workbench/libs/lcms2/utils/jpgicc/iccjpeg.h

   1 /*
   2  * iccprofile.h
   3  *
   4  * This file provides code to read and write International Color Consortium
   5  * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
   6  * defined a standard format for including such data in JPEG "APP2" markers.
   7  * The code given here does not know anything about the internal structure
   8  * of the ICC profile data; it just knows how to put the profile data into
   9  * a JPEG file being written, or get it back out when reading.
  10  *
  11  * This code depends on new features added to the IJG JPEG library as of
  12  * IJG release 6b; it will not compile or work with older IJG versions.
  13  *
  14  * NOTE: this code would need surgery to work on 16-bit-int machines
  15  * with ICC profiles exceeding 64K bytes in size.  See iccprofile.c
  16  * for details.
  17  */
  18
  19 #include <stdio.h>              /* needed to define "FILE", "NULL" */
  20 #include "jpeglib.h"
  21
  22
  23 /*
  24  * This routine writes the given ICC profile data into a JPEG file.
  25  * It *must* be called AFTER calling jpeg_start_compress() and BEFORE
  26  * the first call to jpeg_write_scanlines().
  27  * (This ordering ensures that the APP2 marker(s) will appear after the
  28  * SOI and JFIF or Adobe markers, but before all else.)
  29  */
  30
  31 extern void write_icc_profile JPP((j_compress_ptr cinfo,
  32                                    const JOCTET *icc_data_ptr,
  33                                    unsigned int icc_data_len));
  34
  35
  36 /*
  37  * Reading a JPEG file that may contain an ICC profile requires two steps:
  38  *
  39  * 1. After jpeg_create_decompress() but before jpeg_read_header(),
  40  *    call setup_read_icc_profile().  This routine tells the IJG library
  41  *    to save in memory any APP2 markers it may find in the file.
  42  *
  43  * 2. After jpeg_read_header(), call read_icc_profile() to find out
  44  *    whether there was a profile and obtain it if so.
  45  */
  46
  47
  48 /*
  49  * Prepare for reading an ICC profile
  50  */
  51
  52 extern void setup_read_icc_profile JPP((j_decompress_ptr cinfo));
  53
  54
  55 /*
  56  * See if there was an ICC profile in the JPEG file being read;
  57  * if so, reassemble and return the profile data.
  58  *
  59  * TRUE is returned if an ICC profile was found, FALSE if not.
  60  * If TRUE is returned, *icc_data_ptr is set to point to the
  61  * returned data, and *icc_data_len is set to its length.
  62  *
  63  * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
  64  * and must be freed by the caller with free() when the caller no longer
  65  * needs it.  (Alternatively, we could write this routine to use the
  66  * IJG library's memory allocator, so that the data would be freed implicitly
  67  * at jpeg_finish_decompress() time.  But it seems likely that many apps
  68  * will prefer to have the data stick around after decompression finishes.)
  69  */
  70
  71 extern boolean read_icc_profile JPP((j_decompress_ptr cinfo,
  72                                      JOCTET **icc_data_ptr,
  73                                      unsigned int *icc_data_len));