 JCS_EXT_BGR, /* blue/green/red */ 271 JCS_EXT_BGRX, /* blue/green/red/x */ 272 JCS_EXT_XBGR, /* x/blue/green/red */ 273 JCS_EXT_XRGB, /* x/red/green/blue */ 274 /* When out_color_space it set to JCS_EXT_RGBX, JCS_EXT_BGRX, JCS_EXT_XBGR, 275 or JCS_EXT_XRGB during decompression, the X byte is undefined, and in 276 order to ensure the best performance, libjpeg-turbo can set that byte to 277 whatever value it wishes. Use the following colorspace constants to 278 ensure that the X byte is set to 0xFF, so that it can be interpreted as an 279 opaque alpha channel. */ 280 JCS_EXT_RGBA, /* red/green/blue/alpha */ 281 JCS_EXT_BGRA, /* blue/green/red/alpha */ 282 JCS_EXT_ABGR, /* alpha/blue/green/red */ 283 JCS_EXT_ARGB, /* alpha/red/green/blue */ 284 JCS_RGB565 /* 5-bit red/6-bit green/5-bit blue 285 [decompression only] */ 286 } J_COLOR_SPACE; 287 288 /* DCT/IDCT algorithm options. */ 289 290 typedef enum { 291 JDCT_ISLOW, /* accurate integer method */ 292 JDCT_IFAST, /* less accurate integer method [legacy feature] */ 293 JDCT_FLOAT /* floating-point method [legacy feature] */ 294 } J_DCT_METHOD; 295 296 #ifndef JDCT_DEFAULT /* may be overridden in jconfig.h */ 297 #define JDCT_DEFAULT JDCT_ISLOW 298 #endif 299 #ifndef JDCT_FASTEST /* may be overridden in jconfig.h */ 300 #define JDCT_FASTEST JDCT_IFAST 301 #endif 302 303 /* Dithering options for decompression. */ 304 305 typedef enum { 306 JDITHER_NONE, /* no dithering */ 307 JDITHER_ORDERED, /* simple ordered dither */ 308 JDITHER_FS /* Floyd-Steinberg error diffusion dither */ 309 } J_DITHER_MODE; 310 311 312 /* Common fields between JPEG compression and decompression master structs. */ 313 314 #define jpeg_common_fields \ 315 struct jpeg_error_mgr *err; /* Error handler module */ \ 316 struct jpeg_memory_mgr *mem; /* Memory manager module */ \ 317 struct jpeg_progress_mgr *progress; /* Progress monitor, or NULL if none */ \ 318 void *client_data; /* Available for use by application */ \ 319 boolean is_decompressor; /* So common code can tell which is which */ \ 320 int global_state /* For checking call sequence validity */ 321 322 /* Routines that are to be used by both halves of the library are declared 323 * to receive a pointer to this structure. There are no actual instances of 324 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct. 325 */ 326 struct jpeg_common_struct { 327 jpeg_common_fields; /* Fields common to both master struct types */ 328 /* Additional fields follow in an actual jpeg_compress_struct or 329 * jpeg_decompress_struct. All three structs must agree on these 330 * initial fields! (This would be a lot cleaner in C++.) 331 */ 332 }; 333 334 typedef struct jpeg_common_struct *j_common_ptr; 335 typedef struct jpeg_compress_struct *j_compress_ptr; 336 typedef struct jpeg_decompress_struct *j_decompress_ptr; 337 338 339 /* Master record for a compression instance */ 340 341 struct jpeg_compress_struct { 342 jpeg_common_fields; /* Fields shared with jpeg_decompress_struct */ 343 344 /* Destination for compressed data */ 345 struct jpeg_destination_mgr *dest; 346 347 /* Description of source image --- these fields must be filled in by 348 * outer application before starting compression. in_color_space must 349 * be correct before you can even call jpeg_set_defaults(). 350 */ 351 352 JDIMENSION image_width; /* input image width */ 353 JDIMENSION image_height; /* input image height */ 354 int input_components; /* # of color components in input image */ 355 J_COLOR_SPACE in_color_space; /* colorspace of input image */ 356 357 double input_gamma; /* image gamma of input image */ 358 359 /* Compression parameters --- these fields must be set before calling 360 * jpeg_start_compress(). We recommend calling jpeg_set_defaults() to 361 * initialize everything to reasonable defaults, then changing anything 362 * the application specifically wants to change. That way you won't get 363 * burnt when new parameters are added. Also note that there are several 364 * helper routines to simplify changing parameters. 365 */ 366 367 #if JPEG_LIB_VERSION >= 70 368 unsigned int scale_num, scale_denom; /* fraction by which to scale image */ 369 370 JDIMENSION jpeg_width; /* scaled JPEG image width */ 371 JDIMENSION jpeg_height; /* scaled JPEG image height */ 372 /* Dimensions of actual JPEG image that will be written to file, 373 * derived from input dimensions by scaling factors above. 374 * These fields are computed by jpeg_start_compress(). 375 * You can also use jpeg_calc_jpeg_dimensions() to determine these values 376 * in advance of calling jpeg_start_compress(). 377 */ 378 #endif 379 380 int data_precision; /* bits of precision in image data */ 381 382 int num_components; /* # of color components in JPEG image */ 383 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */ 384 385 jpeg_component_info *comp_info; 386 /* comp_info[i] describes component that appears i'th in SOF */ 387 388 JQUANT_TBL *quant_tbl_ptrs[NUM_QUANT_TBLS]; 389 #if JPEG_LIB_VERSION >= 70 390 int q_scale_factor[NUM_QUANT_TBLS]; 391 #endif 392 /* ptrs to coefficient quantization tables, or NULL if not defined, 393 * and corresponding scale factors (percentage, initialized 100). 