/** * Uses jpeg library api to write APP01 segment consisting * of JPEG_XMP_SEGMENT_HEADER and metadata associated with * given image. If there is no metadata, or its size exceeds * JPEG_METADATA_LIMIT, then nothing is written. * * @param cinfo * @param decoded_image */ static void writeMetadata( jpeg_compress_struct& cinfo, const DecodedImage& decoded_image) { const unsigned metadata_length = decoded_image.getMetadataLength(); if (metadata_length == 0 || metadata_length > JPEG_METADATA_LIMIT) { return; } jpeg_write_m_header( &cinfo, JPEG_APP0 + 1, JPEG_XMP_SEGMENT_HEADER_LENGTH + metadata_length); auto jpeg_metadata_writer = [&] (int c) { jpeg_write_m_byte(&cinfo, c); }; // Write xmp header std::for_each( JPEG_XMP_SEGMENT_HEADER, JPEG_XMP_SEGMENT_HEADER + JPEG_XMP_SEGMENT_HEADER_LENGTH, jpeg_metadata_writer); // Write xmp data std::for_each( decoded_image.getMetadataPtr(), decoded_image.getMetadataPtr() + metadata_length, jpeg_metadata_writer); }
static void write_icc_profile (j_compress_ptr cinfo, const JOCTET *icc_data_ptr, unsigned int icc_data_len) { unsigned int num_markers; /* total number of markers we'll write */ int cur_marker = 1; /* per spec, counting starts at 1 */ unsigned int length; /* number of bytes to write in this marker */ /* Calculate the number of markers we'll need, rounding up of course */ num_markers = icc_data_len / MAX_DATA_BYTES_IN_MARKER; if (num_markers * MAX_DATA_BYTES_IN_MARKER != icc_data_len) num_markers++; while (icc_data_len > 0) { /* length of profile to put in this marker */ length = icc_data_len; if (length > MAX_DATA_BYTES_IN_MARKER) length = MAX_DATA_BYTES_IN_MARKER; icc_data_len -= length; /* Write the JPEG marker header (APP2 code and marker length) */ jpeg_write_m_header(cinfo, ICC_MARKER, (unsigned int) (length + ICC_OVERHEAD_LEN)); /* Write the marker identifying string "ICC_PROFILE" (null-terminated). * We code it in this less-than-transparent way so that the code works * even if the local character set is not ASCII. */ jpeg_write_m_byte(cinfo, 0x49); jpeg_write_m_byte(cinfo, 0x43); jpeg_write_m_byte(cinfo, 0x43); jpeg_write_m_byte(cinfo, 0x5F); jpeg_write_m_byte(cinfo, 0x50); jpeg_write_m_byte(cinfo, 0x52); jpeg_write_m_byte(cinfo, 0x4F); jpeg_write_m_byte(cinfo, 0x46); jpeg_write_m_byte(cinfo, 0x49); jpeg_write_m_byte(cinfo, 0x4C); jpeg_write_m_byte(cinfo, 0x45); jpeg_write_m_byte(cinfo, 0x0); /* Add the sequencing info */ jpeg_write_m_byte(cinfo, cur_marker); jpeg_write_m_byte(cinfo, (int) num_markers); /* Add the profile data */ while (length--) { jpeg_write_m_byte(cinfo, *icc_data_ptr); icc_data_ptr++; } cur_marker++; } }
static void jcopy_markers_execute(j_decompress_ptr srcinfo, j_compress_ptr dstinfo) { jpeg_saved_marker_ptr marker; /* In the current implementation, we don't actually need to examine the * option flag here; we just copy everything that got saved. * But to avoid confusion, we do not output JFIF and Adobe APP14 markers * if the encoder library already wrote one. */ for (marker = srcinfo->marker_list; marker != NULL; marker = marker->next) { if (dstinfo->write_JFIF_header && marker->marker == JPEG_APP0 && marker->data_length >= 5 && GETJOCTET(marker->data[0]) == 0x4A && GETJOCTET(marker->data[1]) == 0x46 && GETJOCTET(marker->data[2]) == 0x49 && GETJOCTET(marker->data[3]) == 0x46 && GETJOCTET(marker->data[4]) == 0) continue; /* reject duplicate JFIF */ if (dstinfo->write_Adobe_marker && marker->marker == JPEG_APP0+14 && marker->data_length >= 5 && GETJOCTET(marker->data[0]) == 0x41 && GETJOCTET(marker->data[1]) == 0x64 && GETJOCTET(marker->data[2]) == 0x6F && GETJOCTET(marker->data[3]) == 0x62 && GETJOCTET(marker->data[4]) == 0x65) continue; /* reject duplicate Adobe */ #ifdef NEED_FAR_POINTERS /* We could use jpeg_write_marker if the data weren't FAR... */ { unsigned int i; jpeg_write_m_header(dstinfo, marker->marker, marker->data_length); for (i = 0; i < marker->data_length; i++) jpeg_write_m_byte(dstinfo, marker->data[i]); } #else jpeg_write_marker(dstinfo, marker->marker, marker->data, marker->data_length); #endif } }