1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 #ifndef DOM_SMIL_SMILKEYSPLINE_H_ 8 #define DOM_SMIL_SMILKEYSPLINE_H_ 9 10 #include "mozilla/ArrayUtils.h" 11 #include "mozilla/PodOperations.h" 12 13 namespace mozilla { 14 15 /** 16 * Utility class to provide scaling defined in a keySplines element. 17 */ 18 class SMILKeySpline { 19 public: SMILKeySpline()20 constexpr SMILKeySpline() : mX1(0), mY1(0), mX2(0), mY2(0) { 21 /* caller must call Init later */\ 22 } 23 24 /** 25 * Creates a new key spline control point description. 26 * 27 * aX1, etc. are the x1, y1, x2, y2 cubic Bezier control points as defined 28 * by SMILANIM 3.2.3. They must each be in the range 0.0 <= x <= 1.0 29 */ SMILKeySpline(double aX1,double aY1,double aX2,double aY2)30 SMILKeySpline(double aX1, double aY1, double aX2, double aY2) 31 : mX1(0), mY1(0), mX2(0), mY2(0) { 32 Init(aX1, aY1, aX2, aY2); 33 } 34 X1()35 double X1() const { return mX1; } Y1()36 double Y1() const { return mY1; } X2()37 double X2() const { return mX2; } Y2()38 double Y2() const { return mY2; } 39 40 void Init(double aX1, double aY1, double aX2, double aY2); 41 42 /** 43 * Gets the output (y) value for an input (x). 44 * 45 * @param aX The input x value. A floating-point number between 0 and 46 * 1 (inclusive). 47 */ 48 double GetSplineValue(double aX) const; 49 50 void GetSplineDerivativeValues(double aX, double& aDX, double& aDY) const; 51 52 bool operator==(const SMILKeySpline& aOther) const { 53 return mX1 == aOther.mX1 && mY1 == aOther.mY1 && mX2 == aOther.mX2 && 54 mY2 == aOther.mY2; 55 } 56 bool operator!=(const SMILKeySpline& aOther) const { 57 return !(*this == aOther); 58 } Compare(const SMILKeySpline & aRhs)59 int32_t Compare(const SMILKeySpline& aRhs) const { 60 if (mX1 != aRhs.mX1) return mX1 < aRhs.mX1 ? -1 : 1; 61 if (mY1 != aRhs.mY1) return mY1 < aRhs.mY1 ? -1 : 1; 62 if (mX2 != aRhs.mX2) return mX2 < aRhs.mX2 ? -1 : 1; 63 if (mY2 != aRhs.mY2) return mY2 < aRhs.mY2 ? -1 : 1; 64 return 0; 65 } 66 67 private: 68 void CalcSampleValues(); 69 70 /** 71 * Returns x(t) given t, x1, and x2, or y(t) given t, y1, and y2. 72 */ 73 static double CalcBezier(double aT, double aA1, double aA2); 74 75 /** 76 * Returns dx/dt given t, x1, and x2, or dy/dt given t, y1, and y2. 77 */ 78 static double GetSlope(double aT, double aA1, double aA2); 79 80 double GetTForX(double aX) const; 81 82 double NewtonRaphsonIterate(double aX, double aGuessT) const; 83 84 double BinarySubdivide(double aX, double aA, double aB) const; 85 A(double aA1,double aA2)86 static double A(double aA1, double aA2) { 87 return 1.0 - 3.0 * aA2 + 3.0 * aA1; 88 } 89 B(double aA1,double aA2)90 static double B(double aA1, double aA2) { return 3.0 * aA2 - 6.0 * aA1; } 91 C(double aA1)92 static double C(double aA1) { return 3.0 * aA1; } 93 94 double mX1; 95 double mY1; 96 double mX2; 97 double mY2; 98 99 enum { kSplineTableSize = 11 }; 100 double mSampleValues[kSplineTableSize] = {}; 101 102 static const double kSampleStepSize; 103 }; 104 105 } // namespace mozilla 106 107 #endif // DOM_SMIL_SMILKEYSPLINE_H_ 108