image/decoders/iccjpeg.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 /*
   6  * iccjpeg.h
   7  *
   8  * This file provides code to read and write International Color Consortium
   9  * (ICC) device profiles embedded in JFIF JPEG image files.  The ICC has
  10  * defined a standard format for including such data in JPEG "APP2" markers.
  11  * The code given here does not know anything about the internal structure
  12  * of the ICC profile data; it just knows how to put the profile data into
  13  * a JPEG file being written, or get it back out when reading.
  14  *
  15  * This code depends on new features added to the IJG JPEG library as of
  16  * IJG release 6b; it will not compile or work with older IJG versions.
  17  *
  18  * NOTE: this code would need surgery to work on 16-bit-int machines
  19  * with ICC profiles exceeding 64K bytes in size.  See iccprofile.c
  20  * for details.
  21  */
  22
  23 #ifndef mozilla_image_decoders_iccjpeg_h
  24 #define mozilla_image_decoders_iccjpeg_h
  25
  26 #include <stdio.h> /* needed to define "FILE", "NULL" */
  27 #include "jpeglib.h"
  28
  29 /*
  30  * Reading a JPEG file that may contain an ICC profile requires two steps:
  31  *
  32  * 1. After jpeg_create_decompress() but before jpeg_read_header(),
  33  *    call setup_read_icc_profile().  This routine tells the IJG library
  34  *    to save in memory any APP2 markers it may find in the file.
  35  *
  36  * 2. After jpeg_read_header(), call read_icc_profile() to find out
  37  *    whether there was a profile and obtain it if so.
  38  */
  39
  40 /*
  41  * Prepare for reading an ICC profile
  42  */
  43
  44 extern void setup_read_icc_profile JPP((j_decompress_ptr cinfo));
  45
  46 /*
  47  * See if there was an ICC profile in the JPEG file being read;
  48  * if so, reassemble and return the profile data.
  49  *
  50  * TRUE is returned if an ICC profile was found, FALSE if not.
  51  * If TRUE is returned, *icc_data_ptr is set to point to the
  52  * returned data, and *icc_data_len is set to its length.
  53  *
  54  * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc()
  55  * and must be freed by the caller with free() when the caller no longer
  56  * needs it.  (Alternatively, we could write this routine to use the
  57  * IJG library's memory allocator, so that the data would be freed implicitly
  58  * at jpeg_finish_decompress() time.  But it seems likely that many apps
  59  * will prefer to have the data stick around after decompression finishes.)
  60  */
  61
  62 extern boolean read_icc_profile JPP((j_decompress_ptr cinfo,
  63                                      JOCTET** icc_data_ptr,
  64                                      unsigned int* icc_data_len));
  65 #endif  // mozilla_image_decoders_iccjpeg_h