| /* |
| * 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 SkBmpRLECodec_DEFINED |
| #define SkBmpRLECodec_DEFINED |
| |
| #include "include/core/SkImageInfo.h" |
| #include "include/core/SkTypes.h" |
| #include "src/codec/SkBmpCodec.h" |
| #include "src/codec/SkColorTable.h" |
| #include "src/codec/SkSampler.h" |
| |
| /* |
| * This class implements the decoding for bmp images that use an RLE encoding |
| */ |
| class SkBmpRLECodec : public SkBmpCodec { |
| public: |
| |
| /* |
| * Creates an instance of the decoder |
| * |
| * Called only by SkBmpCodec::MakeFromStream |
| * There should be no other callers despite this being public |
| * |
| * @param info contains properties of the encoded data |
| * @param stream the stream of encoded image data |
| * @param bitsPerPixel the number of bits used to store each pixel |
| * @param numColors the number of colors in the color table |
| * @param bytesPerColor the number of bytes in the stream used to represent |
| each color in the color table |
| * @param offset the offset of the image pixel data from the end of the |
| * headers |
| * @param rowOrder indicates whether rows are ordered top-down or bottom-up |
| */ |
| SkBmpRLECodec(SkEncodedInfo&& info, std::unique_ptr<SkStream>, |
| uint16_t bitsPerPixel, uint32_t numColors, uint32_t bytesPerColor, |
| uint32_t offset, SkCodec::SkScanlineOrder rowOrder); |
| |
| int setSampleX(int); |
| |
| int fillWidth() const; |
| |
| protected: |
| |
| Result onGetPixels(const SkImageInfo& dstInfo, void* dst, |
| size_t dstRowBytes, const Options&, |
| int*) override; |
| |
| SkCodec::Result onPrepareToDecode(const SkImageInfo& dstInfo, |
| const SkCodec::Options& options) override; |
| |
| private: |
| |
| /* |
| * Creates the color table |
| * Sets colorCount to the new color count if it is non-nullptr |
| */ |
| bool createColorTable(SkColorType dstColorType); |
| |
| bool initializeStreamBuffer(); |
| |
| /* |
| * Before signalling kIncompleteInput, we should attempt to load the |
| * stream buffer with additional data. |
| * |
| * @return the number of bytes remaining in the stream buffer after |
| * attempting to read more bytes from the stream |
| */ |
| size_t checkForMoreData(); |
| |
| /* |
| * Set an RLE pixel using the color table |
| */ |
| void setPixel(void* dst, size_t dstRowBytes, |
| const SkImageInfo& dstInfo, uint32_t x, uint32_t y, |
| uint8_t index); |
| /* |
| * Set an RLE24 pixel from R, G, B values |
| */ |
| void setRGBPixel(void* dst, size_t dstRowBytes, |
| const SkImageInfo& dstInfo, uint32_t x, uint32_t y, |
| uint8_t red, uint8_t green, uint8_t blue); |
| |
| /* |
| * If dst is NULL, this is a signal to skip the rows. |
| */ |
| int decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, |
| const Options& opts) override; |
| int decodeRLE(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes); |
| |
| bool skipRows(int count) override; |
| |
| SkSampler* getSampler(bool createIfNecessary) override; |
| |
| sk_sp<SkColorTable> fColorTable; |
| // fNumColors is the number specified in the header, or 0 if not present in the header. |
| const uint32_t fNumColors; |
| const uint32_t fBytesPerColor; |
| const uint32_t fOffset; |
| |
| static constexpr size_t kBufferSize = 4096; |
| uint8_t fStreamBuffer[kBufferSize]; |
| size_t fBytesBuffered; |
| |
| uint32_t fCurrRLEByte; |
| int fSampleX; |
| std::unique_ptr<SkSampler> fSampler; |
| |
| // Scanline decodes allow the client to ask for a single scanline at a time. |
| // This can be tricky when the RLE encoding instructs the decoder to jump down |
| // multiple lines. This field keeps track of lines that need to be skipped |
| // on subsequent calls to decodeRows(). |
| int fLinesToSkip; |
| |
| using INHERITED = SkBmpCodec; |
| }; |
| #endif // SkBmpRLECodec_DEFINED |