| /* | |
| * 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 "SkBmpStandardCodec.h" | |
| #include "SkCodecPriv.h" | |
| #include "SkColorData.h" | |
| #include "SkStream.h" | |
| /* | |
| * Creates an instance of the decoder | |
| * Called only by NewFromStream | |
| */ | |
| SkBmpStandardCodec::SkBmpStandardCodec(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream, | |
| uint16_t bitsPerPixel, uint32_t numColors, | |
| uint32_t bytesPerColor, uint32_t offset, | |
| SkCodec::SkScanlineOrder rowOrder, | |
| bool isOpaque, bool inIco) | |
| : INHERITED(std::move(info), std::move(stream), bitsPerPixel, rowOrder) | |
| , fColorTable(nullptr) | |
| , fNumColors(numColors) | |
| , fBytesPerColor(bytesPerColor) | |
| , fOffset(offset) | |
| , fSwizzler(nullptr) | |
| , fIsOpaque(isOpaque) | |
| , fInIco(inIco) | |
| , fAndMaskRowBytes(fInIco ? SkAlign4(compute_row_bytes(this->getInfo().width(), 1)) : 0) | |
| {} | |
| /* | |
| * Initiates the bitmap decode | |
| */ | |
| SkCodec::Result SkBmpStandardCodec::onGetPixels(const SkImageInfo& dstInfo, | |
| void* dst, size_t dstRowBytes, | |
| const Options& opts, | |
| int* rowsDecoded) { | |
| if (opts.fSubset) { | |
| // Subsets are not supported. | |
| return kUnimplemented; | |
| } | |
| if (dstInfo.dimensions() != this->getInfo().dimensions()) { | |
| SkCodecPrintf("Error: scaling not supported.\n"); | |
| return kInvalidScale; | |
| } | |
| Result result = this->prepareToDecode(dstInfo, opts); | |
| if (kSuccess != result) { | |
| return result; | |
| } | |
| int rows = this->decodeRows(dstInfo, dst, dstRowBytes, opts); | |
| if (rows != dstInfo.height()) { | |
| *rowsDecoded = rows; | |
| return kIncompleteInput; | |
| } | |
| return kSuccess; | |
| } | |
| /* | |
| * Process the color table for the bmp input | |
| */ | |
| bool SkBmpStandardCodec::createColorTable(SkColorType dstColorType, SkAlphaType dstAlphaType) { | |
| // Allocate memory for color table | |
| uint32_t colorBytes = 0; | |
| SkPMColor colorTable[256]; | |
| if (this->bitsPerPixel() <= 8) { | |
| // Inform the caller of the number of colors | |
| uint32_t maxColors = 1 << this->bitsPerPixel(); | |
| // Don't bother reading more than maxColors. | |
| const uint32_t numColorsToRead = | |
| fNumColors == 0 ? maxColors : SkTMin(fNumColors, maxColors); | |
| // Read the color table from the stream | |
| colorBytes = numColorsToRead * fBytesPerColor; | |
| std::unique_ptr<uint8_t[]> cBuffer(new uint8_t[colorBytes]); | |
| if (stream()->read(cBuffer.get(), colorBytes) != colorBytes) { | |
| SkCodecPrintf("Error: unable to read color table.\n"); | |
| return false; | |
| } | |
| SkColorType packColorType = dstColorType; | |
| SkAlphaType packAlphaType = dstAlphaType; | |
| if (this->colorXform()) { | |
| packColorType = kBGRA_8888_SkColorType; | |
| packAlphaType = kUnpremul_SkAlphaType; | |
| } | |
| // Choose the proper packing function | |
| bool isPremul = (kPremul_SkAlphaType == packAlphaType) && !fIsOpaque; | |
| PackColorProc packARGB = choose_pack_color_proc(isPremul, packColorType); | |
| // Fill in the color table | |
| uint32_t i = 0; | |
| for (; i < numColorsToRead; i++) { | |
| uint8_t blue = get_byte(cBuffer.get(), i*fBytesPerColor); | |
| uint8_t green = get_byte(cBuffer.get(), i*fBytesPerColor + 1); | |
| uint8_t red = get_byte(cBuffer.get(), i*fBytesPerColor + 2); | |
| uint8_t alpha; | |
| if (fIsOpaque) { | |
| alpha = 0xFF; | |
| } else { | |
| alpha = get_byte(cBuffer.get(), i*fBytesPerColor + 3); | |
| } | |
| colorTable[i] = packARGB(alpha, red, green, blue); | |
| } | |
| // To avoid segmentation faults on bad pixel data, fill the end of the | |
| // color table with black. This is the same the behavior as the | |
| // chromium decoder. | |
| for (; i < maxColors; i++) { | |
| colorTable[i] = SkPackARGB32NoCheck(0xFF, 0, 0, 0); | |
| } | |
| if (this->colorXform() && !this->xformOnDecode()) { | |
| this->applyColorXform(colorTable, colorTable, maxColors); | |
| } | |
| // Set the color table | |
| fColorTable.reset(new SkColorTable(colorTable, maxColors)); | |
| } | |
| // Bmp-in-Ico files do not use an offset to indicate where the pixel data | |
| // begins. Pixel data always begins immediately after the color table. | |
