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