bool SkJpegCodec::ReadHeader(SkStream* stream, SkCodec** codecOut,
JpegDecoderMgr** decoderMgrOut) {
// Create a JpegDecoderMgr to own all of the decompress information
SkAutoTDelete<JpegDecoderMgr> decoderMgr(new JpegDecoderMgr(stream));
// libjpeg errors will be caught and reported here
if (setjmp(decoderMgr->getJmpBuf())) {
return decoderMgr->returnFalse("setjmp");
}
// Initialize the decompress info and the source manager
decoderMgr->init();
// Read the jpeg header
if (JPEG_HEADER_OK != jpeg_read_header(decoderMgr->dinfo(), true)) {
return decoderMgr->returnFalse("read_header");
}
if (nullptr != codecOut) {
// Recommend the color type to decode to
const SkColorType colorType = decoderMgr->getColorType();
// Create image info object and the codec
const SkImageInfo& imageInfo = SkImageInfo::Make(decoderMgr->dinfo()->image_width,
decoderMgr->dinfo()->image_height, colorType, kOpaque_SkAlphaType);
*codecOut = new SkJpegCodec(imageInfo, stream, decoderMgr.detach());
} else {
SkASSERT(nullptr != decoderMgrOut);
*decoderMgrOut = decoderMgr.detach();
}
return true;
}
bool SkJpegCodec::ReadHeader(SkStream* stream, SkCodec** codecOut,
JpegDecoderMgr** decoderMgrOut) {
// Create a JpegDecoderMgr to own all of the decompress information
SkAutoTDelete<JpegDecoderMgr> decoderMgr(new JpegDecoderMgr(stream));
// libjpeg errors will be caught and reported here
if (setjmp(decoderMgr->getJmpBuf())) {
return decoderMgr->returnFalse("ReadHeader");
}
// Initialize the decompress info and the source manager
decoderMgr->init();
// Instruct jpeg library to save the markers that we care about. Since
// the orientation and color profile will not change, we can skip this
// step on rewinds.
if (codecOut) {
jpeg_save_markers(decoderMgr->dinfo(), kExifMarker, 0xFFFF);
jpeg_save_markers(decoderMgr->dinfo(), kICCMarker, 0xFFFF);
}
// Read the jpeg header
if (JPEG_HEADER_OK != jpeg_read_header(decoderMgr->dinfo(), true)) {
return decoderMgr->returnFalse("ReadHeader");
}
if (codecOut) {
// Get the encoded color type
SkEncodedInfo::Color color;
if (!decoderMgr->getEncodedColor(&color)) {
return false;
}
// Create image info object and the codec
SkEncodedInfo info = SkEncodedInfo::Make(color, SkEncodedInfo::kOpaque_Alpha, 8);
Origin orientation = get_exif_orientation(decoderMgr->dinfo());
sk_sp<SkData> iccData = get_icc_profile(decoderMgr->dinfo());
sk_sp<SkColorSpace> colorSpace = nullptr;
if (iccData) {
colorSpace = SkColorSpace::NewICC(iccData->data(), iccData->size());
if (!colorSpace) {
SkCodecPrintf("Could not create SkColorSpace from ICC data.\n");
}
}
if (!colorSpace) {
// Treat unmarked jpegs as sRGB.
colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named);
}
const int width = decoderMgr->dinfo()->image_width;
const int height = decoderMgr->dinfo()->image_height;
*codecOut = new SkJpegCodec(width, height, info, stream, decoderMgr.release(),
std::move(colorSpace), orientation, std::move(iccData));
} else {
SkASSERT(nullptr != decoderMgrOut);
*decoderMgrOut = decoderMgr.release();
}
return true;
}
