| // Copyright 2020 Joe Drago. All rights reserved. |
| // SPDX-License-Identifier: BSD-2-Clause |
| |
| #include "avifpng.h" |
| #include "avifexif.h" |
| #include "avifutil.h" |
| #include "iccmaker.h" |
| |
| #include "png.h" |
| |
| #include <ctype.h> |
| #include <limits.h> |
| #include <stdint.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| |
| #if !defined(PNG_eXIf_SUPPORTED) || !defined(PNG_iTXt_SUPPORTED) |
| #error "libpng 1.6.32 or above with PNG_eXIf_SUPPORTED and PNG_iTXt_SUPPORTED is required." |
| #endif |
| |
| //------------------------------------------------------------------------------ |
| // Reading |
| |
| // Converts a hexadecimal string which contains 2-byte character representations of hexadecimal values to raw data (bytes). |
| // hexString may contain values consisting of [A-F][a-f][0-9] in pairs, e.g., 7af2..., separated by any number of newlines. |
| // On success the bytes are filled and AVIF_TRUE is returned. |
| // AVIF_FALSE is returned if fewer than numExpectedBytes hexadecimal pairs are converted. |
| static avifBool avifHexStringToBytes(const char * hexString, size_t hexStringLength, size_t numExpectedBytes, avifRWData * bytes) |
| { |
| if (avifRWDataRealloc(bytes, numExpectedBytes) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Metadata extraction failed: out of memory\n"); |
| return AVIF_FALSE; |
| } |
| size_t numBytes = 0; |
| for (size_t i = 0; (i + 1 < hexStringLength) && (numBytes < numExpectedBytes);) { |
| if (hexString[i] == '\n') { |
| ++i; |
| continue; |
| } |
| if (!isxdigit(hexString[i]) || !isxdigit(hexString[i + 1])) { |
| avifRWDataFree(bytes); |
| fprintf(stderr, "Metadata extraction failed: invalid character at %" AVIF_FMT_ZU "\n", i); |
| return AVIF_FALSE; |
| } |
| const char twoHexDigits[] = { hexString[i], hexString[i + 1], '\0' }; |
| bytes->data[numBytes] = (uint8_t)strtol(twoHexDigits, NULL, 16); |
| ++numBytes; |
| i += 2; |
| } |
| |
| if (numBytes != numExpectedBytes) { |
| avifRWDataFree(bytes); |
| fprintf(stderr, "Metadata extraction failed: expected %" AVIF_FMT_ZU " tokens but got %" AVIF_FMT_ZU "\n", numExpectedBytes, numBytes); |
| return AVIF_FALSE; |
| } |
| return AVIF_TRUE; |
| } |
| |
| // Parses the raw profile string of profileLength characters and extracts the payload. |
| static avifBool avifCopyRawProfile(const char * profile, size_t profileLength, avifRWData * payload) |
| { |
| // ImageMagick formats 'raw profiles' as "\n<name>\n<length>(%8lu)\n<hex payload>\n". |
| if (!profile || (profileLength == 0) || (profile[0] != '\n')) { |
| fprintf(stderr, "Metadata extraction failed: truncated or malformed raw profile\n"); |
| return AVIF_FALSE; |
| } |
| |
| const char * lengthStart = NULL; |
| for (size_t i = 1; i < profileLength; ++i) { // i starts at 1 because the first '\n' was already checked above. |
| if (profile[i] == '\0') { |
| // This should not happen as libpng provides this guarantee but extra safety does not hurt. |
| fprintf(stderr, "Metadata extraction failed: malformed raw profile, unexpected null character at %" AVIF_FMT_ZU "\n", i); |
| return AVIF_FALSE; |
| } |
| if (profile[i] == '\n') { |
| if (!lengthStart) { |
| // Skip the name and store the beginning of the string containing the length of the payload. |
| lengthStart = &profile[i + 1]; |
| } else { |
| const char * hexPayloadStart = &profile[i + 1]; |
| const size_t hexPayloadMaxLength = profileLength - (i + 1); |
| // Parse the length, now that we are sure that it is surrounded by '\n' within the profileLength characters. |
| char * lengthEnd; |
| const long expectedLength = strtol(lengthStart, &lengthEnd, 10); |
| if (lengthEnd != &profile[i]) { |
