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Revert of Revert of Fixing libpng transform use (patchset #1 id:1 of https://codereview.chromium.org/1213743004/)

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Reason for revert:
This appears to have been reverted in order to fix the DEPS roll in https://codereview.chromium.org/1214943004/

However, it only affects SkCodec, which is not used by Chromium. Relanding

Original issue's description:
> Revert of Fixing libpng transform use  (patchset #5 id:80001 of https://codereview.chromium.org/1214203005/)
>
> Reason for revert:
> DEPS roll failing
>
> Original issue's description:
> > This change:
> > - supports kGray correctly
> > - avoid extra call to png_get_IHDR by storing the bit depth
> > - call transforms as needed
> > - checks for tRNS alpha value in RGB and GRAY color types
> >
> >
> > BUG=skia:
> >
> > Committed: https://skia.googlesource.com/skia/+/9693037fd41b7ce545b44beaa3489dcfd915018c
>
> TBR=scroggo@google.com,msarett@google.com,emmaleer@google.com
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/6c90e09575c1a77aee060aa475fdb3d25a17d6a0

TBR=msarett@google.com,emmaleer@google.com,jvanverth@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1215853005
This commit is contained in:
scroggo 2015-07-07 06:09:08 -07:00 committed by Commit bot
parent 07abbbec4b
commit 6f29a3c92c
2 changed files with 91 additions and 98 deletions
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182
src/codec/SkCodec_libpng.cpp
View File

