jpeglib.h

这是一个用于生成等值线的源代码

  boolean saw_JFIF_marker;	/* TRUE iff a JFIF APP0 marker was found */
  /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
  UINT8 JFIF_major_version;	/* JFIF version number */
  UINT8 JFIF_minor_version;
  UINT8 density_unit;		/* JFIF code for pixel size units */
  UINT16 X_density;		/* Horizontal pixel density */
  UINT16 Y_density;		/* Vertical pixel density */
  boolean saw_Adobe_marker;	/* TRUE iff an Adobe APP14 marker was found */
  UINT8 Adobe_transform;	/* Color transform code from Adobe marker */

  boolean CCIR601_sampling;	/* TRUE=first samples are cosited */

  /* Aside from the specific data retained from APPn markers known to the
   * library, the uninterpreted contents of any or all APPn and COM markers
   * can be saved in a list for examination by the application.
   */
  jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */

  /* Remaining fields are known throughout decompressor, but generally
   * should not be touched by a surrounding application.
   */

  /*
   * These fields are computed during decompression startup
   */
  int max_h_samp_factor;	/* largest h_samp_factor */
  int max_v_samp_factor;	/* largest v_samp_factor */

  int min_DCT_scaled_size;	/* smallest DCT_scaled_size of any component */

  JDIMENSION total_iMCU_rows;	/* # of iMCU rows in image */
  /* The coefficient controller's input and output progress is measured in
   * units of "iMCU" (interleaved MCU) rows.  These are the same as MCU rows
   * in fully interleaved JPEG scans, but are used whether the scan is
   * interleaved or not.  We define an iMCU row as v_samp_factor DCT block
   * rows of each component.  Therefore, the IDCT output contains
   * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
   */

  JSAMPLE * sample_range_limit; /* table for fast range-limiting */

  /*
   * These fields are valid during any one scan.
   * They describe the components and MCUs actually appearing in the scan.
   * Note that the decompressor output side must not use these fields.
   */
  int comps_in_scan;		/* # of JPEG components in this scan */
  jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
  /* *cur_comp_info[i] describes component that appears i'th in SOS */

  JDIMENSION MCUs_per_row;	/* # of MCUs across the image */
  JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */

  int blocks_in_MCU;		/* # of DCT blocks per MCU */
  int MCU_membership[D_MAX_BLOCKS_IN_MCU];
  /* MCU_membership[i] is index in cur_comp_info of component owning */
  /* i'th block in an MCU */

  int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */

  /* This field is shared between entropy decoder and marker parser.
   * It is either zero or the code of a JPEG marker that has been
   * read from the data source, but has not yet been processed.
   */
  int unread_marker;

  /*
   * Links to decompression subobjects (methods, private variables of modules)
   */
  struct jpeg_decomp_master * master;
  struct jpeg_d_main_controller * main;
  struct jpeg_d_coef_controller * coef;
  struct jpeg_d_post_controller * post;
  struct jpeg_input_controller * inputctl;
  struct jpeg_marker_reader * marker;
  struct jpeg_entropy_decoder * entropy;
  struct jpeg_inverse_dct * idct;
  struct jpeg_upsampler * upsample;
  struct jpeg_color_deconverter * cconvert;
  struct jpeg_color_quantizer * cquantize;
};


/* "Object" declarations for JPEG modules that may be supplied or called
 * directly by the surrounding application.
 * As with all objects in the JPEG library, these structs only define the
 * publicly visible methods and state variables of a module.  Additional
 * private fields may exist after the public ones.
 */


/* Error handler object */

struct jpeg_error_mgr {
  /* Error exit handler: does not return to caller */
  JMETHOD(void, error_exit, (j_common_ptr cinfo));
  /* Conditionally emit a trace or warning message */
  JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
  /* Routine that actually outputs a trace or error message */
  JMETHOD(void, output_message, (j_common_ptr cinfo));
  /* Format a message string for the most recent JPEG error or message */
  JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
#define JMSG_LENGTH_MAX  200	/* recommended size of format_message buffer */
  /* Reset error state variables at start of a new image */
  JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));
  
  /* The message ID code and any parameters are saved here.
   * A message can have one string parameter or up to 8 int parameters.
   */
  int msg_code;
#define JMSG_STR_PARM_MAX  80
  union {
    int i[8];
    char s[JMSG_STR_PARM_MAX];
  } msg_parm;
  
  /* Standard state variables for error facility */
  
  int trace_level;		/* max msg_level that will be displayed */
  
  /* For recoverable corrupt-data errors, we emit a warning message,
   * but keep going unless emit_message chooses to abort.  emit_message
   * should count warnings in num_warnings.  The surrounding application
   * can check for bad data by seeing if num_warnings is nonzero at the
   * end of processing.
   */
  long num_warnings;		/* number of corrupt-data warnings */