394 */ 395 396 JHUFF_TBL *dc_huff_tbl_ptrs[NUM_HUFF_TBLS]; 397 JHUFF_TBL *ac_huff_tbl_ptrs[NUM_HUFF_TBLS]; 398 /* ptrs to Huffman coding tables, or NULL if not defined */ 399 400 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */ 401 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */ 402 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */ 403 404 int num_scans; /* # of entries in scan_info array */ 405 const jpeg_scan_info *scan_info; /* script for multi-scan file, or NULL */ 406 /* The default value of scan_info is NULL, which causes a single-scan 407 * sequential JPEG file to be emitted. To create a multi-scan file, 408 * set num_scans and scan_info to point to an array of scan definitions. 409 */ 410 411 boolean raw_data_in; /* TRUE=caller supplies downsampled data */ 412 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */ 413 boolean optimize_coding; /* TRUE=optimize entropy encoding parms */ 414 boolean CCIR601_sampling; /* TRUE=first samples are cosited */ 415 #if JPEG_LIB_VERSION >= 70 416 boolean do_fancy_downsampling; /* TRUE=apply fancy downsampling */ 417 #endif 418 int smoothing_factor; /* 1..100, or 0 for no input smoothing */ 419 J_DCT_METHOD dct_method; /* DCT algorithm selector */ 420 421 /* The restart interval can be specified in absolute MCUs by setting 422 * restart_interval, or in MCU rows by setting restart_in_rows 423 * (in which case the correct restart_interval will be figured 424 * for each scan). 425 */ 426 unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */ 427 int restart_in_rows; /* if > 0, MCU rows per restart interval */ 428 429 /* Parameters controlling emission of special markers. */ 430 431 boolean write_JFIF_header; /* should a JFIF marker be written? */ 432 UINT8 JFIF_major_version; /* What to write for the JFIF version number */ 433 UINT8 JFIF_minor_version; 434 /* These three values are not used by the JPEG code, merely copied */ 435 /* into the JFIF APP0 marker. density_unit can be 0 for unknown, */ 436 /* 1 for dots/inch, or 2 for dots/cm. Note that the pixel aspect */ 437 /* ratio is defined by X_density/Y_density even when density_unit=0. */ 438 UINT8 density_unit; /* JFIF code for pixel size units */ 439 UINT16 X_density; /* Horizontal pixel density */ 440 UINT16 Y_density; /* Vertical pixel density */ 441 boolean write_Adobe_marker; /* should an Adobe marker be written? */ 442 443 /* State variable: index of next scanline to be written to 444 * jpeg_write_scanlines(). Application may use this to control its 445 * processing loop, e.g., "while (next_scanline < image_height)". 446 */ 447 448 JDIMENSION next_scanline; /* 0 .. image_height-1 */ 449 450 /* Remaining fields are known throughout compressor, but generally 451 * should not be touched by a surrounding application. 452 */ 453 454 /* 455 * These fields are computed during compression startup 456 */ 457 boolean progressive_mode; /* TRUE if scan script uses progressive mode */ 458 int max_h_samp_factor; /* largest h_samp_factor */ 459 int max_v_samp_factor; /* largest v_samp_factor */ 460 461 #if JPEG_LIB_VERSION >= 70 462 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */ 463 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */ 464 #endif 465 466 JDIMENSION total_iMCU_rows; /* # of iMCU rows to be input to coefficient or 467 difference controller */ 468 /* The coefficient or difference controller receives data in units of MCU 469 * rows as defined for fully interleaved scans (whether the JPEG file is 470 * interleaved or not). In lossy mode, there are v_samp_factor * DCTSIZE 471 * sample rows of each component in an "iMCU" (interleaved MCU) row. In 472 * lossless mode, total_iMCU_rows is always equal to the image height. 473 */ 474 475 /* 476 * These fields are valid during any one scan. 477 * They describe the components and MCUs actually appearing in the scan. 478 */ 479 int comps_in_scan; /* # of JPEG components in this scan */ 480 jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN]; 481 /* *cur_comp_info[i] describes component that appears i'th in SOS */ 482 483 JDIMENSION MCUs_per_row; /* # of MCUs across the image */ 484 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */ 485 486 int blocks_in_MCU; /* # of data units per MCU */ 487 int MCU_membership[C_MAX_BLOCKS_IN_MCU]; 488 /* MCU_membership[i] is index in cur_comp_info of component owning */ 489 /* i'th data unit in an MCU */ 490 491 int Ss, Se, Ah, Al; /* progressive/lossless JPEG parameters for 492 scan */ 493 494 #if JPEG_LIB_VERSION >= 80 495 int block_size; /* the basic DCT block size: 1..16 */ 496 const int *natural_order; /* natural-order position array */ 497 int lim_Se; /* min( Se, DCTSIZE2-1 ) */ 498 #endif 499 500 /* 501 * Links to compression subobjects (methods and private variables of modules) 502 */ 503 struct jpeg_comp_master *master; 504 struct jpeg_c_main_controller *main; 505 struct jpeg_c_prep_controller *prep; 506 struct jpeg_c_coef_controller *coef; 507 struct jpeg_marker_writer *marker; 508 struct jpeg_color_converter *cconvert; 509 struct jpeg_downsampler *downsample; 510 struct jpeg_forward_dct *fdct; 511 struct jpeg_entropy_encoder *entropy; 512 jpeg_scan_info *script_space; /* workspace for jpeg_simple_progression */ 513 int script_space_size; 514 }; 515 