/* * Copyright 2015 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #include "SkBitmap.h" #include "SkCodecPriv.h" #include "SkColorPriv.h" #include "SkColorSpace.h" #include "SkColorTable.h" #include "SkMath.h" #include "SkOpts.h" #include "SkPngCodec.h" #include "SkPoint3.h" #include "SkSize.h" #include "SkStream.h" #include "SkSwizzler.h" #include "SkTemplates.h" #include "SkUtils.h" #include "png.h" // This warning triggers false postives way too often in here. #if defined(__GNUC__) && !defined(__clang__) #pragma GCC diagnostic ignored "-Wclobbered" #endif #if PNG_LIBPNG_VER_MAJOR > 1 || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 5) // This is not needed with version 1.5 #undef SK_GOOGLE3_PNG_HACK #endif // FIXME (scroggo): We can use png_jumpbuf directly once Google3 is on 1.6 #define PNG_JMPBUF(x) png_jmpbuf((png_structp) x) /////////////////////////////////////////////////////////////////////////////// // Callback functions /////////////////////////////////////////////////////////////////////////////// // When setjmp is first called, it returns 0, meaning longjmp was not called. constexpr int kSetJmpOkay = 0; // An error internal to libpng. constexpr int kPngError = 1; // Passed to longjmp when we have decoded as many lines as we need. constexpr int kStopDecoding = 2; static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { SkCodecPrintf("------ png error %s\n", msg); longjmp(PNG_JMPBUF(png_ptr), kPngError); } void sk_warning_fn(png_structp, png_const_charp msg) { SkCodecPrintf("----- png warning %s\n", msg); } #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED static int sk_read_user_chunk(png_structp png_ptr, png_unknown_chunkp chunk) { SkPngChunkReader* chunkReader = (SkPngChunkReader*)png_get_user_chunk_ptr(png_ptr); // readChunk() returning true means continue decoding return chunkReader->readChunk((const char*)chunk->name, chunk->data, chunk->size) ? 1 : -1; } #endif /////////////////////////////////////////////////////////////////////////////// // Helpers /////////////////////////////////////////////////////////////////////////////// class AutoCleanPng : public SkNoncopyable { public: /* * This class does not take ownership of stream or reader, but if codecPtr * is non-NULL, and decodeBounds succeeds, it will have created a new * SkCodec (pointed to by *codecPtr) which will own/ref them, as well as * the png_ptr and info_ptr. */ AutoCleanPng(png_structp png_ptr, SkStream* stream, SkPngChunkReader* reader, SkCodec** codecPtr) : fPng_ptr(png_ptr) , fInfo_ptr(nullptr) , fDecodedBounds(false) , fReadHeader(false) , fStream(stream) , fChunkReader(reader) , fOutCodec(codecPtr) {} ~AutoCleanPng() { // fInfo_ptr will never be non-nullptr unless fPng_ptr is. if (fPng_ptr) { png_infopp info_pp = fInfo_ptr ? &fInfo_ptr : nullptr; png_destroy_read_struct(&fPng_ptr, info_pp, nullptr); } } void setInfoPtr(png_infop info_ptr) { SkASSERT(nullptr == fInfo_ptr); fInfo_ptr = info_ptr; } /** * Reads enough of the input stream to decode the bounds. * @return false if the stream is not a valid PNG (or too short). * true if it read enough of the stream to determine the bounds. * In the latter case, the stream may have been read beyond the * point to determine the bounds, and the png_ptr will have saved * any extra data. Further, if the codecPtr supplied to the * constructor was not NULL, it will now point to a new SkCodec, * which owns (or refs, in the case of the SkPngChunkReader) the * inputs. If codecPtr was NULL, the png_ptr and info_ptr are * unowned, and it is up to the caller to destroy them. */ bool decodeBounds(); private: png_structp fPng_ptr; png_infop fInfo_ptr; bool fDecodedBounds; bool fReadHeader; SkStream* fStream; SkPngChunkReader* fChunkReader; SkCodec** fOutCodec; /** * Supplied to libpng to call when it has read enough data to determine * bounds. */ static void InfoCallback(png_structp png_ptr, png_infop) { // png_get_progressive_ptr returns the pointer we set on the png_ptr with // png_set_progressive_read_fn static_cast(png_get_progressive_ptr(png_ptr))->infoCallback(); } void infoCallback(); #ifdef SK_GOOGLE3_PNG_HACK // public so it can be called by SkPngCodec::rereadHeaderIfNecessary(). public: #endif void releasePngPtrs() { fPng_ptr = nullptr; fInfo_ptr = nullptr; } }; #define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng) bool AutoCleanPng::decodeBounds() { if (setjmp(PNG_JMPBUF(fPng_ptr))) { return false; } png_set_progressive_read_fn(fPng_ptr, this, InfoCallback, nullptr, nullptr); // Arbitrary buffer size, though note that it matches (below) // SkPngCodec::processData(). FIXME: Can we better suit this to the size of // the PNG header? constexpr size_t kBufferSize = 4096; char buffer[kBufferSize]; while (true) { const size_t