| if (!fInIco) { | |
| // Check that we have not read past the pixel array offset | |
| if(fOffset < colorBytes) { | |
| // This may occur on OS 2.1 and other old versions where the color | |
| // table defaults to max size, and the bmp tries to use a smaller | |
| // color table. This is invalid, and our decision is to indicate | |
| // an error, rather than try to guess the intended size of the | |
| // color table. | |
| SkCodecPrintf("Error: pixel data offset less than color table size.\n"); | |
| return false; | |
| } | |
| // After reading the color table, skip to the start of the pixel array | |
| if (stream()->skip(fOffset - colorBytes) != fOffset - colorBytes) { | |
| SkCodecPrintf("Error: unable to skip to image data.\n"); | |
| return false; | |
| } | |
| } | |
| // Return true on success | |
| return true; | |
| } | |
| static SkEncodedInfo make_info(SkEncodedInfo::Color color, | |
| SkEncodedInfo::Alpha alpha, int bitsPerPixel) { | |
| // This is just used for the swizzler, which does not need the width or height. | |
| return SkEncodedInfo::Make(0, 0, color, alpha, bitsPerPixel); | |
| } | |
| SkEncodedInfo SkBmpStandardCodec::swizzlerInfo() const { | |
| const auto& info = this->getEncodedInfo(); | |
| if (fInIco) { | |
| if (this->bitsPerPixel() <= 8) { | |
| return make_info(SkEncodedInfo::kPalette_Color, | |
| info.alpha(), this->bitsPerPixel()); | |
| } | |
| if (this->bitsPerPixel() == 24) { | |
| return make_info(SkEncodedInfo::kBGR_Color, | |
| SkEncodedInfo::kOpaque_Alpha, 8); | |
| } | |
| } | |
| return make_info(info.color(), info.alpha(), info.bitsPerComponent()); | |
| } | |
| void SkBmpStandardCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts) { | |
| // In the case of bmp-in-icos, we will report BGRA to the client, | |
| // since we may be required to apply an alpha mask after the decode. | |
| // However, the swizzler needs to know the actual format of the bmp. | |
| SkEncodedInfo encodedInfo = this->swizzlerInfo(); | |
| // Get a pointer to the color table if it exists | |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); | |
| SkImageInfo swizzlerInfo = dstInfo; | |
| SkCodec::Options swizzlerOptions = opts; | |
| if (this->colorXform()) { | |
| swizzlerInfo = swizzlerInfo.makeColorType(kXformSrcColorType); | |
| if (kPremul_SkAlphaType == dstInfo.alphaType()) { | |
| swizzlerInfo = swizzlerInfo.makeAlphaType(kUnpremul_SkAlphaType); | |
| } | |
| swizzlerOptions.fZeroInitialized = kNo_ZeroInitialized; | |
| } | |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(encodedInfo, colorPtr, swizzlerInfo, | |
| swizzlerOptions)); | |
| SkASSERT(fSwizzler); | |
| } | |
| SkCodec::Result SkBmpStandardCodec::onPrepareToDecode(const SkImageInfo& dstInfo, | |
| const SkCodec::Options& options) { | |
| if (this->xformOnDecode()) { | |
| this->resetXformBuffer(dstInfo.width()); | |
| } | |
| // Create the color table if necessary and prepare the stream for decode | |
| // Note that if it is non-NULL, inputColorCount will be modified | |
| if (!this->createColorTable(dstInfo.colorType(), dstInfo.alphaType())) { | |
| SkCodecPrintf("Error: could not create color table.\n"); | |
| return SkCodec::kInvalidInput; | |
| } | |
| // Initialize a swizzler | |
| this->initializeSwizzler(dstInfo, options); | |
| return SkCodec::kSuccess; | |
| } | |
| /* | |
| * Performs the bitmap decoding for standard input format | |
| */ | |
| int SkBmpStandardCodec::decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, | |
| const Options& opts) { | |
| // Iterate over rows of the image | |
| const int height = dstInfo.height(); | |
| for (int y = 0; y < height; y++) { | |
| // Read a row of the input | |
| if (this->stream()->read(this->srcBuffer(), this->srcRowBytes()) != this->srcRowBytes()) { | |
| SkCodecPrintf("Warning: incomplete input stream.\n"); | |
| return y; | |
| } | |
| // Decode the row in destination format | |
| uint32_t row = this->getDstRow(y, dstInfo.height()); | |
| void* dstRow = SkTAddOffset<void>(dst, row * dstRowBytes); | |
| if (this->xformOnDecode()) { | |
| SkASSERT(this->colorXform()); | |
| fSwizzler->swizzle(this->xformBuffer(), this->srcBuffer()); | |
| this->applyColorXform(dstRow, this->xformBuffer(), fSwizzler->swizzleWidth()); | |
