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      1 /*
      2  * Copyright 2016 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 
      8 #ifndef SkLinearBitmapPipeline_DEFINED
      9 #define SkLinearBitmapPipeline_DEFINED
     10 
     11 
     12 #include "SkColor.h"
     13 #include "SkImageInfo.h"
     14 #include "SkMatrix.h"
     15 #include "SkNx.h"
     16 #include "SkShader.h"
     17 
     18 class SkLinearBitmapPipeline {
     19 public:
     20     SkLinearBitmapPipeline(
     21         const SkMatrix& inverse,
     22         SkFilterQuality filterQuality,
     23         SkShader::TileMode xTile, SkShader::TileMode yTile,
     24         const SkPixmap& srcPixmap);
     25     ~SkLinearBitmapPipeline();
     26 
     27     void shadeSpan4f(int x, int y, SkPM4f* dst, int count);
     28 
     29     template<typename Base, size_t kSize>
     30     class PolymorphicUnion {
     31     public:
     32         PolymorphicUnion() {}
     33 
     34         ~PolymorphicUnion() { get()->~Base(); }
     35 
     36         template<typename Variant, typename... Args>
     37         void Initialize(Args&&... args) {
     38             SkASSERTF(sizeof(Variant) <= sizeof(fSpace),
     39                       "Size Variant: %d, Space: %d", sizeof(Variant), sizeof(fSpace));
     40 
     41             new(&fSpace) Variant(std::forward<Args>(args)...);
     42         };
     43 
     44         Base* get() const { return reinterpret_cast<Base*>(&fSpace); }
     45         Base* operator->() const { return get(); }
     46         Base& operator*() const { return *get(); }
     47 
     48     private:
     49         struct SK_STRUCT_ALIGN(16) Space {
     50             char space[kSize];
     51         };
     52         mutable Space fSpace;
     53     };
     54 
     55     class PointProcessorInterface;
     56     class BilerpProcessorInterface;
     57     class PixelPlacerInterface;
     58 
     59     using MatrixStage = PolymorphicUnion<PointProcessorInterface, 112>;
     60     using FilterStage = PolymorphicUnion<PointProcessorInterface,   8>;
     61     using TileStage   = PolymorphicUnion<BilerpProcessorInterface, 96>;
     62     using SampleStage = PolymorphicUnion<BilerpProcessorInterface, 80>;
     63     using PixelStage  = PolymorphicUnion<PixelPlacerInterface,     80>;
     64 
     65 private:
     66     PointProcessorInterface* fFirstStage;
     67     MatrixStage fMatrixStage;
     68     FilterStage fFilterStage;
     69     TileStage   fTileXOrBothStage;
     70     TileStage   fTileYStage;
     71     SampleStage fSampleStage;
     72     PixelStage  fPixelStage;
     73 };
     74 
     75 #endif  // SkLinearBitmapPipeline_DEFINED
     76