516 517 /* Master record for a decompression instance */ 518 519 struct jpeg_decompress_struct { 520 jpeg_common_fields; /* Fields shared with jpeg_compress_struct */ 521 522 /* Source of compressed data */ 523 struct jpeg_source_mgr *src; 524 525 /* Basic description of image --- filled in by jpeg_read_header(). */ 526 /* Application may inspect these values to decide how to process image. */ 527 528 JDIMENSION image_width; /* nominal image width (from SOF marker) */ 529 JDIMENSION image_height; /* nominal image height */ 530 int num_components; /* # of color components in JPEG image */ 531 J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */ 532 533 /* Decompression processing parameters --- these fields must be set before 534 * calling jpeg_start_decompress(). Note that jpeg_read_header() initializes 535 * them to default values. 536 */ 537 538 J_COLOR_SPACE out_color_space; /* colorspace for output */ 539 540 unsigned int scale_num, scale_denom; /* fraction by which to scale image */ 541 542 double output_gamma; /* image gamma wanted in output */ 543 544 boolean buffered_image; /* TRUE=multiple output passes */ 545 boolean raw_data_out; /* TRUE=downsampled data wanted */ 546 547 J_DCT_METHOD dct_method; /* IDCT algorithm selector */ 548 boolean do_fancy_upsampling; /* TRUE=apply fancy upsampling */ 549 boolean do_block_smoothing; /* TRUE=apply interblock smoothing */ 550 551 boolean quantize_colors; /* TRUE=colormapped output wanted */ 552 /* the following are ignored if not quantize_colors: */ 553 J_DITHER_MODE dither_mode; /* type of color dithering to use */ 554 boolean two_pass_quantize; /* TRUE=use two-pass color quantization */ 555 int desired_number_of_colors; /* max # colors to use in created colormap */ 556 /* these are significant only in buffered-image mode: */ 557 boolean enable_1pass_quant; /* enable future use of 1-pass quantizer */ 558 boolean enable_external_quant;/* enable future use of external colormap */ 559 boolean enable_2pass_quant; /* enable future use of 2-pass quantizer */ 560 561 /* Description of actual output image that will be returned to application. 562 * These fields are computed by jpeg_start_decompress(). 563 * You can also use jpeg_calc_output_dimensions() to determine these values 564 * in advance of calling jpeg_start_decompress(). 565 */ 566 567 JDIMENSION output_width; /* scaled image width */ 568 JDIMENSION output_height; /* scaled image height */ 569 int out_color_components; /* # of color components in out_color_space */ 570 int output_components; /* # of color components returned */ 571 /* output_components is 1 (a colormap index) when quantizing colors; 572 * otherwise it equals out_color_components. 573 */ 574 int rec_outbuf_height; /* min recommended height of scanline buffer */ 575 /* If the buffer passed to jpeg_read_scanlines() is less than this many rows 576 * high, space and time will be wasted due to unnecessary data copying. 577 * Usually rec_outbuf_height will be 1 or 2, at most 4. 578 */ 579 580 /* When quantizing colors, the output colormap is described by these fields. 581 * The application can supply a colormap by setting colormap non-NULL before 582 * calling jpeg_start_decompress; otherwise a colormap is created during 583 * jpeg_start_decompress or jpeg_start_output. 584 * The map has out_color_components rows and actual_number_of_colors columns. 585 */ 586 int actual_number_of_colors; /* number of entries in use */ 587 JSAMPARRAY colormap; /* The color map as a 2-D pixel array 588 If data_precision is 12, then this is 589 actually a J12SAMPARRAY, so callers must 590 type-cast it in order to read/write 12-bit 591 samples from/to the array. */ 592 593 /* State variables: these variables indicate the progress of decompression. 594 * The application may examine these but must not modify them. 595 */ 596 597 /* Row index of next scanline to be read from jpeg_read_scanlines(). 598 * Application may use this to control its processing loop, e.g., 599 * "while (output_scanline < output_height)". 600 */ 601 JDIMENSION output_scanline; /* 0 .. output_height-1 */ 602 603 /* Current input scan number and number of iMCU rows completed in scan. 604 * These indicate the progress of the decompressor input side. 605 */ 606 int input_scan_number; /* Number of SOS markers seen so far */ 607 JDIMENSION input_iMCU_row; /* Number of iMCU rows completed */ 608 609 /* The "output scan number" is the notional scan being displayed by the 610 * output side. The decompressor will not allow output scan/row number 611 * to get ahead of input scan/row, but it can fall arbitrarily far behind. 612 */ 613 int output_scan_number; /* Nominal scan number being displayed */ 614 JDIMENSION output_iMCU_row; /* Number of iMCU rows read */ 615 616 /* Current progression status. coef_bits[c][i] indicates the precision 617 * with which component c's DCT coefficient i (in zigzag order) is known. 618 * It is -1 when no data has yet been received, otherwise it is the point 619 * transform (shift) value for the most recent scan of the coefficient 620 * (thus, 0 at completion of the progression). 