1 /*
2
3 dsh-interpolate Interpolation and easing functions.
4 Copyright (c) 2009-2013 held jointly by the individual authors.
5
6 This library is free software; you can redistribute it and/or modify it
7 under the terms of the GNU Lesser General Public License as published
8 by the Free Software Foundation; either version 3 of the License, or (at
9 your option) any later version.
10
11 This library is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
14 License for more details.
15
16 You should have received a copy of the GNU Lesser General Public License
17 along with this library; if not, write to the Free Software Foundation,
18 Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
19
20 > http://www.fsf.org/licensing/licenses/lgpl.html
21 > http://www.opensource.org/licenses/lgpl-license.php
22
23 */
24 package org.dishevelled.interpolate;
25
26 /**
27 * Ease-in-out quartic interpolation function.
28 * <p><img src="../../../../images/ease-in-out-quartic.png" alt="ease-in-out quartic graph" /></p>
29 *
30 * @author Michael Heuer
31 * @version $Revision$ $Date$
32 */
33 public final class EaseInOutQuartic
34 implements EasingFunction
35 {
36
37 /** {@inheritDoc} */
38 public String toString()
39 {
40 return "ease-in-out-quartic";
41 }
42
43 /** {@inheritDoc} */
44 public Double evaluate(final Double value)
45 {
46 double v = 2.0d * value;
47 if (v < 1.0d)
48 {
49 return 0.5d * Math.pow(v, 4.0d);
50 }
51 v -= 2.0d;
52 return -0.5d * (Math.pow(v, 4.0d) - 2.0d);
53 }
54 }