| /* |
| * 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 "SkCodec_libpng.h" |
| #include "SkCodecPriv.h" |
| #include "SkColorPriv.h" |
| #include "SkColorTable.h" |
| #include "SkBitmap.h" |
| #include "SkMath.h" |
| #include "SkScaledCodec.h" |
| #include "SkScanlineDecoder.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Helper macros |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #ifndef png_jmpbuf |
| # define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf) |
| #endif |
| |
| /* These were dropped in libpng >= 1.4 */ |
| #ifndef png_infopp_NULL |
| #define png_infopp_NULL nullptr |
| #endif |
| |
| #ifndef png_bytepp_NULL |
| #define png_bytepp_NULL nullptr |
| #endif |
| |
| #ifndef int_p_NULL |
| #define int_p_NULL nullptr |
| #endif |
| |
| #ifndef png_flush_ptr_NULL |
| #define png_flush_ptr_NULL nullptr |
| #endif |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // 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!"); |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // 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, png_infopp_NULL); |
| } |
| } |
| |
| 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) |
| |
| //checks if there is transparency info in the tRNS chunk |
| //image types which could have data in the tRNS chunk include: Index8, Gray8, RGB |
| static bool has_transparency_in_tRNS(png_structp png_ptr, |
| png_infop info_ptr) { |
| if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)) { |
| return false; |
| } |
| |
| png_bytep trans; |
| int num_trans; |
| png_get_tRNS(png_ptr, info_ptr, &trans, &num_trans, nullptr); |
| return num_trans > 0; |
| } |
| |
| // 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. |
| bool SkPngCodec::decodePalette(bool premultiply, int* ctableCount) { |
| int numPalette; |
| png_colorp palette; |
| png_bytep trans; |
| |
| if (!png_get_PLTE(fPng_ptr, fInfo_ptr, &palette, &numPalette)) { |
| return false; |
| } |
| |
| // Note: These are not necessarily SkPMColors |
| SkPMColor colorStorage[256]; // worst-case storage |
| SkPMColor* colorPtr = colorStorage; |
| |
| int numTrans; |
| if (png_get_valid(fPng_ptr, fInfo_ptr, PNG_INFO_tRNS)) { |
| png_get_tRNS(fPng_ptr, fInfo_ptr, &trans, &numTrans, nullptr); |
| } else { |
| numTrans = 0; |
| } |
| |
| // check for bad images that might make us crash |
| if (numTrans > numPalette) { |
| numTrans = numPalette; |
| } |
| |
| int index = 0; |
| int transLessThanFF = 0; |
| |
| // Choose which function to use to create the color table. If the final destination's |
| // colortype is unpremultiplied, the color table will store unpremultiplied colors. |
| PackColorProc proc; |
| if (premultiply) { |
| proc = &SkPreMultiplyARGB; |
| } else { |
| proc = &SkPackARGB32NoCheck; |
| } |
| for (; index < numTrans; index++) { |
| transLessThanFF |= (int)*trans - 0xFF; |
| *colorPtr++ = proc(*trans++, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| |
| fReallyHasAlpha = transLessThanFF < 0; |
| |
| for (; index < numPalette; index++) { |
| *colorPtr++ = SkPackARGB32(0xFF, palette->red, palette->green, palette->blue); |
| palette++; |
| } |
| |
| /* BUGGY IMAGE WORKAROUND |
| Invalid images could contain pixel values that are greater than the number of palette |
| entries. Since we use pixel values as indices into the palette this could result in reading |
| beyond the end of the palette which could leak the contents of uninitialized memory. To |
