| /* |
| * 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 "SkCodecPriv.h" |
| #include "SkColorPriv.h" |
| #include "SkColorTable.h" |
| #include "SkBitmap.h" |
| #include "SkMath.h" |
| #include "SkOpts.h" |
| #include "SkPngCodec.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| #include "SkTemplates.h" |
| #include "SkUtils.h" |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Callback functions |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| static void sk_error_fn(png_structp png_ptr, png_const_charp msg) { |
| SkCodecPrintf("------ png error %s\n", msg); |
| longjmp(png_jmpbuf(png_ptr), 1); |
| } |
| |
| void sk_warning_fn(png_structp, png_const_charp msg) { |
| SkCodecPrintf("----- png warning %s\n", msg); |
| } |
| |
| static void sk_read_fn(png_structp png_ptr, png_bytep data, |
| png_size_t length) { |
| SkStream* stream = static_cast<SkStream*>(png_get_io_ptr(png_ptr)); |
| const size_t bytes = stream->read(data, length); |
| if (bytes != length) { |
| // FIXME: We want to report the fact that the stream was truncated. |
| // One way to do that might be to pass a enum to longjmp so setjmp can |
| // specify the failure. |
| 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* 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: |
| AutoCleanPng(png_structp png_ptr) |
| : fPng_ptr(png_ptr) |
| , fInfo_ptr(nullptr) {} |
| |
| ~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; |
| } |
| |
| void detach() { |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| |
| private: |
| png_structp fPng_ptr; |
| png_infop fInfo_ptr; |
| }; |
| #define AutoCleanPng(...) SK_REQUIRE_LOCAL_VAR(AutoCleanPng) |
| |
| // Method for coverting to either an SkPMColor or a similarly packed |
| // unpremultiplied color. |
| typedef uint32_t (*PackColorProc)(U8CPU a, U8CPU r, U8CPU g, U8CPU b); |
| |
| // Note: SkColorTable claims to store SkPMColors, which is not necessarily |
| // the case here. |
| // TODO: If we add support for non-native swizzles, we'll need to handle that here. |
| bool SkPngCodec::decodePalette(bool premultiply, int* ctableCount) { |
| |
| int numColors; |
| png_color* palette; |
| if (!png_get_PLTE(fPng_ptr, fInfo_ptr, &palette, &numColors)) { |
| return false; |
| } |
| |
| // Note: These are not necessarily SkPMColors. |
| SkPMColor colorPtr[256]; |
| |
| png_bytep alphas; |
| int numColorsWithAlpha = 0; |
| if (png_get_tRNS(fPng_ptr, fInfo_ptr, &alphas, &numColorsWithAlpha, nullptr)) { |
| // 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 (premultiply) { |
| proc = &SkPremultiplyARGBInline; |
| } else { |
| proc = &SkPackARGB32NoCheck; |
| } |
| |
| 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. |
| colorPtr[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 |
| |
| #ifdef SK_PMCOLOR_IS_RGBA |
| SkOpts::RGB_to_RGB1(colorPtr + numColorsWithAlpha, palette, numColors - numColorsWithAlpha); |
| #else |
| SkOpts::RGB_to_BGR1(colorPtr + numColorsWithAlpha, palette, numColors - numColorsWithAlpha); |
| #endif |
| } |
| |
| // 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 ? colorPtr[numColors - 1] : SK_ColorBLACK; |
| sk_memset32(colorPtr + numColors, lastColor, maxColors - numColors); |
| } |
| |
| // Set the new color count. |
| if (ctableCount != nullptr) { |
| *ctableCount = maxColors; |
| } |
| |
| fColorTable.reset(new SkColorTable(colorPtr, 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); |
| } |
| |
| // 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 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; |
| // @param imageInfo Optional output variable. If non-NULL, will be set to |
| // reflect the properties of the encoded image on success. |
| // @param bitDepthPtr Optional output variable. If non-NULL, will be set to the |
| // bit depth of the encoded image on success. |
| // @param numberPassesPtr Optional output variable. If non-NULL, will be set to |
| // the number_passes of the encoded image 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, |
| png_structp* png_ptrp, png_infop* info_ptrp, |
| SkImageInfo* imageInfo, int* bitDepthPtr, int* numberPassesPtr) { |
