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108 lines
3.1 KiB
C++
108 lines
3.1 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef DOM_SMIL_SMILKEYSPLINE_H_
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#define DOM_SMIL_SMILKEYSPLINE_H_
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#include "mozilla/ArrayUtils.h"
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#include "mozilla/PodOperations.h"
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namespace mozilla {
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/**
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* Utility class to provide scaling defined in a keySplines element.
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*/
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class SMILKeySpline {
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public:
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SMILKeySpline() : mX1(0), mY1(0), mX2(0), mY2(0) {
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/* caller must call Init later */\
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}
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/**
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* Creates a new key spline control point description.
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*
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* aX1, etc. are the x1, y1, x2, y2 cubic Bezier control points as defined
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* by SMILANIM 3.2.3. They must each be in the range 0.0 <= x <= 1.0
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*/
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SMILKeySpline(double aX1, double aY1, double aX2, double aY2)
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: mX1(0), mY1(0), mX2(0), mY2(0) {
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Init(aX1, aY1, aX2, aY2);
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}
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double X1() const { return mX1; }
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double Y1() const { return mY1; }
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double X2() const { return mX2; }
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double Y2() const { return mY2; }
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void Init(double aX1, double aY1, double aX2, double aY2);
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/**
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* Gets the output (y) value for an input (x).
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*
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* @param aX The input x value. A floating-point number between 0 and
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* 1 (inclusive).
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*/
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double GetSplineValue(double aX) const;
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void GetSplineDerivativeValues(double aX, double& aDX, double& aDY) const;
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bool operator==(const SMILKeySpline& aOther) const {
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return mX1 == aOther.mX1 && mY1 == aOther.mY1 && mX2 == aOther.mX2 &&
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mY2 == aOther.mY2;
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}
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bool operator!=(const SMILKeySpline& aOther) const {
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return !(*this == aOther);
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}
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int32_t Compare(const SMILKeySpline& aRhs) const {
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if (mX1 != aRhs.mX1) return mX1 < aRhs.mX1 ? -1 : 1;
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if (mY1 != aRhs.mY1) return mY1 < aRhs.mY1 ? -1 : 1;
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if (mX2 != aRhs.mX2) return mX2 < aRhs.mX2 ? -1 : 1;
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if (mY2 != aRhs.mY2) return mY2 < aRhs.mY2 ? -1 : 1;
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return 0;
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}
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private:
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void CalcSampleValues();
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/**
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* Returns x(t) given t, x1, and x2, or y(t) given t, y1, and y2.
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*/
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static double CalcBezier(double aT, double aA1, double aA2);
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/**
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* Returns dx/dt given t, x1, and x2, or dy/dt given t, y1, and y2.
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*/
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static double GetSlope(double aT, double aA1, double aA2);
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double GetTForX(double aX) const;
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double NewtonRaphsonIterate(double aX, double aGuessT) const;
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double BinarySubdivide(double aX, double aA, double aB) const;
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static double A(double aA1, double aA2) {
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return 1.0 - 3.0 * aA2 + 3.0 * aA1;
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}
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static double B(double aA1, double aA2) { return 3.0 * aA2 - 6.0 * aA1; }
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static double C(double aA1) { return 3.0 * aA1; }
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double mX1;
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double mY1;
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double mX2;
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double mY2;
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enum { kSplineTableSize = 11 };
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double mSampleValues[kSplineTableSize];
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static const double kSampleStepSize;
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};
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} // namespace mozilla
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#endif // DOM_SMIL_SMILKEYSPLINE_H_
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