| ensure this doesn't happen, we grow the colortable to the maximum size that can be |
| addressed by the bitdepth of the image and fill it with the last palette color or black if |
| the palette is empty (really broken image). |
| */ |
| int colorCount = SkTMax(numPalette, 1 << SkTMin(fBitDepth, 8)); |
| SkPMColor lastColor = index > 0 ? colorPtr[-1] : SkPackARGB32(0xFF, 0, 0, 0); |
| for (; index < colorCount; index++) { |
| *colorPtr++ = lastColor; |
| } |
| |
| // Set the new color count |
| if (ctableCount != nullptr) { |
| *ctableCount = colorCount; |
| } |
| |
| fColorTable.reset(new SkColorTable(colorStorage, colorCount)); |
| return true; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Creation |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| #define PNG_BYTES_TO_CHECK 4 |
| |
| bool SkPngCodec::IsPng(SkStream* stream) { |
| char buf[PNG_BYTES_TO_CHECK]; |
| if (stream->read(buf, PNG_BYTES_TO_CHECK) != PNG_BYTES_TO_CHECK) { |
| return false; |
| } |
| if (png_sig_cmp((png_bytep) buf, (png_size_t)0, PNG_BYTES_TO_CHECK)) { |
| return false; |
| } |
| return true; |
| } |
| |
| // Reads the header, and initializes the passed in fields, if not nullptr (except |
| // stream, which is passed to the read function). |
| // Returns true on success, in which case the caller is responsible for calling |
| // png_destroy_read_struct. If it returns false, the passed in fields (except |
| // stream) are unchanged. |
| static bool read_header(SkStream* stream, png_structp* png_ptrp, |
| png_infop* info_ptrp, SkImageInfo* imageInfo, int* bitDepthPtr) { |
| // The image is known to be a PNG. Decode enough to know the SkImageInfo. |
| png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, 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); |
| |
| // FIXME: This is where the old code hooks up the Peeker. Does it need to |
| // be set this early? (i.e. where are the user chunks? early in the stream, |
| // potentially?) |
| // If it does, we need to figure out a way to set it here. |
| |
| // The call to png_read_info() gives us all of the information from the |
| // PNG file before the first IDAT (image data chunk). |
| png_read_info(png_ptr, info_ptr); |
| png_uint_32 origWidth, origHeight; |
| int bitDepth, colorType; |
| png_get_IHDR(png_ptr, info_ptr, &origWidth, &origHeight, &bitDepth, |
| &colorType, int_p_NULL, int_p_NULL, int_p_NULL); |
| |
| if (bitDepthPtr) { |
| *bitDepthPtr = bitDepth; |
| } |
| |
| // sanity check for size |
| { |
| int64_t size = sk_64_mul(origWidth, origHeight); |
| // now check that if we are 4-bytes per pixel, we also don't overflow |
| if (size < 0 || size > (0x7FFFFFFF >> 2)) { |
| return false; |
| } |
| } |
| |
| // Tell libpng to strip 16 bit/color files down to 8 bits/color |
| if (bitDepth == 16) { |
| png_set_strip_16(png_ptr); |
| } |
| #ifdef PNG_READ_PACK_SUPPORTED |
| // Extract multiple pixels with bit depths of 1, 2, and 4 from a single |
| // byte into separate bytes (useful for paletted and grayscale images). |
| if (bitDepth < 8) { |
| png_set_packing(png_ptr); |
| } |
| #endif |
| // Expand grayscale images to the full 8 bits from 1, 2, or 4 bits/pixel. |
| if (colorType == PNG_COLOR_TYPE_GRAY && bitDepth < 8) { |
| png_set_expand_gray_1_2_4_to_8(png_ptr); |
| } |
| |
| // Now determine the default SkColorType and SkAlphaType and set required transforms |
| SkColorType skColorType; |
| SkAlphaType skAlphaType; |
| switch (colorType) { |
| case PNG_COLOR_TYPE_PALETTE: |
| skColorType = kIndex_8_SkColorType; |