621 * This pointer is NULL when reading a non-progressive file. 622 */ 623 int (*coef_bits)[DCTSIZE2]; /* -1 or current Al value for each coef */ 624 625 /* Internal JPEG parameters --- the application usually need not look at 626 * these fields. Note that the decompressor output side may not use 627 * any parameters that can change between scans. 628 */ 629 630 /* Quantization and Huffman tables are carried forward across input 631 * datastreams when processing abbreviated JPEG datastreams. 632 */ 633 634 JQUANT_TBL *quant_tbl_ptrs[NUM_QUANT_TBLS]; 635 /* ptrs to coefficient quantization tables, or NULL if not defined */ 636 637 JHUFF_TBL *dc_huff_tbl_ptrs[NUM_HUFF_TBLS]; 638 JHUFF_TBL *ac_huff_tbl_ptrs[NUM_HUFF_TBLS]; 639 /* ptrs to Huffman coding tables, or NULL if not defined */ 640 641 /* These parameters are never carried across datastreams, since they 642 * are given in SOF/SOS markers or defined to be reset by SOI. 643 */ 644 645 int data_precision; /* bits of precision in image data */ 646 647 jpeg_component_info *comp_info; 648 /* comp_info[i] describes component that appears i'th in SOF */ 649 650 #if JPEG_LIB_VERSION >= 80 651 boolean is_baseline; /* TRUE if Baseline SOF0 encountered */ 652 #endif 653 boolean progressive_mode; /* TRUE if SOFn specifies progressive mode */ 654 boolean arith_code; /* TRUE=arithmetic coding, FALSE=Huffman */ 655 656 UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */ 657 UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */ 658 UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */ 659 660 unsigned int restart_interval; /* MCUs per restart interval, or 0 for no restart */ 661 662 /* These fields record data obtained from optional markers recognized by 663 * the JPEG library. 664 */ 665 boolean saw_JFIF_marker; /* TRUE iff a JFIF APP0 marker was found */ 666 /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */ 667 UINT8 JFIF_major_version; /* JFIF version number */ 668 UINT8 JFIF_minor_version; 669 UINT8 density_unit; /* JFIF code for pixel size units */ 670 UINT16 X_density; /* Horizontal pixel density */ 671 UINT16 Y_density; /* Vertical pixel density */ 672 boolean saw_Adobe_marker; /* TRUE iff an Adobe APP14 marker was found */ 673 UINT8 Adobe_transform; /* Color transform code from Adobe marker */ 674 675 boolean CCIR601_sampling; /* TRUE=first samples are cosited */ 676 677 /* Aside from the specific data retained from APPn markers known to the 678 * library, the uninterpreted contents of any or all APPn and COM markers 679 * can be saved in a list for examination by the application. 680 */ 681 jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */ 682 683 /* Remaining fields are known throughout decompressor, but generally 684 * should not be touched by a surrounding application. 685 */ 686 687 /* 688 * These fields are computed during decompression startup 689 */ 690 int max_h_samp_factor; /* largest h_samp_factor */ 691 int max_v_samp_factor; /* largest v_samp_factor */ 692 693 #if JPEG_LIB_VERSION >= 70 694 int min_DCT_h_scaled_size; /* smallest DCT_h_scaled_size of any component */ 695 int min_DCT_v_scaled_size; /* smallest DCT_v_scaled_size of any component */ 696 #else 697 int min_DCT_scaled_size; /* smallest DCT_scaled_size of any component */ 698 #endif 699 700 JDIMENSION total_iMCU_rows; /* # of iMCU rows in image */ 701 /* The coefficient or difference controller's input and output progress is 702 * measured in units of "iMCU" (interleaved MCU) rows. These are the same as 703 * MCU rows in fully interleaved JPEG scans, but are used whether the scan is 704 * interleaved or not. In lossy mode, we define an iMCU row as v_samp_factor 705 * DCT block rows of each component. Therefore, the IDCT output contains 706 * v_samp_factor*DCT_[v_]scaled_size sample rows of a component per iMCU row. 707 * In lossless mode, total_iMCU_rows is always equal to the image height. 708 */ 709 710 JSAMPLE *sample_range_limit; /* table for fast range-limiting 711 If data_precision is 12 or 16, then this is 712 actually a J12SAMPLE pointer or a J16SAMPLE 713 pointer, so callers must type-cast it in 714 order to read 12-bit or 16-bit samples from 715 the array. */ 716 717 /* 718 * These fields are valid during any one scan. 719 * They describe the components and MCUs actually appearing in the scan. 720 * Note that the decompressor output side must not use these fields. 721 */ 722 int comps_in_scan; /* # of JPEG components in this scan */ 723 jpeg_component_info *cur_comp_info[MAX_COMPS_IN_SCAN]; 724 /* *cur_comp_info[i] describes component that appears i'th in SOS */ 725 726 JDIMENSION MCUs_per_row; /* # of MCUs across the image */ 727 JDIMENSION MCU_rows_in_scan; /* # of MCU rows in the image */ 728 729 int blocks_in_MCU; /* # of data units per MCU */ 730 int MCU_membership[D_MAX_BLOCKS_IN_MCU]; 731 /* MCU_membership[i] is index in cur_comp_info of component owning */ 732 /* i'th data unit in an MCU */ 733 734 int Ss, Se, Ah, Al; /* progressive/lossless JPEG parameters for 735 scan */ 736 737 #if JPEG_LIB_VERSION >= 80 738 /* These fields are derived from Se of first SOS marker. 739 */ 740 int block_size; /* the basic DCT block size: 1..16 */ 741 const int *natural_order; /* natural-order position array for entropy decode */ 742 int lim_Se; /* min( Se, DCTSIZE2-1 ) for entropy decode */ 743 #endif 744 745 /* This field is shared between entropy decoder and marker parser. 