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
8 #include "src/shaders/gradients/SkLinearGradient.h"
9
10 #include "src/core/SkKeyHelpers.h"
11 #include "src/core/SkReadBuffer.h"
12 #include "src/core/SkWriteBuffer.h"
13 #include "src/shaders/gradients/Sk4fLinearGradient.h"
14
pts_to_unit_matrix(const SkPoint pts[2])15 static SkMatrix pts_to_unit_matrix(const SkPoint pts[2]) {
16 SkVector vec = pts[1] - pts[0];
17 SkScalar mag = vec.length();
18 SkScalar inv = mag ? SkScalarInvert(mag) : 0;
19
20 vec.scale(inv);
21 SkMatrix matrix;
22 matrix.setSinCos(-vec.fY, vec.fX, pts[0].fX, pts[0].fY);
23 matrix.postTranslate(-pts[0].fX, -pts[0].fY);
24 matrix.postScale(inv, inv);
25 return matrix;
26 }
27
28 ///////////////////////////////////////////////////////////////////////////////
29
SkLinearGradient(const SkPoint pts[2],const Descriptor & desc)30 SkLinearGradient::SkLinearGradient(const SkPoint pts[2], const Descriptor& desc)
31 : SkGradientShaderBase(desc, pts_to_unit_matrix(pts))
32 , fStart(pts[0])
33 , fEnd(pts[1]) {
34 }
35
CreateProc(SkReadBuffer & buffer)36 sk_sp<SkFlattenable> SkLinearGradient::CreateProc(SkReadBuffer& buffer) {
37 DescriptorScope desc;
38 if (!desc.unflatten(buffer)) {
39 return nullptr;
40 }
41 SkPoint pts[2];
42 pts[0] = buffer.readPoint();
43 pts[1] = buffer.readPoint();
44 return SkGradientShader::MakeLinear(pts, desc.fColors, std::move(desc.fColorSpace), desc.fPos,
45 desc.fCount, desc.fTileMode, desc.fGradFlags,
46 desc.fLocalMatrix);
47 }
48
flatten(SkWriteBuffer & buffer) const49 void SkLinearGradient::flatten(SkWriteBuffer& buffer) const {
50 this->INHERITED::flatten(buffer);
51 buffer.writePoint(fStart);
52 buffer.writePoint(fEnd);
53 }
54
55 #ifdef SK_ENABLE_LEGACY_SHADERCONTEXT
onMakeContext(const ContextRec & rec,SkArenaAlloc * alloc) const56 SkShaderBase::Context* SkLinearGradient::onMakeContext(
57 const ContextRec& rec, SkArenaAlloc* alloc) const
58 {
59 // make sure our colorspaces are compatible with legacy blits
60 if (!rec.isLegacyCompatible(fColorSpace.get())) {
61 return nullptr;
62 }
63 // Can't use legacy blit if we can't represent our colors as SkColors
64 if (!this->colorsCanConvertToSkColor()) {
65 return nullptr;
66 }
67
68 return fTileMode != SkTileMode::kDecal
69 ? CheckedMakeContext<LinearGradient4fContext>(alloc, *this, rec)
70 : nullptr;
71 }
72 #endif
73
appendGradientStages(SkArenaAlloc *,SkRasterPipeline *,SkRasterPipeline *) const74 void SkLinearGradient::appendGradientStages(SkArenaAlloc*, SkRasterPipeline*,
75 SkRasterPipeline*) const {
76 // No extra stage needed for linear gradients.
77 }
78
transformT(skvm::Builder * p,skvm::Uniforms *,skvm::Coord coord,skvm::I32 * mask) const79 skvm::F32 SkLinearGradient::transformT(skvm::Builder* p, skvm::Uniforms*,
80 skvm::Coord coord, skvm::I32* mask) const {
81 // We've baked getting t in x into the matrix, so this is pretty trivial.
82 return coord.x;
83 }
84
asAGradient(GradientInfo * info) const85 SkShader::GradientType SkLinearGradient::asAGradient(GradientInfo* info) const {
86 if (info) {
87 commonAsAGradient(info);
88 info->fPoint[0] = fStart;
89 info->fPoint[1] = fEnd;
90 }
91 return kLinear_GradientType;
92 }
93
94 /////////////////////////////////////////////////////////////////////
95
96 #if SK_SUPPORT_GPU
97
98 #include "src/gpu/gradients/GrGradientShader.h"
99
asFragmentProcessor(const GrFPArgs & args) const100 std::unique_ptr<GrFragmentProcessor> SkLinearGradient::asFragmentProcessor(
101 const GrFPArgs& args) const {
102 return GrGradientShader::MakeLinear(*this, args);
103 }
104
105 #endif
106
addToKey(SkShaderCodeDictionary * dict,SkBackend backend,SkPaintParamsKeyBuilder * builder,SkUniformBlock * uniformBlock) const107 void SkLinearGradient::addToKey(SkShaderCodeDictionary* dict,
108 SkBackend backend,
109 SkPaintParamsKeyBuilder* builder,
110 SkUniformBlock* uniformBlock) const {
111 GradientShaderBlocks::GradientData data(kLinear_GradientType,
112 fStart, fEnd,
113 0.0f, 0.0f,
114 fTileMode,
115 fColorCount,
116 fOrigColors4f,
117 fOrigPos);
118
119 GradientShaderBlocks::AddToKey(dict, backend, builder, uniformBlock, data);
120 }
121