| /* |
| * 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 "src/codec/SkPngCodec.h" |
| |
| #include "include/core/SkAlphaType.h" |
| #include "include/core/SkColor.h" |
| #include "include/core/SkColorType.h" |
| #include "include/core/SkData.h" |
| #include "include/core/SkImageInfo.h" |
| #include "include/core/SkPngChunkReader.h" |
| #include "include/core/SkRect.h" |
| #include "include/core/SkSize.h" |
| #include "include/core/SkStream.h" |
| #include "include/core/SkTypes.h" |
| #include "include/private/SkEncodedInfo.h" |
| #include "include/private/base/SkNoncopyable.h" |
| #include "include/private/base/SkTemplates.h" |
| #include "modules/skcms/skcms.h" |
| #include "src/codec/SkCodecPriv.h" |
| #include "src/codec/SkColorTable.h" |
| #include "src/codec/SkPngPriv.h" |
| #include "src/codec/SkSwizzler.h" |
| #include "src/core/SkOpts.h" |
| |
| #include <csetjmp> |
| #include <algorithm> |
| #include <cstring> |
| #include <utility> |
| |
| #include <png.h> |
| #include <pngconf.h> |
| |
| using namespace skia_private; |
| |
| class SkSampler; |
| |
| #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK |
| #include "include/android/SkAndroidFrameworkUtils.h" |
| #endif |
| |
| // This warning triggers false positives way too often in here. |
| #if defined(__GNUC__) && !defined(__clang__) |
| #pragma GCC diagnostic ignored "-Wclobbered" |
| #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) |
| , 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; |
| SkStream* fStream; |
| SkPngChunkReader* fChunkReader; |
| SkCodec** fOutCodec; |
| |
| void infoCallback(size_t idatLength); |
| |
| void releasePngPtrs() { |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| }; |
| |
| static inline bool is_chunk(const png_byte* chunk, const char* tag) { |
| return memcmp(chunk + 4, tag, 4) == 0; |
| } |
| |
| static inline bool process_data(png_structp png_ptr, png_infop info_ptr, |
| SkStream* stream, void* buffer, size_t bufferSize, size_t length) { |
| while (length > 0) { |
| const size_t bytesToProcess = std::min(bufferSize, length); |
| const size_t bytesRead = stream->read(buffer, bytesToProcess); |
| png_process_data(png_ptr, info_ptr, (png_bytep) buffer, bytesRead); |
| if (bytesRead < bytesToProcess) { |
| return false; |
| } |
| length -= bytesToProcess; |
| } |
| return true; |
| } |
| |
| bool AutoCleanPng::decodeBounds() { |
| if (setjmp(PNG_JMPBUF(fPng_ptr))) { |
| return false; |
| } |
| |
| png_set_progressive_read_fn(fPng_ptr, nullptr, nullptr, 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]; |
| |
| { |
| // Parse the signature. |
| if (fStream->read(buffer, 8) < 8) { |
| return false; |
| } |
| |
| png_process_data(fPng_ptr, fInfo_ptr, (png_bytep) buffer, 8); |
| } |
| |
| while (true) { |
| // Parse chunk length and type. |
| if (fStream->read(buffer, 8) < 8) { |
| // We have read to the end of the input without decoding bounds. |
| break; |
| } |
| |
| png_byte* chunk = reinterpret_cast<png_byte*>(buffer); |
| const size_t length = png_get_uint_32(chunk); |
| |
| if (is_chunk(chunk, "IDAT")) { |
| this->infoCallback(length); |
| return true; |
| } |
| |
| png_process_data(fPng_ptr, fInfo_ptr, chunk, 8); |
| // Process the full chunk + CRC. |
| if (!process_data(fPng_ptr, fInfo_ptr, fStream, buffer, kBufferSize, length + 4)) { |
| return false; |
| } |
| } |
| |
| return false; |
| } |
| |