746 * It is either zero or the code of a JPEG marker that has been 747 * read from the data source, but has not yet been processed. 748 */ 749 int unread_marker; 750 751 /* 752 * Links to decompression subobjects (methods, private variables of modules) 753 */ 754 struct jpeg_decomp_master *master; 755 struct jpeg_d_main_controller *main; 756 struct jpeg_d_coef_controller *coef; 757 struct jpeg_d_post_controller *post; 758 struct jpeg_input_controller *inputctl; 759 struct jpeg_marker_reader *marker; 760 struct jpeg_entropy_decoder *entropy; 761 struct jpeg_inverse_dct *idct; 762 struct jpeg_upsampler *upsample; 763 struct jpeg_color_deconverter *cconvert; 764 struct jpeg_color_quantizer *cquantize; 765 }; 766 767 768 /* "Object" declarations for JPEG modules that may be supplied or called 769 * directly by the surrounding application. 770 * As with all objects in the JPEG library, these structs only define the 771 * publicly visible methods and state variables of a module. Additional 772 * private fields may exist after the public ones. 773 */ 774 775 776 /* Error handler object */ 777 778 struct jpeg_error_mgr { 779 /* Error exit handler: does not return to caller */ 780 void (*error_exit) (j_common_ptr cinfo); 781 /* Conditionally emit a trace or warning message */ 782 void (*emit_message) (j_common_ptr cinfo, int msg_level); 783 /* Routine that actually outputs a trace or error message */ 784 void (*output_message) (j_common_ptr cinfo); 785 /* Format a message string for the most recent JPEG error or message */ 786 void (*format_message) (j_common_ptr cinfo, char *buffer); 787 #define JMSG_LENGTH_MAX 200 /* recommended size of format_message buffer */ 788 /* Reset error state variables at start of a new image */ 789 void (*reset_error_mgr) (j_common_ptr cinfo); 790 791 /* The message ID code and any parameters are saved here. 792 * A message can have one string parameter or up to 8 int parameters. 793 */ 794 int msg_code; 795 #define JMSG_STR_PARM_MAX 80 796 union { 797 int i[8]; 798 char s[JMSG_STR_PARM_MAX]; 799 } msg_parm; 800 801 /* Standard state variables for error facility */ 802 803 int trace_level; /* max msg_level that will be displayed */ 804 805 /* For recoverable corrupt-data errors, we emit a warning message, 806 * but keep going unless emit_message chooses to abort. emit_message 807 * should count warnings in num_warnings. The surrounding application 808 * can check for bad data by seeing if num_warnings is nonzero at the 809 * end of processing. 810 */ 811 long num_warnings; /* number of corrupt-data warnings */ 812 813 /* These fields point to the table(s) of error message strings. 814 * An application can change the table pointer to switch to a different 815 * message list (typically, to change the language in which errors are 816 * reported). Some applications may wish to add additional error codes 817 * that will be handled by the JPEG library error mechanism; the second 818 * table pointer is used for this purpose. 819 * 820 * First table includes all errors generated by JPEG library itself. 821 * Error code 0 is reserved for a "no such error string" message. 822 */ 823 const char * const *jpeg_message_table; /* Library errors */ 824 int last_jpeg_message; /* Table contains strings 0..last_jpeg_message */ 825 /* Second table can be added by application (see cjpeg/djpeg for example). 826 * It contains strings numbered first_addon_message..last_addon_message. 827 */ 828 const char * const *addon_message_table; /* Non-library errors */ 829 int first_addon_message; /* code for first string in addon table */ 830 int last_addon_message; /* code for last string in addon table */ 831 }; 832 833 834 /* Progress monitor object */ 835 836 struct jpeg_progress_mgr { 837 void (*progress_monitor) (j_common_ptr cinfo); 838 839 long pass_counter; /* work units completed in this pass */ 840 long pass_limit; /* total number of work units in this pass */ 841 int completed_passes; /* passes completed so far */ 842 int total_passes; /* total number of passes expected */ 843 }; 844 845 846 /* Data destination object for compression */ 847 848 struct jpeg_destination_mgr { 849 JOCTET *next_output_byte; /* => next byte to write in buffer */ 850 size_t free_in_buffer; /* # of byte spaces remaining in buffer */ 851 852 void (*init_destination) (j_compress_ptr cinfo); 853 boolean (*empty_output_buffer) (j_compress_ptr cinfo); 854 void (*term_destination) (j_compress_ptr cinfo); 855 }; 856 857 858 /* Data source object for decompression */ 859 860 struct jpeg_source_mgr { 861 const JOCTET *next_input_byte; /* => next byte to read from buffer */ 862 size_t bytes_in_buffer; /* # of bytes remaining in buffer */ 863 864 void (*init_source) (j_decompress_ptr cinfo); 865 boolean (*fill_input_buffer) (j_decompress_ptr cinfo); 866 void (*skip_input_data) (j_decompress_ptr cinfo, long num_bytes); 867 boolean (*resync_to_restart) (j_decompress_ptr cinfo, int desired); 868 void (*term_source) (j_decompress_ptr cinfo); 869 }; 870 871 872 /* Memory manager object. 873 * Allocates "small" objects (a few K total), "large" objects (tens of K), 874 * and "really big" objects (virtual arrays with backing store if needed). 