| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| #ifndef SkBmpCodec_DEFINED |
| #define SkBmpCodec_DEFINED |
| |
| #include "SkCodec.h" |
| #include "SkColorSpace.h" |
| #include "SkColorTable.h" |
| #include "SkImageInfo.h" |
| #include "SkStream.h" |
| #include "SkSwizzler.h" |
| #include "SkTypes.h" |
| |
| /* |
| * This class enables code sharing between its bmp codec subclasses. The |
| * subclasses actually do the work. |
| */ |
| class SkBmpCodec : public SkCodec { |
| public: |
| static bool IsBmp(const void*, size_t); |
| |
| /* |
| * Assumes IsBmp was called and returned true |
| * Creates a bmp decoder |
| * Reads enough of the stream to determine the image format |
| */ |
| static SkCodec* NewFromStream(SkStream*, Result*); |
| |
| /* |
| * Creates a bmp decoder for a bmp embedded in ico |
| * Reads enough of the stream to determine the image format |
| */ |
| static SkCodec* NewFromIco(SkStream*, Result*); |
| |
| protected: |
| |
| SkBmpCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream, |
| uint16_t bitsPerPixel, SkCodec::SkScanlineOrder rowOrder); |
| |
| SkEncodedImageFormat onGetEncodedFormat() const override { return SkEncodedImageFormat::kBMP; } |
| |
| /* |
| * Read enough of the stream to initialize the SkBmpCodec. |
| * On kSuccess, if codecOut is not nullptr, it will be set to a new SkBmpCodec. |
| * If an SkCodec is created, it will take ownership of the SkStream. |
| */ |
| static Result ReadHeader(SkStream*, bool inIco, std::unique_ptr<SkCodec>* codecOut); |
| |
| bool onRewind() override; |
| |
| /* |
| * Returns whether this BMP is part of an ICO image. |
| */ |
| bool inIco() const { |
| return this->onInIco(); |
| } |
| |
| virtual bool onInIco() const { |
| return false; |
| } |
| |
| /* |
| * Get the destination row number corresponding to the encoded row number. |
| * For kTopDown, we simply return y, but for kBottomUp, the rows will be |
| * decoded in reverse order. |
| * |
| * @param y Iterates from 0 to height, indicating the current row. |
| * @param height The height of the current subset of the image that we are |
| * decoding. This is generally equal to the full height |
| * when we want to decode the full or one when we are |
| * sampling. |
| */ |
| int32_t getDstRow(int32_t y, int32_t height) const; |
| |
| /* |
| * Accessors used by subclasses |
| */ |
| uint16_t bitsPerPixel() const { return fBitsPerPixel; } |
| SkScanlineOrder onGetScanlineOrder() const override { return fRowOrder; } |
| size_t srcRowBytes() const { return fSrcRowBytes; } |
| |
| /* |
| * To be overriden by bmp subclasses, which provide unique implementations. |
| * Performs subclass specific setup. |
| * |
| * @param dstInfo Contains output information. Height specifies |
| * the total number of rows that will be decoded. |
| * @param options Additonal options to pass to the decoder. |
| */ |
| virtual SkCodec::Result onPrepareToDecode(const SkImageInfo& dstInfo, |
| const SkCodec::Options& options) = 0; |
| SkCodec::Result prepareToDecode(const SkImageInfo& dstInfo, |
| const SkCodec::Options& options); |
| |
| uint32_t* xformBuffer() const { return fXformBuffer.get(); } |
| void resetXformBuffer(int count) { fXformBuffer.reset(new uint32_t[count]); } |
| |
| /* |
| * BMPs are typically encoded as BGRA/BGR so this is a more efficient choice |
| * than RGBA. |
| */ |
| static const SkColorType kXformSrcColorType = kBGRA_8888_SkColorType; |
| static const auto kXformSrcColorFormat = SkColorSpaceXform::kBGRA_8888_ColorFormat; |
| |
| private: |
| |
| /* |
| * Creates a bmp decoder |
| * Reads enough of the stream to determine the image format |
| */ |
| static SkCodec* NewFromStream(SkStream*, Result*, bool inIco); |
| |
| /* |
| * Decodes the next dstInfo.height() lines. |
| * |
| * onGetPixels() uses this for full image decodes. |
| * SkScaledCodec::onGetPixels() uses the scanline decoder to call this with |
| * dstInfo.height() = 1, in order to implement sampling. |
| * A potential future use is to allow the caller to decode a subset of the |
| * lines in the image. |
| * |
| * @param dstInfo Contains output information. Height specifies the |
| * number of rows to decode at this time. |
| * @param dst Memory location to store output pixels |
| * @param dstRowBytes Bytes in a row of the destination |
| * @return Number of rows successfully decoded |
| */ |
| virtual int decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, |
| const Options& opts) = 0; |
| |
| virtual bool skipRows(int count); |
| |
| Result onStartScanlineDecode(const SkImageInfo& dstInfo, |
| const SkCodec::Options&) override; |
| |
| int onGetScanlines(void* dst, int count, size_t rowBytes) override; |
| |
| bool onSkipScanlines(int count) override; |
| |
| const uint16_t fBitsPerPixel; |
| const SkScanlineOrder fRowOrder; |
| const size_t fSrcRowBytes; |
| std::unique_ptr<uint32_t[]> fXformBuffer; |
| |
| typedef SkCodec INHERITED; |
| }; |
| |
| #endif |