bool SkPngCodec::initializeXforms(const SkImageInfo& dstInfo, const Options& options,
SkPMColor ctable[], int* ctableCount) {
if (setjmp(png_jmpbuf(fPng_ptr))) {
SkCodecPrintf("Failed on png_read_update_info.\n");
return false;
}
png_read_update_info(fPng_ptr, fInfo_ptr);
// It's important to reset fColorXform to nullptr. We don't do this on rewinding
// because the interlaced scanline decoder may need to rewind.
fColorXform = nullptr;
SkImageInfo swizzlerInfo = dstInfo;
bool needsColorXform = needs_color_xform(dstInfo, this->getInfo());
if (needsColorXform) {
switch (dstInfo.colorType()) {
case kRGBA_8888_SkColorType:
case kBGRA_8888_SkColorType:
case kRGBA_F16_SkColorType:
swizzlerInfo = swizzlerInfo.makeColorType(kRGBA_8888_SkColorType);
if (kPremul_SkAlphaType == dstInfo.alphaType()) {
swizzlerInfo = swizzlerInfo.makeAlphaType(kUnpremul_SkAlphaType);
}
break;
case kIndex_8_SkColorType:
break;
default:
return false;
}
fColorXform = SkColorSpaceXform::New(sk_ref_sp(this->getInfo().colorSpace()),
sk_ref_sp(dstInfo.colorSpace()));
if (!fColorXform && kRGBA_F16_SkColorType == dstInfo.colorType()) {
return false;
}
}
if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) {
if (!this->createColorTable(dstInfo, ctableCount)) {
return false;
}
}
// Copy the color table to the client if they request kIndex8 mode
copy_color_table(swizzlerInfo, fColorTable, ctable, ctableCount);
// Create the swizzler. SkPngCodec retains ownership of the color table.
const SkPMColor* colors = get_color_ptr(fColorTable.get());
fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colors, swizzlerInfo,
options));
SkASSERT(fSwizzler);
return true;
}
/*
* Performs the jpeg decode
*/
SkCodec::Result SkJpegCodec::onGetPixels(const SkImageInfo& dstInfo,
void* dst, size_t dstRowBytes,
const Options& options, SkPMColor*, int*,
int* rowsDecoded) {
if (options.fSubset) {
// Subsets are not supported.
return kUnimplemented;
}
// Get a pointer to the decompress info since we will use it quite frequently
jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
// Set the jump location for libjpeg errors
if (setjmp(fDecoderMgr->getJmpBuf())) {
return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
}
// Check if we can decode to the requested destination and set the output color space
bool needsColorXform = needs_color_xform(dstInfo, this->getInfo());
if (!this->setOutputColorSpace(dstInfo, needsColorXform)) {
return fDecoderMgr->returnFailure("setOutputColorSpace", kInvalidConversion);
}
if (!this->initializeColorXform(dstInfo, needsColorXform)) {
return fDecoderMgr->returnFailure("initializeColorXform", kInvalidParameters);
}
if (!jpeg_start_decompress(dinfo)) {
return fDecoderMgr->returnFailure("startDecompress", kInvalidInput);
}
// The recommended output buffer height should always be 1 in high quality modes.
// If it's not, we want to know because it means our strategy is not optimal.
SkASSERT(1 == dinfo->rec_outbuf_height);
J_COLOR_SPACE colorSpace = dinfo->out_color_space;
if (JCS_CMYK == colorSpace || JCS_RGB == colorSpace) {
this->initializeSwizzler(dstInfo, options);
}
this->allocateStorage(dstInfo);
int rows = this->readRows(dstInfo, dst, dstRowBytes, dstInfo.height());
if (rows < dstInfo.height()) {
*rowsDecoded = rows;
return fDecoderMgr->returnFailure("Incomplete image data", kIncompleteInput);
}
return kSuccess;
}
SkCodec::Result SkJpegCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
const Options& options, SkPMColor ctable[], int* ctableCount) {
// Set the jump location for libjpeg errors
if (setjmp(fDecoderMgr->getJmpBuf())) {
SkCodecPrintf("setjmp: Error from libjpeg\n");
return kInvalidInput;
}
// Check if we can decode to the requested destination and set the output color space
bool needsColorXform = needs_color_xform(dstInfo, this->getInfo());
if (!this->setOutputColorSpace(dstInfo, needsColorXform)) {
return kInvalidConversion;
}
if (!this->initializeColorXform(dstInfo, needsColorXform)) {
return fDecoderMgr->returnFailure("initializeColorXform", kInvalidParameters);
}
if (!jpeg_start_decompress(fDecoderMgr->dinfo())) {
SkCodecPrintf("start decompress failed\n");
return kInvalidInput;
}
#ifdef TURBO_HAS_CROP
if (options.fSubset) {
uint32_t startX = options.fSubset->x();
uint32_t width = options.fSubset->width();
// libjpeg-turbo may need to align startX to a multiple of the IDCT
// block size. If this is the case, it will decrease the value of
// startX to the appropriate alignment and also increase the value
// of width so that the right edge of the requested subset remains
// the same.
jpeg_crop_scanline(fDecoderMgr->dinfo(), &startX, &width);
SkASSERT(startX <= (uint32_t) options.fSubset->x());
SkASSERT(width >= (uint32_t) options.fSubset->width());
SkASSERT(startX + width >= (uint32_t) options.fSubset->right());
// Instruct the swizzler (if it is necessary) to further subset the
// output provided by libjpeg-turbo.
//
// We set this here (rather than in the if statement below), so that
// if (1) we don't need a swizzler for the subset, and (2) we need a
// swizzler for CMYK, the swizzler will still use the proper subset
// dimensions.
//
// Note that the swizzler will ignore the y and height parameters of
// the subset. Since the scanline decoder (and the swizzler) handle
// one row at a time, only the subsetting in the x-dimension matters.
fSwizzlerSubset.setXYWH(options.fSubset->x() - startX, 0,
options.fSubset->width(), options.fSubset->height());
// We will need a swizzler if libjpeg-turbo cannot provide the exact
// subset that we request.
if (startX != (uint32_t) options.fSubset->x() ||
width != (uint32_t) options.fSubset->width()) {
this->initializeSwizzler(dstInfo, options);
}
}
// Make sure we have a swizzler if we are converting from CMYK.
if (!fSwizzler && JCS_CMYK == fDecoderMgr->dinfo()->out_color_space) {
this->initializeSwizzler(dstInfo, options);
}
#else
if (options.fSubset) {
fSwizzlerSubset = *options.fSubset;
}
// We will need a swizzler if we are performing a subset decode or
// converting from CMYK.
J_COLOR_SPACE colorSpace = fDecoderMgr->dinfo()->out_color_space;
if (options.fSubset || JCS_CMYK == colorSpace || JCS_RGB == colorSpace) {
this->initializeSwizzler(dstInfo, options);
}
#endif
this->allocateStorage(dstInfo);
return kSuccess;
}