875 * The memory manager does not allow individual objects to be freed; rather, 876 * each created object is assigned to a pool, and whole pools can be freed 877 * at once. This is faster and more convenient than remembering exactly what 878 * to free, especially where malloc()/free() are not too speedy. 879 * NB: alloc routines never return NULL. They exit to error_exit if not 880 * successful. 881 */ 882 883 #define JPOOL_PERMANENT 0 /* lasts until master record is destroyed */ 884 #define JPOOL_IMAGE 1 /* lasts until done with image/datastream */ 885 #define JPOOL_NUMPOOLS 2 886 887 typedef struct jvirt_sarray_control *jvirt_sarray_ptr; 888 typedef struct jvirt_barray_control *jvirt_barray_ptr; 889 890 891 struct jpeg_memory_mgr { 892 /* Method pointers */ 893 void *(*alloc_small) (j_common_ptr cinfo, int pool_id, size_t sizeofobject); 894 void *(*alloc_large) (j_common_ptr cinfo, int pool_id, 895 size_t sizeofobject); 896 /* If cinfo->data_precision is 12 or 16, then this method and the 897 * access_virt_sarray method actually return a J12SAMPARRAY or a 898 * J16SAMPARRAY, so callers must type-cast the return value in order to 899 * read/write 12-bit or 16-bit samples from/to the array. 900 */ 901 JSAMPARRAY (*alloc_sarray) (j_common_ptr cinfo, int pool_id, 902 JDIMENSION samplesperrow, JDIMENSION numrows); 903 JBLOCKARRAY (*alloc_barray) (j_common_ptr cinfo, int pool_id, 904 JDIMENSION blocksperrow, JDIMENSION numrows); 905 jvirt_sarray_ptr (*request_virt_sarray) (j_common_ptr cinfo, int pool_id, 906 boolean pre_zero, 907 JDIMENSION samplesperrow, 908 JDIMENSION numrows, 909 JDIMENSION maxaccess); 910 jvirt_barray_ptr (*request_virt_barray) (j_common_ptr cinfo, int pool_id, 911 boolean pre_zero, 912 JDIMENSION blocksperrow, 913 JDIMENSION numrows, 914 JDIMENSION maxaccess); 915 void (*realize_virt_arrays) (j_common_ptr cinfo); 916 JSAMPARRAY (*access_virt_sarray) (j_common_ptr cinfo, jvirt_sarray_ptr ptr, 917 JDIMENSION start_row, JDIMENSION num_rows, 918 boolean writable); 919 JBLOCKARRAY (*access_virt_barray) (j_common_ptr cinfo, jvirt_barray_ptr ptr, 920 JDIMENSION start_row, JDIMENSION num_rows, 921 boolean writable); 922 void (*free_pool) (j_common_ptr cinfo, int pool_id); 923 void (*self_destruct) (j_common_ptr cinfo); 924 925 /* Limit on memory allocation for this JPEG object. (Note that this is 926 * merely advisory, not a guaranteed maximum; it only affects the space 927 * used for virtual-array buffers.) May be changed by outer application 928 * after creating the JPEG object. 929 */ 930 long max_memory_to_use; 931 932 /* Maximum allocation request accepted by alloc_large. */ 933 long max_alloc_chunk; 934 }; 935 936 937 /* Routine signature for application-supplied marker processing methods. 938 * Need not pass marker code since it is stored in cinfo->unread_marker. 939 */ 940 typedef boolean (*jpeg_marker_parser_method) (j_decompress_ptr cinfo); 941 942 943 /* Originally, this macro was used as a way of defining function prototypes 944 * for both modern compilers as well as older compilers that did not support 945 * prototype parameters. libjpeg-turbo has never supported these older, 946 * non-ANSI compilers, but the macro is still included because there is some 947 * software out there that uses it. 948 */ 949 950 #define JPP(arglist) arglist 951 952 953 /* Default error-management setup */ 954 EXTERN(struct jpeg_error_mgr *) jpeg_std_error(struct jpeg_error_mgr *err); 955 956 /* Initialization of JPEG compression objects. 957 * jpeg_create_compress() and jpeg_create_decompress() are the exported 958 * names that applications should call. These expand to calls on 959 * jpeg_CreateCompress and jpeg_CreateDecompress with additional information 960 * passed for version mismatch checking. 961 * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx. 962 */ 963 #define jpeg_create_compress(cinfo) \ 964 jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \ 965 (size_t)sizeof(struct jpeg_compress_struct)) 966 #define jpeg_create_decompress(cinfo) \ 967 jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \ 968 (size_t)sizeof(struct jpeg_decompress_struct)) 969 EXTERN(void) jpeg_CreateCompress(j_compress_ptr cinfo, int version, 970 size_t structsize); 971 EXTERN(void) jpeg_CreateDecompress(j_decompress_ptr cinfo, int version, 972 size_t structsize); 973 /* Destruction of JPEG compression objects */ 974 EXTERN(void) jpeg_destroy_compress(j_compress_ptr cinfo); 975 EXTERN(void) jpeg_destroy_decompress(j_decompress_ptr cinfo); 976 977 /* Standard data source and destination managers: stdio streams. */ 978 /* Caller is responsible for opening the file before and closing after. */ 979 EXTERN(void) jpeg_stdio_dest(j_compress_ptr cinfo, FILE *outfile); 980 EXTERN(void) jpeg_stdio_src(j_decompress_ptr cinfo, FILE *infile); 981 982 /* Data source and destination managers: memory buffers. */ 983 EXTERN(void) jpeg_mem_dest(j_compress_ptr cinfo, unsigned char **outbuffer, 984 unsigned long *outsize); 985 EXTERN(void) jpeg_mem_src(j_decompress_ptr cinfo, 986 const unsigned char *inbuffer, unsigned long insize); 987 988 /* Default parameter setup for compression */ 989 EXTERN(void) jpeg_set_defaults(j_compress_ptr cinfo); 990 /* Compression parameter setup aids */ 991 EXTERN(void) jpeg_set_colorspace(j_compress_ptr cinfo, 992 J_COLOR_SPACE colorspace); 993 EXTERN(void) jpeg_default_colorspace(j_compress_ptr cinfo); 994 EXTERN(void) jpeg_set_quality(j_compress_ptr cinfo, int quality, 995 boolean force_baseline); 996 EXTERN(void) jpeg_set_linear_quality(j_compress_ptr cinfo, int scale_factor, 997 boolean force_baseline); 998 #if JPEG_LIB_VERSION >= 70 999 EXTERN(void) jpeg_default_qtables(j_compress_ptr cinfo, 1000 boolean force_baseline); 1001 #endif 1002 EXTERN(void) jpeg_add_quant_table(j_compress_ptr cinfo, int which_tbl, 1003 const unsigned int *basic_table, 1004 int scale_factor, boolean force_baseline); 1005 EXTERN(int) jpeg_quality_scaling(int quality); 1006 EXTERN(void) jpeg_enable_lossless(j_compress_ptr cinfo, 1007 int predictor_selection_value, 1008 int point_transform); 1009 EXTERN(void) jpeg_simple_progression(j_compress_ptr cinfo); 1010 EXTERN(void) jpeg_suppress_tables(j_compress_ptr cinfo, boolean suppress); 1011 EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table(j_common_ptr cinfo); 1012 EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table(j_common_ptr cinfo); 1013 1014 /* Main entry points for compression */ 1015 EXTERN(void) jpeg_start_compress(j_compress_ptr cinfo, 1016 boolean write_all_tables); 1017 EXTERN(JDIMENSION) jpeg_write_scanlines(j_compress_ptr cinfo, 1018 JSAMPARRAY scanlines, 1019 JDIMENSION num_lines); 1020 EXTERN(JDIMENSION) jpeg12_write_scanlines(j_compress_ptr cinfo, 1021 J12SAMPARRAY scanlines, 1022 JDIMENSION num_lines); 1023 EXTERN(JDIMENSION) jpeg16_write_scanlines(j_compress_ptr cinfo, 1024 J16SAMPARRAY scanlines, 1025 JDIMENSION num_lines); 1026 EXTERN(void) jpeg_finish_compress(j_compress_ptr cinfo); 1027 1028 #if JPEG_LIB_VERSION >= 70 1029 /* Precalculate JPEG dimensions for current compression parameters. */ 1030 EXTERN(void) jpeg_calc_jpeg_dimensions(j_compress_ptr cinfo); 1031 #endif 1032 1033 /* Replaces jpeg_write_scanlines when writing raw downsampled data. */ 1034 EXTERN(JDIMENSION) jpeg_write_raw_data(j_compress_ptr cinfo, JSAMPIMAGE data, 1035 JDIMENSION num_lines); 1036 EXTERN(JDIMENSION) jpeg12_write_raw_data(j_compress_ptr cinfo, 1037 J12SAMPIMAGE data, 1038 JDIMENSION num_lines); 1039 1040 /* Write a special marker. See libjpeg.txt concerning safe usage. */ 1041 EXTERN(void) jpeg_write_marker(j_compress_ptr cinfo, int marker, 1042 const JOCTET *dataptr, unsigned int datalen); 1043 /* Same, but piecemeal. */ 1044 EXTERN(void) jpeg_write_m_header(j_compress_ptr cinfo, int marker, 1045 unsigned int datalen); 1046 EXTERN(void) jpeg_write_m_byte(j_compress_ptr cinfo, int val); 1047 1048 /* Alternate compression function: just write an abbreviated table file */ 1049 EXTERN(void) jpeg_write_tables(j_compress_ptr cinfo); 1050 1051 /* Write ICC profile. See libjpeg.txt for usage information. */ 1052 EXTERN(void) jpeg_write_icc_profile(j_compress_ptr cinfo, 1053 const JOCTET *icc_data_ptr, 1054 unsigned int icc_data_len); 1055 1056 1057 /* Decompression startup: read start of JPEG datastream to see what's there */ 1058 EXTERN(int) jpeg_read_header(j_decompress_ptr cinfo, boolean require_image); 1059 /* Return value is one of: */ 1060 #define JPEG_SUSPENDED 0 /* Suspended due to lack of input data */ 1061 #define JPEG_HEADER_OK 1 /* Found valid image datastream */ 1062 #define JPEG_HEADER_TABLES_ONLY 2 /* Found valid table-specs-only datastream */ 1063 /* If you pass require_image = TRUE (normal case), you need not check for 1064 * a TABLES_ONLY return code; an abbreviated file will cause an error exit. 1065 * JPEG_SUSPENDED is only possible if you use a data source module that can 1066 * give a suspension return (the stdio source module doesn't). 1067 */ 1068 1069 /* Main entry points for decompression */ 1070 EXTERN(boolean) jpeg_start_decompress(j_decompress_ptr cinfo); 1071 EXTERN(JDIMENSION) jpeg_read_scanlines(j_decompress_ptr cinfo, 1072 JSAMPARRAY scanlines, 1073 JDIMENSION max_lines); 1074 EXTERN(JDIMENSION) jpeg12_read_scanlines(j_decompress_ptr cinfo, 1075 J12SAMPARRAY scanlines, 1076 JDIMENSION max_lines); 1077 EXTERN(JDIMENSION) jpeg16_read_scanlines(j_decompress_ptr cinfo, 1078 J16SAMPARRAY scanlines, 1079 JDIMENSION max_lines); 1080 EXTERN(JDIMENSION) jpeg_skip_scanlines(j_decompress_ptr cinfo, 1081 JDIMENSION num_lines); 1082 EXTERN(JDIMENSION) jpeg12_skip_scanlines(j_decompress_ptr cinfo, 1083 JDIMENSION num_lines); 1084 EXTERN(void) jpeg_crop_scanline(j_decompress_ptr cinfo, JDIMENSION *xoffset, 1085 JDIMENSION *width); 1086 EXTERN(void) jpeg12_crop_scanline(j_decompress_ptr cinfo, JDIMENSION *xoffset, 1087 JDIMENSION *width); 1088 EXTERN(boolean) jpeg_finish_decompress(j_decompress_ptr cinfo); 1089 1090 /* Replaces jpeg_read_scanlines when reading raw downsampled data. */ 1091 EXTERN(JDIMENSION) jpeg_read_raw_data(j_decompress_ptr cinfo, JSAMPIMAGE data, 1092 JDIMENSION max_lines); 1093 EXTERN(JDIMENSION) jpeg12_read_raw_data(j_decompress_ptr cinfo, 1094 J12SAMPIMAGE data, 1095 JDIMENSION max_lines); 1096 1097 /* Additional entry points for buffered-image mode. */ 1098 EXTERN(boolean) jpeg_has_multiple_scans(j_decompress_ptr cinfo); 1099 EXTERN(boolean) jpeg_start_output(j_decompress_ptr