| // 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); |
| |
| 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; |
| } |
| |
| png_set_read_fn(png_ptr, static_cast<void*>(stream), sk_read_fn); |
| |
| #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 |
| |
| // 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, encodedColorType; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| &encodedColorType, nullptr, nullptr, nullptr); |
| |
| if (bitDepthPtr) { |
| *bitDepthPtr = bitDepth; |
| } |
| |
| // 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. |
| SkColorType colorType = kUnknown_SkColorType; |
| SkAlphaType alphaType = kUnknown_SkAlphaType; |
| 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); |
| } |
| |
| colorType = kIndex_8_SkColorType; |
| // Set the alpha type depending on if a transparency chunk exists. |
| alphaType = png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS) ? |
| kUnpremul_SkAlphaType : kOpaque_SkAlphaType; |
| 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); |
| alphaType = kUnpremul_SkAlphaType; |
| } else { |
| alphaType = kOpaque_SkAlphaType; |
| } |
| colorType = kN32_SkColorType; |
| 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); |
| |
| // We will recommend kN32 here since we do not support kGray |
| // with alpha. |
| colorType = kN32_SkColorType; |
| alphaType = kUnpremul_SkAlphaType; |
| } else { |
| colorType = kGray_8_SkColorType; |
| alphaType = kOpaque_SkAlphaType; |
| } |
| break; |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| // We will recommend kN32 here since we do not support anything |
| // similar to GRAY_ALPHA. |
| colorType = kN32_SkColorType; |
| alphaType = kUnpremul_SkAlphaType; |
| break; |
| case PNG_COLOR_TYPE_RGBA: |
| colorType = kN32_SkColorType; |
| alphaType = kUnpremul_SkAlphaType; |
| break; |
| default: |
| // All the color types have been covered above. |
| SkASSERT(false); |
| } |
| |
| int numberPasses = png_set_interlace_handling(png_ptr); |
| if (numberPassesPtr) { |
| *numberPassesPtr = numberPasses; |
| } |
| |
| SkColorProfileType profileType = kLinear_SkColorProfileType; |
| if (png_get_valid(png_ptr, info_ptr, PNG_INFO_sRGB)) { |
| profileType = kSRGB_SkColorProfileType; |
| } |
| |
| if (imageInfo) { |
| *imageInfo = SkImageInfo::Make(origWidth, origHeight, colorType, alphaType, profileType); |
| } |
| autoClean.detach(); |
| if (png_ptrp) { |
| *png_ptrp = png_ptr; |
| } |
| if (info_ptrp) { |
| *info_ptrp = info_ptr; |
| } |
| |
| return true; |
| } |
| |
| SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream, SkPngChunkReader* chunkReader, |
| png_structp png_ptr, png_infop info_ptr, int bitDepth, int numberPasses) |
| : INHERITED(info, stream) |
| , fPngChunkReader(SkSafeRef(chunkReader)) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) |
| , fSrcConfig(SkSwizzler::kUnknown) |
| , fNumberPasses(numberPasses) |
| , fBitDepth(bitDepth) |
| {} |
| |
| 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(&fPng_ptr, &fInfo_ptr, nullptr); |
| fPng_ptr = nullptr; |
| fInfo_ptr = nullptr; |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Getting the pixels |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| SkCodec::Result SkPngCodec::initializeSwizzler(const SkImageInfo& requestedInfo, |
| const Options& options, |
| SkPMColor ctable[], |
| int* ctableCount) { |
| // FIXME: Could we use the return value of setjmp to specify the type of |
| // error? |
| if (setjmp(png_jmpbuf(fPng_ptr))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| return kInvalidInput; |
| } |
| png_read_update_info(fPng_ptr, fInfo_ptr); |
| |
| // suggestedColorType was determined in read_header() based on the encodedColorType |
| const SkColorType suggestedColorType = this->getInfo().colorType(); |
| |
| switch (suggestedColorType) { |
| case kIndex_8_SkColorType: |
| //decode palette to Skia format |
| fSrcConfig = SkSwizzler::kIndex; |
| if (!this->decodePalette(kPremul_SkAlphaType == requestedInfo.alphaType(), |
| ctableCount)) { |
| return kInvalidInput; |
| } |
| break; |
| case kGray_8_SkColorType: |
| fSrcConfig = SkSwizzler::kGray; |
| break; |
