xref: /aosp_15_r20/external/skia/src/shaders/SkBitmapProcShader.cpp (revision c8dee2aa9b3f27cf6c858bd81872bdeb2c07ed17)
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 "src/shaders/SkBitmapProcShader.h"
9 
10 #include "include/core/SkColor.h"
11 #include "include/core/SkMatrix.h"
12 #include "include/core/SkPixmap.h"
13 #include "include/private/base/SkAssert.h"
14 #include "src/base/SkArenaAlloc.h"
15 #include "src/core/SkBitmapProcState.h"
16 
17 #include <algorithm>
18 #include <cstdint>
19 
20 enum class SkTileMode;
21 
22 class BitmapProcShaderContext : public SkShaderBase::Context {
23 public:
BitmapProcShaderContext(const SkShaderBase & shader,const SkShaderBase::ContextRec & rec,SkBitmapProcState * state)24     BitmapProcShaderContext(const SkShaderBase& shader, const SkShaderBase::ContextRec& rec,
25                             SkBitmapProcState* state)
26         : INHERITED(shader, rec)
27         , fState(state)
28         , fFlags(0)
29     {
30         if (fState->fPixmap.isOpaque() && (255 == this->getPaintAlpha())) {
31             fFlags |= SkShaderBase::kOpaqueAlpha_Flag;
32         }
33     }
34 
getFlags() const35     uint32_t getFlags() const override { return fFlags; }
36 
shadeSpan(int x,int y,SkPMColor dstC[],int count)37     void shadeSpan(int x, int y, SkPMColor dstC[], int count) override {
38         const SkBitmapProcState& state = *fState;
39         if (state.getShaderProc32()) {
40             state.getShaderProc32()(&state, x, y, dstC, count);
41             return;
42         }
43 
44         const int BUF_MAX = 128;
45         uint32_t buffer[BUF_MAX];
46         SkBitmapProcState::MatrixProc   mproc = state.getMatrixProc();
47         SkBitmapProcState::SampleProc32 sproc = state.getSampleProc32();
48         const int max = state.maxCountForBufferSize(sizeof(buffer[0]) * BUF_MAX);
49 
50         SkASSERT(state.fPixmap.addr());
51 
52         for (;;) {
53             int n = std::min(count, max);
54             SkASSERT(n > 0 && n < BUF_MAX*2);
55             mproc(state, buffer, n, x, y);
56             sproc(state, buffer, n, dstC);
57 
58             if ((count -= n) == 0) {
59                 break;
60             }
61             SkASSERT(count > 0);
62             x += n;
63             dstC += n;
64         }
65     }
66 
67 private:
68     SkBitmapProcState*  fState;
69     uint32_t            fFlags;
70 
71     using INHERITED = SkShaderBase::Context;
72 };
73 
74 ///////////////////////////////////////////////////////////////////////////////////////////////////
75 
MakeContext(const SkShaderBase & shader,SkTileMode tmx,SkTileMode tmy,const SkSamplingOptions & sampling,const SkImage_Base * image,const ContextRec & rec,SkArenaAlloc * alloc)76 SkShaderBase::Context* SkBitmapProcLegacyShader::MakeContext(
77     const SkShaderBase& shader, SkTileMode tmx, SkTileMode tmy, const SkSamplingOptions& sampling,
78     const SkImage_Base* image, const ContextRec& rec, SkArenaAlloc* alloc)
79 {
80     SkMatrix totalInverse;
81     // Do this first, so we know the matrix can be inverted.
82     if (!rec.fMatrixRec.totalInverse(&totalInverse)) {
83         return nullptr;
84     }
85 
86     SkBitmapProcState* state = alloc->make<SkBitmapProcState>(image, tmx, tmy);
87     if (!state->setup(totalInverse, rec.fPaintAlpha, sampling)) {
88         return nullptr;
89     }
90     return alloc->make<BitmapProcShaderContext>(shader, rec, state);
91 }
92