bytesRead = fStream->read(buffer, kBufferSize); if (!bytesRead) { // We have read to the end of the input without decoding bounds. break; } png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, bytesRead); if (fReadHeader) { break; } } // For safety, clear the pointer to this object. png_set_progressive_read_fn(fPng_ptr, nullptr, nullptr, nullptr, nullptr); return fDecodedBounds; } void SkPngCodec::processData() { switch (setjmp(PNG_JMPBUF(fPng_ptr))) { case kPngError: // There was an error. Stop processing data. // FIXME: Do we need to discard png_ptr? return; case kStopDecoding: // We decoded all the lines we want. return; case kSetJmpOkay: // Everything is okay. break; default: // No other values should be passed to longjmp. SkASSERT(false); } // Arbitrary buffer size constexpr size_t kBufferSize = 4096; char buffer[kBufferSize]; while (true) { const size_t bytesRead = this->stream()->read(buffer, kBufferSize); png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, bytesRead); if (!bytesRead) { // We have read to the end of the input. Note that we quit *after* // calling png_process_data, because decodeBounds may have told // libpng to save the remainder of the buffer, in which case // png_process_data will process the saved buffer, though the // stream has no more to read. break; } } } // Note: SkColorTable claims to store SkPMColors, which is not necessarily the case here. bool SkPngCodec::createColorTable(const SkImageInfo& dstInfo, int* ctableCount) { int numColors; png_color* palette; if (!png_get_PLTE(fPng_ptr, fInfo_ptr, &palette, &numColors)) { return false; } // Contents depend on tableColorType and our choice of if/when to premultiply: // { kPremul, kUnpremul, kOpaque } x { RGBA, BGRA } SkPMColor colorTable[256]; SkColorType tableColorType = fColorXform ? kRGBA_8888_SkColorType : dstInfo.colorType(); png_bytep alphas; int numColorsWithAlpha = 0; if (png_get_tRNS(fPng_ptr, fInfo_ptr, &alphas, &numColorsWithAlpha, nullptr)) { // If we are performing a color xform, it will handle the premultiply. Otherwise, // we'll do it here. bool premultiply = !fColorXform && needs_premul(dstInfo, this->getInfo()); // 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 = choose_pack_color_proc(premultiply, tableColorType); for (int i = 0; i < numColorsWithAlpha; i++) { // We don't have a function in SkOpts that combines a set of alphas with a set // of RGBs. We could write one, but it's hardly worth it, given that this // is such a small fraction of the total decode time. colorTable[i] = proc(alphas[i], palette->red, palette->green, palette->blue); palette++; } } if (numColorsWithAlpha < numColors) { // The optimized code depends on a 3-byte png_color struct with the colors // in RGB order. These checks make sure it is safe to use. static_assert(3 == sizeof(png_color), "png_color struct has changed. Opts are broken."); #ifdef SK_DEBUG SkASSERT(&palette->red < &palette->green); SkASSERT(&palette->green < &palette->blue); #endif if (is_rgba(tableColorType)) { SkOpts::RGB_to_RGB1(colorTable + numColorsWithAlpha, palette, numColors - numColorsWithAlpha); } else { SkOpts::RGB_to_BGR1(colorTable + numColorsWithAlpha, palette, numColors - numColorsWithAlpha); } } // If we are not decoding to F16, we can color xform now and store the results // in the color table. if (fColorXform && kRGBA_F16_SkColorType != dstInfo.colorType()) { SkColorSpaceXform::ColorFormat xformColorFormat = is_rgba(dstInfo.colorType()) ? SkColorSpaceXform::kRGBA_8888_ColorFormat : SkColorSpaceXform::kBGRA_8888_ColorFormat; SkAlphaType xformAlphaType = select_xform_alpha(dstInfo.alphaType(), this->getInfo().alphaType()); SkAssertResult(fColorXform->apply(xformColorFormat, colorTable, SkColorSpaceXform::kRGBA_8888_ColorFormat, colorTable, numColors, xformAlphaType)); } // Pad the color table with the last color in the table (or black) in the case that // invalid pixel indices exceed the number of colors in the table. const int maxColors = 1 << fBitDepth; if (numColors < maxColors) { SkPMColor lastColor = numColors > 0 ? colorTable[numColors - 1] : SK_ColorBLACK; sk_memset32(colorTable + numColors, lastColor, maxColors - numColors); } // Set the new color count. if (ctableCount != nullptr) { *ctableCount = maxColors; } fColorTable.reset(new SkColorTable(colorTable, maxColors)); return true; } /////////////////////////////////////////////////////////////////////////////// // Creation /////////////////////////////////////////////////////////////////////////////// bool SkPngCodec::IsPng(const char* buf, size_t bytesRead) { return !png_sig_cmp((png_bytep) buf, (png_size_t)0, bytesRead); } #if (PNG_LIBPNG_VER_MAJOR > 1) || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 6) static float png_fixed_point_to_float(png_fixed_point