| bool 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 false; |
| case kStopDecoding: |
| // We decoded all the lines we want. |
| return true; |
| 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]; |
| |
| bool iend = false; |
| while (true) { |
| size_t length; |
| if (fDecodedIdat) { |
| // Parse chunk length and type. |
| if (this->stream()->read(buffer, 8) < 8) { |
| break; |
| } |
| |
| png_byte* chunk = reinterpret_cast<png_byte*>(buffer); |
| png_process_data(fPng_ptr, fInfo_ptr, chunk, 8); |
| if (is_chunk(chunk, "IEND")) { |
| iend = true; |
| } |
| |
| length = png_get_uint_32(chunk); |
| } else { |
| length = fIdatLength; |
| png_byte idat[] = {0, 0, 0, 0, 'I', 'D', 'A', 'T'}; |
| png_save_uint_32(idat, length); |
| png_process_data(fPng_ptr, fInfo_ptr, idat, 8); |
| fDecodedIdat = true; |
| } |
| |
| // Process the full chunk + CRC. |
| if (!process_data(fPng_ptr, fInfo_ptr, this->stream(), buffer, kBufferSize, length + 4) |
| || iend) { |
| break; |
| } |
| } |
| |
| return true; |
| } |
| |
| static constexpr SkColorType kXformSrcColorType = kRGBA_8888_SkColorType; |
| |
| static inline bool needs_premul(SkAlphaType dstAT, SkEncodedInfo::Alpha encodedAlpha) { |
| return kPremul_SkAlphaType == dstAT && SkEncodedInfo::kUnpremul_Alpha == encodedAlpha; |
| } |
| |
| // Note: SkColorTable claims to store SkPMColors, which is not necessarily the case here. |
| bool SkPngCodec::createColorTable(const SkImageInfo& dstInfo) { |
| |
| 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 = this->colorXform() ? kXformSrcColorType : dstInfo.colorType(); |
| |
| png_bytep alphas; |
| int numColorsWithAlpha = 0; |
| if (png_get_tRNS(fPng_ptr, fInfo_ptr, &alphas, &numColorsWithAlpha, nullptr)) { |
| bool premultiply = needs_premul(dstInfo.alphaType(), this->getEncodedInfo().alpha()); |
| |
| // 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, (const uint8_t*)palette, |
| numColors - numColorsWithAlpha); |
| } else { |
| SkOpts::RGB_to_BGR1(colorTable + numColorsWithAlpha, (const uint8_t*)palette, |
| numColors - numColorsWithAlpha); |
| } |
| } |
| |
| if (this->colorXform() && !this->xformOnDecode()) { |
| this->applyColorXform(colorTable, colorTable, numColors); |
| } |
| |
| // 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); |
| } |
| |
| fColorTable.reset(new SkColorTable(colorTable, maxColors)); |
| return true; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Creation |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| bool SkPngCodec::IsPng(const void* 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); |
| } |
| |
| #endif // LIBPNG >= 1.6 |
| |
| // If there is no color profile information, it will use sRGB. |
| std::unique_ptr<SkEncodedInfo::ICCProfile> read_color_profile(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)) { |
| auto data = SkData::MakeWithCopy(profile, length); |
| return SkEncodedInfo::ICCProfile::Make(std::move(data)); |
| } |
| |
| // Second, check for sRGB. |
| // Note that Blink does this first. This code checks ICC first, with the thinking that |
| // an image has both truly wants the potentially more specific ICC chunk, with sRGB as a |
| // backup in case the decoder does not support full color management. |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) { |
| // sRGB chunks also store a rendering intent: Absolute, Relative, |
| // Perceptual, and Saturation. |
