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Unified Diff: src/images/SkImageDecoder_libpng.cpp

Issue 1820503002: Delete SkImageDecoder (Closed) Base URL: https://skia.googlesource.com/skia.git@fix-animator
Patch Set: Include SkImage Created 4 years, 9 months ago
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Index: src/images/SkImageDecoder_libpng.cpp
diff --git a/src/images/SkImageDecoder_libpng.cpp b/src/images/SkImageDecoder_libpng.cpp
index cd8152a36bbf808387bca3c7399f29424de2dad4..c3df5d10a874e5243b94d84c16b2e6f375aeb910 100644
--- a/src/images/SkImageDecoder_libpng.cpp
+++ b/src/images/SkImageDecoder_libpng.cpp
@@ -5,14 +5,12 @@
* found in the LICENSE file.
*/
-#include "SkImageDecoder.h"
#include "SkImageEncoder.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkDither.h"
#include "SkMath.h"
#include "SkRTConf.h"
-#include "SkScaledBitmapSampler.h"
#include "SkStream.h"
#include "SkTemplates.h"
#include "SkUtils.h"
@@ -44,88 +42,10 @@ SK_CONF_DECLARE(bool, c_suppressPNGImageDecoderWarnings,
"Suppress most PNG warnings when calling image decode "
"functions.");
-class SkPNGImageIndex {
-public:
- // Takes ownership of stream.
- SkPNGImageIndex(SkStreamRewindable* stream, png_structp png_ptr, png_infop info_ptr)
- : fStream(stream)
- , fPng_ptr(png_ptr)
- , fInfo_ptr(info_ptr)
- , fColorType(kUnknown_SkColorType) {
- SkASSERT(stream != nullptr);
- }
- ~SkPNGImageIndex() {
- if (fPng_ptr) {
- png_destroy_read_struct(&fPng_ptr, &fInfo_ptr, png_infopp_NULL);
- }
- }
-
- SkAutoTDelete<SkStreamRewindable> fStream;
- png_structp fPng_ptr;
- png_infop fInfo_ptr;
- SkColorType fColorType;
-};
-
-class SkPNGImageDecoder : public SkImageDecoder {
-public:
- SkPNGImageDecoder() {
- fImageIndex = nullptr;
- }
- Format getFormat() const override {
- return kPNG_Format;
- }
-
- virtual ~SkPNGImageDecoder() { delete fImageIndex; }
-
-protected:
- Result onDecode(SkStream* stream, SkBitmap* bm, Mode) override;
-
-private:
- SkPNGImageIndex* fImageIndex;
-
- bool onDecodeInit(SkStream* stream, png_structp *png_ptrp, png_infop *info_ptrp);
- bool decodePalette(png_structp png_ptr, png_infop info_ptr, int bitDepth,
- bool * SK_RESTRICT hasAlphap, bool *reallyHasAlphap,
- SkColorTable **colorTablep);
- bool getBitmapColorType(png_structp, png_infop, SkColorType*, bool* hasAlpha,
- SkPMColor* theTranspColor);
-
- typedef SkImageDecoder INHERITED;
-};
-
-#ifndef png_jmpbuf
-# define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
-#endif
-
-#define PNG_BYTES_TO_CHECK 4
-
-/* Automatically clean up after throwing an exception */
-struct PNGAutoClean {
- PNGAutoClean(png_structp p, png_infop i): png_ptr(p), info_ptr(i) {}
- ~PNGAutoClean() {
- png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
- }
-private:
- png_structp png_ptr;
- png_infop info_ptr;
-};
-
-static void sk_read_fn(png_structp png_ptr, png_bytep data, png_size_t length) {
- SkStream* sk_stream = (SkStream*) png_get_io_ptr(png_ptr);
- size_t bytes = sk_stream->read(data, length);
- if (bytes != length) {
- png_error(png_ptr, "Read Error!");
- }
-}
+///////////////////////////////////////////////////////////////////////////////
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
-static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) {
- SkPngChunkReader* peeker = (SkPngChunkReader*)png_get_user_chunk_ptr(png_ptr);
- // readChunk() returning true means continue decoding
- return peeker->readChunk((const char*)chunk->name, chunk->data, chunk->size) ?