x) { // We multiply by the same factor that libpng used to convert // fixed point -> double. Since we want floats, we choose to // do the conversion ourselves rather than convert // fixed point -> double -> float. return ((float) x) * 0.00001f; } static float png_inverted_fixed_point_to_float(png_fixed_point x) { // This is necessary because the gAMA chunk actually stores 1/gamma. return 1.0f / png_fixed_point_to_float(x); } static constexpr float gSRGB_toXYZD50[] { 0.4358f, 0.3853f, 0.1430f, // Rx, Gx, Bx 0.2224f, 0.7170f, 0.0606f, // Ry, Gy, Gz 0.0139f, 0.0971f, 0.7139f, // Rz, Gz, Bz }; #endif // LIBPNG >= 1.6 // Returns a colorSpace object that represents any color space information in // the encoded data. If the encoded data contains no color space, this will // return NULL. sk_sp read_color_space(png_structp png_ptr, png_infop info_ptr) { #if (PNG_LIBPNG_VER_MAJOR > 1) || (PNG_LIBPNG_VER_MAJOR == 1 && PNG_LIBPNG_VER_MINOR >= 6) // First check for an ICC profile png_bytep profile; png_uint_32 length; // The below variables are unused, however, we need to pass them in anyway or // png_get_iCCP() will return nothing. // Could knowing the |name| of the profile ever be interesting? Maybe for debugging? png_charp name; // The |compression| is uninteresting since: // (1) libpng has already decompressed the profile for us. // (2) "deflate" is the only mode of decompression that libpng supports. int compression; if (PNG_INFO_iCCP == png_get_iCCP(png_ptr, info_ptr, &name, &compression, &profile, &length)) { return SkColorSpace::NewICC(profile, length); } // Second, check for sRGB. if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) { // sRGB chunks also store a rendering intent: Absolute, Relative, // Perceptual, and Saturation. // FIXME (msarett): Extract this information from the sRGB chunk once // we are able to handle this information in // SkColorSpace. return SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named); } // Next, check for chromaticities. png_fixed_point chrm[8]; png_fixed_point gamma; float gammas[3]; if (png_get_cHRM_fixed(png_ptr, info_ptr, &chrm[0], &chrm[1], &chrm[2], &chrm[3], &chrm[4], &chrm[5], &chrm[6], &chrm[7])) { SkColorSpacePrimaries primaries; primaries.fRX = png_fixed_point_to_float(chrm[2]); primaries.fRY = png_fixed_point_to_float(chrm[3]); primaries.fGX = png_fixed_point_to_float(chrm[4]); primaries.fGY = png_fixed_point_to_float(chrm[5]); primaries.fBX = png_fixed_point_to_float(chrm[6]); primaries.fBY = png_fixed_point_to_float(chrm[7]); primaries.fWX = png_fixed_point_to_float(chrm[0]); primaries.fWY = png_fixed_point_to_float(chrm[1]); SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor); if (!primaries.toXYZD50(&toXYZD50)) { toXYZD50.set3x3RowMajorf(gSRGB_toXYZD50); } if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) { float value = png_inverted_fixed_point_to_float(gamma); gammas[0] = value; gammas[1] = value; gammas[2] = value; return SkColorSpace::NewRGB(gammas, toXYZD50); } // Default to sRGB gamma if the image has color space information, // but does not specify gamma. return SkColorSpace::NewRGB(SkColorSpace::kSRGB_RenderTargetGamma, toXYZD50); } // Last, check for gamma. if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) { // Set the gammas. float value = png_inverted_fixed_point_to_float(gamma); gammas[0] = value; gammas[1] = value; gammas[2] = value; // Since there is no cHRM, we will guess sRGB gamut. SkMatrix44 toXYZD50(SkMatrix44::kUninitialized_Constructor); toXYZD50.set3x3RowMajorf(gSRGB_toXYZD50); return SkColorSpace::NewRGB(gammas, toXYZD50); } #endif // LIBPNG >= 1.6 // Report that there is no color space information in the PNG. SkPngCodec is currently // implemented to guess sRGB in this case. return nullptr; } void SkPngCodec::allocateStorage(const SkImageInfo& dstInfo) { switch (fXformMode) { case kSwizzleOnly_XformMode: break; case kColorOnly_XformMode: // Intentional fall through. A swizzler hasn't been created yet, but one will // be created later if we are sampling. We'll go ahead and allocate // enough memory to swizzle if necessary. case kSwizzleColor_XformMode: { const size_t colorXformBytes = dstInfo.width() * sizeof(uint32_t); fStorage.reset(colorXformBytes); fColorXformSrcRow = (uint32_t*) fStorage.get(); break; } } } void SkPngCodec::applyXformRow(void* dst, const void* src) { const SkColorSpaceXform::ColorFormat srcColorFormat = SkColorSpaceXform::kRGBA_8888_ColorFormat; switch (fXformMode) { case kSwizzleOnly_XformMode: fSwizzler->swizzle(dst, (const uint8_t*) src); break; case kColorOnly_XformMode: SkAssertResult(fColorXform->apply(fXformColorFormat, dst, srcColorFormat, src, fXformWidth, fXformAlphaType)); break; case kSwizzleColor_XformMode: fSwizzler->swizzle(fColorXformSrcRow, (const