| // FIXME (scroggo): Extract this information from the sRGB chunk once |
| // we are able to handle this information in |
| // skcms_ICCProfile |
| return nullptr; |
| } |
| |
| // Default to SRGB gamut. |
| skcms_Matrix3x3 toXYZD50 = skcms_sRGB_profile()->toXYZD50; |
| // Next, check for chromaticities. |
| png_fixed_point chrm[8]; |
| png_fixed_point gamma; |
| 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])) |
| { |
| float rx = png_fixed_point_to_float(chrm[2]); |
| float ry = png_fixed_point_to_float(chrm[3]); |
| float gx = png_fixed_point_to_float(chrm[4]); |
| float gy = png_fixed_point_to_float(chrm[5]); |
| float bx = png_fixed_point_to_float(chrm[6]); |
| float by = png_fixed_point_to_float(chrm[7]); |
| float wx = png_fixed_point_to_float(chrm[0]); |
| float wy = png_fixed_point_to_float(chrm[1]); |
| |
| skcms_Matrix3x3 tmp; |
| if (skcms_PrimariesToXYZD50(rx, ry, gx, gy, bx, by, wx, wy, &tmp)) { |
| toXYZD50 = tmp; |
| } else { |
| // Note that Blink simply returns nullptr in this case. We'll fall |
| // back to srgb. |
| } |
| } |
| |
| skcms_TransferFunction fn; |
| if (PNG_INFO_gAMA == png_get_gAMA_fixed(png_ptr, info_ptr, &gamma)) { |
| fn.a = 1.0f; |
| fn.b = fn.c = fn.d = fn.e = fn.f = 0.0f; |
| fn.g = png_inverted_fixed_point_to_float(gamma); |
| } else { |
| // Default to sRGB gamma if the image has color space information, |
| // but does not specify gamma. |
| // Note that Blink would again return nullptr in this case. |
| fn = *skcms_sRGB_TransferFunction(); |
| } |
| |
| skcms_ICCProfile skcmsProfile; |
| skcms_Init(&skcmsProfile); |
| skcms_SetTransferFunction(&skcmsProfile, &fn); |
| skcms_SetXYZD50(&skcmsProfile, &toXYZD50); |
| |
| return SkEncodedInfo::ICCProfile::Make(skcmsProfile); |
| #else // LIBPNG >= 1.6 |
| return nullptr; |
| #endif // LIBPNG >= 1.6 |
| } |
| |
| 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 int bitsPerPixel = this->getEncodedInfo().bitsPerPixel(); |
| |
| // If we have more than 8-bits (per component) of precision, we will keep that |
| // extra precision. Otherwise, we will swizzle to RGBA_8888 before transforming. |
| const size_t bytesPerPixel = (bitsPerPixel > 32) ? bitsPerPixel / 8 : 4; |
| const size_t colorXformBytes = dstInfo.width() * bytesPerPixel; |
| fStorage.reset(colorXformBytes); |
| fColorXformSrcRow = fStorage.get(); |
| break; |
| } |
| } |
| } |
| |
| static skcms_PixelFormat png_select_xform_format(const SkEncodedInfo& info) { |
| // We use kRGB and kRGBA formats because color PNGs are always RGB or RGBA. |
| if (16 == info.bitsPerComponent()) { |
| if (SkEncodedInfo::kRGBA_Color == info.color()) { |
| return skcms_PixelFormat_RGBA_16161616BE; |
| } else if (SkEncodedInfo::kRGB_Color == info.color()) { |
| return skcms_PixelFormat_RGB_161616BE; |
| } |
| } else if (SkEncodedInfo::kGray_Color == info.color()) { |
| return skcms_PixelFormat_G_8; |
| } |
| |
| return skcms_PixelFormat_RGBA_8888; |
| } |
| |
| void SkPngCodec::applyXformRow(void* dst, const void* src) { |
| switch (fXformMode) { |
| case kSwizzleOnly_XformMode: |
| fSwizzler->swizzle(dst, (const uint8_t*) src); |
| break; |
| case kColorOnly_XformMode: |
| this->applyColorXform(dst, src, fXformWidth); |
| break; |
| case kSwizzleColor_XformMode: |
| fSwizzler->swizzle(fColorXformSrcRow, (const uint8_t*) src); |
| this->applyColorXform(dst, fColorXformSrcRow, fXformWidth); |
| break; |
| } |
| } |
| |