| skAlphaType = has_transparency_in_tRNS(png_ptr, info_ptr) ? |
| kUnpremul_SkAlphaType : kOpaque_SkAlphaType; |
| break; |
| case PNG_COLOR_TYPE_RGB: |
| if (has_transparency_in_tRNS(png_ptr, info_ptr)) { |
| //convert to RGBA with tranparency information in tRNS chunk if it exists |
| png_set_tRNS_to_alpha(png_ptr); |
| skAlphaType = kUnpremul_SkAlphaType; |
| } else { |
| //convert to RGBA with Opaque Alpha |
| png_set_filler(png_ptr, 0xff, PNG_FILLER_AFTER); |
| skAlphaType = kOpaque_SkAlphaType; |
| } |
| skColorType = kN32_SkColorType; |
| break; |
| case PNG_COLOR_TYPE_GRAY: |
| if (has_transparency_in_tRNS(png_ptr, info_ptr)) { |
| //FIXME: support gray with alpha as a color type |
| //convert to RGBA if there is transparentcy info in the tRNS chunk |
| png_set_tRNS_to_alpha(png_ptr); |
| png_set_gray_to_rgb(png_ptr); |
| skColorType = kN32_SkColorType; |
| skAlphaType = kUnpremul_SkAlphaType; |
| } else { |
| skColorType = kGray_8_SkColorType; |
| skAlphaType = kOpaque_SkAlphaType; |
| } |
| break; |
| case PNG_COLOR_TYPE_GRAY_ALPHA: |
| //FIXME: support gray with alpha as a color type |
| //convert to RGBA |
| png_set_gray_to_rgb(png_ptr); |
| skColorType = kN32_SkColorType; |
| skAlphaType = kUnpremul_SkAlphaType; |
| break; |
| case PNG_COLOR_TYPE_RGBA: |
| skColorType = kN32_SkColorType; |
| skAlphaType = kUnpremul_SkAlphaType; |
| break; |
| default: |
| //all the color types have been covered above |
| SkASSERT(false); |
| } |
| |
| // FIXME: Also need to check for sRGB (skbug.com/3471). |
| |
| if (imageInfo) { |
| *imageInfo = SkImageInfo::Make(origWidth, origHeight, skColorType, skAlphaType); |
| } |
| autoClean.detach(); |
| if (png_ptrp) { |
| *png_ptrp = png_ptr; |
| } |
| if (info_ptrp) { |
| *info_ptrp = info_ptr; |
| } |
| |
| return true; |
| } |
| |
| SkCodec* SkPngCodec::NewFromStream(SkStream* stream) { |
| SkAutoTDelete<SkStream> streamDeleter(stream); |
| png_structp png_ptr; |
| png_infop info_ptr; |
| SkImageInfo imageInfo; |
| int bitDepth; |
| if (read_header(stream, &png_ptr, &info_ptr, &imageInfo, &bitDepth)) { |
| return new SkPngCodec(imageInfo, streamDeleter.detach(), png_ptr, info_ptr, bitDepth); |
| } |
| return nullptr; |
| } |
| |
| #define INVALID_NUMBER_PASSES -1 |
| SkPngCodec::SkPngCodec(const SkImageInfo& info, SkStream* stream, |
| png_structp png_ptr, png_infop info_ptr, int bitDepth) |
| : INHERITED(info, stream) |
| , fPng_ptr(png_ptr) |
| , fInfo_ptr(info_ptr) |
| , fSrcConfig(SkSwizzler::kUnknown) |
| , fNumberPasses(INVALID_NUMBER_PASSES) |
| , fReallyHasAlpha(false) |
| , fBitDepth(bitDepth) |
| {} |
| |
| SkPngCodec::~SkPngCodec() { |
| 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, png_infopp_NULL); |
| 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; |
| } |
| fNumberPasses = png_set_interlace_handling(fPng_ptr); |
| png_read_update_info(fPng_ptr, fInfo_ptr); |
| |
| // Set to the default before calling decodePalette, which may change it. |
| fReallyHasAlpha = false; |
| |
| //srcColorType was determined in readHeader() which determined png color type |
| const SkColorType srcColorType = this->getInfo().colorType(); |
| |
| switch (srcColorType) { |
| case kIndex_8_SkColorType: |
| //decode palette to Skia format |
| fSrcConfig = SkSwizzler::kIndex; |
| if (!this->decodePalette(kPremul_SkAlphaType == requestedInfo.alphaType(), |
| ctableCount)) { |
| return kInvalidInput; |
| } |
| break; |
| case kGray_8_SkColorType: |
| fSrcConfig = SkSwizzler::kGray; |
