зеркало из https://github.com/mozilla/gecko-dev.git
127 строки
3.6 KiB
C++
127 строки
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is the Mozilla SMIL module.
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*
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* The Initial Developer of the Original Code is Brian Birtles.
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* Portions created by the Initial Developer are Copyright (C) 2005
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Brian Birtles <birtles@gmail.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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#ifndef NS_SMILKEYSPLINE_H_
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#define NS_SMILKEYSPLINE_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() { /* caller must call Init later */ }
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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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{
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Init(aX1, aY1, aX2, aY2);
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}
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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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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_
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