/* jsjpeg_image.h - routines to read and write JPEG files. */
/* Last edited on 2012-06-09 19:29:11 by stolfilocal */

/* Created by R. Minetto (IC-UNICAMP) sometime in 2008--2009. */
/* Adapted by J. Stolfi (IC-UNICMP) on 2011-05-14. */

#ifndef jsjpeg_image_H
#define jsjpeg_image_H

#define _GNU_SOURCE
#include <stdio.h>

#undef FALSE
#undef TRUE
#include <jpeglib.h>
#undef FALSE
#undef TRUE

#include <bool.h>
#include <jspnm_image.h>

/* These procedures read/write a JPEG file into/from the {pnm_image_t} 
  memory format defined in {jspnm_image.h}. */
  
#define jsjpeg_BITS_PER_SAMPLE (BITS_PER_JSAMPLE)
  /* The number of bits per sample of decompressed images:
     either 8 or 12, usually 8. */

pnm_image_t *jsjpeg_image_read (char *name, bool_t verbose, int *kind);
  /* Reads an image from the named JPEG file. 
  
    If {*kind} is not NULL, sets it to the image color space
    as in the {J_COLOR_SPACE} codes of {jpeglib.h}. 
    Note that the PNM files support only {JCS_GRAYSCALE} and
    {JCS_RGB} spaces. Note also that {JCS_CMYK} and {JCS_YCCK}
    images have {chns=4}.
    
    The routine can read only JPEG files whose number of bits
    per pixel (8 or 12) is equal to the parameter {BITS_IN_JSAMPLE}
    in the {jpeglib.h} header and compiled into the JPEG library. If
    that parameter is defined as 8 then the JPEG library (and therefoe this
    procedure) cannot read 12-bit files, and vice-versa. What a crock.
    In any case the {maxval} of the returned image is set to the
    correct value (255 or 4095, respectively).
    
    If the {name} is "-", reads from {stdin}. If {verbose} is TRUE,
    prints a notice to {stderr}. */

void jsjpeg_image_write (char *name, pnm_image_t *img, int quality, bool_t verbose);
  /* Writes image {img} to the specified file in JPEG format.
  
    If {img.chns} is 1 uses colorspace {JCS_GRAYSCALE}, if 3 assumes
    {JCS_RGB}. Other values are invalid.
    
    The {quality} parameter is an integer in {1..100} that specifies
    the fidelity of the compressed image to the original: 100 means no
    compression; typical values range in {80..98}.
    
    The routine can write only JPEG files whose number of bits per
    pixel (8 or 12) is equal to the parameter {BITS_IN_JSAMPLE} in the
    {jpeglib.h} header and compiled into the JPEG library. If that
    parameter is defined as 8 then the JPEG library (and therefore
    this procedure) cannot write 12-bit files, and vice-versa. What a
    crock. In any case the samples of {img} are linearly scaled from
    the range {0..img.maxval} to the appropriate range, {0..255} or
    {0..4095}.
    
    If {name} is "-", writes to {stdout}. If {verbose} is TRUE, prints
    a notice to {stderr}. */

pnm_image_t *jsjpeg_image_fread (FILE *rd, int *kind);
void jsjpeg_image_fwrite (FILE *wr, pnm_image_t *img, int quality);
  /* Same as {jsjpeg_image_read} and {jsjpeg_image_write}, 
    but from/to a previously opened file handle. */

#endif