uint8_t*) src); SkAssertResult(fColorXform->apply(fXformColorFormat, dst, srcColorFormat, fColorXformSrcRow, fXformWidth, fXformAlphaType)); break; } } class SkPngNormalDecoder : public SkPngCodec { public: SkPngNormalDecoder(const SkEncodedInfo& info, const SkImageInfo& imageInfo, SkStream* stream, SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth) : INHERITED(info, imageInfo, stream, reader, png_ptr, info_ptr, bitDepth) , fLinesDecoded(0) , fRowsWrittenToOutput(0) , fDst(nullptr) , fRowBytes(0) , fFirstRow(0) , fLastRow(0) {} static void AllRowsCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int /*pass*/) { GetDecoder(png_ptr)->allRowsCallback(row, rowNum); } static void RowCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int /*pass*/) { GetDecoder(png_ptr)->rowCallback(row, rowNum); } #ifdef SK_GOOGLE3_PNG_HACK static void RereadInfoCallback(png_structp png_ptr, png_infop) { GetDecoder(png_ptr)->rereadInfoCallback(); } #endif private: // This represents the number of lines reported by libpng, minus any we skipped at the // beginning. Only used when we are skipping lines (i.e. not in decodeAllRows). int fLinesDecoded; // While fLinesDecoded include lines that we skipped, this only includes lines written to the // output so we can report it to the caller for filling. // FIXME: Can we remove fLinesDecoded and just rely on fRowsWrittenToOutput? int fRowsWrittenToOutput; void* fDst; size_t fRowBytes; // Variables for partial decode int fFirstRow; // FIXME: Move to baseclass? int fLastRow; typedef SkPngCodec INHERITED; static SkPngNormalDecoder* GetDecoder(png_structp png_ptr) { return static_cast(png_get_progressive_ptr(png_ptr)); } Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override { const int height = this->getInfo().height(); png_progressive_info_ptr callback = nullptr; #ifdef SK_GOOGLE3_PNG_HACK callback = RereadInfoCallback; #endif png_set_progressive_read_fn(this->png_ptr(), this, callback, AllRowsCallback, nullptr); fDst = dst; fRowBytes = rowBytes; fRowsWrittenToOutput = 0; fFirstRow = 0; fLastRow = height - 1; this->processData(); if (fRowsWrittenToOutput == height) { return SkCodec::kSuccess; } if (rowsDecoded) { *rowsDecoded = fRowsWrittenToOutput; } return SkCodec::kIncompleteInput; } void allRowsCallback(png_bytep row, int rowNum) { SkASSERT(rowNum == fRowsWrittenToOutput); fRowsWrittenToOutput++; this->applyXformRow(fDst, row); fDst = SkTAddOffset(fDst, fRowBytes); } void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override { png_progressive_info_ptr callback = nullptr; #ifdef SK_GOOGLE3_PNG_HACK callback = RereadInfoCallback; #endif png_set_progressive_read_fn(this->png_ptr(), this, callback, RowCallback, nullptr); fFirstRow = firstRow; fLastRow = lastRow; fDst = dst; fRowBytes = rowBytes; fLinesDecoded = 0; fRowsWrittenToOutput = 0; } SkCodec::Result decode(int* rowsDecoded) override { this->processData(); if (fLinesDecoded == fLastRow - fFirstRow + 1) { return SkCodec::kSuccess; } if (rowsDecoded) { *rowsDecoded = fRowsWrittenToOutput; } return SkCodec::kIncompleteInput; } void rowCallback(png_bytep row, int rowNum) { if (rowNum < fFirstRow) { // Ignore this row. return; } SkASSERT(rowNum <= fLastRow); // If there is no swizzler, all rows are needed. if (!this->swizzler() || this->swizzler()->rowNeeded(fLinesDecoded)) { this->applyXformRow(fDst, row); fDst = SkTAddOffset(fDst, fRowBytes); fRowsWrittenToOutput++; } fLinesDecoded++; if (rowNum == fLastRow) { // Fake error to stop decoding scanlines. longjmp(PNG_JMPBUF(this->png_ptr()), kStopDecoding); } } }; class SkPngInterlacedDecoder : public SkPngCodec { public: SkPngInterlacedDecoder(const SkEncodedInfo& info, const SkImageInfo& imageInfo, SkStream* stream, SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth, int numberPasses) : INHERITED(info, imageInfo, stream, reader, png_ptr, info_ptr, bitDepth) , fNumberPasses(numberPasses) , fFirstRow(0) , fLastRow(0) , fLinesDecoded(0) , fInterlacedComplete(false) , fPng_rowbytes(0) {} static void InterlacedRowCallback(png_structp png_ptr, png_bytep row, png_uint_32 rowNum, int pass) { auto decoder = static_cast(png_get_progressive_ptr(png_ptr)); decoder->interlacedRowCallback(row, rowNum, pass); } #ifdef SK_GOOGLE3_PNG_HACK static void RereadInfoInterlacedCallback(png_structp png_ptr, png_infop) { static_cast(png_get_progressive_ptr(png_ptr))->rereadInfoInterlaced(); } #endif private: const int fNumberPasses; int fFirstRow; int fLastRow; void* fDst; size_t fRowBytes; int fLinesDecoded; bool fInterlacedComplete; size_t fPng_rowbytes; SkAutoTMalloc fInterlaceBuffer; typedef SkPngCodec INHERITED; #ifdef SK_GOOGLE3_PNG_HACK void rereadInfoInterlaced() { this->rereadInfoCallback(); // Note: This allocates more memory