1 /* 2 * Copyright 2018 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 #ifndef SkCubicMap_DEFINED 9 #define SkCubicMap_DEFINED 10 11 #include "include/core/SkPoint.h" 12 #include "include/core/SkScalar.h" 13 #include "include/core/SkTypes.h" 14 15 /** 16 * Fast evaluation of a cubic ease-in / ease-out curve. This is defined as a parametric cubic 17 * curve inside the unit square. 18 * 19 * pt[0] is implicitly { 0, 0 } 20 * pt[3] is implicitly { 1, 1 } 21 * pts[1,2].X are inside the unit [0..1] 22 */ 23 class SK_API SkCubicMap { 24 public: 25 SkCubicMap(SkPoint p1, SkPoint p2); 26 IsLinear(SkPoint p1,SkPoint p2)27 static bool IsLinear(SkPoint p1, SkPoint p2) { 28 return SkScalarNearlyEqual(p1.fX, p1.fY) && SkScalarNearlyEqual(p2.fX, p2.fY); 29 } 30 31 float computeYFromX(float x) const; 32 33 SkPoint computeFromT(float t) const; 34 35 private: 36 enum Type { 37 kLine_Type, // x == y 38 kCubeRoot_Type, // At^3 == x 39 kSolver_Type, // general monotonic cubic solver 40 }; 41 42 SkPoint fCoeff[3]; 43 Type fType; 44 }; 45 46 #endif 47 48