- 1 : -1;
-}
-#endif
+#include "SkColorPriv.h"
+#include "SkUnPreMultiply.h"
static void sk_error_fn(png_structp png_ptr, png_const_charp msg) {
if (!c_suppressPNGImageDecoderWarnings) {
@@ -134,577 +54,6 @@ static void sk_error_fn(png_structp png_ptr, png_const_charp msg) {
longjmp(png_jmpbuf(png_ptr), 1);
}
-static void skip_src_rows(png_structp png_ptr, uint8_t storage[], int count) {
- for (int i = 0; i < count; i++) {
- uint8_t* tmp = storage;
- png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1);
- }
-}
-
-static bool pos_le(int value, int max) {
- return value > 0 && value <= max;
-}
-
-static bool substituteTranspColor(SkBitmap* bm, SkPMColor match) {
- SkASSERT(bm->colorType() == kN32_SkColorType);
-
- bool reallyHasAlpha = false;
-
- for (int y = bm->height() - 1; y >= 0; --y) {
- SkPMColor* p = bm->getAddr32(0, y);
- for (int x = bm->width() - 1; x >= 0; --x) {
- if (match == *p) {
- *p = 0;
- reallyHasAlpha = true;
- }
- p += 1;
- }
- }
- return reallyHasAlpha;
-}
-
-static bool canUpscalePaletteToConfig(SkColorType dstColorType, bool srcHasAlpha) {
- switch (dstColorType) {
- case kN32_SkColorType:
- case kARGB_4444_SkColorType:
- return true;
- case kRGB_565_SkColorType:
- // only return true if the src is opaque (since 565 is opaque)
- return !srcHasAlpha;
- default:
- return false;
- }
-}
-
-// call only if color_type is PALETTE. Returns true if the ctable has alpha
-static bool hasTransparencyInPalette(png_structp png_ptr, png_infop info_ptr) {
- png_bytep trans;
- int num_trans;
-
- if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
- png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, nullptr);
- return num_trans > 0;
- }
- return false;
-}
-
-void do_nothing_warning_fn(png_structp, png_const_charp) {
- /* do nothing */
-}
-
-bool SkPNGImageDecoder::onDecodeInit(SkStream* sk_stream, png_structp *png_ptrp,
- png_infop *info_ptrp) {
- /* Create and initialize the png_struct with the desired error handler
- * functions. If you want to use the default stderr and longjump method,
- * you can supply nullptr for the last three parameters. We also supply the
- * the compiler header file version, so that we know if the application
- * was compiled with a compatible version of the library. */
-
- png_error_ptr user_warning_fn =
- (c_suppressPNGImageDecoderWarnings) ? (&do_nothing_warning_fn) : nullptr;
- /* nullptr means to leave as default library behavior. */
- /* c_suppressPNGImageDecoderWarnings default depends on SK_DEBUG. */
- /* To suppress warnings with a SK_DEBUG binary, set the
- * environment variable "skia_images_png_suppressDecoderWarnings"
- * to "true". Inside a program that links to skia:
- * SK_CONF_SET("images.png.suppressDecoderWarnings", true); */
-
- png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING,
- nullptr, sk_error_fn, user_warning_fn);
- // png_voidp user_error_ptr, user_error_fn, user_warning_fn);
- if (png_ptr == nullptr) {
- return false;
- }
-
- *png_ptrp = png_ptr;
-
- /* Allocate/initialize the memory for image information. */
- png_infop info_ptr = png_create_info_struct(png_ptr);
- if (info_ptr == nullptr) {
- png_destroy_read_struct(&png_ptr, png_infopp_NULL, png_infopp_NULL);
- return false;
- }
- *info_ptrp = info_ptr;
-
- /* Set error handling if you are using the setjmp/longjmp method (this is
- * the normal method of doing things with libpng). REQUIRED unless you
- * set up your own error handlers in the png_create_read_struct() earlier.