| fprintf(stderr, "Metadata extraction failed: malformed raw profile, expected '\\n' but got '\\x%.2X'\n", *lengthEnd); |
| return AVIF_FALSE; |
| } |
| // No need to check for errno. Just make sure expectedLength is not LONG_MIN and not LONG_MAX. |
| if ((expectedLength <= 0) || (expectedLength == LONG_MAX) || |
| ((unsigned long)expectedLength > (hexPayloadMaxLength / 2))) { |
| fprintf(stderr, "Metadata extraction failed: invalid length %ld\n", expectedLength); |
| return AVIF_FALSE; |
| } |
| // Note: The profile may be malformed by containing more data than the extracted expectedLength bytes. |
| // Be lenient about it and consider it as a valid payload. |
| return avifHexStringToBytes(hexPayloadStart, hexPayloadMaxLength, (size_t)expectedLength, payload); |
| } |
| } |
| } |
| fprintf(stderr, "Metadata extraction failed: malformed or truncated raw profile\n"); |
| return AVIF_FALSE; |
| } |
| |
| static avifBool avifRemoveHeader(const avifROData * header, avifRWData * payload) |
| { |
| if (payload->size > header->size && !memcmp(payload->data, header->data, header->size)) { |
| memmove(payload->data, payload->data + header->size, payload->size - header->size); |
| payload->size -= header->size; |
| return AVIF_TRUE; |
| } |
| return AVIF_FALSE; |
| } |
| |
| // Extracts metadata to avif->exif and avif->xmp unless the corresponding *ignoreExif or *ignoreXMP is set to AVIF_TRUE. |
| // *ignoreExif and *ignoreXMP may be set to AVIF_TRUE if the corresponding Exif or XMP metadata was extracted. |
| // Returns AVIF_FALSE in case of a parsing error. |
| static avifBool avifExtractExifAndXMP(png_structp png, png_infop info, avifBool * ignoreExif, avifBool * ignoreXMP, avifImage * avif) |
| { |
| if (!*ignoreExif) { |
| png_uint_32 exifSize = 0; |
| png_bytep exif = NULL; |
| if (png_get_eXIf_1(png, info, &exifSize, &exif) == PNG_INFO_eXIf) { |
| if ((exifSize == 0) || !exif) { |
| fprintf(stderr, "Exif extraction failed: empty eXIf chunk\n"); |
| return AVIF_FALSE; |
| } |
| // Avoid avifImageSetMetadataExif() that sets irot/imir. |
| if (avifRWDataSet(&avif->exif, exif, exifSize) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Exif extraction failed: out of memory\n"); |
| return AVIF_FALSE; |
| } |
| // According to the Extensions to the PNG 1.2 Specification, Version 1.5.0, section 3.7: |
| // "It is recommended that unless a decoder has independent knowledge of the validity of the Exif data, |
| // the data should be considered to be of historical value only." |
| // Try to remove any Exif orientation data to be safe. |
| // It is easier to set it to 1 (the default top-left) than actually removing the tag. |
| // libheif has the same behavior, see |
| // https://github.com/strukturag/libheif/blob/18291ddebc23c924440a8a3c9a7267fe3beb5901/examples/heif_enc.cc#L703 |
| // Ignore errors because not being able to set Exif orientation now means it cannot be parsed later either. |
| (void)avifSetExifOrientation(&avif->exif, 1); |
| *ignoreExif = AVIF_TRUE; // Ignore any other Exif chunk. |
| } |
| } |
| |
| // HEIF specification ISO-23008 section A.2.1 allows including and excluding the Exif\0\0 header from AVIF files. |
| // The PNG 1.5 extension mentions the omission of this header for the modern standard eXIf chunk. |
| const avifROData exifApp1Header = { (const uint8_t *)"Exif\0\0", 6 }; |
| const avifROData xmpApp1Header = { (const uint8_t *)"http://ns.adobe.com/xap/1.0/\0", 29 }; |
| |
| // tXMP could be retrieved using the png_get_unknown_chunks() API but tXMP is deprecated |
| // and there is no PNG file example with a tXMP chunk lying around, so it is not worth the hassle. |
| |
| png_textp text = NULL; |
| const png_uint_32 numTextChunks = png_get_text(png, info, &text, NULL); |
