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 "src/core/SkArenaAlloc.h"
11#include "src/core/SkBitmapProcState.h"
12#include "src/core/SkPaintPriv.h"
13#include "src/core/SkXfermodePriv.h"
14
15class BitmapProcShaderContext : public SkShaderBase::Context {
16public:
17    BitmapProcShaderContext(const SkShaderBase& shader, const SkShaderBase::ContextRec& rec,
18                            SkBitmapProcState* state)
19        : INHERITED(shader, rec)
20        , fState(state)
21        , fFlags(0)
22    {
23        if (fState->fPixmap.isOpaque() && (255 == this->getPaintAlpha())) {
24            fFlags |= SkShaderBase::kOpaqueAlpha_Flag;
25        }
26
27        auto only_scale_and_translate = [](const SkMatrix& matrix) {
28            unsigned mask = SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask;
29            return (matrix.getType() & ~mask) == 0;
30        };
31
32        if (1 == fState->fPixmap.height() && only_scale_and_translate(this->getTotalInverse())) {
33            fFlags |= SkShaderBase::kConstInY32_Flag;
34        }
35    }
36
37    uint32_t getFlags() const override { return fFlags; }
38
39    void shadeSpan(int x, int y, SkPMColor dstC[], int count) override {
40        const SkBitmapProcState& state = *fState;
41        if (state.getShaderProc32()) {
42            state.getShaderProc32()(&state, x, y, dstC, count);
43            return;
44        }
45
46        const int BUF_MAX = 128;
47        uint32_t buffer[BUF_MAX];
48        SkBitmapProcState::MatrixProc   mproc = state.getMatrixProc();
49        SkBitmapProcState::SampleProc32 sproc = state.getSampleProc32();
50        const int max = state.maxCountForBufferSize(sizeof(buffer[0]) * BUF_MAX);
51
52        SkASSERT(state.fPixmap.addr());
53
54        for (;;) {
55            int n = std::min(count, max);
56            SkASSERT(n > 0 && n < BUF_MAX*2);
57            mproc(state, buffer, n, x, y);
58            sproc(state, buffer, n, dstC);
59
60            if ((count -= n) == 0) {
61                break;
62            }
63            SkASSERT(count > 0);
64            x += n;
65            dstC += n;
66        }
67    }
68
69private:
70    SkBitmapProcState*  fState;
71    uint32_t            fFlags;
72
73    using INHERITED = SkShaderBase::Context;
74};
75
76///////////////////////////////////////////////////////////////////////////////////////////////////
77
78SkShaderBase::Context* SkBitmapProcLegacyShader::MakeContext(
79    const SkShaderBase& shader, SkTileMode tmx, SkTileMode tmy, const SkSamplingOptions& sampling,
80    const SkImage_Base* image, const ContextRec& rec, SkArenaAlloc* alloc)
81{
82    SkMatrix totalInverse;
83    // Do this first, so we know the matrix can be inverted.
84    if (!shader.computeTotalInverse(*rec.fMatrix, rec.fLocalMatrix, &totalInverse)) {
85        return nullptr;
86    }
87
88    SkBitmapProcState* state = alloc->make<SkBitmapProcState>(image, tmx, tmy);
89    if (!state->setup(totalInverse, rec.fPaintAlpha, sampling)) {
90        return nullptr;
91    }
92    return alloc->make<BitmapProcShaderContext>(shader, rec, state);
93}
94