| break; |
| case kN32_SkColorType: |
| if (this->getInfo().alphaType() == kOpaque_SkAlphaType) { |
| fSrcConfig = SkSwizzler::kRGBX; |
| } else { |
| fSrcConfig = SkSwizzler::kRGBA; |
| } |
| break; |
| default: |
| //would have exited before now if the colorType was supported by png |
| SkASSERT(false); |
| } |
| |
| // Copy the color table to the client if they request kIndex8 mode |
| copy_color_table(requestedInfo, fColorTable, ctable, ctableCount); |
| |
| // 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.fZeroInitialized, this->getInfo())); |
| if (!fSwizzler) { |
| // FIXME: CreateSwizzler could fail for another reason. |
| return kUnimplemented; |
| } |
| 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(), &png_ptr, &info_ptr, 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) { |
| if (!conversion_possible(requestedInfo, this->getInfo())) { |
| return kInvalidConversion; |
| } |
| if (options.fSubset) { |
| // Subsets are not supported. |
| return kUnimplemented; |
| } |
| if (requestedInfo.dimensions() != this->getInfo().dimensions()) { |
| return kInvalidScale; |
| } |
| if (!this->rewindIfNeeded()) { |
| return kCouldNotRewind; |
| } |
| |
| // 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; |
| } |
| // 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; |
| } |
| |
| SkASSERT(fNumberPasses != INVALID_NUMBER_PASSES); |
| SkAutoMalloc storage; |
| void* dstRow = dst; |
| if (fNumberPasses > 1) { |
| const int width = requestedInfo.width(); |
| const int height = requestedInfo.height(); |
| const int bpp = SkSwizzler::BytesPerPixel(fSrcConfig); |
| const size_t srcRowBytes = width * bpp; |
| |
| storage.reset(width * height * bpp); |
| uint8_t* const base = static_cast<uint8_t*>(storage.get()); |
| |
| for (int i = 0; i < fNumberPasses; i++) { |
| uint8_t* srcRow = base; |
| for (int y = 0; y < height; y++) { |
| uint8_t* bmRow = srcRow; |
| png_read_rows(fPng_ptr, &bmRow, png_bytepp_NULL, 1); |
| srcRow += srcRowBytes; |
| } |
| } |
| |
| // Now swizzle it. |
| uint8_t* srcRow = base; |
| for (int y = 0; y < height; y++) { |
| fReallyHasAlpha |= !SkSwizzler::IsOpaque(fSwizzler->swizzle(dstRow, srcRow)); |
| dstRow = SkTAddOffset<void>(dstRow, dstRowBytes); |
| srcRow += srcRowBytes; |
| } |
| } else { |
| storage.reset(requestedInfo.width() * SkSwizzler::BytesPerPixel(fSrcConfig)); |
| uint8_t* srcRow = static_cast<uint8_t*>(storage.get()); |
| for (int y = 0; y < requestedInfo.height(); y++) { |
| png_read_rows(fPng_ptr, &srcRow, png_bytepp_NULL, 1); |
| fReallyHasAlpha |= !SkSwizzler::IsOpaque(fSwizzler->swizzle(dstRow, srcRow)); |
| dstRow = SkTAddOffset<void>(dstRow, dstRowBytes); |
| } |
| } |
| |
| // FIXME: do we need substituteTranspColor? Note that we cannot do it for |
| // scanline decoding, but we could do it here. Alternatively, we could do |
| // it as we go, instead of in post-processing like SkPNGImageDecoder. |
| |
| if (setjmp(png_jmpbuf(fPng_ptr))) { |
| // We've already read all the scanlines. This is a success. |
| return kSuccess; |
| } |
| |
| // read rest of file, and get additional comment and time chunks in info_ptr |
| png_read_end(fPng_ptr, fInfo_ptr); |
| return kSuccess; |
| } |
| |
| class SkPngScanlineDecoder : public SkScanlineDecoder { |
| public: |
| SkPngScanlineDecoder(const SkImageInfo& srcInfo, SkPngCodec* codec) |
| : INHERITED(srcInfo) |
| , fCodec(codec) |
| , fHasAlpha(false) |
| {} |
| |
| SkCodec::Result onStart(const SkImageInfo& dstInfo, |
