Coverage Report

Created: 2018-09-25 14:53

/src/mozilla-central/dom/smil/nsSMILKeySpline.h
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/* -*- 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 NS_SMILKEYSPLINE_H_
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#define NS_SMILKEYSPLINE_H_
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#include "mozilla/ArrayUtils.h"
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#include "mozilla/PodOperations.h"
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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 nsSMILKeySpline
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{
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public:
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  nsSMILKeySpline()
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    : mX1(0)
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    , mY1(0)
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    , mX2(0)
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    , mY2(0)
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  {
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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 by
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   * SMILANIM 3.2.3. They must each be in the range 0.0 <= x <= 1.0
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   */
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  nsSMILKeySpline(double aX1, double aY1,
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                  double aX2, double aY2)
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    : mX1(0)
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    , mY1(0)
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    , mX2(0)
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    , mY2(0)
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  {
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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,
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            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 nsSMILKeySpline& aOther) const {
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    return mX1 == aOther.mX1 &&
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           mY1 == aOther.mY1 &&
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           mX2 == aOther.mX2 &&
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           mY2 == aOther.mY2;
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  }
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  bool operator!=(const nsSMILKeySpline& aOther) const {
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    return !(*this == aOther);
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  }
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  int32_t Compare(const nsSMILKeySpline& 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
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  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
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  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
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  GetSlope(double aT, double aA1, double aA2);
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  double
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  GetTForX(double aX) const;
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  double
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  NewtonRaphsonIterate(double aX, double aGuessT) const;
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  double
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  BinarySubdivide(double aX, double aA, double aB) const;
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  static double
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  A(double aA1, double aA2)
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  {
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    return 1.0 - 3.0 * aA2 + 3.0 * aA1;
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  }
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  static double
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  B(double aA1, double aA2)
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  {
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    return 3.0 * aA2 - 6.0 * aA1;
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  }
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  static double
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  C(double aA1)
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  {
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    return 3.0 * aA1;
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  }
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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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#endif // NS_SMILKEYSPLINE_H_