| case kN32_SkColorType: { |
| const uint8_t encodedColorType = png_get_color_type(fPng_ptr, fInfo_ptr); |
| if (PNG_COLOR_TYPE_GRAY_ALPHA == encodedColorType || |
| PNG_COLOR_TYPE_GRAY == encodedColorType) { |
| // If encodedColorType is GRAY, there must be a transparent chunk. |
| // Otherwise, suggestedColorType would be kGray. We have already |
| // instructed libpng to convert the transparent chunk to alpha, |
| // so we can treat both GRAY and GRAY_ALPHA as kGrayAlpha. |
| SkASSERT(encodedColorType == PNG_COLOR_TYPE_GRAY_ALPHA || |
| png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)); |
| |
| fSrcConfig = SkSwizzler::kGrayAlpha; |
| } else { |
| if (this->getInfo().alphaType() == kOpaque_SkAlphaType) { |
| fSrcConfig = SkSwizzler::kRGB; |
| } else { |
| fSrcConfig = SkSwizzler::kRGBA; |
| } |
| } |
| break; |
| } |
| default: |
| // We will always recommend one of the above colorTypes. |
| SkASSERT(false); |
| } |
| |
| // Copy the color table to the client if they request kIndex8 mode |
| copy_color_table(requestedInfo, fColorTable, ctable, ctableCount); |
| |
| // Create the swizzler. SkPngCodec retains ownership of the color table. |
| const SkPMColor* colors = get_color_ptr(fColorTable.get()); |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(fSrcConfig, colors, requestedInfo, options)); |
| SkASSERT(fSwizzler); |
| |
| return kSuccess; |
| } |
| |
| |
| 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 (!read_header(this->stream(), fPngChunkReader.get(), &png_ptr, &info_ptr, |
| nullptr, nullptr, nullptr)) { |
| return false; |
| } |
| |
| fPng_ptr = png_ptr; |
| fInfo_ptr = info_ptr; |
| return true; |
| } |
| |
| SkCodec::Result SkPngCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst, |
| size_t dstRowBytes, const Options& options, |
| SkPMColor ctable[], int* ctableCount, |
| int* rowsDecoded) { |
| if (!conversion_possible(requestedInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| if (options.fSubset) { |
| // Subsets are not supported. |
| return kUnimplemented; |
| } |
| |
| // Note that ctable and ctableCount may be modified if there is a color table |
| const Result result = this->initializeSwizzler(requestedInfo, options, ctable, ctableCount); |
| if (result != kSuccess) { |
| return result; |
| } |
| |
| const int width = requestedInfo.width(); |
| const int height = requestedInfo.height(); |
| const int bpp = SkSwizzler::BytesPerPixel(fSrcConfig); |
| const size_t srcRowBytes = width * bpp; |
| |
| // FIXME: Could we use the return value of setjmp to specify the type of |
| // error? |
| int row = 0; |
| // This must be declared above the call to setjmp to avoid memory leaks on incomplete images. |
| SkAutoTMalloc<uint8_t> storage; |
| if (setjmp(png_jmpbuf(fPng_ptr))) { |
| // Assume that any error that occurs while reading rows is caused by an incomplete input. |
| if (fNumberPasses > 1) { |
| // FIXME (msarett): Handle incomplete interlaced pngs. |
| return (row == height) ? kSuccess : kInvalidInput; |
| } |
| // FIXME: We do a poor job on incomplete pngs compared to other decoders (ex: Chromium, |
| // Ubuntu Image Viewer). This is because we use the default buffer size in libpng (8192 |
| // bytes), and if we can't fill the buffer, we immediately fail. |
| // For example, if we try to read 8192 bytes, and the image (incorrectly) only contains |
| // half that, which may have been enough to contain a non-zero number of lines, we fail |
| // when we could have decoded a few more lines and then failed. |
| // The read function that we provide for libpng has no way of indicating that we have |
| // made a partial read. |
| // Making our buffer size smaller improves our incomplete decodes, but what impact does |
| // it have on regular decode performance? Should we investigate using a different API |
| // instead of png_read_row? Chromium uses png_process_data. |
| *rowsDecoded = row; |
| return (row == height) ? kSuccess : kIncompleteInput; |
| } |
| |
| // FIXME: We could split these out based on subclass. |
| void* dstRow = dst; |
| if (fNumberPasses > 1) { |
| storage.reset(height * srcRowBytes); |
| uint8_t* const base = storage.get(); |
