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      1 /*
      2  * Copyright 2011 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 #include "SkBitmapProcShader.h"
      9 
     10 #include "SkArenaAlloc.h"
     11 #include "SkBitmapProcState.h"
     12 #include "SkBitmapProvider.h"
     13 #include "SkXfermodePriv.h"
     14 
     15 static bool only_scale_and_translate(const SkMatrix& matrix) {
     16     unsigned mask = SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask;
     17     return (matrix.getType() & ~mask) == 0;
     18 }
     19 
     20 class BitmapProcInfoContext : public SkShaderBase::Context {
     21 public:
     22     // The info has been allocated elsewhere, but we are responsible for calling its destructor.
     23     BitmapProcInfoContext(const SkShaderBase& shader, const SkShaderBase::ContextRec& rec,
     24                             SkBitmapProcInfo* info)
     25         : INHERITED(shader, rec)
     26         , fInfo(info)
     27     {
     28         fFlags = 0;
     29         if (fInfo->fPixmap.isOpaque() && (255 == this->getPaintAlpha())) {
     30             fFlags |= SkShaderBase::kOpaqueAlpha_Flag;
     31         }
     32 
     33         if (1 == fInfo->fPixmap.height() && only_scale_and_translate(this->getTotalInverse())) {
     34             fFlags |= SkShaderBase::kConstInY32_Flag;
     35         }
     36     }
     37 
     38     uint32_t getFlags() const override { return fFlags; }
     39 
     40 private:
     41     SkBitmapProcInfo*   fInfo;
     42     uint32_t            fFlags;
     43 
     44     typedef SkShaderBase::Context INHERITED;
     45 };
     46 
     47 ///////////////////////////////////////////////////////////////////////////////////////////////////
     48 
     49 class BitmapProcShaderContext : public BitmapProcInfoContext {
     50 public:
     51     BitmapProcShaderContext(const SkShaderBase& shader, const SkShaderBase::ContextRec& rec,
     52                             SkBitmapProcState* state)
     53         : INHERITED(shader, rec, state)
     54         , fState(state)
     55     {}
     56 
     57     void shadeSpan(int x, int y, SkPMColor dstC[], int count) override {
     58         const SkBitmapProcState& state = *fState;
     59         if (state.getShaderProc32()) {
     60             state.getShaderProc32()(&state, x, y, dstC, count);
     61             return;
     62         }
     63 
     64         const int BUF_MAX = 128;
     65         uint32_t buffer[BUF_MAX];
     66         SkBitmapProcState::MatrixProc   mproc = state.getMatrixProc();
     67         SkBitmapProcState::SampleProc32 sproc = state.getSampleProc32();
     68         const int max = state.maxCountForBufferSize(sizeof(buffer[0]) * BUF_MAX);
     69 
     70         SkASSERT(state.fPixmap.addr());
     71 
     72         for (;;) {
     73             int n = SkTMin(count, max);
     74             SkASSERT(n > 0 && n < BUF_MAX*2);
     75             mproc(state, buffer, n, x, y);
     76             sproc(state, buffer, n, dstC);
     77 
     78             if ((count -= n) == 0) {
     79                 break;
     80             }
     81             SkASSERT(count > 0);
     82             x += n;
     83             dstC += n;
     84         }
     85     }
     86 
     87 private:
     88     SkBitmapProcState*  fState;
     89 
     90     typedef BitmapProcInfoContext INHERITED;
     91 };
     92 
     93 ///////////////////////////////////////////////////////////////////////////////////////////////////
     94 
     95 SkShaderBase::Context* SkBitmapProcLegacyShader::MakeContext(
     96     const SkShaderBase& shader, TileMode tmx, TileMode tmy,
     97     const SkBitmapProvider& provider, const ContextRec& rec, SkArenaAlloc* alloc)
     98 {
     99     SkMatrix totalInverse;
    100     // Do this first, so we know the matrix can be inverted.
    101     if (!shader.computeTotalInverse(*rec.fMatrix, rec.fLocalMatrix, &totalInverse)) {
    102         return nullptr;
    103     }
    104 
    105     SkBitmapProcState* state = alloc->make<SkBitmapProcState>(provider, tmx, tmy);
    106     if (!state->setup(totalInverse, *rec.fPaint)) {
    107         return nullptr;
    108     }
    109     return alloc->make<BitmapProcShaderContext>(shader, rec, state);
    110 }
    111