| } else { | |
| fSwizzler->swizzle(dstRow, this->srcBuffer()); | |
| } | |
| } | |
| if (fInIco && fIsOpaque) { | |
| const int startScanline = this->currScanline(); | |
| if (startScanline < 0) { | |
| // We are not performing a scanline decode. | |
| // Just decode the entire ICO mask and return. | |
| decodeIcoMask(this->stream(), dstInfo, dst, dstRowBytes); | |
| return height; | |
| } | |
| // In order to perform a scanline ICO decode, we must be able | |
| // to skip ahead in the stream in order to apply the AND mask | |
| // to the requested scanlines. | |
| // We will do this by taking advantage of the fact that | |
| // SkIcoCodec always uses a SkMemoryStream as its underlying | |
| // representation of the stream. | |
| const void* memoryBase = this->stream()->getMemoryBase(); | |
| SkASSERT(nullptr != memoryBase); | |
| SkASSERT(this->stream()->hasLength()); | |
| SkASSERT(this->stream()->hasPosition()); | |
| const size_t length = this->stream()->getLength(); | |
| const size_t currPosition = this->stream()->getPosition(); | |
| // Calculate how many bytes we must skip to reach the AND mask. | |
| const int remainingScanlines = this->getInfo().height() - startScanline - height; | |
| const size_t bytesToSkip = remainingScanlines * this->srcRowBytes() + | |
| startScanline * fAndMaskRowBytes; | |
| const size_t subStreamStartPosition = currPosition + bytesToSkip; | |
| if (subStreamStartPosition >= length) { | |
| // FIXME: How can we indicate that this decode was actually incomplete? | |
| return height; | |
| } | |
| // Create a subStream to pass to decodeIcoMask(). It is useful to encapsulate | |
| // the memory base into a stream in order to safely handle incomplete images | |
| // without reading out of bounds memory. | |
| const void* subStreamMemoryBase = SkTAddOffset<const void>(memoryBase, | |
| subStreamStartPosition); | |
| const size_t subStreamLength = length - subStreamStartPosition; | |
| // This call does not transfer ownership of the subStreamMemoryBase. | |
| SkMemoryStream subStream(subStreamMemoryBase, subStreamLength, false); | |
| // FIXME: If decodeIcoMask does not succeed, is there a way that we can | |
| // indicate the decode was incomplete? | |
| decodeIcoMask(&subStream, dstInfo, dst, dstRowBytes); | |
| } | |
| return height; | |
| } | |
| void SkBmpStandardCodec::decodeIcoMask(SkStream* stream, const SkImageInfo& dstInfo, | |
| void* dst, size_t dstRowBytes) { | |
| // BMP in ICO have transparency, so this cannot be 565. The below code depends | |
| // on the output being an SkPMColor. | |
| SkASSERT(kRGBA_8888_SkColorType == dstInfo.colorType() || | |
| kBGRA_8888_SkColorType == dstInfo.colorType() || | |
| kRGBA_F16_SkColorType == dstInfo.colorType()); | |
| // If we are sampling, make sure that we only mask the sampled pixels. | |
| // We do not need to worry about sampling in the y-dimension because that | |
| // should be handled by SkSampledCodec. | |
| const int sampleX = fSwizzler->sampleX(); | |
| const int sampledWidth = get_scaled_dimension(this->getInfo().width(), sampleX); | |
| const int srcStartX = get_start_coord(sampleX); | |
| SkPMColor* dstPtr = (SkPMColor*) dst; | |
| for (int y = 0; y < dstInfo.height(); y++) { | |
| // The srcBuffer will at least be large enough | |
| if (stream->read(this->srcBuffer(), fAndMaskRowBytes) != fAndMaskRowBytes) { | |
| SkCodecPrintf("Warning: incomplete AND mask for bmp-in-ico.\n"); | |
| return; | |
| } | |
| auto applyMask = [dstInfo](void* dstRow, int x, uint64_t bit) { | |
| if (kRGBA_F16_SkColorType == dstInfo.colorType()) { | |
| uint64_t* dst64 = (uint64_t*) dstRow; | |
| dst64[x] &= bit - 1; | |
| } else { | |
| uint32_t* dst32 = (uint32_t*) dstRow; | |
| dst32[x] &= bit - 1; | |
| } | |
| }; | |
| int row = this->getDstRow(y, dstInfo.height()); | |
| void* dstRow = SkTAddOffset<SkPMColor>(dstPtr, row * dstRowBytes); | |
| int srcX = srcStartX; | |
| for (int dstX = 0; dstX < sampledWidth; dstX++) { | |
| int quotient; | |
| int modulus; | |
| SkTDivMod(srcX, 8, "ient, &modulus); | |
| uint32_t shift = 7 - modulus; | |
| uint64_t alphaBit = (this->srcBuffer()[quotient] >> shift) & 0x1; | |
| applyMask(dstRow, dstX, alphaBit); | |
| srcX += sampleX; | |
| } | |
| } | |
| } |