| |
| for (int i = 0; i < fNumberPasses; i++) { |
| uint8_t* srcRow = base; |
| for (int y = 0; y < height; y++) { |
| png_read_row(fPng_ptr, srcRow, nullptr); |
| srcRow += srcRowBytes; |
| } |
| } |
| |
| // Now swizzle it. |
| uint8_t* srcRow = base; |
| for (; row < height; row++) { |
| fSwizzler->swizzle(dstRow, srcRow); |
| dstRow = SkTAddOffset<void>(dstRow, dstRowBytes); |
| srcRow += srcRowBytes; |
| } |
| } else { |
| storage.reset(srcRowBytes); |
| uint8_t* srcRow = storage.get(); |
| for (; row < height; row++) { |
| png_read_row(fPng_ptr, srcRow, nullptr); |
| fSwizzler->swizzle(dstRow, srcRow); |
| dstRow = SkTAddOffset<void>(dstRow, dstRowBytes); |
| } |
| } |
| |
| // read rest of file, and get additional comment and time chunks in info_ptr |
| png_read_end(fPng_ptr, fInfo_ptr); |
| |
| return kSuccess; |
| } |
| |
| uint32_t SkPngCodec::onGetFillValue(SkColorType colorType) const { |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); |
| if (colorPtr) { |
| return get_color_table_fill_value(colorType, colorPtr, 0); |
| } |
| return INHERITED::onGetFillValue(colorType); |
| } |
| |
| // Subclass of SkPngCodec which supports scanline decoding |
| class SkPngScanlineDecoder : public SkPngCodec { |
| public: |
| SkPngScanlineDecoder(const SkImageInfo& srcInfo, SkStream* stream, |
| SkPngChunkReader* chunkReader, png_structp png_ptr, png_infop info_ptr, int bitDepth) |
| : INHERITED(srcInfo, stream, chunkReader, png_ptr, info_ptr, bitDepth, 1) |
| , fSrcRow(nullptr) |
| {} |
| |
| Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options, |
| SkPMColor ctable[], int* ctableCount) override { |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| |
| const Result result = this->initializeSwizzler(dstInfo, options, ctable, |
| ctableCount); |
| if (result != kSuccess) { |
| return result; |
| } |
| |
| fStorage.reset(this->getInfo().width() * SkSwizzler::BytesPerPixel(this->srcConfig())); |
| fSrcRow = fStorage.get(); |
| |
| return kSuccess; |
| } |
| |
| int onGetScanlines(void* dst, int count, size_t rowBytes) override { |
| // Assume that an error in libpng indicates an incomplete input. |
| int row = 0; |
| if (setjmp(png_jmpbuf(this->png_ptr()))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| return row; |
| } |
| |
| void* dstRow = dst; |
| for (; row < count; row++) { |
| png_read_row(this->png_ptr(), fSrcRow, nullptr); |
| this->swizzler()->swizzle(dstRow, fSrcRow); |
| dstRow = SkTAddOffset<void>(dstRow, rowBytes); |
| } |
| |
| return row; |
| } |
| |
| bool onSkipScanlines(int count) override { |
| // Assume that an error in libpng indicates an incomplete input. |
| if (setjmp(png_jmpbuf(this->png_ptr()))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| return false; |
| } |
| |
| for (int row = 0; row < count; row++) { |
| png_read_row(this->png_ptr(), fSrcRow, nullptr); |
| } |
| return true; |
| } |
| |
| private: |
| SkAutoTMalloc<uint8_t> fStorage; |
| uint8_t* fSrcRow; |
| |
| typedef SkPngCodec INHERITED; |
| }; |
| |
| |
| class SkPngInterlacedScanlineDecoder : public SkPngCodec { |
| public: |
| SkPngInterlacedScanlineDecoder(const SkImageInfo& srcInfo, SkStream* stream, |
| SkPngChunkReader* chunkReader, png_structp png_ptr, png_infop info_ptr, |
| int bitDepth, int numberPasses) |
| : INHERITED(srcInfo, stream, chunkReader, png_ptr, info_ptr, bitDepth, numberPasses) |
| , fHeight(-1) |
| , fCanSkipRewind(false) |
| { |
| SkASSERT(numberPasses != 1); |
| } |
| |
| Result onStartScanlineDecode(const SkImageInfo& dstInfo, const Options& options, |
| SkPMColor ctable[], int* ctableCount) override { |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| |
| const Result result = this->initializeSwizzler(dstInfo, options, ctable, |
| ctableCount); |
| if (result != kSuccess) { |
| return result; |
| } |
| |
| fHeight = dstInfo.height(); |
| // FIXME: This need not be called on a second call to onStartScanlineDecode. |
| fSrcRowBytes = this->getInfo().width() * SkSwizzler::BytesPerPixel(this->srcConfig()); |
| fGarbageRow.reset(fSrcRowBytes); |
| fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get()); |