| for (png_uint_32 i = 0; (!*ignoreExif || !*ignoreXMP) && (i < numTextChunks); ++i, ++text) { |
| png_size_t textLength = text->text_length; |
| if ((text->compression == PNG_ITXT_COMPRESSION_NONE) || (text->compression == PNG_ITXT_COMPRESSION_zTXt)) { |
| textLength = text->itxt_length; |
| } |
| |
| if (!*ignoreExif && !strcmp(text->key, "Raw profile type exif")) { |
| if (!avifCopyRawProfile(text->text, textLength, &avif->exif)) { |
| return AVIF_FALSE; |
| } |
| avifRemoveHeader(&exifApp1Header, &avif->exif); // Ignore the return value because the header is optional. |
| (void)avifSetExifOrientation(&avif->exif, 1); // See above. |
| *ignoreExif = AVIF_TRUE; // Ignore any other Exif chunk. |
| } else if (!*ignoreXMP && !strcmp(text->key, "Raw profile type xmp")) { |
| if (!avifCopyRawProfile(text->text, textLength, &avif->xmp)) { |
| return AVIF_FALSE; |
| } |
| avifRemoveHeader(&xmpApp1Header, &avif->xmp); // Ignore the return value because the header is optional. |
| *ignoreXMP = AVIF_TRUE; // Ignore any other XMP chunk. |
| } else if (!strcmp(text->key, "Raw profile type APP1")) { |
| // This can be either Exif, XMP or something else. |
| avifRWData metadata = { NULL, 0 }; |
| if (!avifCopyRawProfile(text->text, textLength, &metadata)) { |
| return AVIF_FALSE; |
| } |
| if (!*ignoreExif && avifRemoveHeader(&exifApp1Header, &metadata)) { |
| avifRWDataFree(&avif->exif); |
| avif->exif = metadata; |
| (void)avifSetExifOrientation(&avif->exif, 1); // See above. |
| *ignoreExif = AVIF_TRUE; // Ignore any other Exif chunk. |
| } else if (!*ignoreXMP && avifRemoveHeader(&xmpApp1Header, &metadata)) { |
| avifRWDataFree(&avif->xmp); |
| avif->xmp = metadata; |
| *ignoreXMP = AVIF_TRUE; // Ignore any other XMP chunk. |
| } else { |
| avifRWDataFree(&metadata); // Discard chunk. |
| } |
| } else if (!*ignoreXMP && !strcmp(text->key, "XML:com.adobe.xmp")) { |
| if (textLength == 0) { |
| fprintf(stderr, "XMP extraction failed: empty XML:com.adobe.xmp payload\n"); |
| return AVIF_FALSE; |
| } |
| if (avifImageSetMetadataXMP(avif, (const uint8_t *)text->text, textLength) != AVIF_RESULT_OK) { |
| fprintf(stderr, "XMP extraction failed: out of memory\n"); |
| return AVIF_FALSE; |
| } |
| *ignoreXMP = AVIF_TRUE; // Ignore any other XMP chunk. |
| } |
| } |
| // The iTXt XMP payload may not contain a zero byte according to section 4.2.3.3 of |
| // the PNG specification, version 1.2. Still remove one trailing null character if any, |
| // in case libpng does not strictly enforce that at decoding. |
| avifImageFixXMP(avif); |
| return AVIF_TRUE; |
| } |
| |
| // Note on setjmp() and volatile variables: |
| // |
| // K & R, The C Programming Language 2nd Ed, p. 254 says: |
| // ... Accessible objects have the values they had when longjmp was called, |
| // except that non-volatile automatic variables in the function calling setjmp |
| // become undefined if they were changed after the setjmp call. |
| // |
| // Therefore, 'rowPointers' is declared as volatile. 'rgb' should be declared as |
| // volatile, but doing so would be inconvenient (try it) and since it is a |
| // struct, the compiler is unlikely to put it in a register. 'readResult' and |
| // 'writeResult' do not need to be declared as volatile because they are not |
| // modified between setjmp and longjmp. But GCC's -Wclobbered warning may have |
| // trouble figuring that out, so we preemptively declare them as volatile. |
| |
| avifBool avifPNGRead(const char * inputFilename, |
| avifImage * avif, |
| avifPixelFormat requestedFormat, |
| uint32_t requestedDepth, |
| avifChromaDownsampling chromaDownsampling, |
| avifBool ignoreColorProfile, |
| avifBool ignoreExif, |
| avifBool ignoreXMP, |