- */
- if (setjmp(png_jmpbuf(png_ptr))) {
- png_destroy_read_struct(&png_ptr, &info_ptr, png_infopp_NULL);
- return false;
- }
-
- /* If you are using replacement read functions, instead of calling
- * png_init_io() here you would call:
- */
- png_set_read_fn(png_ptr, (void *)sk_stream, sk_read_fn);
- /* where user_io_ptr is a structure you want available to the callbacks */
- /* If we have already read some of the signature */
-// png_set_sig_bytes(png_ptr, 0 /* sig_read */ );
-
-#ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
- // hookup our peeker so we can see any user-chunks the caller may be interested in
- png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0);
- if (this->getPeeker()) {
- png_set_read_user_chunk_fn(png_ptr, (png_voidp)this->getPeeker(), sk_read_user_chunk);
- }
-#endif
- /* The call to png_read_info() gives us all of the information from the
- * PNG file before the first IDAT (image data chunk). */
- png_read_info(png_ptr, info_ptr);
- png_uint_32 origWidth, origHeight;
- int bitDepth, colorType;
- png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
- &colorType, int_p_NULL, int_p_NULL, int_p_NULL);
-
- /* tell libpng to strip 16 bit/color files down to 8 bits/color */
- if (bitDepth == 16) {
- png_set_strip_16(png_ptr);
- }
-#ifdef PNG_READ_PACK_SUPPORTED
- /* Extract multiple pixels with bit depths of 1, 2, and 4 from a single
- * byte into separate bytes (useful for paletted and grayscale images). */
- if (bitDepth < 8) {
- png_set_packing(png_ptr);
- }
-#endif
- /* Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel */
- if (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8) {
- png_set_expand_gray_1_2_4_to_8(png_ptr);
- }
-
- return true;
-}
-
-SkImageDecoder::Result SkPNGImageDecoder::onDecode(SkStream* sk_stream, SkBitmap* decodedBitmap,
- Mode mode) {
- png_structp png_ptr;
- png_infop info_ptr;
-
- if (!onDecodeInit(sk_stream, &png_ptr, &info_ptr)) {
- return kFailure;
- }
-
- PNGAutoClean autoClean(png_ptr, info_ptr);
-
- if (setjmp(png_jmpbuf(png_ptr))) {
- return kFailure;
- }
-
- png_uint_32 origWidth, origHeight;
- int bitDepth, pngColorType, interlaceType;
- png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
- &pngColorType, &interlaceType, int_p_NULL, int_p_NULL);
-
- SkColorType colorType;
- bool hasAlpha = false;
- SkPMColor theTranspColor = 0; // 0 tells us not to try to match
-
- if (!this->getBitmapColorType(png_ptr, info_ptr, &colorType, &hasAlpha, &theTranspColor)) {
- return kFailure;
- }
-
- SkAlphaType alphaType = this->getRequireUnpremultipliedColors() ?
- kUnpremul_SkAlphaType : kPremul_SkAlphaType;
- const int sampleSize = this->getSampleSize();
- SkScaledBitmapSampler sampler(origWidth, origHeight, sampleSize);
- decodedBitmap->setInfo(SkImageInfo::Make(sampler.scaledWidth(), sampler.scaledHeight(),
- colorType, alphaType));
-
- if (SkImageDecoder::kDecodeBounds_Mode == mode) {
- return kSuccess;
- }
-
- // from here down we are concerned with colortables and pixels
-
- // we track if we actually see a non-opaque pixels, since sometimes a PNG sets its colortype
- // to |= PNG_COLOR_MASK_ALPHA, but all of its pixels are in fact opaque. We care, since we
- // draw lots faster if we can flag the bitmap has being opaque
- bool reallyHasAlpha = false;
- SkColorTable* colorTable = nullptr;
-
- if (pngColorType == PNG_COLOR_TYPE_PALETTE) {
- decodePalette(png_ptr, info_ptr, bitDepth, &hasAlpha, &reallyHasAlpha, &colorTable);
- }
-
- SkAutoUnref aur(colorTable);
-
- if (!this->allocPixelRef(decodedBitmap,
- kIndex_8_SkColorType == colorType ? colorTable : nullptr)) {
- return kFailure;
- }
-
- SkAutoLockPixels alp(*decodedBitmap);
-
- // Repeat setjmp, otherwise variables declared since the last call (e.g. alp
- // and aur) won't get their destructors called in case of a failure.