| static SkCodec::Result log_and_return_error(bool success) { |
| if (success) return SkCodec::kIncompleteInput; |
| #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK |
| SkAndroidFrameworkUtils::SafetyNetLog("117838472"); |
| #endif |
| return SkCodec::kErrorInInput; |
| } |
| |
| class SkPngNormalDecoder : public SkPngCodec { |
| public: |
| SkPngNormalDecoder(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream, |
| SkPngChunkReader* reader, png_structp png_ptr, png_infop info_ptr, int bitDepth) |
| : INHERITED(std::move(info), std::move(stream), reader, png_ptr, info_ptr, bitDepth) |
| , 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); |
| } |
| |
| private: |
| int fRowsWrittenToOutput; |
| void* fDst; |
| size_t fRowBytes; |
| |
| // Variables for partial decode |
| int fFirstRow; // FIXME: Move to baseclass? |
| int fLastRow; |
| int fRowsNeeded; |
| |
| using INHERITED = SkPngCodec; |
| |
| static SkPngNormalDecoder* GetDecoder(png_structp png_ptr) { |
| return static_cast<SkPngNormalDecoder*>(png_get_progressive_ptr(png_ptr)); |
| } |
| |
| Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override { |
| const int height = this->dimensions().height(); |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, AllRowsCallback, nullptr); |
| fDst = dst; |
| fRowBytes = rowBytes; |
| |
| fRowsWrittenToOutput = 0; |
| fFirstRow = 0; |
| fLastRow = height - 1; |
| |
| const bool success = this->processData(); |
| if (success && fRowsWrittenToOutput == height) { |
| return kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fRowsWrittenToOutput; |
| } |
| |
| return log_and_return_error(success); |
| } |
| |
| void allRowsCallback(png_bytep row, int rowNum) { |
| SkASSERT(rowNum == fRowsWrittenToOutput); |
| fRowsWrittenToOutput++; |
| this->applyXformRow(fDst, row); |
| fDst = SkTAddOffset<void>(fDst, fRowBytes); |
| } |
| |
| void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) override { |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, RowCallback, nullptr); |
| fFirstRow = firstRow; |
| fLastRow = lastRow; |
| fDst = dst; |
| fRowBytes = rowBytes; |
| fRowsWrittenToOutput = 0; |
| fRowsNeeded = fLastRow - fFirstRow + 1; |
| } |
| |
| Result decode(int* rowsDecoded) override { |
| if (this->swizzler()) { |
| const int sampleY = this->swizzler()->sampleY(); |
| fRowsNeeded = get_scaled_dimension(fLastRow - fFirstRow + 1, sampleY); |
| } |
| |
| const bool success = this->processData(); |
| if (success && fRowsWrittenToOutput == fRowsNeeded) { |
| return kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fRowsWrittenToOutput; |
| } |
| |
| return log_and_return_error(success); |
| } |
| |
| void rowCallback(png_bytep row, int rowNum) { |
| if (rowNum < fFirstRow) { |
| // Ignore this row. |
| return; |
| } |
| |
| SkASSERT(rowNum <= fLastRow); |
| SkASSERT(fRowsWrittenToOutput < fRowsNeeded); |
| |
| // If there is no swizzler, all rows are needed. |
| if (!this->swizzler() || this->swizzler()->rowNeeded(rowNum - fFirstRow)) { |
| this->applyXformRow(fDst, row); |
| fDst = SkTAddOffset<void>(fDst, fRowBytes); |
| fRowsWrittenToOutput++; |
| } |
| |
| if (fRowsWrittenToOutput == fRowsNeeded) { |
| // Fake error to stop decoding scanlines. |
| longjmp(PNG_JMPBUF(this->png_ptr()), kStopDecoding); |
| } |
| } |
| }; |
| |
| class SkPngInterlacedDecoder : public SkPngCodec { |
| public: |
