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