- if (setjmp(png_jmpbuf(png_ptr))) {
- return kFailure;
- }
-
- /* Turn on interlace handling. REQUIRED if you are not using
- * png_read_image(). To see how to handle interlacing passes,
- * see the png_read_row() method below:
- */
- const int number_passes = (interlaceType != PNG_INTERLACE_NONE) ?
- png_set_interlace_handling(png_ptr) : 1;
-
- /* Optional call to gamma correct and add the background to the palette
- * and update info structure. REQUIRED if you are expecting libpng to
- * update the palette for you (ie you selected such a transform above).
- */
- png_read_update_info(png_ptr, info_ptr);
-
- if ((kAlpha_8_SkColorType == colorType || kIndex_8_SkColorType == colorType) &&
- 1 == sampleSize) {
- if (kAlpha_8_SkColorType == colorType) {
- // For an A8 bitmap, we assume there is an alpha for speed. It is
- // possible the bitmap is opaque, but that is an unlikely use case
- // since it would not be very interesting.
- reallyHasAlpha = true;
- // A8 is only allowed if the original was GRAY.
- SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType);
- }
- for (int i = 0; i < number_passes; i++) {
- for (png_uint_32 y = 0; y < origHeight; y++) {
- uint8_t* bmRow = decodedBitmap->getAddr8(0, y);
- png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1);
- }
- }
- } else {
- SkScaledBitmapSampler::SrcConfig sc;
- int srcBytesPerPixel = 4;
-
- if (colorTable != nullptr) {
- sc = SkScaledBitmapSampler::kIndex;
- srcBytesPerPixel = 1;
- } else if (kAlpha_8_SkColorType == colorType) {
- // A8 is only allowed if the original was GRAY.
- SkASSERT(PNG_COLOR_TYPE_GRAY == pngColorType);
- sc = SkScaledBitmapSampler::kGray;
- srcBytesPerPixel = 1;
- } else if (hasAlpha) {
- sc = SkScaledBitmapSampler::kRGBA;
- } else {
- sc = SkScaledBitmapSampler::kRGBX;
- }
-
- /* We have to pass the colortable explicitly, since we may have one
- even if our decodedBitmap doesn't, due to the request that we
- upscale png's palette to a direct model
- */
- const SkPMColor* colors = colorTable ? colorTable->readColors() : nullptr;
- if (!sampler.begin(decodedBitmap, sc, *this, colors)) {
- return kFailure;
- }
- const int height = decodedBitmap->height();
-
- if (number_passes > 1) {
- SkAutoTMalloc<uint8_t> storage(origWidth * origHeight * srcBytesPerPixel);
- uint8_t* base = storage.get();
- size_t rowBytes = origWidth * srcBytesPerPixel;
-
- for (int i = 0; i < number_passes; i++) {
- uint8_t* row = base;
- for (png_uint_32 y = 0; y < origHeight; y++) {
- uint8_t* bmRow = row;
- png_read_rows(png_ptr, &bmRow, png_bytepp_NULL, 1);
- row += rowBytes;
- }
- }
- // now sample it
- base += sampler.srcY0() * rowBytes;
- for (int y = 0; y < height; y++) {
- reallyHasAlpha |= sampler.next(base);
- base += sampler.srcDY() * rowBytes;
- }
- } else {
- SkAutoTMalloc<uint8_t> storage(origWidth * srcBytesPerPixel);
- uint8_t* srcRow = storage.get();
- skip_src_rows(png_ptr, srcRow, sampler.srcY0());
-
- for (int y = 0; y < height; y++) {
- uint8_t* tmp = srcRow;
- png_read_rows(png_ptr, &tmp, png_bytepp_NULL, 1);
- reallyHasAlpha |= sampler.next(srcRow);
- if (y < height - 1) {
- skip_src_rows(png_ptr, srcRow, sampler.srcDY() - 1);
- }
- }
-
- // skip the rest of the rows (if any)
- png_uint_32 read = (height - 1) * sampler.srcDY() +
- sampler.srcY0() + 1;
- SkASSERT(read <= origHeight);
- skip_src_rows(png_ptr, srcRow, origHeight - read);
- }
- }
-
- /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
- png_read_end(png_ptr, info_ptr);
-
- if (0 != theTranspColor) {
- reallyHasAlpha |= substituteTranspColor(decodedBitmap, theTranspColor);
- }
- if (reallyHasAlpha && this->getRequireUnpremultipliedColors()) {
- switch (decodedBitmap->colorType()) {
- case kIndex_8_SkColorType:
- // Fall through.