than necessary, if we are sampling/subset. this->setUpInterlaceBuffer(this->getInfo().height()); } #endif // FIXME: Currently sharing interlaced callback for all rows and subset. It's not // as expensive as the subset version of non-interlaced, but it still does extra // work. void interlacedRowCallback(png_bytep row, int rowNum, int pass) { if (rowNum < fFirstRow || rowNum > fLastRow) { // Ignore this row return; } png_bytep oldRow = fInterlaceBuffer.get() + (rowNum - fFirstRow) * fPng_rowbytes; png_progressive_combine_row(this->png_ptr(), oldRow, row); if (0 == pass) { // The first pass initializes all rows. SkASSERT(row); SkASSERT(fLinesDecoded == rowNum - fFirstRow); fLinesDecoded++; } else { SkASSERT(fLinesDecoded == fLastRow - fFirstRow + 1); if (fNumberPasses - 1 == pass && rowNum == fLastRow) { // Last pass, and we have read all of the rows we care about. Note that // we do not care about reading anything beyond the end of the image (or // beyond the last scanline requested). fInterlacedComplete = true; // Fake error to stop decoding scanlines. longjmp(PNG_JMPBUF(this->png_ptr()), kStopDecoding); } } } SkCodec::Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override { const int height = this->getInfo().height(); this->setUpInterlaceBuffer(height); png_progressive_info_ptr callback = nullptr; #ifdef SK_GOOGLE3_PNG_HACK callback = RereadInfoInterlacedCallback; #endif png_set_progressive_read_fn(this->png_ptr(), this, callback, InterlacedRowCallback, nullptr); fFirstRow = 0; fLastRow = height - 1; fLinesDecoded = 0; this->processData(); png_bytep srcRow = fInterlaceBuffer.get(); // FIXME: When resuming, this may rewrite rows that did not change. for (int rowNum = 0; rowNum < fLinesDecoded; rowNum++) { this->applyXformRow(dst, srcRow); dst = SkTAddOffset(dst, rowBytes); srcRow = SkTAddOffset(srcRow, fPng_rowbytes); } if (fInterlacedComplete) { return SkCodec::kSuccess; } if (rowsDecoded) { *rowsDecoded = fLinesDecoded; } return SkCodec::kIncompleteInput; } void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override { // FIXME: We could skip rows in the interlace buffer that we won't put in the output. this->setUpInterlaceBuffer(lastRow - firstRow + 1); png_progressive_info_ptr callback = nullptr; #ifdef SK_GOOGLE3_PNG_HACK callback = RereadInfoInterlacedCallback; #endif png_set_progressive_read_fn(this->png_ptr(), this, callback, InterlacedRowCallback, nullptr); fFirstRow = firstRow; fLastRow = lastRow; fDst = dst; fRowBytes = rowBytes; fLinesDecoded = 0; } SkCodec::Result decode(int* rowsDecoded) override { this->processData(); // Now apply Xforms on all the rows that were decoded. if (!fLinesDecoded) { if (rowsDecoded) { *rowsDecoded = 0; } return SkCodec::kIncompleteInput; } const int lastRow = fLinesDecoded + fFirstRow - 1; SkASSERT(lastRow <= fLastRow); int rowsWrittenToOutput = 0; // FIXME: For resuming interlace, we may swizzle a row that hasn't changed. But it // may be too tricky/expensive to handle that correctly. png_bytep srcRow = fInterlaceBuffer.get(); const int sampleY = this->swizzler() ? this->swizzler()->sampleY() : 1; void* dst = fDst; for (int rowNum = fFirstRow; rowNum <= lastRow; rowNum += sampleY) { this->applyXformRow(dst, srcRow); dst = SkTAddOffset(dst, fRowBytes); srcRow = SkTAddOffset(srcRow, fPng_rowbytes * sampleY); rowsWrittenToOutput++; } if (fInterlacedComplete) { return SkCodec::kSuccess; } if (rowsDecoded) { *rowsDecoded = rowsWrittenToOutput; } return SkCodec::kIncompleteInput; } void setUpInterlaceBuffer(int height) { fPng_rowbytes = png_get_rowbytes(this->png_ptr(), this->info_ptr()); fInterlaceBuffer.reset(fPng_rowbytes * height); fInterlacedComplete = false; } }; #ifdef SK_GOOGLE3_PNG_HACK bool SkPngCodec::rereadHeaderIfNecessary() { if (!fNeedsToRereadHeader) { return true; } // On the first call, we'll need to rewind ourselves. Future calls will // have already rewound in rewindIfNecessary. if (this->stream()->getPosition() > 0) { this->stream()->rewind(); } this->destroyReadStruct(); png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, sk_error_fn, sk_warning_fn); if (!png_ptr) { return false; } // Only use the AutoCleanPng to delete png_ptr as necessary. // (i.e. not for reading bounds etc.) AutoCleanPng autoClean(png_ptr, nullptr, nullptr, nullptr); png_infop info_ptr = png_create_info_struct(png_ptr); if (info_ptr == nullptr) { return false; } autoClean.setInfoPtr(info_ptr); #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED // Hookup our chunkReader so we can see any user-chunks the caller may be interested in. // This needs to be installed before we read the png header. Android may store ninepatch // chunks in the header. if (fPngChunkReader.get()) { png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0); png_set_read_user_chunk_fn(png_ptr, (png_voidp) fPngChunkReader.get(), sk_read_user_chunk); } #endif fPng_ptr = png_ptr; fInfo_ptr = info_ptr; autoClean.releasePngPtrs(); fNeedsToRereadHeader = false; return true; } #endif // SK_GOOGLE3_PNG_HACK // Reads the header and initializes the output fields, if not NULL. // // @param stream Input data. Will be read to get enough information to properly // setup the codec. // @param chunkReader SkPngChunkReader, for reading unknown chunks. May be NULL. // If not NULL, png_ptr will hold an *unowned* pointer to it. The caller is // expected to continue to own it for the lifetime of the png_ptr. // @param outCodec Optional output variable. If non-NULL, will be set to a new // SkPngCodec on success. // @param png_ptrp Optional output variable. If non-NULL, will be set to a new // png_structp on success. // @param info_ptrp Optional output variable. If non-NULL, will be set to a new // png_infop on success; // @return true on success, in which case the caller is responsible for calling // png_destroy_read_struct(png_ptrp, info_ptrp). // If it returns false, the passed in fields (except stream) are unchanged. static bool read_header(SkStream* stream, SkPngChunkReader* chunkReader, SkCodec** outCodec, png_structp* png_ptrp, png_infop* info_ptrp) { // 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, nullptr, sk_error_fn, sk_warning_fn); if (!png_ptr) { return false; } AutoCleanPng autoClean(png_ptr, stream, chunkReader, outCodec); png_infop info_ptr = png_create_info_struct(png_ptr); if (info_ptr == nullptr) { return false; } autoClean.setInfoPtr(info_ptr); // FIXME: Could we use the return value of setjmp to specify the type of // error? if (setjmp(PNG_JMPBUF(png_ptr))) { return false; } #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED // Hookup our chunkReader so we can see any user-chunks the caller may be interested in. // This needs to be installed before we read the png header. Android may store ninepatch // chunks in the header. if (chunkReader) { png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_ALWAYS, (png_byte*)"", 0); png_set_read_user_chunk_fn(png_ptr, (png_voidp) chunkReader, sk_read_user_chunk); } #endif const bool decodedBounds = autoClean.decodeBounds(); if (!decodedBounds) { return false; } // On success, decodeBounds releases ownership of png_ptr and info_ptr. if (png_ptrp) { *png_ptrp = png_ptr; } if (info_ptrp) { *info_ptrp = info_ptr; } // decodeBounds takes care of setting outCodec if (outCodec) { SkASSERT(*outCodec); } return true; } // FIXME (scroggo): Once SK_GOOGLE3_PNG_HACK is no more, this method can be inline in // AutoCleanPng::infoCallback static void general_info_callback(png_structp png_ptr, png_infop info_ptr, SkEncodedInfo::Color* outColor, SkEncodedInfo::Alpha* outAlpha) { png_uint_32 origWidth, origHeight; int bitDepth, encodedColorType; png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, &encodedColorType, nullptr, nullptr, nullptr); // Tell libpng to strip 16 bit/color files down to 8 bits/color. // TODO: Should we handle this in SkSwizzler? Could this also benefit // RAW decodes? if (bitDepth == 16) { SkASSERT(PNG_COLOR_TYPE_PALETTE != encodedColorType); png_set_strip_16(png_ptr); } // Now determine the default colorType and alphaType and set the required transforms. // Often, we depend on SkSwizzler to perform any transforms that we need. However, we // still depend on libpng for many of the rare and PNG-specific cases. SkEncodedInfo::Color color; SkEncodedInfo::Alpha alpha; switch (encodedColorType) { case PNG_COLOR_TYPE_PALETTE: // 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) { // TODO: Should we use SkSwizzler here? png_set_packing(png_ptr); } color = SkEncodedInfo::kPalette_Color; // Set the alpha depending on if a transparency chunk exists. alpha = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) ? SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha; break; case PNG_COLOR_TYPE_RGB: if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { // Convert to RGBA if transparency chunk exists. png_set_tRNS_to_alpha(png_ptr); color = SkEncodedInfo::kRGBA_Color; alpha = SkEncodedInfo::kBinary_Alpha; } else { color = SkEncodedInfo::kRGB_Color; alpha = SkEncodedInfo::kOpaque_Alpha; } break; case PNG_COLOR_TYPE_GRAY: // Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel. if (bitDepth < 8) { // TODO: Should we use SkSwizzler here? png_set_expand_gray_1_2_4_to_8(png_ptr); } if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { png_set_tRNS_to_alpha(png_ptr); color = SkEncodedInfo::kGrayAlpha_Color; alpha = SkEncodedInfo::kBinary_Alpha; } else { color = SkEncodedInfo::kGray_Color; alpha = SkEncodedInfo::kOpaque_Alpha; } break; case PNG_COLOR_TYPE_GRAY_ALPHA: