| /* |
| * 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 SkSwizzler_DEFINED |
| #define SkSwizzler_DEFINED |
| |
| #include "SkCodec.h" |
| #include "SkColor.h" |
| #include "SkImageInfo.h" |
| #include "SkSampler.h" |
| |
| class SkSwizzler : public SkSampler { |
| public: |
| /** |
| * Enum describing the config of the source data. |
| */ |
| enum SrcConfig { |
| kUnknown, // Invalid type. |
| kBit, // A single bit to distinguish between white and black |
| kGray, |
| kIndex1, |
| kIndex2, |
| kIndex4, |
| kIndex, |
| kRGB, |
| kBGR, |
| kRGBX, |
| kBGRX, |
| kRGBA, |
| kBGRA, |
| kRGB_565, |
| }; |
| |
| /* |
| * |
| * Result code for the alpha components of a row. |
| * |
| */ |
| typedef uint16_t ResultAlpha; |
| static const ResultAlpha kOpaque_ResultAlpha = 0xFFFF; |
| static const ResultAlpha kTransparent_ResultAlpha = 0x0000; |
| |
| /* |
| * |
| * Checks if the result of decoding a row indicates that the row was |
| * transparent. |
| * |
| */ |
| static bool IsTransparent(ResultAlpha r) { |
| return kTransparent_ResultAlpha == r; |
| } |
| |
| /* |
| * |
| * Checks if the result of decoding a row indicates that the row was |
| * opaque. |
| * |
| */ |
| static bool IsOpaque(ResultAlpha r) { |
| return kOpaque_ResultAlpha == r; |
| } |
| |
| /* |
| * |
| * Constructs the proper result code based on accumulated alpha masks |
| * |
| */ |
| static ResultAlpha GetResult(uint8_t zeroAlpha, uint8_t maxAlpha); |
| |
| /* |
| * |
| * Returns bits per pixel for source config |
| * |
| */ |
| static int BitsPerPixel(SrcConfig sc) { |
| switch (sc) { |
| case kBit: |
| case kIndex1: |
| return 1; |
| case kIndex2: |
| return 2; |
| case kIndex4: |
| return 4; |
| case kGray: |
| case kIndex: |
| return 8; |
| case kRGB_565: |
| return 16; |
| case kRGB: |
| case kBGR: |
| return 24; |
| case kRGBX: |
| case kRGBA: |
| case kBGRX: |
| case kBGRA: |
| return 32; |
| default: |
| SkASSERT(false); |
| return 0; |
| } |
| } |
| |
| /* |
| * |
| * Returns bytes per pixel for source config |
| * Raises an error if each pixel is not stored in an even number of bytes |
| * |
| */ |
| static int BytesPerPixel(SrcConfig sc) { |
| SkASSERT(SkIsAlign8(BitsPerPixel(sc))); |
| return BitsPerPixel(sc) >> 3; |
| } |
| |
| /** |
| * Create a new SkSwizzler. |
| * @param SrcConfig Description of the format of the source. |
| * @param ctable Unowned pointer to an array of up to 256 colors for an |
| * index source. |
| * @param dstInfo Describes the destination. |
| * @param options Indicates if dst is zero-initialized. The |
| * implementation may choose to skip writing zeroes |
| * if set to kYes_ZeroInitialized. |
| * Contains subset information. |
| * @return A new SkSwizzler or nullptr on failure. |
| */ |
| static SkSwizzler* CreateSwizzler(SrcConfig, const SkPMColor* ctable, |
| const SkImageInfo& dstInfo, const SkCodec::Options&); |
| |
| /** |
| * Swizzle a line. Generally this will be called height times, once |
| * for each row of source. |
| * By allowing the caller to pass in the dst pointer, we give the caller |
| * flexibility to use the swizzler even when the encoded data does not |
| * store the rows in order. This also improves usability for scaled and |
| * subset decodes. |
| * @param dst Where we write the output. |
| * @param src The next row of the source data. |
| * @return A result code describing if the row was fully opaque, fully |
| * transparent, or neither |
| */ |
| ResultAlpha swizzle(void* dst, const uint8_t* SK_RESTRICT src); |
| |
| /** |
| * Implement fill using a custom width. |
| */ |
| void fill(const SkImageInfo& info, void* dst, size_t rowBytes, uint32_t colorOrIndex, |
| SkCodec::ZeroInitialized zeroInit) override { |
| const SkImageInfo fillInfo = info.makeWH(fDstWidth, info.height()); |
| SkSampler::Fill(fillInfo, dst, rowBytes, colorOrIndex, zeroInit); |
| } |
| |
| private: |
| |
| /** |
| * Method for converting raw data to Skia pixels. |
| * @param dstRow Row in which to write the resulting pixels. |
| * @param src Row of src data, in format specified by SrcConfig |
| * @param dstWidth Width in pixels of the destination |
| * @param bpp if bitsPerPixel % 8 == 0, deltaSrc is bytesPerPixel |
| * else, deltaSrc is bitsPerPixel |
| * @param deltaSrc bpp * sampleX |
| * @param ctable Colors (used for kIndex source). |
| * @param offset The offset before the first pixel to sample. |
| Is in bytes or bits based on what deltaSrc is in. |
| */ |
| typedef ResultAlpha (*RowProc)(void* SK_RESTRICT dstRow, |
| const uint8_t* SK_RESTRICT src, |
| int dstWidth, int bpp, int deltaSrc, int offset, |
| const SkPMColor ctable[]); |
| |
| const RowProc fRowProc; |
| const SkPMColor* fColorTable; // Unowned pointer |
| const int fSrcOffset; // Offset of the src in pixels, allows for partial |
| // scanline decodes. |
| int fX0; // Start coordinate for the src, may be different than |
| // fSrcOffset if we are sampling. |
| const int fSubsetWidth; // Width of the subset of the source before any sampling. |
| int fDstWidth; // Width of dst, which may differ with sampling. |
| int fSampleX; // step between X samples |
| const int fBPP; // if bitsPerPixel % 8 == 0 |
| // fBPP is bytesPerPixel |
| // else |
| // fBPP is bitsPerPixel |
| |
| SkSwizzler(RowProc proc, const SkPMColor* ctable, int srcOffset, int subsetWidth, int bpp); |
| |
| int onSetSampleX(int) override; |
| |
| }; |
| #endif // SkSwizzler_DEFINED |