- case kARGB_4444_SkColorType:
- // We have chosen not to support unpremul for these colortypes.
- return kFailure;
- default: {
- // Fall through to finish the decode. This colortype either
- // supports unpremul or it is irrelevant because it has no
- // alpha (or only alpha).
- // These brackets prevent a warning.
- }
- }
- }
-
- if (!reallyHasAlpha) {
- decodedBitmap->setAlphaType(kOpaque_SkAlphaType);
- }
- return kSuccess;
-}
-
-
-
-bool SkPNGImageDecoder::getBitmapColorType(png_structp png_ptr, png_infop info_ptr,
- SkColorType* colorTypep,
- bool* hasAlphap,
- SkPMColor* SK_RESTRICT theTranspColorp) {
- png_uint_32 origWidth, origHeight;
- int bitDepth, colorType;
- png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth,
- &colorType, int_p_NULL, int_p_NULL, int_p_NULL);
-
-#ifdef PNG_sBIT_SUPPORTED
- // check for sBIT chunk data, in case we should disable dithering because
- // our data is not truely 8bits per component
- png_color_8p sig_bit;
- if (this->getDitherImage() && png_get_sBIT(png_ptr, info_ptr, &sig_bit)) {
-#if 0
- SkDebugf("----- sBIT %d %d %d %d\n", sig_bit->red, sig_bit->green,
- sig_bit->blue, sig_bit->alpha);
-#endif
- // 0 seems to indicate no information available
- if (pos_le(sig_bit->red, SK_R16_BITS) &&
- pos_le(sig_bit->green, SK_G16_BITS) &&
- pos_le(sig_bit->blue, SK_B16_BITS)) {
- this->setDitherImage(false);
- }
- }
-#endif
-
- if (colorType == PNG_COLOR_TYPE_PALETTE) {
- bool paletteHasAlpha = hasTransparencyInPalette(png_ptr, info_ptr);
- *colorTypep = this->getPrefColorType(kIndex_SrcDepth, paletteHasAlpha);
- // now see if we can upscale to their requested colortype
- if (!canUpscalePaletteToConfig(*colorTypep, paletteHasAlpha)) {
- *colorTypep = kIndex_8_SkColorType;
- }
- } else {
- png_color_16p transpColor = nullptr;
- int numTransp = 0;
-
- png_get_tRNS(png_ptr, info_ptr, nullptr, &numTransp, &transpColor);
-
- bool valid = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS);
-
- if (valid && numTransp == 1 && transpColor != nullptr) {
- /* Compute our transparent color, which we'll match against later.
- We don't really handle 16bit components properly here, since we
- do our compare *after* the values have been knocked down to 8bit
- which means we will find more matches than we should. The real
- fix seems to be to see the actual 16bit components, do the
- compare, and then knock it down to 8bits ourselves.
