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