| avifBool allowChangingCicp, |
| uint32_t imageSizeLimit, |
| uint32_t * outPNGDepth) |
| { |
| volatile avifBool readResult = AVIF_FALSE; |
| png_structp png = NULL; |
| png_infop info = NULL; |
| png_bytep * volatile rowPointers = NULL; |
| |
| avifRGBImage rgb; |
| memset(&rgb, 0, sizeof(avifRGBImage)); |
| |
| FILE * f = fopen(inputFilename, "rb"); |
| if (!f) { |
| fprintf(stderr, "Can't open PNG file for read: %s\n", inputFilename); |
| goto cleanup; |
| } |
| |
| uint8_t header[8]; |
| size_t bytesRead = fread(header, 1, 8, f); |
| if (bytesRead != 8) { |
| fprintf(stderr, "Can't read PNG header: %s\n", inputFilename); |
| goto cleanup; |
| } |
| if (png_sig_cmp(header, 0, 8)) { |
| fprintf(stderr, "Not a PNG: %s\n", inputFilename); |
| goto cleanup; |
| } |
| |
| png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); |
| if (!png) { |
| fprintf(stderr, "Cannot init libpng (png): %s\n", inputFilename); |
| goto cleanup; |
| } |
| info = png_create_info_struct(png); |
| if (!info) { |
| fprintf(stderr, "Cannot init libpng (info): %s\n", inputFilename); |
| goto cleanup; |
| } |
| |
| if (setjmp(png_jmpbuf(png))) { |
| fprintf(stderr, "Error reading PNG: %s\n", inputFilename); |
| goto cleanup; |
| } |
| |
| png_init_io(png, f); |
| png_set_sig_bytes(png, 8); |
| png_read_info(png, info); |
| |
| int rawWidth = png_get_image_width(png, info); |
| int rawHeight = png_get_image_height(png, info); |
| png_byte rawColorType = png_get_color_type(png, info); |
| png_byte rawBitDepth = png_get_bit_depth(png, info); |
| |
| if (rawColorType == PNG_COLOR_TYPE_PALETTE) { |
| png_set_palette_to_rgb(png); |
| } |
| |
| if ((rawColorType == PNG_COLOR_TYPE_GRAY) && (rawBitDepth < 8)) { |
| png_set_expand_gray_1_2_4_to_8(png); |
| } |
| |
| if (png_get_valid(png, info, PNG_INFO_tRNS)) { |
| png_set_tRNS_to_alpha(png); |
| } |
| |
| if ((rawColorType == PNG_COLOR_TYPE_GRAY) || (rawColorType == PNG_COLOR_TYPE_GRAY_ALPHA)) { |
| png_set_gray_to_rgb(png); |
| } |
| |
| int imgBitDepth = 8; |
| if (rawBitDepth == 16) { |
| png_set_swap(png); |
| imgBitDepth = 16; |
| } |
| |
| if (outPNGDepth) { |
| *outPNGDepth = imgBitDepth; |
| } |
| |
| png_read_update_info(png, info); |
| |
| avif->width = rawWidth; |
| avif->height = rawHeight; |
| avif->yuvFormat = requestedFormat; |
| #if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R) |
| if (avif->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RO) { |
| fprintf(stderr, "AVIF_MATRIX_COEFFICIENTS_YCGCO_RO cannot be used with PNG because it has an even bit depth.\n"); |
| goto cleanup; |
| } |
| const avifBool useYCgCoR = (avif->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RE); |
| #endif |
| if (avif->yuvFormat == AVIF_PIXEL_FORMAT_NONE) { |
| if ((rawColorType == PNG_COLOR_TYPE_GRAY) || (rawColorType == PNG_COLOR_TYPE_GRAY_ALPHA)) { |
| avif->yuvFormat = AVIF_PIXEL_FORMAT_YUV400; |
| } else if (avif->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_IDENTITY |
| #if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R) |
| || useYCgCoR |
| #endif |
| ) { |
| // Identity and YCgCo-R are only valid with YUV444. |
| avif->yuvFormat = AVIF_PIXEL_FORMAT_YUV444; |
| } else { |
| avif->yuvFormat = AVIF_APP_DEFAULT_PIXEL_FORMAT; |
| } |
| } |
| avif->depth = requestedDepth; |
| if (avif->depth == 0) { |
| if (imgBitDepth == 8) { |
| avif->depth = 8; |
| } else { |
| avif->depth = 12; |
| } |
| } |
| #if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R) |
| if (useYCgCoR) { |
| if (imgBitDepth != 8) { |
| fprintf(stderr, "AVIF_MATRIX_COEFFICIENTS_YCGCO_RE cannot be used on 16 bit input because it adds two bits.\n"); |
| goto cleanup; |
| } |
| if (requestedDepth && requestedDepth != 10) { |