@ -214,7 +214,7 @@ bool SkPngCodec::IsPng(SkStream* stream) {
// png_destroy_read_struct. If it returns false, the passed in fields (except
// stream) are unchanged.
static bool read_header(SkStream* stream, png_structp* png_ptrp,
png_infop* info_ptrp, SkImageInfo* imageInfo) {
png_infop* info_ptrp, SkImageInfo* imageInfo, int* bitDepthPtr) {
// The image is known to be a PNG. Decode enough to know the SkImageInfo.
png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL,
sk_error_fn, sk_warning_fn);
@ -252,6 +252,10 @@ static bool read_header(SkStream* stream, png_structp* png_ptrp,
png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
&colorType, int_p_NULL, int_p_NULL, int_p_NULL);
if (bitDepthPtr) {
*bitDepthPtr = bitDepth;
}
// sanity check for size
{
int64_t size = sk_64_mul(origWidth, origHeight);
@ -277,8 +281,7 @@ static bool read_header(SkStream* stream, png_structp* png_ptrp,
png_set_expand_gray_1_2_4_to_8(png_ptr);
}
// Now determine the default SkColorType and SkAlphaType.
// Now determine the default SkColorType and SkAlphaType and set required transforms
SkColorType skColorType;
SkAlphaType skAlphaType;
switch (colorType) {
@ -287,57 +290,51 @@ static bool read_header(SkStream* stream, png_structp* png_ptrp,
skAlphaType = has_transparency_in_palette(png_ptr, info_ptr) ?
kUnpremul_SkAlphaType : kOpaque_SkAlphaType;
break;
case PNG_COLOR_TYPE_GRAY:
if (false) {
// FIXME: Is this the wrong default behavior? This means if the
// caller supplies the info we gave them, they'll get Alpha 8.
skColorType = kAlpha_8_SkColorType;
// FIXME: Strangely, the canonical type for Alpha 8 is Premul.
skAlphaType = kPremul_SkAlphaType;
} else {
skColorType = kN32_SkColorType;
skAlphaType = kOpaque_SkAlphaType;
}
break;
default:
// Note: This *almost* mimics the code in SkImageDecoder_libpng.
// has_transparency_in_palette makes an additional check - whether
// numTrans is greater than 0. Why does the other code not make that
// check?
if (has_transparency_in_palette(png_ptr, info_ptr)
|| PNG_COLOR_TYPE_RGB_ALPHA == colorType
|| PNG_COLOR_TYPE_GRAY_ALPHA == colorType)
{
case PNG_COLOR_TYPE_RGB:
if (has_transparency_in_palette(png_ptr, info_ptr)) {
//convert to RGBA with tranparency information in tRNS chunk if it exists
png_set_tRNS_to_alpha(png_ptr);
skAlphaType = kUnpremul_SkAlphaType;
} else {
//convert to RGBA with Opaque Alpha
png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
skAlphaType = kOpaque_SkAlphaType;
}
skColorType = kN32_SkColorType;
break;
}
{
// FIXME: Again, this block needs to go into onGetPixels.
bool convertGrayToRGB = PNG_COLOR_TYPE_GRAY == colorType && skColorType != kAlpha_8_SkColorType;
// Unless the user is requesting A8, convert a grayscale image into RGB.
// GRAY_ALPHA will always be converted to RGB
if (convertGrayToRGB || colorType == PNG_COLOR_TYPE_GRAY_ALPHA) {
case PNG_COLOR_TYPE_GRAY:
if (has_transparency_in_palette(png_ptr, info_ptr)) {
//FIXME: support gray with alpha as a color type
//convert to RGBA if there is transparentcy info in the tRNS chunk
png_set_tRNS_to_alpha(png_ptr);
png_set_gray_to_rgb(png_ptr);
skColorType = kN32_SkColorType;
skAlphaType = kUnpremul_SkAlphaType;
} else {
skColorType = kGray_8_SkColorType;
skAlphaType = kOpaque_SkAlphaType;
}
break;
case PNG_COLOR_TYPE_GRAY_ALPHA:
//FIXME: support gray with alpha as a color type
//convert to RGBA
png_set_gray_to_rgb(png_ptr);
}
// Add filler (or alpha) byte (after each RGB triplet) if necessary.
// FIXME: It seems like we could just use RGB as the SrcConfig here.
if (colorType == PNG_COLOR_TYPE_RGB || convertGrayToRGB) {
png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
}
skColorType = kN32_SkColorType;
skAlphaType = kUnpremul_SkAlphaType;
break;
case PNG_COLOR_TYPE_RGBA:
skColorType = kN32_SkColorType;
skAlphaType = kUnpremul_SkAlphaType;
break;
default:
//all the color types have been covered above
SkASSERT(false);
}
// FIXME: Also need to check for sRGB (skbug.com/3471).
if (imageInfo) {
*imageInfo = SkImageInfo::Make(origWidth, origHeight, skColorType,
skAlphaType);
*imageInfo = SkImageInfo::Make(origWidth, origHeight, skColorType, skAlphaType);
}
autoClean.detach();
if (png_ptrp) {
@ -346,6 +343,7 @@ static bool read_header(SkStream* stream, png_structp* png_ptrp,
if (info_ptrp) {
*info_ptrp = info_ptr;
}
return true;
}
@ -354,21 +352,24 @@ SkCodec* SkPngCodec::NewFromStream(SkStream* stream) {
png_structp png_ptr;
png_infop info_ptr;
SkImageInfo imageInfo;
if (read_header(stream, &png_ptr, &info_ptr, &imageInfo)) {
return SkNEW_ARGS(SkPngCodec, (imageInfo, streamDeleter.detach(), png_ptr, info_ptr));
int bitDepth;
if (read_header(stream, &png_ptr, &info_ptr, &imageInfo, &bitDepth)) {
return SkNEW_ARGS(SkPngCodec, (imageInfo, streamDeleter.detach(),
png_ptr, info_ptr, bitDepth));
}
return NULL;
}
#define INVALID_NUMBER_PASSES -1
SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream,
png_structp png_ptr, png_infop info_ptr)
png_structp png_ptr, png_infop info_ptr, int bitDepth)
: INHERITED(info, stream)
, fPng_ptr(png_ptr)
, fInfo_ptr(info_ptr)
, fSrcConfig(SkSwizzler::kUnknown)
, fNumberPasses(INVALID_NUMBER_PASSES)
, fReallyHasAlpha(false)
, fBitDepth(bitDepth)
{}
SkPngCodec::~SkPngCodec() {
@ -419,10 +420,8 @@ static bool conversion_possible(const SkImageInfo& dst, const SkImageInfo& src)
return false;
}
}
// Check for supported color types
switch (dst.colorType()) {
// Allow output to kN32 from any type of input
case kN32_SkColorType:
return true;
default:
@ -441,34 +440,38 @@ SkCodec::Result SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
SkCodecPrintf("setjmp long jump!\n");
return kInvalidInput;
}
// FIXME: We already retrieved this information. Store it in SkPngCodec?
