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src/Source/LibJPEG/jpeglib.h  view on Meta::CPAN

  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, standard RGB (sRGB) */
	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV), standard YCC */
	JCS_CMYK,		/* C/M/Y/K */
	JCS_YCCK,		/* Y/Cb/Cr/K */
	JCS_BG_RGB,		/* big gamut red/green/blue, bg-sRGB */
	JCS_BG_YCC		/* big gamut Y/Cb/Cr, bg-sYCC */
} J_COLOR_SPACE;

/* Supported color transforms. */

typedef enum {
	JCT_NONE           = 0,
	JCT_SUBTRACT_GREEN = 1
} J_COLOR_TRANSFORM;

/* 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
   * be correct before you can even call jpeg_set_defaults().
   */

  JDIMENSION image_width;	/* input image width */
  JDIMENSION image_height;	/* input image height */
  int input_components;		/* # of color components in input image */
  J_COLOR_SPACE in_color_space;	/* colorspace of input image */

  double input_gamma;		/* image gamma of input image */

  /* Compression parameters --- these fields must be set before calling
   * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to
   * initialize everything to reasonable defaults, then changing anything
   * the application specifically wants to change.  That way you won't get
   * burnt when new parameters are added.  Also note that there are several
   * helper routines to simplify changing parameters.
   */

  unsigned int scale_num, scale_denom; /* fraction by which to scale image */

  JDIMENSION jpeg_width;	/* scaled JPEG image width */
  JDIMENSION jpeg_height;	/* scaled JPEG image height */
  /* Dimensions of actual JPEG image that will be written to file,
   * derived from input dimensions by scaling factors above.
   * These fields are computed by jpeg_start_compress().
   * You can also use jpeg_calc_jpeg_dimensions() to determine these values
   * in advance of calling jpeg_start_compress().
   */

  int data_precision;		/* bits of precision in image data */

  int num_components;		/* # of color components in JPEG image */