| fprintf(stderr, "Cannot request %u bits for YCgCo-Re as it uses 2 extra bits.\n", requestedDepth); |
| goto cleanup; |
| } |
| avif->depth = 10; |
| } |
| #endif |
| |
| if (!ignoreColorProfile) { |
| char * iccpProfileName = NULL; |
| int iccpCompression = 0; |
| unsigned char * iccpData = NULL; |
| png_uint_32 iccpDataLen = 0; |
| int srgbIntent; |
| |
| // PNG specification 1.2 Section 4.2.2: |
| // The sRGB and iCCP chunks should not both appear. |
| // |
| // When the sRGB / iCCP chunk is present, applications that recognize it and are capable of color management |
| // must ignore the gAMA and cHRM chunks and use the sRGB / iCCP chunk instead. |
| if (png_get_iCCP(png, info, &iccpProfileName, &iccpCompression, &iccpData, &iccpDataLen) == PNG_INFO_iCCP) { |
| if (avifImageSetProfileICC(avif, iccpData, iccpDataLen) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Setting ICC profile failed: out of memory.\n"); |
| goto cleanup; |
| } |
| } else if (allowChangingCicp) { |
| if (png_get_sRGB(png, info, &srgbIntent) == PNG_INFO_sRGB) { |
| // srgbIntent ignored |
| avif->colorPrimaries = AVIF_COLOR_PRIMARIES_SRGB; |
| avif->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_SRGB; |
| } else { |
| avifBool needToGenerateICC = AVIF_FALSE; |
| double gamma; |
| double wX, wY, rX, rY, gX, gY, bX, bY; |
| float primaries[8]; |
| if (png_get_gAMA(png, info, &gamma) == PNG_INFO_gAMA) { |
| gamma = 1.0 / gamma; |
| avif->transferCharacteristics = avifTransferCharacteristicsFindByGamma((float)gamma); |
| if (avif->transferCharacteristics == AVIF_TRANSFER_CHARACTERISTICS_UNKNOWN) { |
| needToGenerateICC = AVIF_TRUE; |
| } |
| } else { |
| // No gamma information in file. Assume the default value. |
| // PNG specification 1.2 Section 10.5: |
| // Assume a CRT exponent of 2.2 unless detailed calibration measurements |
| // of this particular CRT are available. |
| gamma = 2.2; |
| } |
| |
| if (png_get_cHRM(png, info, &wX, &wY, &rX, &rY, &gX, &gY, &bX, &bY) == PNG_INFO_cHRM) { |
| primaries[0] = (float)rX; |
| primaries[1] = (float)rY; |
| primaries[2] = (float)gX; |
| primaries[3] = (float)gY; |
| primaries[4] = (float)bX; |
| primaries[5] = (float)bY; |
| primaries[6] = (float)wX; |
| primaries[7] = (float)wY; |
| avif->colorPrimaries = avifColorPrimariesFind(primaries, NULL); |
| if (avif->colorPrimaries == AVIF_COLOR_PRIMARIES_UNKNOWN) { |
| needToGenerateICC = AVIF_TRUE; |
| } |
| } else { |
| // No chromaticity information in file. Assume the default value. |
| // PNG specification 1.2 Section 10.6: |
| // Decoders may wish to do this for PNG files with no cHRM chunk. |
| // In that case, a reasonable default would be the CCIR 709 primaries [ITU-R-BT709]. |
| avifColorPrimariesGetValues(AVIF_COLOR_PRIMARIES_BT709, primaries); |
| } |
| |
| if (needToGenerateICC) { |
| avif->colorPrimaries = AVIF_COLOR_PRIMARIES_UNSPECIFIED; |
| avif->transferCharacteristics = AVIF_TRANSFER_CHARACTERISTICS_UNSPECIFIED; |
| fprintf(stderr, |
| "INFO: legacy PNG color space information found in file %s not matching any CICP value. libavif is generating an ICC profile for it." |
| " Use --ignore-profile to ignore color space information instead (may affect the colors of the encoded AVIF image).\n", |
| inputFilename); |
| |
| avifBool generateICCResult = AVIF_FALSE; |
| if (avif->yuvFormat == AVIF_PIXEL_FORMAT_YUV400) { |
| generateICCResult = avifGenerateGrayICC(&avif->icc, (float)gamma, &primaries[6]); |
| } else { |
| generateICCResult = avifGenerateRGBICC(&avif->icc, (float)gamma, primaries); |
| } |
| |
| if (!generateICCResult) { |
| fprintf(stderr, |
| "WARNING: libavif could not generate an ICC profile for file %s. " |
| "It may be caused by invalid values in the color space information. " |