| fCanSkipRewind = true; |
| |
| return SkCodec::kSuccess; |
| } |
| |
| int onGetScanlines(void* dst, int count, size_t dstRowBytes) override { |
| // rewind stream if have previously called onGetScanlines, |
| // since we need entire progressive image to get scanlines |
| if (fCanSkipRewind) { |
| // We already rewound in onStartScanlineDecode, so there is no reason to rewind. |
| // Next time onGetScanlines is called, we will need to rewind. |
| fCanSkipRewind = false; |
| } else { |
| // rewindIfNeeded resets fCurrScanline, since it assumes that start |
| // needs to be called again before scanline decoding. PNG scanline |
| // decoding is the exception, since it needs to rewind between |
| // calls to getScanlines. Keep track of fCurrScanline, to undo the |
| // reset. |
| const int currScanline = this->nextScanline(); |
| // This method would never be called if currScanline is -1 |
| SkASSERT(currScanline != -1); |
| |
| if (!this->rewindIfNeeded()) { |
| return kCouldNotRewind; |
| } |
| this->updateCurrScanline(currScanline); |
| } |
| |
| if (setjmp(png_jmpbuf(this->png_ptr()))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| // FIXME (msarett): Returning 0 is pessimistic. If we can complete a single pass, |
| // we may be able to report that all of the memory has been initialized. Even if we |
| // fail on the first pass, we can still report than some scanlines are initialized. |
| return 0; |
| } |
| SkAutoTMalloc<uint8_t> storage(count * fSrcRowBytes); |
| uint8_t* storagePtr = storage.get(); |
| uint8_t* srcRow; |
| const int startRow = this->nextScanline(); |
| for (int i = 0; i < this->numberPasses(); i++) { |
| // read rows we planned to skip into garbage row |
| for (int y = 0; y < startRow; y++){ |
| png_read_row(this->png_ptr(), fGarbageRowPtr, nullptr); |
| } |
| // read rows we care about into buffer |
| srcRow = storagePtr; |
| for (int y = 0; y < count; y++) { |
| png_read_row(this->png_ptr(), srcRow, nullptr); |
| srcRow += fSrcRowBytes; |
| } |
| // read rows we don't want into garbage buffer |
| for (int y = 0; y < fHeight - startRow - count; y++) { |
| png_read_row(this->png_ptr(), fGarbageRowPtr, nullptr); |
| } |
| } |
| //swizzle the rows we care about |
| srcRow = storagePtr; |
| void* dstRow = dst; |
| for (int y = 0; y < count; y++) { |
| this->swizzler()->swizzle(dstRow, srcRow); |
| dstRow = SkTAddOffset<void>(dstRow, dstRowBytes); |
| srcRow += fSrcRowBytes; |
| } |
| |
| return count; |
| } |
| |
| bool onSkipScanlines(int count) override { |
| // The non-virtual version will update fCurrScanline. |
| return true; |
| } |
| |
| SkScanlineOrder onGetScanlineOrder() const override { |
| return kNone_SkScanlineOrder; |
| } |
| |
| private: |
| int fHeight; |
| size_t fSrcRowBytes; |
| SkAutoMalloc fGarbageRow; |
| uint8_t* fGarbageRowPtr; |
| // FIXME: This imitates behavior in SkCodec::rewindIfNeeded. That function |
| // is called whenever some action is taken that reads the stream and |
| // therefore the next call will require a rewind. So it modifies a boolean |
| // to note that the *next* time it is called a rewind is needed. |
| // SkPngInterlacedScanlineDecoder has an extra wrinkle - calling |
| // onStartScanlineDecode followed by onGetScanlines does *not* require a |
| // rewind. Since rewindIfNeeded does not have this flexibility, we need to |
| // add another layer. |
| bool fCanSkipRewind; |
| |
| typedef SkPngCodec INHERITED; |
| }; |
| |
| SkCodec* SkPngCodec::NewFromStream(SkStream* stream, SkPngChunkReader* chunkReader) { |
| SkAutoTDelete<SkStream> streamDeleter(stream); |
| png_structp png_ptr; |
| png_infop info_ptr; |
| SkImageInfo imageInfo; |
| int bitDepth; |
| int numberPasses; |
| |
| if (!read_header(stream, chunkReader, &png_ptr, &info_ptr, &imageInfo, &bitDepth, |
| &numberPasses)) { |
| return nullptr; |
| } |
| |
| if (1 == numberPasses) { |
| return new SkPngScanlineDecoder(imageInfo, streamDeleter.detach(), chunkReader, |
| png_ptr, info_ptr, bitDepth); |
| } |
| |
| return new SkPngInterlacedScanlineDecoder(imageInfo, streamDeleter.detach(), chunkReader, |
| png_ptr, info_ptr, bitDepth, numberPasses); |
| } |
