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