| const SkCodec::Options& options, |
| SkPMColor ctable[], int* ctableCount) override { |
| if (!fCodec->rewindIfNeeded()) { |
| return SkCodec::kCouldNotRewind; |
| } |
| |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| return SkCodec::kInvalidConversion; |
| } |
| |
| // Check to see if scaling was requested. |
| if (dstInfo.dimensions() != this->getInfo().dimensions()) { |
| if (!SkScaledCodec::DimensionsSupportedForSampling(this->getInfo(), dstInfo)) { |
| return SkCodec::kInvalidScale; |
| } |
| } |
| |
| const SkCodec::Result result = fCodec->initializeSwizzler(dstInfo, options, ctable, |
| ctableCount); |
| if (result != SkCodec::kSuccess) { |
| return result; |
| } |
| |
| fHasAlpha = false; |
| fStorage.reset(this->getInfo().width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig)); |
| fSrcRow = static_cast<uint8_t*>(fStorage.get()); |
| |
| return SkCodec::kSuccess; |
| } |
| |
| SkCodec::Result onGetScanlines(void* dst, int count, size_t rowBytes) override { |
| if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| return SkCodec::kInvalidInput; |
| } |
| |
| void* dstRow = dst; |
| for (int i = 0; i < count; i++) { |
| png_read_rows(fCodec->fPng_ptr, &fSrcRow, png_bytepp_NULL, 1); |
| fHasAlpha |= !SkSwizzler::IsOpaque(fCodec->fSwizzler->swizzle(dstRow, fSrcRow)); |
| dstRow = SkTAddOffset<void>(dstRow, rowBytes); |
| } |
| return SkCodec::kSuccess; |
| } |
| |
| SkCodec::Result onSkipScanlines(int count) override { |
| // FIXME: Could we use the return value of setjmp to specify the type of |
| // error? |
| if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| return SkCodec::kInvalidInput; |
| } |
| //there is a potential tradeoff of memory vs speed created by putting this in a loop. |
| //calling png_read_rows in a loop is insignificantly slower than calling it once with count |
| //as png_read_rows has it's own loop which calls png_read_row count times. |
| for (int i = 0; i < count; i++) { |
| png_read_rows(fCodec->fPng_ptr, &fSrcRow, png_bytepp_NULL, 1); |
| } |
| return SkCodec::kSuccess; |
| } |
| |
| bool onReallyHasAlpha() const override { return fHasAlpha; } |
| |
| SkEncodedFormat onGetEncodedFormat() const override { |
| return kPNG_SkEncodedFormat; |
| } |
| |
| |
| private: |
| SkAutoTDelete<SkPngCodec> fCodec; |
| bool fHasAlpha; |
| SkAutoMalloc fStorage; |
| uint8_t* fSrcRow; |
| |
| typedef SkScanlineDecoder INHERITED; |
| }; |
| |
| |
| class SkPngInterlacedScanlineDecoder : public SkScanlineDecoder { |
| public: |
| SkPngInterlacedScanlineDecoder(const SkImageInfo& srcInfo, SkPngCodec* codec) |
| : INHERITED(srcInfo) |
| , fCodec(codec) |
| , fHasAlpha(false) |
| , fCurrentRow(0) |
| , fHeight(srcInfo.height()) |
| , fCanSkipRewind(false) |
| {} |
| |
| SkCodec::Result onStart(const SkImageInfo& dstInfo, |
| const SkCodec::Options& options, |
| SkPMColor ctable[], int* ctableCount) override |
| { |
| if (!fCodec->rewindIfNeeded()) { |
| return SkCodec::kCouldNotRewind; |
| } |
| |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| return SkCodec::kInvalidConversion; |
| } |
| |
| // Check to see if scaling was requested. |
| if (dstInfo.dimensions() != this->getInfo().dimensions()) { |
| if (!SkScaledCodec::DimensionsSupportedForSampling(this->getInfo(), dstInfo)) { |
| return SkCodec::kInvalidScale; |
| } |
| } |
| |
| const SkCodec::Result result = fCodec->initializeSwizzler(dstInfo, options, ctable, |
| ctableCount); |
| if (result != SkCodec::kSuccess) { |