| SkPngInterlacedDecoder(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream, |
| SkPngChunkReader* reader, png_structp png_ptr, |
| png_infop info_ptr, int bitDepth, int numberPasses) |
| : INHERITED(std::move(info), std::move(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<SkPngInterlacedDecoder*>(png_get_progressive_ptr(png_ptr)); |
| decoder->interlacedRowCallback(row, rowNum, pass); |
| } |
| |
| private: |
| const int fNumberPasses; |
| int fFirstRow; |
| int fLastRow; |
| void* fDst; |
| size_t fRowBytes; |
| int fLinesDecoded; |
| bool fInterlacedComplete; |
| size_t fPng_rowbytes; |
| AutoTMalloc<png_byte> fInterlaceBuffer; |
| |
| using INHERITED = SkPngCodec; |
| |
| // 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 || fInterlacedComplete) { |
| // 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. |
| fInterlacedComplete = true; |
| if (fLastRow != this->dimensions().height() - 1 || |
| (this->swizzler() && this->swizzler()->sampleY() != 1)) { |
| // Fake error to stop decoding scanlines. Only stop if we're not decoding the |
| // whole image, in which case processing the rest of the image might be |
| // expensive. When decoding the whole image, read through the IEND chunk to |
| // preserve Android behavior of leaving the input stream in the right place. |
| longjmp(PNG_JMPBUF(this->png_ptr()), kStopDecoding); |
| } |
| } |
| } |
| } |
| |
| Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) override { |
| const int height = this->dimensions().height(); |
| this->setUpInterlaceBuffer(height); |
| png_set_progressive_read_fn(this->png_ptr(), this, nullptr, InterlacedRowCallback, |
| nullptr); |
| |
| fFirstRow = 0; |
| fLastRow = height - 1; |
| fLinesDecoded = 0; |
| |
| const bool success = 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<void>(dst, rowBytes); |
| srcRow = SkTAddOffset<png_byte>(srcRow, fPng_rowbytes); |
| } |
| if (success && fInterlacedComplete) { |
| return kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = fLinesDecoded; |
| } |
| |
| return log_and_return_error(success); |
| } |
| |
| 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_set_progressive_read_fn(this->png_ptr(), this, nullptr, InterlacedRowCallback, nullptr); |
| fFirstRow = firstRow; |
| fLastRow = lastRow; |
| fDst = dst; |
| fRowBytes = rowBytes; |
| fLinesDecoded = 0; |
| } |
| |
| Result decode(int* rowsDecoded) override { |
| const bool success = this->processData(); |
| |
| // Now apply Xforms on all the rows that were decoded. |
| if (!fLinesDecoded) { |
| if (rowsDecoded) { |
| *rowsDecoded = 0; |
| } |
| return log_and_return_error(success); |
| } |
| |
| const int sampleY = this->swizzler() ? this->swizzler()->sampleY() : 1; |
| const int rowsNeeded = get_scaled_dimension(fLastRow - fFirstRow + 1, sampleY); |
| |
| // FIXME: For resuming interlace, we may swizzle a row that hasn't changed. But it |
| // may be too tricky/expensive to handle that correctly. |
| |
| // Offset srcRow by get_start_coord rows. We do not need to account for fFirstRow, |
| // since the first row in fInterlaceBuffer corresponds to fFirstRow. |
| int srcRow = get_start_coord(sampleY); |
| void* dst = fDst; |
| int rowsWrittenToOutput = 0; |
| while (rowsWrittenToOutput < rowsNeeded && srcRow < fLinesDecoded) { |
| png_bytep src = SkTAddOffset<png_byte>(fInterlaceBuffer.get(), fPng_rowbytes * srcRow); |
| this->applyXformRow(dst, src); |