  /* These fields point to the table(s) of error message strings.
   * An application can change the table pointer to switch to a different
   * message list (typically, to change the language in which errors are
   * reported).  Some applications may wish to add additional error codes
   * that will be handled by the JPEG library error mechanism; the second
   * table pointer is used for this purpose.
   *
   * First table includes all errors generated by JPEG library itself.
   * Error code 0 is reserved for a "no such error string" message.
   */
  const char * const * jpeg_message_table; /* Library errors */
  int last_jpeg_message;    /* Table contains strings 0..last_jpeg_message */
  /* Second table can be added by application (see cjpeg/djpeg for example).
   * It contains strings numbered first_addon_message..last_addon_message.
   */
  const char * const * addon_message_table; /* Non-library errors */
  int first_addon_message;	/* code for first string in addon table */
  int last_addon_message;	/* code for last string in addon table */
};


/* Progress monitor object */

struct jpeg_progress_mgr {
  JMETHOD(void, progress_monitor, (j_common_ptr cinfo));

  long pass_counter;		/* work units completed in this pass */
  long pass_limit;		/* total number of work units in this pass */
  int completed_passes;		/* passes completed so far */
  int total_passes;		/* total number of passes expected */
};


/* Data destination object for compression */

struct jpeg_destination_mgr {
  JOCTET * next_output_byte;	/* => next byte to write in buffer */
  size_t free_in_buffer;	/* # of byte spaces remaining in buffer */

  JMETHOD(void, init_destination, (j_compress_ptr cinfo));
  JMETHOD(boolean, empty_output_buffer, (j_compress_ptr cinfo));
  JMETHOD(void, term_destination, (j_compress_ptr cinfo));
};


/* Data source object for decompression */

struct jpeg_source_mgr {
  const JOCTET * next_input_byte; /* => next byte to read from buffer */
  size_t bytes_in_buffer;	/* # of bytes remaining in buffer */

  JMETHOD(void, init_source, (j_decompress_ptr cinfo));
  JMETHOD(boolean, fill_input_buffer, (j_decompress_ptr cinfo));
  JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
  JMETHOD(boolean, resync_to_restart, (j_decompress_ptr cinfo, int desired));
  JMETHOD(void, term_source, (j_decompress_ptr cinfo));
};


/* Memory manager object.
 * Allocates "small" objects (a few K total), "large" objects (tens of K),
 * and "really big" objects (virtual arrays with backing store if needed).
 * The memory manager does not allow individual objects to be freed; rather,
 * each created object is assigned to a pool, and whole pools can be freed
 * at once.  This is faster and more convenient than remembering exactly what
 * to free, especially where malloc()/free() are not too speedy.
 * NB: alloc routines never return NULL.  They exit to error_exit if not
 * successful.
 */

#define JPOOL_PERMANENT	0	/* lasts until master record is destroyed */
#define JPOOL_IMAGE	1	/* lasts until done with image/datastream */
#define JPOOL_NUMPOOLS	2

typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
typedef struct jvirt_barray_control * jvirt_barray_ptr;


struct jpeg_memory_mgr {
  /* Method pointers */
  JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
				size_t sizeofobject));
  JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
				     size_t sizeofobject));
  JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
				     JDIMENSION samplesperrow,
				     JDIMENSION numrows));
  JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
				      JDIMENSION blocksperrow,
				      JDIMENSION numrows));
  JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
						  int pool_id,
						  boolean pre_zero,
						  JDIMENSION samplesperrow,
						  JDIMENSION numrows,
						  JDIMENSION maxaccess));
  JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
						  int pool_id,
						  boolean pre_zero,
						  JDIMENSION blocksperrow,
						  JDIMENSION numrows,
						  JDIMENSION maxaccess));
  JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
  JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
					   jvirt_sarray_ptr ptr,
					   JDIMENSION start_row,
					   JDIMENSION num_rows,
					   boolean writable));
  JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
					    jvirt_barray_ptr ptr,
					    JDIMENSION start_row,
					    JDIMENSION num_rows,
					    boolean writable));
  JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
  JMETHOD(void, self_destruct, (j_common_ptr cinfo));

  /* Limit on memory allocation for this JPEG object.  (Note that this is
   * merely advisory, not a guaranteed maximum; it only affects the space
   * used for virtual-array buffers.)  May be changed by outer application
   * after creating the JPEG object.
   */
  long max_memory_to_use;

  /* Maximum allocation request accepted by alloc_large. */
  long max_alloc_chunk;
};


/* Routine signature for application-supplied marker processing methods.
 * Need not pass marker code since it is stored in cinfo->unread_marker.
 */
typedef JMETHOD(boolean, jpeg_marker_parser_method, (j_decompress_ptr cinfo));


/* Declarations for routines called by application.
 * The JPP macro hides prototype parameters from compilers that can't cope.
 * Note JPP requires double parentheses.
 */

#ifdef HAVE_PROTOTYPES
#define JPP(arglist)	arglist
#else
#define JPP(arglist)	()
#endif


/* Short forms of external names for systems with brain-damaged linkers.