png_uint_32 origWidth, origHeight;
int bitDepth, pngColorType, interlaceType;
png_get_IHDR(fPng_ptr, fInfo_ptr, &origWidth, &origHeight, &bitDepth,
&pngColorType, &interlaceType, int_p_NULL, int_p_NULL);
fNumberPasses = (interlaceType != PNG_INTERLACE_NONE) ?
png_set_interlace_handling(fPng_ptr) : 1;
fNumberPasses = png_set_interlace_handling(fPng_ptr);
png_read_update_info(fPng_ptr, fInfo_ptr);
// Set to the default before calling decodePalette, which may change it.
fReallyHasAlpha = false;
if (PNG_COLOR_TYPE_PALETTE == pngColorType) {
fSrcConfig = SkSwizzler::kIndex;
if (!this->decodePalette(kPremul_SkAlphaType == requestedInfo.alphaType(), bitDepth,
ctableCount)) {
return kInvalidInput;
}
} else if (kAlpha_8_SkColorType == requestedInfo.colorType()) {
// Note: we check the destination, since otherwise we would have
// told png to upscale.
SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType);
fSrcConfig = SkSwizzler::kGray;
} else if (this->getInfo().alphaType() == kOpaque_SkAlphaType) {
fSrcConfig = SkSwizzler::kRGBX;
} else {
fSrcConfig = SkSwizzler::kRGBA;
}
//srcColorType was determined in readHeader() which determined png color type
const SkColorType srcColorType = this->getInfo().colorType();
switch (srcColorType) {
case kIndex_8_SkColorType:
//decode palette to Skia format
fSrcConfig = SkSwizzler::kIndex;
if (!this->decodePalette(kPremul_SkAlphaType == requestedInfo.alphaType(), fBitDepth,
ctableCount)) {
return kInvalidInput;
}
break;
case kGray_8_SkColorType:
fSrcConfig = SkSwizzler::kGray;
break;
case kN32_SkColorType:
if (this->getInfo().alphaType() == kOpaque_SkAlphaType) {
fSrcConfig = SkSwizzler::kRGBX;
} else {
fSrcConfig = SkSwizzler::kRGBA;
}
break;
default:
//would have exited before now if the colorType was supported by png
SkASSERT(false);
}
// Copy the color table to the client if they request kIndex8 mode
copy_color_table(requestedInfo, fColorTable, ctable, ctableCount);
@ -481,14 +484,10 @@ SkCodec::Result SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo,
// FIXME: CreateSwizzler could fail for another reason.
return kUnimplemented;
}
// FIXME: Here is where we should likely insert some of the modifications
// made in the factory.
png_read_update_info(fPng_ptr, fInfo_ptr);
return kSuccess;
}
bool SkPngCodec::handleRewind() {
switch (this->rewindIfNeeded()) {
case kNoRewindNecessary_RewindState:
@ -504,7 +503,7 @@ bool SkPngCodec::handleRewind() {
this->destroyReadStruct();
png_structp png_ptr;
png_infop info_ptr;
if (read_header(this->stream(), &png_ptr, &info_ptr, NULL)) {
if (read_header(this->stream(), &png_ptr, &info_ptr, NULL, NULL)) {
fPng_ptr = png_ptr;
fInfo_ptr = info_ptr;
return true;
@ -520,30 +519,27 @@ bool SkPngCodec::handleRewind() {
SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst,
size_t rowBytes, const Options& options,
SkPMColor ctable[], int* ctableCount) {
if (!conversion_possible(requestedInfo, this->getInfo())) {
return kInvalidConversion;
}
// Do not allow a regular decode if the caller has asked for a scanline decoder
if (NULL != this->scanlineDecoder()) {
SkCodecPrintf("cannot getPixels() if a scanline decoder has been created\n");
return kInvalidParameters;
}
if (!this->handleRewind()) {
return kCouldNotRewind;
}
if (requestedInfo.dimensions() != this->getInfo().dimensions()) {
return kInvalidScale;
}
if (!conversion_possible(requestedInfo, this->getInfo())) {
return kInvalidConversion;
if (!this->handleRewind()) {
return kCouldNotRewind;
}
// Note that ctable and ctableCount may be modified if there is a color table
const Result result = this->initializeSwizzler(requestedInfo, dst, rowBytes,
options, ctable, ctableCount);
if (result != kSuccess) {
return result;
}
// FIXME: Could we use the return value of setjmp to specify the type of
// error?
if (setjmp(png_jmpbuf(fPng_ptr))) {
@ -665,9 +661,9 @@ public:
, fHasAlpha(false)
, fCurrentRow(0)
, fHeight(dstInfo.height())
, fSrcRowBytes(dstInfo.minRowBytes())
, fRewindNeeded(false)
{
fSrcRowBytes = dstInfo.width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig);
fGarbageRow.reset(fSrcRowBytes);
fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get());
}
@ -735,10 +731,6 @@ private:
bool fRewindNeeded;
SkAutoMalloc fGarbageRow;
uint8_t* fGarbageRowPtr;
typedef SkScanlineDecoder INHERITED;
};
@ -746,17 +738,15 @@ private:
SkScanlineDecoder* SkPngCodec::onGetScanlineDecoder(const SkImageInfo& dstInfo,
const Options& options, SkPMColor ctable[], int* ctableCount) {
if (!this->handleRewind()) {
if (!conversion_possible(dstInfo, this->getInfo())) {
SkCodecPrintf("no conversion possible\n");
return NULL;
}
// Check to see if scaling was requested.
if (dstInfo.dimensions() != this->getInfo().dimensions()) {
return NULL;
}
if (!conversion_possible(dstInfo, this->getInfo())) {
SkCodecPrintf("no conversion possible\n");
if (!this->handleRewind()) {
return NULL;
}

7
src/codec/SkCodec_libpng.h
View File

@ -44,14 +44,17 @@ private:
SkSwizzler::SrcConfig fSrcConfig;
int fNumberPasses;
bool fReallyHasAlpha;
int fBitDepth;
SkPngCodec(const SkImageInfo&, SkStream*, png_structp, png_infop);
SkPngCodec(const SkImageInfo&, SkStream*, png_structp, png_infop, int);
~SkPngCodec();
// Helper to set up swizzler and color table. Also calls png_read_update_info.
Result initializeSwizzler(const SkImageInfo& requestedInfo, void* dst,
size_t rowBytes, const Options&, SkPMColor*, int* ctableCount);
// Calls rewindIfNeeded, and returns true if the decoder can continue.
// Calls rewindIfNeeded and returns true if the decoder can continue.
bool handleRewind();
bool decodePalette(bool premultiply, int bitDepth, int* ctableCount);
void finish();