/* * Copyright 2012 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ #ifndef SkTwoPointConicalGradient_DEFINED #define SkTwoPointConicalGradient_DEFINED #include "SkColorSpaceXformer.h" #include "SkGradientShaderPriv.h" class SkTwoPointConicalGradient final : public SkGradientShaderBase { public: // See https://skia.org/dev/design/conical for what focal data means and how our shader works. // We make it public so the GPU shader can also use it. struct FocalData { SkScalar fR1; // r1 after mapping focal point to (0, 0) SkScalar fFocalX; // f bool fIsSwapped; // whether we swapped r0, r1 // The input r0, r1 are the radii when we map centers to {(0, 0), (1, 0)}. // We'll post concat matrix with our transformation matrix that maps focal point to (0, 0). void set(SkScalar r0, SkScalar r1, SkMatrix& matrix); // Whether the focal point (0, 0) is on the end circle with center (1, 0) and radius r1. If // this is true, it's as if an aircraft is flying at Mach 1 and all circles (soundwaves) // will go through the focal point (aircraft). In our previous implementations, this was // known as the edge case where the inside circle touches the outside circle (on the focal // point). If we were to solve for t bruteforcely using a quadratic equation, this case // implies that the quadratic equation degenerates to a linear equation. bool isFocalOnCircle() const { return SkScalarNearlyZero(1 - fR1); } bool isSwapped() const { return fIsSwapped; } bool isWellBehaved() const { return !this->isFocalOnCircle() && fR1 > 1; } bool isNativelyFocal() const { return SkScalarNearlyZero(fFocalX); } }; enum class Type { kRadial, kStrip, kFocal }; static sk_sp<SkShader> Create(const SkPoint& start, SkScalar startRadius, const SkPoint& end, SkScalar endRadius, const Descriptor&); SkShader::GradientType asAGradient(GradientInfo* info) const override; #if SK_SUPPORT_GPU std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(const GrFPArgs&) const override; #endif bool isOpaque() const override; SkScalar getCenterX1() const { return SkPoint::Distance(fCenter1, fCenter2); } SkScalar getStartRadius() const { return fRadius1; } SkScalar getDiffRadius() const { return fRadius2 - fRadius1; } const SkPoint& getStartCenter() const { return fCenter1; } const SkPoint& getEndCenter() const { return fCenter2; } SkScalar getEndRadius() const { return fRadius2; } Type getType() const { return fType; } const SkMatrix& getGradientMatrix() const { return fPtsToUnit; } const FocalData& getFocalData() const { return fFocalData; } SK_TO_STRING_OVERRIDE() SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTwoPointConicalGradient) protected: void flatten(SkWriteBuffer& buffer) const override; sk_sp<SkShader> onMakeColorSpace(SkColorSpaceXformer* xformer) const override; void appendGradientStages(SkArenaAlloc* alloc, SkRasterPipeline* tPipeline, SkRasterPipeline* postPipeline) const override; bool onIsRasterPipelineOnly(const SkMatrix&) const override { return true; } private: SkTwoPointConicalGradient(const SkPoint& c0, SkScalar r0, const SkPoint& c1, SkScalar r1, const Descriptor&, Type, const SkMatrix&, const FocalData&); SkPoint fCenter1; SkPoint fCenter2; SkScalar fRadius1; SkScalar fRadius2; Type fType; FocalData fFocalData; friend class SkGradientShader; typedef SkGradientShaderBase INHERITED; }; #endif