| "The encoded AVIF image's colors may be affected.\n", |
| inputFilename); |
| } |
| } |
| } |
| } |
| // Note: There is no support for the rare "Raw profile type icc" or "Raw profile type icm" text chunks. |
| // TODO(yguyon): Also check if there is a cICp chunk (https://github.com/AOMediaCodec/libavif/pull/1065#discussion_r958534232) |
| } |
| |
| const int numChannels = png_get_channels(png, info); |
| if ((numChannels != 3) && (numChannels != 4)) { |
| fprintf(stderr, "png_get_channels() should return 3 or 4 but returns %d.\n", numChannels); |
| goto cleanup; |
| } |
| if (avif->width > imageSizeLimit / avif->height) { |
| fprintf(stderr, "Too big PNG dimensions (%d x %d > %u px): %s\n", avif->width, avif->height, imageSizeLimit, inputFilename); |
| goto cleanup; |
| } |
| |
| avifRGBImageSetDefaults(&rgb, avif); |
| rgb.chromaDownsampling = chromaDownsampling; |
| rgb.depth = imgBitDepth; |
| if (numChannels == 3) { |
| rgb.format = AVIF_RGB_FORMAT_RGB; |
| } |
| if (avifRGBImageAllocatePixels(&rgb) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Conversion to YUV failed: %s (out of memory)\n", inputFilename); |
| goto cleanup; |
| } |
| // png_read_image() receives the row pointers but not the row buffer size. Verify the row |
| // buffer size is exactly what libpng expects. If they are different, we have a bug and should |
| // not proceed. |
| const size_t rowBytes = png_get_rowbytes(png, info); |
| if (rgb.rowBytes != rowBytes) { |
| fprintf(stderr, "avifPNGRead internal error: rowBytes mismatch libavif %u vs libpng %" AVIF_FMT_ZU "\n", rgb.rowBytes, rowBytes); |
| goto cleanup; |
| } |
| rowPointers = (png_bytep *)malloc(sizeof(png_bytep) * rgb.height); |
| if (rowPointers == NULL) { |
| fprintf(stderr, "avifPNGRead internal error: memory allocation failure"); |
| goto cleanup; |
| } |
| for (uint32_t y = 0; y < rgb.height; ++y) { |
| rowPointers[y] = &rgb.pixels[y * rgb.rowBytes]; |
| } |
| png_read_image(png, rowPointers); |
| if (avifImageRGBToYUV(avif, &rgb) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Conversion to YUV failed: %s\n", inputFilename); |
| goto cleanup; |
| } |
| |
| // Read Exif metadata at the beginning of the file. |
| if (!avifExtractExifAndXMP(png, info, &ignoreExif, &ignoreXMP, avif)) { |
| goto cleanup; |
| } |
| // Read Exif or XMP metadata at the end of the file if there was none at the beginning. |
| if (!ignoreExif || !ignoreXMP) { |
| png_read_end(png, info); |
| if (!avifExtractExifAndXMP(png, info, &ignoreExif, &ignoreXMP, avif)) { |
| goto cleanup; |
| } |
| } |
| readResult = AVIF_TRUE; |
| |
| cleanup: |
| if (f) { |
| fclose(f); |
| } |
| if (png) { |
| png_destroy_read_struct(&png, &info, NULL); |
| } |
| if (rowPointers) { |
| free(rowPointers); |
| } |
| avifRGBImageFreePixels(&rgb); |
| return readResult; |
| } |
| |
| //------------------------------------------------------------------------------ |
| // Writing |
| |
| avifBool avifPNGWrite(const char * outputFilename, const avifImage * avif, uint32_t requestedDepth, avifChromaUpsampling chromaUpsampling, int compressionLevel) |
| { |
| volatile avifBool writeResult = AVIF_FALSE; |
| png_structp png = NULL; |
| png_infop info = NULL; |
| avifRWData xmp = { NULL, 0 }; |
| png_bytep * volatile rowPointers = NULL; |
| FILE * volatile f = NULL; |
| |
| avifRGBImage rgb; |
| memset(&rgb, 0, sizeof(avifRGBImage)); |
| |
| volatile int rgbDepth = requestedDepth; |
| if (rgbDepth == 0) { |
| rgbDepth = (avif->depth > 8) ? 16 : 8; |
| } |
| #if defined(AVIF_ENABLE_EXPERIMENTAL_YCGCO_R) |
| if (avif->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RO) { |
| fprintf(stderr, "AVIF_MATRIX_COEFFICIENTS_YCGCO_RO cannot be used with PNG because it has an even bit depth.\n"); |
