/* * jpeglib.h * * Copyright (C) 1991-1998, Thomas G. Lane. * This file is part of the Independent JPEG Group's software. * For conditions of distribution and use, see the accompanying README file. * * This file defines the application interface for the JPEG library. * Most applications using the library need only include this file, * and perhaps jerror.h if they want to know the exact error codes. */#ifndef JPEGLIB_H#define JPEGLIB_H/* * First we include the configuration files that record how this * installation of the JPEG library is set up.  jconfig.h can be * generated automatically for many systems.  jmorecfg.h contains * manual configuration options that most people need not worry about. */#ifndef JCONFIG_INCLUDED	/* in case jinclude.h already did */#include "jconfig.h"		/* widely used configuration options */#endif#include "jmorecfg.h"		/* seldom changed options *//* Version ID for the JPEG library. * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60". */#define JPEG_LIB_VERSION  62	/* Version 6b *//* Various constants determining the sizes of things. * All of these are specified by the JPEG standard, so don't change them * if you want to be compatible. */#define DCTSIZE		    8	/* The basic DCT block is 8x8 samples */#define DCTSIZE2	    64	/* DCTSIZE squared; # of elements in a block */#define NUM_QUANT_TBLS      4	/* Quantization tables are numbered 0..3 */#define NUM_HUFF_TBLS       4	/* Huffman tables are numbered 0..3 */#define NUM_ARITH_TBLS      16	/* Arith-coding tables are numbered 0..15 */#define MAX_COMPS_IN_SCAN   4	/* JPEG limit on # of components in one scan */#define MAX_SAMP_FACTOR     4	/* JPEG limit on sampling factors *//* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard; * the PostScript DCT filter can emit files with many more than 10 blocks/MCU. * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU * to handle it.  We even let you do this from the jconfig.h file.  However, * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe * sometimes emits noncompliant files doesn't mean you should too. */#define C_MAX_BLOCKS_IN_MCU   10 /* compressor's limit on blocks per MCU */#ifndef D_MAX_BLOCKS_IN_MCU#define D_MAX_BLOCKS_IN_MCU   10 /* decompressor's limit on blocks per MCU */#endif/* Data structures for images (arrays of samples and of DCT coefficients). * On 80x86 machines, the image arrays are too big for near pointers, * but the pointer arrays can fit in near memory. */typedef JSAMPLE FAR *JSAMPROW;	/* ptr to one image row of pixel samples. */typedef JSAMPROW *JSAMPARRAY;	/* ptr to some rows (a 2-D sample array) */typedef JSAMPARRAY *JSAMPIMAGE;	/* a 3-D sample array: top index is color */typedef JCOEF JBLOCK[DCTSIZE2];	/* one block of coefficients */typedef JBLOCK FAR *JBLOCKROW;	/* pointer to one row of coefficient blocks */typedef JBLOCKROW *JBLOCKARRAY;		/* a 2-D array of coefficient blocks */typedef JBLOCKARRAY *JBLOCKIMAGE;	/* a 3-D array of coefficient blocks */typedef JCOEF FAR *JCOEFPTR;	/* useful in a couple of places *//* Types for JPEG compression parameters and working tables. *//* DCT coefficient quantization tables. */typedef struct {  /* This array gives the coefficient quantizers in natural array order   * (not the zigzag order in which they are stored in a JPEG DQT marker).   * CAUTION: IJG versions prior to v6a kept this array in zigzag order.   */  UINT16 quantval[DCTSIZE2];	/* quantization step for each coefficient */  /* This field is used only during compression.  It's initialized FALSE when   * the table is created, and set TRUE when it's been output to the file.   * You could suppress output of a table by setting this to TRUE.   * (See jpeg_suppress_tables for an example.)   */  boolean sent_table;		/* TRUE when table has been output */} JQUANT_TBL;/* Huffman coding tables. */typedef struct {  /* These two fields directly represent the contents of a JPEG DHT marker */  UINT8 bits[17];		/* bits[k] = # of symbols with codes of */				/* length k bits; bits[0] is unused */  UINT8 huffval[256];		/* The symbols, in order of incr code length */  /* This field is used only during compression.  It's initialized FALSE when   * the table is created, and set TRUE when it's been output to the file.   * You could suppress output of a table by setting this to TRUE.   * (See jpeg_suppress_tables for an example.)   */  boolean sent_table;		/* TRUE when table has been output */} JHUFF_TBL;/* Basic info about one component (color channel). */typedef struct {  /* These values are fixed over the whole image. */  /* For compression, they must be supplied by parameter setup; */  /* for decompression, they are read from the SOF marker. */  int component_id;		/* identifier for this component (0..255) */  int component_index;		/* its index in SOF or cinfo->comp_info[] */  int h_samp_factor;		/* horizontal sampling factor (1..4) */  int v_samp_factor;		/* vertical sampling factor (1..4) */  int quant_tbl_no;		/* quantization table selector (0..3) */  /* These values may vary between scans. */  /* For compression, they must be supplied by parameter setup; */  /* for decompression, they are read from the SOS marker. */  /* The decompressor output side may not use these variables. */  int dc_tbl_no;		/* DC entropy table selector (0..3) */  int ac_tbl_no;		/* AC entropy table selector (0..3) */    /* Remaining fields should be treated as private by applications. */    /* These values are computed during compression or decompression startup: */  /* Component's size in DCT blocks.   * Any dummy blocks added to complete an MCU are not counted; therefore   * these values do not depend on whether a scan is interleaved or not.   */  JDIMENSION width_in_blocks;  JDIMENSION height_in_blocks;  /* Size of a DCT block in samples.  Always DCTSIZE for compression.   * For decompression this is the size of the output from one DCT block,   * reflecting any scaling we choose to apply during the IDCT step.   * Values of 1,2,4,8 are likely to be supported.  Note that different   * components may receive different IDCT scalings.   */  int DCT_scaled_size;  /* The downsampled dimensions are the component's actual, unpadded number   * of samples at the main buffer (preprocessing/compression interface), thus   * downsampled_width = ceil(image_width * Hi/Hmax)   * and similarly for height.  For decompression, IDCT scaling is included, so   * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)   */  JDIMENSION downsampled_width;	 /* actual width in samples */  JDIMENSION downsampled_height; /* actual height in samples */  /* This flag is used only for decompression.  In cases where some of the   * components will be ignored (eg grayscale output from YCbCr image),   * we can skip most computations for the unused components.   */  boolean component_needed;	/* do we need the value of this component? */  /* These values are computed before starting a scan of the component. */  /* The decompressor output side may not use these variables. */  int MCU_width;		/* number of blocks per MCU, horizontally */  int MCU_height;		/* number of blocks per MCU, vertically */  int MCU_blocks;		/* MCU_width * MCU_height */  int MCU_sample_width;		/* MCU width in samples, MCU_width*DCT_scaled_size */  int last_col_width;		/* # of non-dummy blocks across in last MCU */  int last_row_height;		/* # of non-dummy blocks down in last MCU */  /* Saved quantization table for component; NULL if none yet saved.   * See jdinput.c comments about the need for this information.   * This field is currently used only for decompression.   */  JQUANT_TBL * quant_table;  /* Private per-component storage for DCT or IDCT subsystem. */  void * dct_table;} jpeg_component_info;/* The script for encoding a multiple-scan file is an array of these: */typedef struct {  int comps_in_scan;		/* number of components encoded in this scan */  int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */  int Ss, Se;			/* progressive JPEG spectral selection parms */  int Ah, Al;			/* progressive JPEG successive approx. parms */} jpeg_scan_info;/* The decompressor can save APPn and COM markers in a list of these: */typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;struct jpeg_marker_struct {  jpeg_saved_marker_ptr next;	/* next in list, or NULL */  UINT8 marker;			/* marker code: JPEG_COM, or JPEG_APP0+n */  unsigned int original_length;	/* # bytes of data in the file */  unsigned int data_length;	/* # bytes of data saved at data[] */  JOCTET FAR * data;		/* the data contained in the marker */  /* the marker length word is not counted in data_length or original_length */};/* Known color spaces. */typedef enum {	JCS_UNKNOWN,		/* error/unspecified */	JCS_GRAYSCALE,		/* monochrome */	JCS_RGB,		/* red/green/blue */	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV) */	JCS_CMYK,		/* C/M/Y/K */	JCS_YCCK		/* Y/Cb/Cr/K */} J_COLOR_SPACE;/* DCT/IDCT algorithm options. */typedef enum {	JDCT_ISLOW,		/* slow but accurate integer algorithm */	JDCT_IFAST,		/* faster, less accurate integer method */	JDCT_FLOAT		/* floating-point: accurate, fast on fast HW */} J_DCT_METHOD;#ifndef JDCT_DEFAULT		/* may be overridden in jconfig.h */#define JDCT_DEFAULT  JDCT_ISLOW#endif#ifndef JDCT_FASTEST		/* may be overridden in jconfig.h */#define JDCT_FASTEST  JDCT_IFAST#endif/* Dithering options for decompression. */typedef enum {	JDITHER_NONE,		/* no dithering */	JDITHER_ORDERED,	/* simple ordered dither */	JDITHER_FS		/* Floyd-Steinberg error diffusion dither */} J_DITHER_MODE;/* Common fields between JPEG compression and decompression master structs. */#define jpeg_common_fields \  struct jpeg_error_mgr * err;	/* Error handler module */\  struct jpeg_memory_mgr * mem;	/* Memory manager module */\  struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\  void * client_data;		/* Available for use by application */\  boolean is_decompressor;	/* So common code can tell which is which */\  int global_state		/* For checking call sequence validity *//* Routines that are to be used by both halves of the library are declared * to receive a pointer to this structure.  There are no actual instances of * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct. */struct jpeg_common_struct {  jpeg_common_fields;		/* Fields common to both master struct types */  /* Additional fields follow in an actual jpeg_compress_struct or   * jpeg_decompress_struct.  All three structs must agree on these   * initial fields!  (This would be a lot cleaner in C++.)   */};typedef struct jpeg_common_struct * j_common_ptr;typedef struct jpeg_compress_struct * j_compress_ptr;typedef struct jpeg_decompress_struct * j_decompress_ptr;/* Master record for a compression instance */struct jpeg_compress_struct {  jpeg_common_fields;		/* Fields shared with jpeg_decompress_struct */  /* Destination for compressed data */  struct jpeg_destination_mgr * dest;  /* Description of source image --- these fields must be filled in by   * outer application before starting compression.  in_color_space must