jpeglib.h

这是一个用ov511摄像头捕捉图像的应用程序

/*
 * 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