Leon Scroggins III | 3993b37 | 2018-07-16 10:43:45 -0400 | [diff] [blame] | 1 | /* |
| 2 | * jcicc.c |
| 3 | * |
| 4 | * Copyright (C) 1997-1998, Thomas G. Lane, Todd Newman. |
| 5 | * Copyright (C) 2017, D. R. Commander. |
| 6 | * For conditions of distribution and use, see the accompanying README.ijg |
| 7 | * file. |
| 8 | * |
| 9 | * This file provides code to write International Color Consortium (ICC) device |
| 10 | * profiles embedded in JFIF JPEG image files. The ICC has defined a standard |
| 11 | * for including such data in JPEG "APP2" markers. The code given here does |
| 12 | * not know anything about the internal structure of the ICC profile data; it |
| 13 | * just knows how to embed the profile data in a JPEG file while writing it. |
| 14 | */ |
| 15 | |
| 16 | #define JPEG_INTERNALS |
| 17 | #include "jinclude.h" |
| 18 | #include "jpeglib.h" |
| 19 | #include "jerror.h" |
| 20 | |
| 21 | |
| 22 | /* |
| 23 | * Since an ICC profile can be larger than the maximum size of a JPEG marker |
| 24 | * (64K), we need provisions to split it into multiple markers. The format |
| 25 | * defined by the ICC specifies one or more APP2 markers containing the |
| 26 | * following data: |
| 27 | * Identifying string ASCII "ICC_PROFILE\0" (12 bytes) |
| 28 | * Marker sequence number 1 for first APP2, 2 for next, etc (1 byte) |
| 29 | * Number of markers Total number of APP2's used (1 byte) |
| 30 | * Profile data (remainder of APP2 data) |
| 31 | * Decoders should use the marker sequence numbers to reassemble the profile, |
| 32 | * rather than assuming that the APP2 markers appear in the correct sequence. |
| 33 | */ |
| 34 | |
| 35 | #define ICC_MARKER (JPEG_APP0 + 2) /* JPEG marker code for ICC */ |
| 36 | #define ICC_OVERHEAD_LEN 14 /* size of non-profile data in APP2 */ |
| 37 | #define MAX_BYTES_IN_MARKER 65533 /* maximum data len of a JPEG marker */ |
| 38 | #define MAX_DATA_BYTES_IN_MARKER (MAX_BYTES_IN_MARKER - ICC_OVERHEAD_LEN) |
| 39 | |
| 40 | |
| 41 | /* |
| 42 | * This routine writes the given ICC profile data into a JPEG file. It *must* |
| 43 | * be called AFTER calling jpeg_start_compress() and BEFORE the first call to |
| 44 | * jpeg_write_scanlines(). (This ordering ensures that the APP2 marker(s) will |
| 45 | * appear after the SOI and JFIF or Adobe markers, but before all else.) |
| 46 | */ |
| 47 | |
| 48 | GLOBAL(void) |
| 49 | jpeg_write_icc_profile(j_compress_ptr cinfo, const JOCTET *icc_data_ptr, |
| 50 | unsigned int icc_data_len) |
| 51 | { |
| 52 | unsigned int num_markers; /* total number of markers we'll write */ |
| 53 | int cur_marker = 1; /* per spec, counting starts at 1 */ |
| 54 | unsigned int length; /* number of bytes to write in this marker */ |
| 55 | |
| 56 | if (icc_data_ptr == NULL || icc_data_len == 0) |
| 57 | ERREXIT(cinfo, JERR_BUFFER_SIZE); |
| 58 | if (cinfo->global_state < CSTATE_SCANNING) |
| 59 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 60 | |
| 61 | /* Calculate the number of markers we'll need, rounding up of course */ |
| 62 | num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER; |
| 63 | if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len) |
| 64 | num_markers++; |
| 65 | |
| 66 | while (icc_data_len > 0) { |
| 67 | /* length of profile to put in this marker */ |
| 68 | length = icc_data_len; |
| 69 | if (length > MAX_DATA_BYTES_IN_MARKER) |
| 70 | length = MAX_DATA_BYTES_IN_MARKER; |
| 71 | icc_data_len -= length; |
| 72 | |
| 73 | /* Write the JPEG marker header (APP2 code and marker length) */ |
| 74 | jpeg_write_m_header(cinfo, ICC_MARKER, |
| 75 | (unsigned int)(length + ICC_OVERHEAD_LEN)); |
| 76 | |
| 77 | /* Write the marker identifying string "ICC_PROFILE" (null-terminated). We |
| 78 | * code it in this less-than-transparent way so that the code works even if |
| 79 | * the local character set is not ASCII. |
| 80 | */ |
| 81 | jpeg_write_m_byte(cinfo, 0x49); |
| 82 | jpeg_write_m_byte(cinfo, 0x43); |
| 83 | jpeg_write_m_byte(cinfo, 0x43); |
| 84 | jpeg_write_m_byte(cinfo, 0x5F); |
| 85 | jpeg_write_m_byte(cinfo, 0x50); |
| 86 | jpeg_write_m_byte(cinfo, 0x52); |
| 87 | jpeg_write_m_byte(cinfo, 0x4F); |
| 88 | jpeg_write_m_byte(cinfo, 0x46); |
| 89 | jpeg_write_m_byte(cinfo, 0x49); |
| 90 | jpeg_write_m_byte(cinfo, 0x4C); |
| 91 | jpeg_write_m_byte(cinfo, 0x45); |
| 92 | jpeg_write_m_byte(cinfo, 0x0); |
| 93 | |
| 94 | /* Add the sequencing info */ |
| 95 | jpeg_write_m_byte(cinfo, cur_marker); |
| 96 | jpeg_write_m_byte(cinfo, (int)num_markers); |
| 97 | |
| 98 | /* Add the profile data */ |
| 99 | while (length--) { |
| 100 | jpeg_write_m_byte(cinfo, *icc_data_ptr); |
| 101 | icc_data_ptr++; |
| 102 | } |
| 103 | cur_marker++; |
| 104 | } |
| 105 | } |