- */
- if (colorType & PNG_COLOR_MASK_COLOR) {
- if (16 == bitDepth) {
- *theTranspColorp = SkPackARGB32(0xFF, transpColor->red >> 8,
- transpColor->green >> 8,
- transpColor->blue >> 8);
- } else {
- /* We apply the mask because in a very small
- number of corrupt PNGs, (transpColor->red > 255)
- and (bitDepth == 8), for certain versions of libpng. */
- *theTranspColorp = SkPackARGB32(0xFF,
- 0xFF & (transpColor->red),
- 0xFF & (transpColor->green),
- 0xFF & (transpColor->blue));
- }
- } else { // gray
- if (16 == bitDepth) {
- *theTranspColorp = SkPackARGB32(0xFF, transpColor->gray >> 8,
- transpColor->gray >> 8,
- transpColor->gray >> 8);
- } else {
- /* We apply the mask because in a very small
- number of corrupt PNGs, (transpColor->red >
- 255) and (bitDepth == 8), for certain versions
- of libpng. For safety we assume the same could
- happen with a grayscale PNG. */
- *theTranspColorp = SkPackARGB32(0xFF,
- 0xFF & (transpColor->gray),
- 0xFF & (transpColor->gray),
- 0xFF & (transpColor->gray));
- }
- }
- }
-
- if (valid ||
- PNG_COLOR_TYPE_RGB_ALPHA == colorType ||
- PNG_COLOR_TYPE_GRAY_ALPHA == colorType) {
- *hasAlphap = true;
- }
-
- SrcDepth srcDepth = k32Bit_SrcDepth;
- if (PNG_COLOR_TYPE_GRAY == colorType) {
- srcDepth = k8BitGray_SrcDepth;
- // Remove this assert, which fails on desk_pokemonwiki.skp
- //SkASSERT(!*hasAlphap);
- }
-
- *colorTypep = this->getPrefColorType(srcDepth, *hasAlphap);
- // now match the request against our capabilities
- if (*hasAlphap) {
- if (*colorTypep != kARGB_4444_SkColorType) {
- *colorTypep = kN32_SkColorType;
- }
- } else {
- if (kAlpha_8_SkColorType == *colorTypep) {
- if (k8BitGray_SrcDepth != srcDepth) {
- // Converting a non grayscale image to A8 is not currently supported.
- *colorTypep = kN32_SkColorType;
- }
- } else if (*colorTypep != kRGB_565_SkColorType &&
- *colorTypep != kARGB_4444_SkColorType) {
- *colorTypep = kN32_SkColorType;
- }
- }
- }
-
- // sanity check for size
- {
- int64_t size = sk_64_mul(origWidth, origHeight);
- // now check that if we are 4-bytes per pixel, we also don't overflow
- if (size < 0 || size > (0x7FFFFFFF >> 2)) {
- return false;
- }
- }
-
- // If the image has alpha and the decoder wants unpremultiplied
- // colors, the only supported colortype is 8888.
- if (this->getRequireUnpremultipliedColors() && *hasAlphap) {
- *colorTypep = kN32_SkColorType;
- }
-
- if (fImageIndex != nullptr) {
- if (kUnknown_SkColorType == fImageIndex->fColorType) {
- // This is the first time for this subset decode. From now on,
- // all decodes must be in the same colortype.
- fImageIndex->fColorType = *colorTypep;
- } else if (fImageIndex->fColorType != *colorTypep) {
- // Requesting a different colortype for a subsequent decode is not
- // supported. Report failure before we make changes to png_ptr.
- return false;
- }
- }
-
- bool convertGrayToRGB = PNG_COLOR_TYPE_GRAY == colorType && *colorTypep != 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) {
- png_set_gray_to_rgb(png_ptr);
- }
-
- // Add filler (or alpha) byte (after each RGB triplet) if necessary.
- if (colorType == PNG_COLOR_TYPE_RGB || convertGrayToRGB) {
- png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER);
- }
-
- return true;
-}
-
-typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b);
-
-bool SkPNGImageDecoder::decodePalette(png_structp png_ptr, png_infop info_ptr,
- int bitDepth, bool *hasAlphap,
- bool *reallyHasAlphap,
- SkColorTable **colorTablep) {
- int numPalette;
- png_colorp palette;
- png_bytep trans;
- int numTrans;
-
- png_get_PLTE(png_ptr, info_ptr, &palette, &numPalette);
-
- SkPMColor colorStorage[256]; // worst-case storage
- SkPMColor* colorPtr = colorStorage;
-
- if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) {
- png_get_tRNS(png_ptr, info_ptr, &trans, &numTrans, nullptr);
- *hasAlphap = (numTrans > 0);
- } else {
- numTrans = 0;
- }
-
- // check for bad images that might make us crash
- if (numTrans > numPalette) {
- numTrans = numPalette;
- }
-
- int index = 0;
- int transLessThanFF = 0;
-
- // Choose which function to use to create the color table. If the final destination's
- // colortype is unpremultiplied, the color table will store unpremultiplied colors.
