44b2399a94
This commit does the following: -- Merges the two glueware functions (read_icc_profile() and write_icc_profile()) from iccjpeg.c, which is contained in downstream projects such as LCMS, Ghostscript, Mozilla, etc. These functions were originally intended for inclusion in libjpeg, but Tom Lane left the IJG before that could be accomplished. Since then, programs and libraries that needed to embed/extract ICC profiles in JPEG files had to include their own local copy of iccjpeg.c, which is suboptimal. -- The new functions were prefixed with jpeg_ and split into separate files for the compressor and decompressor, per the existing libjpeg coding standards. -- jpeg_write_icc_profile() was made slightly more fault-tolerant. It will now trigger a libjpeg error if it is called before jpeg_start_compress() or if it is passed NULL arguments. -- jpeg_read_icc_profile() was made slightly more fault-tolerant. It will now trigger a libjpeg error if it is called before jpeg_read_header() or if it is passed NULL arguments. It will also now trigger libjpeg warnings if the ICC profile data is corrupt. -- The code comments have been wordsmithed. -- Note that the one-line setup_read_icc_profile() function was not included. Instead, libjpeg.txt now documents the need to call jpeg_save_markers(cinfo, JPEG_APP0 + 2, 0xFFFF) prior to calling jpeg_read_header(), if jpeg_read_icc_profile() is to be used. -- Adds documentation for the new functions to libjpeg.txt. -- Adds an -icc switch to cjpeg and jpegtran that allows those programs to embed an ICC profile in the JPEG files they generate. -- Adds an -icc switch to djpeg that allows that program to extract an ICC profile from a JPEG file while decompressing. -- Adds appropriate unit tests for all of the above. -- Bumps the SO_AGE of the libjpeg API library to indicate the presence of new API functions. Note that the licensing information was obtained from: https://github.com/mm2/Little-CMS/issues/37#issuecomment-66450180
106 lines
4.0 KiB
C
106 lines
4.0 KiB
C
/*
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* jcicc.c
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*
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* Copyright (C) 1997-1998, Thomas G. Lane, Todd Newman.
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* Copyright (C) 2017, D. R. Commander.
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* For conditions of distribution and use, see the accompanying README.ijg
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* file.
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*
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* This file provides code to write International Color Consortium (ICC) device
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* profiles embedded in JFIF JPEG image files. The ICC has defined a standard
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* for including such data in JPEG "APP2" markers. The code given here does
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* not know anything about the internal structure of the ICC profile data; it
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* just knows how to embed the profile data in a JPEG file while writing it.
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*/
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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#include "jerror.h"
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/*
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* Since an ICC profile can be larger than the maximum size of a JPEG marker
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* (64K), we need provisions to split it into multiple markers. The format
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* defined by the ICC specifies one or more APP2 markers containing the
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* following data:
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* Identifying string ASCII "ICC_PROFILE\0" (12 bytes)
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* Marker sequence number 1 for first APP2, 2 for next, etc (1 byte)
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* Number of markers Total number of APP2's used (1 byte)
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* Profile data (remainder of APP2 data)
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* Decoders should use the marker sequence numbers to reassemble the profile,
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* rather than assuming that the APP2 markers appear in the correct sequence.
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*/
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#define ICC_MARKER (JPEG_APP0 + 2) /* JPEG marker code for ICC */
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#define ICC_OVERHEAD_LEN 14 /* size of non-profile data in APP2 */
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#define MAX_BYTES_IN_MARKER 65533 /* maximum data len of a JPEG marker */
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#define MAX_DATA_BYTES_IN_MARKER (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN)
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/*
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* This routine writes the given ICC profile data into a JPEG file. It *must*
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* be called AFTER calling jpeg_start_compress() and BEFORE the first call to
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* jpeg_write_scanlines(). (This ordering ensures that the APP2 marker(s) will
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* appear after the SOI and JFIF or Adobe markers, but before all else.)
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*/
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GLOBAL(void)
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jpeg_write_icc_profile (j_compress_ptr cinfo, const JOCTET *icc_data_ptr,
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unsigned int icc_data_len)
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{
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unsigned int num_markers; /* total number of markers we'll write */
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int cur_marker = 1; /* per spec, counting starts at 1 */
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unsigned int length; /* number of bytes to write in this marker */
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if (icc_data_ptr == NULL || icc_data_len == 0)
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ERREXIT(cinfo, JERR_BUFFER_SIZE);
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if (cinfo->global_state < CSTATE_SCANNING)
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ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state);
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/* Calculate the number of markers we'll need, rounding up of course */
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num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER;
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if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len)
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num_markers++;
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while (icc_data_len > 0) {
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/* length of profile to put in this marker */
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length = icc_data_len;
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if (length > MAX_DATA_BYTES_IN_MARKER)
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length = MAX_DATA_BYTES_IN_MARKER;
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icc_data_len -= length;
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/* Write the JPEG marker header (APP2 code and marker length) */
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jpeg_write_m_header(cinfo, ICC_MARKER,
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(unsigned int) (length + ICC_OVERHEAD_LEN));
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/* Write the marker identifying string "ICC_PROFILE" (null-terminated). We
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* code it in this less-than-transparent way so that the code works even if
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* the local character set is not ASCII.
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*/
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jpeg_write_m_byte(cinfo, 0x49);
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jpeg_write_m_byte(cinfo, 0x43);
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jpeg_write_m_byte(cinfo, 0x43);
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jpeg_write_m_byte(cinfo, 0x5F);
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jpeg_write_m_byte(cinfo, 0x50);
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jpeg_write_m_byte(cinfo, 0x52);
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jpeg_write_m_byte(cinfo, 0x4F);
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jpeg_write_m_byte(cinfo, 0x46);
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jpeg_write_m_byte(cinfo, 0x49);
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jpeg_write_m_byte(cinfo, 0x4C);
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jpeg_write_m_byte(cinfo, 0x45);
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jpeg_write_m_byte(cinfo, 0x0);
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/* Add the sequencing info */
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jpeg_write_m_byte(cinfo, cur_marker);
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jpeg_write_m_byte(cinfo, (int) num_markers);
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/* Add the profile data */
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while (length--) {
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jpeg_write_m_byte(cinfo, *icc_data_ptr);
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icc_data_ptr++;
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}
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cur_marker++;
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}
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}
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