cinfo, int scan_number); 1100 EXTERN(boolean) jpeg_finish_output(j_decompress_ptr cinfo); 1101 EXTERN(boolean) jpeg_input_complete(j_decompress_ptr cinfo); 1102 EXTERN(void) jpeg_new_colormap(j_decompress_ptr cinfo); 1103 EXTERN(int) jpeg_consume_input(j_decompress_ptr cinfo); 1104 /* Return value is one of: */ 1105 /* #define JPEG_SUSPENDED 0 Suspended due to lack of input data */ 1106 #define JPEG_REACHED_SOS 1 /* Reached start of new scan */ 1107 #define JPEG_REACHED_EOI 2 /* Reached end of image */ 1108 #define JPEG_ROW_COMPLETED 3 /* Completed one iMCU row */ 1109 #define JPEG_SCAN_COMPLETED 4 /* Completed last iMCU row of a scan */ 1110 1111 /* Precalculate output dimensions for current decompression parameters. */ 1112 #if JPEG_LIB_VERSION >= 80 1113 EXTERN(void) jpeg_core_output_dimensions(j_decompress_ptr cinfo); 1114 #endif 1115 EXTERN(void) jpeg_calc_output_dimensions(j_decompress_ptr cinfo); 1116 1117 /* Control saving of COM and APPn markers into marker_list. */ 1118 EXTERN(void) jpeg_save_markers(j_decompress_ptr cinfo, int marker_code, 1119 unsigned int length_limit); 1120 1121 /* Install a special processing method for COM or APPn markers. */ 1122 EXTERN(void) jpeg_set_marker_processor(j_decompress_ptr cinfo, 1123 int marker_code, 1124 jpeg_marker_parser_method routine); 1125 1126 /* Read or write raw DCT coefficients --- useful for lossless transcoding. */ 1127 EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients(j_decompress_ptr cinfo); 1128 EXTERN(void) jpeg_write_coefficients(j_compress_ptr cinfo, 1129 jvirt_barray_ptr *coef_arrays); 1130 EXTERN(void) jpeg_copy_critical_parameters(j_decompress_ptr srcinfo, 1131 j_compress_ptr dstinfo); 1132 1133 /* If you choose to abort compression or decompression before completing 1134 * jpeg_finish_(de)compress, then you need to clean up to release memory, 1135 * temporary files, etc. You can just call jpeg_destroy_(de)compress 1136 * if you're done with the JPEG object, but if you want to clean it up and 1137 * reuse it, call this: 1138 */ 1139 EXTERN(void) jpeg_abort_compress(j_compress_ptr cinfo); 1140 EXTERN(void) jpeg_abort_decompress(j_decompress_ptr cinfo); 1141 1142 /* Generic versions of jpeg_abort and jpeg_destroy that work on either 1143 * flavor of JPEG object. These may be more convenient in some places. 1144 */ 1145 EXTERN(void) jpeg_abort(j_common_ptr cinfo); 1146 EXTERN(void) jpeg_destroy(j_common_ptr cinfo); 1147 1148 /* Default restart-marker-resync procedure for use by data source modules */ 1149 EXTERN(boolean) jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired); 1150 1151 /* Read ICC profile. See libjpeg.txt for usage information. */ 1152 EXTERN(boolean) jpeg_read_icc_profile(j_decompress_ptr cinfo, 1153 JOCTET **icc_data_ptr, 1154 unsigned int *icc_data_len); 1155 1156 1157 /* These marker codes are exported since applications and data source modules 1158 * are likely to want to use them. 1159 */ 1160 1161 #define JPEG_RST0 0xD0 /* RST0 marker code */ 1162 #define JPEG_EOI 0xD9 /* EOI marker code */ 1163 #define JPEG_APP0 0xE0 /* APP0 marker code */ 1164 #define JPEG_COM 0xFE /* COM marker code */ 1165 1166 1167 /* If we have a brain-damaged compiler that emits warnings (or worse, errors) 1168 * for structure definitions that are never filled in, keep it quiet by 1169 * supplying dummy definitions for the various substructures. 1170 */ 1171 1172 #ifdef INCOMPLETE_TYPES_BROKEN 1173 #ifndef JPEG_INTERNALS /* will be defined in jpegint.h */ 1174 struct jvirt_sarray_control { long dummy; }; 1175 struct jvirt_barray_control { long dummy; }; 1176 struct jpeg_comp_master { long dummy; }; 1177 struct jpeg_c_main_controller { long dummy; }; 1178 struct jpeg_c_prep_controller { long dummy; }; 1179 struct jpeg_c_coef_controller { long dummy; }; 1180 struct jpeg_marker_writer { long dummy; }; 1181 struct jpeg_color_converter { long dummy; }; 1182 struct jpeg_downsampler { long dummy; }; 1183 struct jpeg_forward_dct { long dummy; }; 1184 struct jpeg_entropy_encoder { long dummy; }; 1185 struct jpeg_decomp_master { long dummy; }; 1186 struct jpeg_d_main_controller { long dummy; }; 1187 struct jpeg_d_coef_controller { long dummy; }; 1188 struct jpeg_d_post_controller { long dummy; }; 1189 struct jpeg_input_controller { long dummy; }; 1190 struct jpeg_marker_reader { long dummy; }; 1191 struct jpeg_entropy_decoder { long dummy; }; 1192 struct jpeg_inverse_dct { long dummy; }; 1193 struct jpeg_upsampler { long dummy; }; 1194 struct jpeg_color_deconverter { long dummy; }; 1195 struct jpeg_color_quantizer { long dummy; }; 1196 #endif /* JPEG_INTERNALS */ 1197 #endif /* INCOMPLETE_TYPES_BROKEN */ 1198 1199 1200 /* 1201 * The JPEG library modules define JPEG_INTERNALS before including this file. 1202 * The internal structure declarations are read only when that is true. 1203 * Applications using the library should not include jpegint.h, but may wish 1204 * to include jerror.h. 1205 */ 1206 1207 #ifdef JPEG_INTERNALS 1208 #include "jpegint.h" /* fetch private declarations */ 1209 #include "jerror.h" /* fetch error codes too */ 1210 #endif 1211 1212 #ifdef __cplusplus 1213 #ifndef DONT_USE_EXTERN_C 1214 } 1215 #endif 1216 #endif 1217 1218 #endif /* JPEGLIB_H */