| dst = SkTAddOffset<void>(dst, fRowBytes); |
| |
| rowsWrittenToOutput++; |
| srcRow += sampleY; |
| } |
| |
| if (success && fInterlacedComplete) { |
| return kSuccess; |
| } |
| |
| if (rowsDecoded) { |
| *rowsDecoded = rowsWrittenToOutput; |
| } |
| return log_and_return_error(success); |
| } |
| |
| void setUpInterlaceBuffer(int height) { |
| fPng_rowbytes = png_get_rowbytes(this->png_ptr(), this->info_ptr()); |
| fInterlaceBuffer.reset(fPng_rowbytes * height); |
| fInterlacedComplete = false; |
| } |
| }; |
| |
| // 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 if kSuccess, the caller is responsible for calling |
| // png_destroy_read_struct(png_ptrp, info_ptrp). |
| // Otherwise, the passed in fields (except stream) are unchanged. |
| static SkCodec::Result 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 SkCodec::kInternalError; |
| } |
| |
| #ifdef PNG_SET_OPTION_SUPPORTED |
| // This setting ensures that we display images with incorrect CMF bytes. |
| // See crbug.com/807324. |
| png_set_option(png_ptr, PNG_MAXIMUM_INFLATE_WINDOW, PNG_OPTION_ON); |
| #endif |
| |
| AutoCleanPng autoClean(png_ptr, stream, chunkReader, outCodec); |
| |
| png_infop info_ptr = png_create_info_struct(png_ptr); |
| if (info_ptr == nullptr) { |
| return SkCodec::kInternalError; |
| } |
| |
| autoClean.setInfoPtr(info_ptr); |
| |
| if (setjmp(PNG_JMPBUF(png_ptr))) { |
| return SkCodec::kInvalidInput; |
| } |
| |
| #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 SkCodec::kIncompleteInput; |
| } |
| |
| // 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 SkCodec::kSuccess; |
| } |
| |
| void AutoCleanPng::infoCallback(size_t idatLength) { |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, encodedColorType; |
| png_get_IHDR(fPng_ptr, fInfo_ptr, &origWidth, &origHeight, &bitDepth, |
| &encodedColorType, nullptr, nullptr, nullptr); |
| |
| // TODO: Should we support 16-bits of precision for gray images? |
| if (bitDepth == 16 && (PNG_COLOR_TYPE_GRAY == encodedColorType || |
| PNG_COLOR_TYPE_GRAY_ALPHA == encodedColorType)) { |
| bitDepth = 8; |
| png_set_strip_16(fPng_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? |
| bitDepth = 8; |
| png_set_packing(fPng_ptr); |
| } |
| |
| color = SkEncodedInfo::kPalette_Color; |
| // Set the alpha depending on if a transparency chunk exists. |
| alpha = png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS) ? |
| SkEncodedInfo::kUnpremul_Alpha : SkEncodedInfo::kOpaque_Alpha; |
| break; |
| case PNG_COLOR_TYPE_RGB: |
| if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) { |
| // Convert to RGBA if transparency chunk exists. |
| png_set_tRNS_to_alpha(fPng_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? |
| bitDepth = 8; |
| png_set_expand_gray_1_2_4_to_8(fPng_ptr); |
| } |
| |
| if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) { |
| png_set_tRNS_to_alpha(fPng_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; |
| } |
| |
| const int numberPasses = png_set_interlace_handling(fPng_ptr); |
| |
| if (fOutCodec) { |
| SkASSERT(nullptr == *fOutCodec); |
| auto profile = read_color_profile(fPng_ptr, fInfo_ptr); |
| if (profile) { |
| switch (profile->profile()->data_color_space) { |
| case skcms_Signature_CMYK: |
| profile = nullptr; |
| break; |
| case skcms_Signature_Gray: |
| if (SkEncodedInfo::kGray_Color != color && |
| SkEncodedInfo::kGrayAlpha_Color != color) |
| { |
