1 /*
2 * Copyright 2012 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 #include "src/shaders/gradients/SkRadialGradient.h"
8
9 #include "include/core/SkColor.h"
10 #include "include/core/SkColorSpace.h"
11 #include "include/core/SkMatrix.h"
12 #include "include/core/SkRefCnt.h"
13 #include "include/core/SkShader.h"
14 #include "include/effects/SkGradientShader.h"
15 #include "include/private/base/SkTArray.h"
16 #include "src/core/SkRasterPipeline.h"
17 #include "src/core/SkRasterPipelineOpList.h"
18 #include "src/core/SkReadBuffer.h"
19 #include "src/core/SkWriteBuffer.h"
20 #include "src/shaders/SkShaderBase.h"
21 #include "src/shaders/gradients/SkGradientBaseShader.h"
22
23 #include <cstdint>
24 #include <utility>
25
26 class SkArenaAlloc;
27 enum class SkTileMode;
28
rad_to_unit_matrix(const SkPoint & center,SkScalar radius)29 static SkMatrix rad_to_unit_matrix(const SkPoint& center, SkScalar radius) {
30 SkScalar inv = SkScalarInvert(radius);
31
32 SkMatrix matrix;
33 matrix.setTranslate(-center.fX, -center.fY);
34 matrix.postScale(inv, inv);
35 return matrix;
36 }
37
SkRadialGradient(const SkPoint & center,SkScalar radius,const Descriptor & desc)38 SkRadialGradient::SkRadialGradient(const SkPoint& center, SkScalar radius, const Descriptor& desc)
39 : SkGradientBaseShader(desc, rad_to_unit_matrix(center, radius))
40 , fCenter(center)
41 , fRadius(radius) {}
42
asGradient(GradientInfo * info,SkMatrix * localMatrix) const43 SkShaderBase::GradientType SkRadialGradient::asGradient(GradientInfo* info,
44 SkMatrix* localMatrix) const {
45 if (info) {
46 commonAsAGradient(info);
47 info->fPoint[0] = fCenter;
48 info->fRadius[0] = fRadius;
49 }
50 if (localMatrix) {
51 *localMatrix = SkMatrix::I();
52 }
53 return GradientType::kRadial;
54 }
55
CreateProc(SkReadBuffer & buffer)56 sk_sp<SkFlattenable> SkRadialGradient::CreateProc(SkReadBuffer& buffer) {
57 DescriptorScope desc;
58 SkMatrix legacyLocalMatrix, *lmPtr = nullptr;
59 if (!desc.unflatten(buffer, &legacyLocalMatrix)) {
60 return nullptr;
61 }
62 if (!legacyLocalMatrix.isIdentity()) {
63 lmPtr = &legacyLocalMatrix;
64 }
65 const SkPoint center = buffer.readPoint();
66 const SkScalar radius = buffer.readScalar();
67 return SkGradientShader::MakeRadial(center,
68 radius,
69 desc.fColors,
70 std::move(desc.fColorSpace),
71 desc.fPositions,
72 desc.fColorCount,
73 desc.fTileMode,
74 desc.fInterpolation,
75 lmPtr);
76 }
77
flatten(SkWriteBuffer & buffer) const78 void SkRadialGradient::flatten(SkWriteBuffer& buffer) const {
79 this->SkGradientBaseShader::flatten(buffer);
80 buffer.writePoint(fCenter);
81 buffer.writeScalar(fRadius);
82 }
83
appendGradientStages(SkArenaAlloc *,SkRasterPipeline * p,SkRasterPipeline *) const84 void SkRadialGradient::appendGradientStages(SkArenaAlloc*, SkRasterPipeline* p,
85 SkRasterPipeline*) const {
86 p->append(SkRasterPipelineOp::xy_to_radius);
87 }
88
MakeRadial(const SkPoint & center,SkScalar radius,const SkColor4f colors[],sk_sp<SkColorSpace> colorSpace,const SkScalar pos[],int colorCount,SkTileMode mode,const Interpolation & interpolation,const SkMatrix * localMatrix)89 sk_sp<SkShader> SkGradientShader::MakeRadial(const SkPoint& center, SkScalar radius,
90 const SkColor4f colors[],
91 sk_sp<SkColorSpace> colorSpace,
92 const SkScalar pos[],
93 int colorCount,
94 SkTileMode mode,
95 const Interpolation& interpolation,
96 const SkMatrix* localMatrix) {
97 if (radius < 0) {
98 return nullptr;
99 }
100 if (!SkGradientBaseShader::ValidGradient(colors, colorCount, mode, interpolation)) {
101 return nullptr;
102 }
103 if (1 == colorCount) {
104 return SkShaders::Color(colors[0], std::move(colorSpace));
105 }
106 if (localMatrix && !localMatrix->invert(nullptr)) {
107 return nullptr;
108 }
109
110 if (SkScalarNearlyZero(radius, SkGradientBaseShader::kDegenerateThreshold)) {
111 // Degenerate gradient optimization, and no special logic needed for clamped radial gradient
112 return SkGradientBaseShader::MakeDegenerateGradient(
113 colors, pos, colorCount, std::move(colorSpace), mode);
114 }
115
116 SkGradientBaseShader::Descriptor desc(
117 colors, std::move(colorSpace), pos, colorCount, mode, interpolation);
118
119 sk_sp<SkShader> s = sk_make_sp<SkRadialGradient>(center, radius, desc);
120 return s->makeWithLocalMatrix(localMatrix ? *localMatrix : SkMatrix::I());
121 }
122
MakeRadial(const SkPoint & center,SkScalar radius,const SkColor colors[],const SkScalar pos[],int colorCount,SkTileMode mode,uint32_t flags,const SkMatrix * localMatrix)123 sk_sp<SkShader> SkGradientShader::MakeRadial(const SkPoint& center, SkScalar radius,
124 const SkColor colors[],
125 const SkScalar pos[],
126 int colorCount,
127 SkTileMode mode,
128 uint32_t flags,
129 const SkMatrix* localMatrix) {
130 SkColorConverter converter(colors, colorCount);
131 return MakeRadial(center, radius, converter.fColors4f.begin(), nullptr, pos, colorCount, mode,
132 flags, localMatrix);
133 }
134
SkRegisterRadialGradientShaderFlattenable()135 void SkRegisterRadialGradientShaderFlattenable() {
136 SK_REGISTER_FLATTENABLE(SkRadialGradient);
137 }
138