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