| profile = nullptr; |
| } |
| break; |
| default: |
| break; |
| } |
| } |
| |
| switch (encodedColorType) { |
| case PNG_COLOR_TYPE_GRAY_ALPHA:{ |
| png_color_8p sigBits; |
| if (png_get_sBIT(fPng_ptr, fInfo_ptr, &sigBits)) { |
| if (8 == sigBits->alpha && kGraySigBit_GrayAlphaIsJustAlpha == sigBits->gray) { |
| color = SkEncodedInfo::kXAlpha_Color; |
| } |
| } |
| break; |
| } |
| case PNG_COLOR_TYPE_RGB:{ |
| 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. |
| color = SkEncodedInfo::k565_Color; |
| } |
| } |
| break; |
| } |
| } |
| |
| #ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK |
| if (encodedColorType != PNG_COLOR_TYPE_GRAY_ALPHA |
| && 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) { |
| SkAndroidFrameworkUtils::SafetyNetLog("190188264"); |
| } |
| } |
| } |
| #endif // SK_BUILD_FOR_ANDROID_FRAMEWORK |
| |
| SkEncodedInfo encodedInfo = SkEncodedInfo::Make(origWidth, origHeight, color, alpha, |
| bitDepth, std::move(profile)); |
| if (1 == numberPasses) { |
| *fOutCodec = new SkPngNormalDecoder(std::move(encodedInfo), |
| std::unique_ptr<SkStream>(fStream), fChunkReader, fPng_ptr, fInfo_ptr, bitDepth); |
| } else { |
| *fOutCodec = new SkPngInterlacedDecoder(std::move(encodedInfo), |
| std::unique_ptr<SkStream>(fStream), fChunkReader, fPng_ptr, fInfo_ptr, bitDepth, |
| numberPasses); |
| } |
| static_cast<SkPngCodec*>(*fOutCodec)->setIdatLength(idatLength); |
| } |
| |
| // Release the pointers, which are now owned by the codec or the caller is expected to |
| // take ownership. |
| this->releasePngPtrs(); |
| } |
| |
| SkPngCodec::SkPngCodec(SkEncodedInfo&& encodedInfo, std::unique_ptr<SkStream> stream, |
| SkPngChunkReader* chunkReader, void* png_ptr, void* info_ptr, int bitDepth) |
| : INHERITED(std::move(encodedInfo), png_select_xform_format(encodedInfo), std::move(stream)) |
| , fPngChunkReader(SkSafeRef(chunkReader)) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) |
| , fColorXformSrcRow(nullptr) |
| , fBitDepth(bitDepth) |
| , fIdatLength(0) |
| , fDecodedIdat(false) |
| {} |
| |
| 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 |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| SkCodec::Result SkPngCodec::initializeXforms(const SkImageInfo& dstInfo, const Options& options) { |
| if (setjmp(PNG_JMPBUF((png_struct*)fPng_ptr))) { |
| SkCodecPrintf("Failed on png_read_update_info.\n"); |
| return kInvalidInput; |
| } |
| png_read_update_info(fPng_ptr, fInfo_ptr); |
| |
| // Reset fSwizzler and this->colorXform(). We can't do this in onRewind() because the |
| // interlaced scanline decoder may need to rewind. |
| fSwizzler.reset(nullptr); |
| |
| // If skcms directly supports the encoded PNG format, we should skip format |
| // conversion in the swizzler (or skip swizzling altogether). |
| bool skipFormatConversion = false; |
| switch (this->getEncodedInfo().color()) { |
| case SkEncodedInfo::kRGB_Color: |
| if (this->getEncodedInfo().bitsPerComponent() != 16) { |
| break; |
| } |
| [[fallthrough]]; |
| case SkEncodedInfo::kRGBA_Color: |
| case SkEncodedInfo::kGray_Color: |
| skipFormatConversion = this->colorXform(); |
| break; |
| default: |
| break; |
| } |
| if (skipFormatConversion && !options.fSubset) { |
| fXformMode = kColorOnly_XformMode; |
| return kSuccess; |
| } |
| |
| if (SkEncodedInfo::kPalette_Color == this->getEncodedInfo().color()) { |
| if (!this->createColorTable(dstInfo)) { |