- PackColorProc proc;
- if (this->getRequireUnpremultipliedColors()) {
- proc = &SkPackARGB32NoCheck;
- } else {
- proc = &SkPreMultiplyARGB;
- }
- for (; index < numTrans; index++) {
- transLessThanFF |= (int)*trans - 0xFF;
- *colorPtr++ = proc(*trans++, palette->red, palette->green, palette->blue);
- palette++;
- }
- bool reallyHasAlpha = (transLessThanFF < 0);
-
- for (; index < numPalette; index++) {
- *colorPtr++ = SkPackARGB32(0xFF, palette->red, palette->green, palette->blue);
- palette++;
- }
-
- /* BUGGY IMAGE WORKAROUND
-
- Invalid images could contain pixel values that are greater than the number of palette
- entries. Since we use pixel values as indices into the palette this could result in reading
- beyond the end of the palette which could leak the contents of uninitialized memory. To
- ensure this doesn't happen, we grow the colortable to the maximum size that can be
- addressed by the bitdepth of the image and fill it with the last palette color or black if
- the palette is empty (really broken image).
- */
- int colorCount = SkTMax(numPalette, 1 << SkTMin(bitDepth, 8));
- SkPMColor lastColor = index > 0 ? colorPtr[-1] : SkPackARGB32(0xFF, 0, 0, 0);
- for (; index < colorCount; index++) {
- *colorPtr++ = lastColor;
- }
-
- *colorTablep = new SkColorTable(colorStorage, colorCount);
- *reallyHasAlphap = reallyHasAlpha;
- return true;
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-#include "SkColorPriv.h"
-#include "SkUnPreMultiply.h"
-
static void sk_write_fn(png_structp png_ptr, png_bytep data, png_size_t len) {
SkWStream* sk_stream = (SkWStream*)png_get_io_ptr(png_ptr);
if (!sk_stream->write(data, len)) {
@@ -985,37 +334,11 @@ bool SkPNGImageEncoder::doEncode(SkWStream* stream, const SkBitmap& bitmap,
}
///////////////////////////////////////////////////////////////////////////////
-DEFINE_DECODER_CREATOR(PNGImageDecoder);
DEFINE_ENCODER_CREATOR(PNGImageEncoder);
///////////////////////////////////////////////////////////////////////////////
-static bool is_png(SkStreamRewindable* stream) {
- char buf[PNG_BYTES_TO_CHECK];
- if (stream->read(buf, PNG_BYTES_TO_CHECK) == PNG_BYTES_TO_CHECK &&
- !png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) {
- return true;
- }
- return false;
-}
-
-SkImageDecoder* sk_libpng_dfactory(SkStreamRewindable* stream) {
- if (is_png(stream)) {
- return new SkPNGImageDecoder;
- }
- return nullptr;
-}
-
-static SkImageDecoder::Format get_format_png(SkStreamRewindable* stream) {
- if (is_png(stream)) {
- return SkImageDecoder::kPNG_Format;
- }
- return SkImageDecoder::kUnknown_Format;
-}
-
SkImageEncoder* sk_libpng_efactory(SkImageEncoder::Type t) {
return (SkImageEncoder::kPNG_Type == t) ? new SkPNGImageEncoder : nullptr;
}
-static SkImageDecoder_DecodeReg gDReg(sk_libpng_dfactory);
-static SkImageDecoder_FormatReg gFormatReg(get_format_png);
static SkImageEncoder_EncodeReg gEReg(sk_libpng_efactory);
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