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Diffstat (limited to 'xicc/iccjpeg.h')
-rw-r--r-- | xicc/iccjpeg.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/xicc/iccjpeg.h b/xicc/iccjpeg.h new file mode 100644 index 0000000..5e1888d --- /dev/null +++ b/xicc/iccjpeg.h @@ -0,0 +1,73 @@ +/* + * iccprofile.h + * + * This file provides code to read and write International Color Consortium + * (ICC) device profiles embedded in JFIF JPEG image files. The ICC has + * defined a standard format for including such data in JPEG "APP2" markers. + * The code given here does not know anything about the internal structure + * of the ICC profile data; it just knows how to put the profile data into + * a JPEG file being written, or get it back out when reading. + * + * This code depends on new features added to the IJG JPEG library as of + * IJG release 6b; it will not compile or work with older IJG versions. + * + * NOTE: this code would need surgery to work on 16-bit-int machines + * with ICC profiles exceeding 64K bytes in size. See iccprofile.c + * for details. + */ + +#include <stdio.h> /* needed to define "FILE", "NULL" */ +#include "jpeglib.h" + + +/* + * This routine writes the given ICC profile data into a JPEG file. + * It *must* be called AFTER calling jpeg_start_compress() and BEFORE + * the first call to jpeg_write_scanlines(). + * (This ordering ensures that the APP2 marker(s) will appear after the + * SOI and JFIF or Adobe markers, but before all else.) + */ + +extern void write_icc_profile JPP((j_compress_ptr cinfo, + const JOCTET *icc_data_ptr, + unsigned int icc_data_len)); + + +/* + * Reading a JPEG file that may contain an ICC profile requires two steps: + * + * 1. After jpeg_create_decompress() but before jpeg_read_header(), + * call setup_read_icc_profile(). This routine tells the IJG library + * to save in memory any APP2 markers it may find in the file. + * + * 2. After jpeg_read_header(), call read_icc_profile() to find out + * whether there was a profile and obtain it if so. + */ + + +/* + * Prepare for reading an ICC profile + */ + +extern void setup_read_icc_profile JPP((j_decompress_ptr cinfo)); + + +/* + * See if there was an ICC profile in the JPEG file being read; + * if so, reassemble and return the profile data. + * + * TRUE is returned if an ICC profile was found, FALSE if not. + * If TRUE is returned, *icc_data_ptr is set to point to the + * returned data, and *icc_data_len is set to its length. + * + * IMPORTANT: the data at **icc_data_ptr has been allocated with malloc() + * and must be freed by the caller with free() when the caller no longer + * needs it. (Alternatively, we could write this routine to use the + * IJG library's memory allocator, so that the data would be freed implicitly + * at jpeg_finish_decompress() time. But it seems likely that many apps + * will prefer to have the data stick around after decompression finishes.) + */ + +extern boolean read_icc_profile JPP((j_decompress_ptr cinfo, + JOCTET **icc_data_ptr, + unsigned int *icc_data_len)); |