| goto cleanup; |
| } |
| if (avif->matrixCoefficients == AVIF_MATRIX_COEFFICIENTS_YCGCO_RE) { |
| if (avif->depth != 10) { |
| fprintf(stderr, "avif->depth must be 10 bits and not %u.\n", avif->depth); |
| goto cleanup; |
| } |
| if (requestedDepth && requestedDepth != 8) { |
| fprintf(stderr, "Cannot request %u bits for YCgCo-Re as it only works for 8 bits.\n", requestedDepth); |
| goto cleanup; |
| } |
| |
| rgbDepth = 8; |
| } |
| #endif |
| |
| volatile avifBool monochrome8bit = (avif->yuvFormat == AVIF_PIXEL_FORMAT_YUV400) && !avif->alphaPlane && (avif->depth == 8) && |
| (rgbDepth == 8); |
| |
| volatile int colorType; |
| if (monochrome8bit) { |
| colorType = PNG_COLOR_TYPE_GRAY; |
| } else { |
| avifRGBImageSetDefaults(&rgb, avif); |
| rgb.chromaUpsampling = chromaUpsampling; |
| rgb.depth = rgbDepth; |
| colorType = PNG_COLOR_TYPE_RGBA; |
| if (avifImageIsOpaque(avif)) { |
| colorType = PNG_COLOR_TYPE_RGB; |
| rgb.format = AVIF_RGB_FORMAT_RGB; |
| } |
| if (avifRGBImageAllocatePixels(&rgb) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Conversion to RGB failed: %s (out of memory)\n", outputFilename); |
| goto cleanup; |
| } |
| if (avifImageYUVToRGB(avif, &rgb) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Conversion to RGB failed: %s\n", outputFilename); |
| goto cleanup; |
| } |
| } |
| |
| f = fopen(outputFilename, "wb"); |
| if (!f) { |
| fprintf(stderr, "Can't open PNG file for write: %s\n", outputFilename); |
| goto cleanup; |
| } |
| |
| png = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL); |
| if (!png) { |
| fprintf(stderr, "Cannot init libpng (png): %s\n", outputFilename); |
| goto cleanup; |
| } |
| info = png_create_info_struct(png); |
| if (!info) { |
| fprintf(stderr, "Cannot init libpng (info): %s\n", outputFilename); |
| goto cleanup; |
| } |
| |
| if (setjmp(png_jmpbuf(png))) { |
| fprintf(stderr, "Error writing PNG: %s\n", outputFilename); |
| goto cleanup; |
| } |
| |
| png_init_io(png, f); |
| |
| // Don't bother complaining about ICC profile's contents when transferring from AVIF to PNG. |
| // It is up to the enduser to decide if they want to keep their ICC profiles or not. |
| #if defined(PNG_SKIP_sRGB_CHECK_PROFILE) && defined(PNG_SET_OPTION_SUPPORTED) // See libpng-manual.txt, section XII. |
| png_set_option(png, PNG_SKIP_sRGB_CHECK_PROFILE, PNG_OPTION_ON); |
| #endif |
| |
| if (compressionLevel >= 0) { |
| png_set_compression_level(png, compressionLevel); |
| } |
| |
| png_set_IHDR(png, info, avif->width, avif->height, rgbDepth, colorType, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT); |
| |
| const avifBool hasIcc = avif->icc.data && (avif->icc.size > 0); |
| if (hasIcc) { |
| // If there is an ICC profile, the CICP values are irrelevant and only the ICC profile |
| // is written. If we could extract the primaries/transfer curve from the ICC profile, |
| // then they could be written in cHRM/gAMA chunks. |
| png_set_iCCP(png, info, "libavif", 0, avif->icc.data, (png_uint_32)avif->icc.size); |
| } else { |
| const avifBool isSrgb = (avif->colorPrimaries == AVIF_COLOR_PRIMARIES_SRGB) && |
| (avif->transferCharacteristics == AVIF_TRANSFER_CHARACTERISTICS_SRGB); |
| if (isSrgb) { |
| png_set_sRGB_gAMA_and_cHRM(png, info, PNG_sRGB_INTENT_PERCEPTUAL); |
| } else { |
| if (avif->colorPrimaries != AVIF_COLOR_PRIMARIES_UNKNOWN && avif->colorPrimaries != AVIF_COLOR_PRIMARIES_UNSPECIFIED) { |
| float primariesCoords[8]; |
| avifColorPrimariesGetValues(avif->colorPrimaries, primariesCoords); |
| png_set_cHRM(png, |
| info, |
| primariesCoords[6], |
| primariesCoords[7], |
| primariesCoords[0], |
| primariesCoords[1], |
| primariesCoords[2], |
