Home | History | Annotate | Download | only in codec 
      1 /*
      2  * Copyright 2015 Google Inc.
      3  *
      4  * Use of this source code is governed by a BSD-style license that can be
      5  * found in the LICENSE file.
      6  */
      7 #ifndef SkMaskSwizzler_DEFINED
      8 #define SkMaskSwizzler_DEFINED
      9 
     10 #include "SkMasks.h"
     11 #include "SkSampler.h"
     12 #include "SkSwizzler.h"
     13 #include "SkTypes.h"
     14 
     15 /*
     16  *
     17  * Used to swizzle images whose pixel components are extracted by bit masks
     18  * Currently only used by bmp
     19  *
     20  */
     21 class SkMaskSwizzler : public SkSampler {
     22 public:
     23 
     24     /*
     25      * Create a new swizzler
     26      * @param masks Unowned pointer to helper class
     27      */
     28     static SkMaskSwizzler* CreateMaskSwizzler(const SkImageInfo& dstInfo,
     29                                               const SkImageInfo& srcInfo,
     30                                               SkMasks* masks,
     31                                               uint32_t bitsPerPixel,
     32                                               const SkCodec::Options& options);
     33 
     34     /*
     35      * Swizzle a row
     36      */
     37     void swizzle(void* dst, const uint8_t* SK_RESTRICT src);
     38 
     39     /**
     40      * Implement fill using a custom width.
     41      */
     42     void fill(const SkImageInfo& info, void* dst, size_t rowBytes, uint64_t colorOrIndex,
     43             SkCodec::ZeroInitialized zeroInit) override {
     44         const SkImageInfo fillInfo = info.makeWH(fDstWidth, info.height());
     45         SkSampler::Fill(fillInfo, dst, rowBytes, colorOrIndex, zeroInit);
     46     }
     47 
     48     /**
     49      *  Returns the byte offset at which we write to destination memory, taking
     50      *  scaling, subsetting, and partial frames into account.
     51      *  A similar function exists on SkSwizzler.
     52      */
     53     int swizzleWidth() const { return fDstWidth; }
     54 
     55 private:
     56 
     57     /*
     58      * Row procedure used for swizzle
     59      */
     60     typedef void (*RowProc)(void* dstRow, const uint8_t* srcRow, int width,
     61             SkMasks* masks, uint32_t startX, uint32_t sampleX);
     62 
     63     SkMaskSwizzler(SkMasks* masks, RowProc proc, int subsetWidth, int srcOffset);
     64 
     65     int onSetSampleX(int) override;
     66 
     67     SkMasks*        fMasks;           // unowned
     68     const RowProc   fRowProc;
     69 
     70     // FIXME: Can this class share more with SkSwizzler? These variables are all the same.
     71     const int       fSubsetWidth;     // Width of the subset of source before any sampling.
     72     int             fDstWidth;        // Width of dst, which may differ with sampling.
     73     int             fSampleX;
     74     int             fSrcOffset;
     75     int             fX0;
     76 };
     77 
     78 #endif
     79