| return kInvalidInput; |
| } |
| } |
| |
| this->initializeSwizzler(dstInfo, options, skipFormatConversion); |
| return kSuccess; |
| } |
| |
| void SkPngCodec::initializeXformParams() { |
| switch (fXformMode) { |
| case kColorOnly_XformMode: |
| fXformWidth = this->dstInfo().width(); |
| break; |
| case kSwizzleColor_XformMode: |
| fXformWidth = this->swizzler()->swizzleWidth(); |
| break; |
| default: |
| break; |
| } |
| } |
| |
| void SkPngCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& options, |
| bool skipFormatConversion) { |
| SkImageInfo swizzlerInfo = dstInfo; |
| Options swizzlerOptions = options; |
| fXformMode = kSwizzleOnly_XformMode; |
| if (this->colorXform() && this->xformOnDecode()) { |
| if (SkEncodedInfo::kGray_Color == this->getEncodedInfo().color()) { |
| swizzlerInfo = swizzlerInfo.makeColorType(kGray_8_SkColorType); |
| } else { |
| swizzlerInfo = swizzlerInfo.makeColorType(kXformSrcColorType); |
| } |
| 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; |
| } |
| |
| if (skipFormatConversion) { |
| // We cannot skip format conversion when there is a color table. |
| SkASSERT(!fColorTable); |
| int srcBPP = 0; |
| switch (this->getEncodedInfo().color()) { |
| case SkEncodedInfo::kRGB_Color: |
| SkASSERT(this->getEncodedInfo().bitsPerComponent() == 16); |
| srcBPP = 6; |
| break; |
| case SkEncodedInfo::kRGBA_Color: |
| srcBPP = this->getEncodedInfo().bitsPerComponent() / 2; |
| break; |
| case SkEncodedInfo::kGray_Color: |
| srcBPP = 1; |
| break; |
| default: |
| SkASSERT(false); |
| break; |
| } |
| fSwizzler = SkSwizzler::MakeSimple(srcBPP, swizzlerInfo, swizzlerOptions); |
| } else { |
| const SkPMColor* colors = get_color_ptr(fColorTable.get()); |
| fSwizzler = SkSwizzler::Make(this->getEncodedInfo(), colors, swizzlerInfo, |
| swizzlerOptions); |
| } |
| SkASSERT(fSwizzler); |
| } |
| |
| SkSampler* SkPngCodec::getSampler(bool createIfNecessary) { |
| if (fSwizzler || !createIfNecessary) { |
| return fSwizzler.get(); |
| } |
| |
| this->initializeSwizzler(this->dstInfo(), this->options(), true); |
| return fSwizzler.get(); |
| } |
| |
| bool SkPngCodec::onRewind() { |
| // 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 (kSuccess != read_header(this->stream(), fPngChunkReader.get(), nullptr, |
| &png_ptr, &info_ptr)) { |
| return false; |
| } |
| |
| fPng_ptr = png_ptr; |
| fInfo_ptr = info_ptr; |
| fDecodedIdat = false; |
| return true; |
| } |
| |
| SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& dstInfo, void* dst, |
| size_t rowBytes, const Options& options, |
| int* rowsDecoded) { |
| Result result = this->initializeXforms(dstInfo, options); |
| if (kSuccess != result) { |
| return result; |
| } |
| |
| 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) { |
| Result result = this->initializeXforms(dstInfo, options); |
| if (kSuccess != result) { |
| return result; |
| } |
| |
| 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); |
| } |
| |
| std::unique_ptr<SkCodec> SkPngCodec::MakeFromStream(std::unique_ptr<SkStream> stream, |
| Result* result, SkPngChunkReader* chunkReader) { |
| SkCodec* outCodec = nullptr; |
| *result = read_header(stream.get(), chunkReader, &outCodec, nullptr, nullptr); |
| if (kSuccess == *result) { |
| // Codec has taken ownership of the stream. |
| SkASSERT(outCodec); |
| stream.release(); |
| } |
| return std::unique_ptr<SkCodec>(outCodec); |
| } |