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-rw-r--r--src/codec/SkCodec_libpng.cpp176
-rw-r--r--src/codec/SkCodec_libpng.h7
2 files changed, 88 insertions, 95 deletions
diff --git a/src/codec/SkCodec_libpng.cpp b/src/codec/SkCodec_libpng.cpp
index 32004366f8..18e973b349 100644
--- a/src/codec/SkCodec_libpng.cpp
+++ b/src/codec/SkCodec_libpng.cpp
@@ -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;
+ 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 {
- skColorType = kN32_SkColorType;
+ //convert to RGBA with Opaque Alpha
+ png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
skAlphaType = kOpaque_SkAlphaType;
}
+ skColorType = kN32_SkColorType;
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_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;
}
- 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_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;
}
diff --git a/src/codec/SkCodec_libpng.h b/src/codec/SkCodec_libpng.h
index a105c3c5e3..c0fee74e96 100644
--- a/src/codec/SkCodec_libpng.h
+++ b/src/codec/SkCodec_libpng.h
@@ -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();
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 12:39:00 +0000