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 * Linear easing interpolation function. 28 * <p><img src="../../../../images/linear.png" alt="linear easing graph" /></p> 29 * 30 * @author Michael Heuer 31 * @version $Revision$ $Date$ 32 */ 33 public final class Linear 34 implements EasingFunction 35 { 36 37 /** {@inheritDoc} */ 38 public String toString() 39 { 40 return "linear"; 41 } 42 43 /** {@inheritDoc} */ 44 public Double evaluate(final Double value) 45 { 46 if (value == null) 47 { 48 throw new NullPointerException("value must not be null"); 49 } 50 return value; 51 } 52 }