| primariesCoords[3], |
| primariesCoords[4], |
| primariesCoords[5]); |
| } |
| float gamma; |
| // Write the transfer characteristics IF it can be represented as a |
| // simple gamma value. Most transfer characteristics cannot be |
| // represented this way. Viewers that support the cICP chunk can use |
| // that instead, but older viewers might show incorrect colors. |
| if (avifTransferCharacteristicsGetGamma(avif->transferCharacteristics, &gamma) == AVIF_RESULT_OK) { |
| png_set_gAMA(png, info, 1.0f / gamma); |
| } |
| } |
| } |
| |
| png_text texts[2]; |
| int numTextMetadataChunks = 0; |
| if (avif->exif.data && (avif->exif.size > 0)) { |
| if (avif->exif.size > UINT32_MAX) { |
| fprintf(stderr, "Error writing PNG: Exif metadata is too big\n"); |
| goto cleanup; |
| } |
| png_set_eXIf_1(png, info, (png_uint_32)avif->exif.size, avif->exif.data); |
| } |
| if (avif->xmp.data && (avif->xmp.size > 0)) { |
| // The iTXt XMP payload may not contain a zero byte according to section 4.2.3.3 of |
| // the PNG specification, version 1.2. |
| // The chunk is given to libpng as is. Bytes after a zero byte may be stripped. |
| |
| // Providing the length through png_text.itxt_length does not work. |
| // The given png_text.text string must end with a zero byte. |
| if (avif->xmp.size >= SIZE_MAX) { |
| fprintf(stderr, "Error writing PNG: XMP metadata is too big\n"); |
| goto cleanup; |
| } |
| if (avifRWDataRealloc(&xmp, avif->xmp.size + 1) != AVIF_RESULT_OK) { |
| fprintf(stderr, "Error writing PNG: out of memory\n"); |
| goto cleanup; |
| } |
| memcpy(xmp.data, avif->xmp.data, avif->xmp.size); |
| xmp.data[avif->xmp.size] = '\0'; |
| png_text * text = &texts[numTextMetadataChunks++]; |
| memset(text, 0, sizeof(*text)); |
| text->compression = PNG_ITXT_COMPRESSION_NONE; |
| text->key = "XML:com.adobe.xmp"; |
| text->text = (char *)xmp.data; |
| text->itxt_length = xmp.size; |
| } |
| if (numTextMetadataChunks != 0) { |
| png_set_text(png, info, texts, numTextMetadataChunks); |
| } |
| |
| png_write_info(png, info); |
| |
| // Custom chunk writing, must appear after png_write_info. |
| // With AVIF, an ICC profile takes priority over CICP, but with PNG files, CICP takes priority over ICC. |
| // Therefore CICP should only be written if there is no ICC profile. |
| if (!hasIcc) { |
| const png_byte cicp[5] = "cICP"; |
| const png_byte cicpData[4] = { (png_byte)avif->colorPrimaries, |
| (png_byte)avif->transferCharacteristics, |
| AVIF_MATRIX_COEFFICIENTS_IDENTITY, |
| 1 /*full range*/ }; |
| png_write_chunk(png, cicp, cicpData, 4); |
| } |
| |
| rowPointers = (png_bytep *)malloc(sizeof(png_bytep) * avif->height); |
| if (rowPointers == NULL) { |
| fprintf(stderr, "Error writing PNG: memory allocation failure"); |
| goto cleanup; |
| } |
| if (monochrome8bit) { |
| uint8_t * yPlane = avif->yuvPlanes[AVIF_CHAN_Y]; |
| uint32_t yRowBytes = avif->yuvRowBytes[AVIF_CHAN_Y]; |
| for (uint32_t y = 0; y < avif->height; ++y) { |
| rowPointers[y] = &yPlane[y * yRowBytes]; |
| } |
| } else { |
| for (uint32_t y = 0; y < avif->height; ++y) { |
| rowPointers[y] = &rgb.pixels[y * rgb.rowBytes]; |
| } |
| } |
| if (avifImageGetExifOrientationFromIrotImir(avif) != 1) { |
| // TODO(yguyon): Rotate the samples. |
| } |
| |
| if (rgbDepth > 8) { |
| png_set_swap(png); |
| } |
| |
| png_write_image(png, rowPointers); |
| png_write_end(png, NULL); |
| |
| writeResult = AVIF_TRUE; |
| printf("Wrote PNG: %s\n", outputFilename); |
| cleanup: |
| if (f) { |
| fclose(f); |
| } |
| if (png) { |
| png_destroy_write_struct(&png, &info); |
| } |
| avifRWDataFree(&xmp); |
| if (rowPointers) { |
| free(rowPointers); |
| } |
| avifRGBImageFreePixels(&rgb); |
| return writeResult; |
| } |