| return result; |
| } |
| |
| fHasAlpha = false; |
| fCurrentRow = 0; |
| fHeight = dstInfo.height(); |
| fSrcRowBytes = this->getInfo().width() * SkSwizzler::BytesPerPixel(fCodec->fSrcConfig); |
| fGarbageRow.reset(fSrcRowBytes); |
| fGarbageRowPtr = static_cast<uint8_t*>(fGarbageRow.get()); |
| fCanSkipRewind = true; |
| |
| return SkCodec::kSuccess; |
| } |
| |
| SkCodec::Result 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 onStart, so there is no reason to rewind. |
| // Next time onGetScanlines is called, we will need to rewind. |
| fCanSkipRewind = false; |
| } else if (!fCodec->rewindIfNeeded()) { |
| return SkCodec::kCouldNotRewind; |
| } |
| |
| if (setjmp(png_jmpbuf(fCodec->fPng_ptr))) { |
| SkCodecPrintf("setjmp long jump!\n"); |
| return SkCodec::kInvalidInput; |
| } |
| const int number_passes = png_set_interlace_handling(fCodec->fPng_ptr); |
| SkAutoMalloc storage(count * fSrcRowBytes); |
| uint8_t* storagePtr = static_cast<uint8_t*>(storage.get()); |
| uint8_t* srcRow; |
| for (int i = 0; i < number_passes; i++) { |
| //read rows we planned to skip into garbage row |
| for (int y = 0; y < fCurrentRow; y++){ |
| png_read_rows(fCodec->fPng_ptr, &fGarbageRowPtr, png_bytepp_NULL, 1); |
| } |
| //read rows we care about into buffer |
| srcRow = storagePtr; |
| for (int y = 0; y < count; y++) { |
| png_read_rows(fCodec->fPng_ptr, &srcRow, png_bytepp_NULL, 1); |
| srcRow += fSrcRowBytes; |
| } |
| //read rows we don't want into garbage buffer |
| for (int y = 0; y < fHeight - fCurrentRow - count; y++) { |
| png_read_rows(fCodec->fPng_ptr, &fGarbageRowPtr, png_bytepp_NULL, 1); |
| } |
| } |
| //swizzle the rows we care about |
| srcRow = storagePtr; |
| void* dstRow = dst; |
| for (int y = 0; y < count; y++) { |
| fHasAlpha |= !SkSwizzler::IsOpaque(fCodec->fSwizzler->swizzle(dstRow, srcRow)); |
| dstRow = SkTAddOffset<void>(dstRow, dstRowBytes); |
| srcRow += fSrcRowBytes; |
| } |
| fCurrentRow += count; |
| return SkCodec::kSuccess; |
| } |
| |
| SkCodec::Result onSkipScanlines(int count) override { |
| //when ongetScanlines is called it will skip to fCurrentRow |
| fCurrentRow += count; |
| return SkCodec::kSuccess; |
| } |
| |
| bool onReallyHasAlpha() const override { return fHasAlpha; } |
| |
| SkScanlineOrder onGetScanlineOrder() const override { |
| return kNone_SkScanlineOrder; |
| } |
| |
| SkEncodedFormat onGetEncodedFormat() const override { |
| return kPNG_SkEncodedFormat; |
| } |
| |
| private: |
| SkAutoTDelete<SkPngCodec> fCodec; |
| bool fHasAlpha; |
| int fCurrentRow; |
| 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 onStart |
| // followed by onGetScanlines does *not* require a rewind. Since |
| // rewindIfNeeded does not have this flexibility, we need to add another |
| // layer. |
| bool fCanSkipRewind; |
| |
| typedef SkScanlineDecoder INHERITED; |
| }; |
| |
| SkScanlineDecoder* SkPngCodec::NewSDFromStream(SkStream* stream) { |
| SkAutoTDelete<SkPngCodec> codec (static_cast<SkPngCodec*>(SkPngCodec::NewFromStream(stream))); |
| if (!codec) { |
| return nullptr; |
| } |
| |
| codec->fNumberPasses = png_set_interlace_handling(codec->fPng_ptr); |
| SkASSERT(codec->fNumberPasses != INVALID_NUMBER_PASSES); |
| |
| const SkImageInfo& srcInfo = codec->getInfo(); |
| if (codec->fNumberPasses > 1) { |
| // interlaced image |
| return new SkPngInterlacedScanlineDecoder(srcInfo, codec.detach()); |
| } |
| |
| return new SkPngScanlineDecoder(srcInfo, codec.detach()); |
| } |
| |