color = SkEncodedInfo::kGrayAlpha_Color; alpha = SkEncodedInfo::kUnpremul_Alpha; break; case PNG_COLOR_TYPE_RGBA: color = SkEncodedInfo::kRGBA_Color; alpha = SkEncodedInfo::kUnpremul_Alpha; break; default: // All the color types have been covered above. SkASSERT(false); color = SkEncodedInfo::kRGBA_Color; alpha = SkEncodedInfo::kUnpremul_Alpha; } if (outColor) { *outColor = color; } if (outAlpha) { *outAlpha = alpha; } } #ifdef SK_GOOGLE3_PNG_HACK void SkPngCodec::rereadInfoCallback() { general_info_callback(fPng_ptr, fInfo_ptr, nullptr, nullptr); png_set_interlace_handling(fPng_ptr); png_read_update_info(fPng_ptr, fInfo_ptr); } #endif void AutoCleanPng::infoCallback() { SkEncodedInfo::Color color; SkEncodedInfo::Alpha alpha; general_info_callback(fPng_ptr, fInfo_ptr, &color, &alpha); const int numberPasses = png_set_interlace_handling(fPng_ptr); fReadHeader = true; fDecodedBounds = true; #ifndef SK_GOOGLE3_PNG_HACK // 1 tells libpng to save any extra data. We may be able to be more efficient by saving // it ourselves. png_process_data_pause(fPng_ptr, 1); #else // Hack to make png_process_data stop. fPng_ptr->buffer_size = 0; #endif if (fOutCodec) { SkASSERT(nullptr == *fOutCodec); sk_sp colorSpace = read_color_space(fPng_ptr, fInfo_ptr); if (!colorSpace) { // Treat unmarked pngs as sRGB. colorSpace = SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named); } SkEncodedInfo encodedInfo = SkEncodedInfo::Make(color, alpha, 8); // FIXME (scroggo): Once we get rid of SK_GOOGLE3_PNG_HACK, general_info_callback can // be inlined, so these values will already be set. png_uint_32 origWidth = png_get_image_width(fPng_ptr, fInfo_ptr); png_uint_32 origHeight = png_get_image_height(fPng_ptr, fInfo_ptr); png_byte bitDepth = png_get_bit_depth(fPng_ptr, fInfo_ptr); SkImageInfo imageInfo = encodedInfo.makeImageInfo(origWidth, origHeight, colorSpace); if (SkEncodedInfo::kOpaque_Alpha == alpha) { png_color_8p sigBits; if (png_get_sBIT(fPng_ptr, fInfo_ptr, &sigBits)) { if (5 == sigBits->red && 6 == sigBits->green && 5 == sigBits->blue) { // Recommend a decode to 565 if the sBIT indicates 565. imageInfo = imageInfo.makeColorType(kRGB_565_SkColorType); } } } if (1 == numberPasses) { *fOutCodec = new SkPngNormalDecoder(encodedInfo, imageInfo, fStream, fChunkReader, fPng_ptr, fInfo_ptr, bitDepth); } else { *fOutCodec = new SkPngInterlacedDecoder(encodedInfo, imageInfo, fStream, fChunkReader, fPng_ptr, fInfo_ptr, bitDepth, numberPasses); } } // Release the pointers, which are now owned by the codec or the caller is expected to // take ownership. this->releasePngPtrs(); } SkPngCodec::SkPngCodec(const SkEncodedInfo& encodedInfo, const SkImageInfo& imageInfo, SkStream* stream, SkPngChunkReader* chunkReader, void* png_ptr, void* info_ptr, int bitDepth) : INHERITED(encodedInfo, imageInfo, stream) , fPngChunkReader(SkSafeRef(chunkReader)) , fPng_ptr(png_ptr) , fInfo_ptr(info_ptr) , fColorXformSrcRow(nullptr) , fBitDepth(bitDepth) #ifdef SK_GOOGLE3_PNG_HACK , fNeedsToRereadHeader(true) #endif {} SkPngCodec::~SkPngCodec() { this->destroyReadStruct(); } void SkPngCodec::destroyReadStruct() { if (fPng_ptr) { // We will never have a nullptr fInfo_ptr with a non-nullptr fPng_ptr SkASSERT(fInfo_ptr); png_destroy_read_struct((png_struct**)&fPng_ptr, (png_info**)&fInfo_ptr, nullptr); fPng_ptr = nullptr; fInfo_ptr = nullptr; } } /////////////////////////////////////////////////////////////////////////////// // Getting the pixels /////////////////////////////////////////////////////////////////////////////// bool SkPngCodec::initializeXforms(const SkImageInfo& dstInfo, const Options& options, SkPMColor ctable[], int* ctableCount) { if (setjmp(PNG_JMPBUF((png_struct*)fPng_ptr))) { SkCodecPrintf("Failed on png_read_update_info.\n"); return false; } png_read_update_info(fPng_ptr, fInfo_ptr); // Reset fSwizzler and fColorXform. We can't do this in onRewind() because the // interlaced scanline decoder may need to rewind. fSwizzler.reset(nullptr); fColorXform = nullptr; if (needs_color_xform(dstInfo, this->getInfo())) { fColorXform = SkColorSpaceXform::New(this->getInfo().colorSpace(), dstInfo.colorSpace()); SkASSERT(fColorXform); } // If the image is RGBA and we have a color xform, we can skip the swizzler. // FIXME (msarett): // Support more input types to fColorXform (ex: RGB, Gray) and skip the swizzler more often. if (fColorXform && SkEncodedInfo::kRGBA_Color == this->getEncodedInfo().color() && !options.fSubset) { fXformMode = kColorOnly_XformMode; return true; } 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(dstInfo, fColorTable, ctable, ctableCount); this->initializeSwizzler(dstInfo, options); return true; } void SkPngCodec::initializeXformParams() { switch (fXformMode) { case kColorOnly_XformMode: fXformColorFormat = select_xform_format(this->dstInfo().colorType()); fXformAlphaType = select_xform_alpha(this->dstInfo().alphaType(), this->getInfo().alphaType()); fXformWidth = this->dstInfo().width(); break; case kSwizzleColor_XformMode: fXformColorFormat = select_xform_format(this->dstInfo().colorType()); fXformAlphaType = select_xform_alpha(this->dstInfo().alphaType(), this->getInfo().alphaType()); fXformWidth = this->swizzler()->swizzleWidth(); break; default: break; } } static inline bool apply_xform_on_decode(SkColorType dstColorType, SkEncodedInfo::Color srcColor) { // We will apply the color xform when reading the color table, unless F16 is requested. return SkEncodedInfo::kPalette_Color != srcColor || kRGBA_F16_SkColorType == dstColorType; } void SkPngCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options) { SkImageInfo swizzlerInfo = dstInfo; Options swizzlerOptions = options; fXformMode = kSwizzleOnly_XformMode; if (fColorXform && apply_xform_on_decode(dstInfo.colorType(), this->getEncodedInfo().color())) { swizzlerInfo = swizzlerInfo.makeColorType(kRGBA_8888_SkColorType); if (kPremul_SkAlphaType == dstInfo.alphaType()) { swizzlerInfo = swizzlerInfo.makeAlphaType(kUnpremul_SkAlphaType); } fXformMode = kSwizzleColor_XformMode; // Here, we swizzle into temporary memory, which is not zero initialized. // FIXME (msarett): // Is this a problem? swizzlerOptions.fZeroInitialized = kNo_ZeroInitialized; } const SkPMColor* colors = get_color_ptr(fColorTable.get()); fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colors, swizzlerInfo, swizzlerOptions)); SkASSERT(fSwizzler); } SkSampler* SkPngCodec::getSampler(bool createIfNecessary) { if (fSwizzler || !createIfNecessary) { return fSwizzler; } this->initializeSwizzler(this->dstInfo(), this->options()); return fSwizzler; } bool SkPngCodec::onRewind() { #ifdef SK_GOOGLE3_PNG_HACK fNeedsToRereadHeader = true; return true; #else // This sets fPng_ptr and fInfo_ptr to nullptr. If read_header // succeeds, they will be repopulated, and if it fails, they will // remain nullptr. Any future accesses to fPng_ptr and fInfo_ptr will // come through this function which will rewind and again attempt // to reinitialize them. this->destroyReadStruct(); png_structp png_ptr; png_infop info_ptr; if (!read_header(this->stream(), fPngChunkReader.get(), nullptr, &png_ptr, &info_ptr)) { return false; } fPng_ptr = png_ptr; fInfo_ptr = info_ptr; return true; #endif } SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, const Options& options, SkPMColor ctable[], int* ctableCount, int* rowsDecoded) { if (!conversion_possible(dstInfo, this->getInfo()) || !this->initializeXforms(dstInfo, options, ctable, ctableCount)) { return kInvalidConversion; } #ifdef SK_GOOGLE3_PNG_HACK // Note that this is done after initializeXforms. Otherwise that method // would not have png_ptr to use. if (!this->rereadHeaderIfNecessary()) { return kCouldNotRewind; } #endif if (options.fSubset) { return kUnimplemented; } this->allocateStorage(dstInfo); this->initializeXformParams(); return this->decodeAllRows(dst, rowBytes, rowsDecoded); } SkCodec::Result SkPngCodec::onStartIncrementalDecode(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, const SkCodec::Options& options, SkPMColor* ctable, int* ctableCount) { if (!conversion_possible(dstInfo, this->getInfo()) || !this->initializeXforms(dstInfo, options, ctable, ctableCount)) { return kInvalidConversion; } #ifdef SK_GOOGLE3_PNG_HACK // See note in onGetPixels. if (!this->rereadHeaderIfNecessary()) { return kCouldNotRewind; } #endif this->allocateStorage(dstInfo); int firstRow, lastRow; if (options.fSubset) { firstRow = options.fSubset->top(); lastRow = options.fSubset->bottom() - 1; } else { firstRow = 0; lastRow = dstInfo.height() - 1; } this->setRange(firstRow, lastRow, dst, rowBytes); return kSuccess; } SkCodec::Result SkPngCodec::onIncrementalDecode(int* rowsDecoded) { // FIXME: Only necessary on the first call. this->initializeXformParams(); return this->decode(rowsDecoded); } uint64_t SkPngCodec::onGetFillValue(const SkImageInfo& dstInfo) const { const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); if (colorPtr) { SkAlphaType alphaType = select_xform_alpha(dstInfo.alphaType(), this->getInfo().alphaType()); return get_color_table_fill_value(dstInfo.colorType(), alphaType, colorPtr, 0, fColorXform.get()); } return INHERITED::onGetFillValue(dstInfo); } SkCodec* SkPngCodec::NewFromStream(SkStream* stream, SkPngChunkReader* chunkReader) { SkAutoTDelete streamDeleter(stream); SkCodec* outCodec = nullptr; if (read_header(streamDeleter.get(), chunkReader, &outCodec, nullptr, nullptr)) { // Codec has taken ownership of the stream. SkASSERT(outCodec); streamDeleter.release(); return outCodec; } return nullptr; }