001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2007, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * -------------------
028 * GrayPaintScale.java
029 * -------------------
030 * (C) Copyright 2006, 2007, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * $Id: GrayPaintScale.java,v 1.1.2.1 2007/01/31 14:15:16 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 05-Jul-2006 : Version 1 (DG);
040 * 31-Jan-2007 : Renamed min and max to lowerBound and upperBound (DG);
041 *
042 */
043
044 package org.jfree.chart.renderer;
045
046 import java.awt.Color;
047 import java.awt.Paint;
048 import java.io.Serializable;
049
050 import org.jfree.util.PublicCloneable;
051
052 /**
053 * A paint scale that returns shades of gray.
054 *
055 * @since 1.0.4
056 */
057 public class GrayPaintScale
058 implements PaintScale, PublicCloneable, Serializable {
059
060 /** The lower bound. */
061 private double lowerBound;
062
063 /** The upper bound. */
064 private double upperBound;
065
066 /**
067 * Creates a new <code>GrayPaintScale</code> instance with default values.
068 */
069 public GrayPaintScale() {
070 this(0.0, 1.0);
071 }
072
073 /**
074 * Creates a new paint scale for values in the specified range.
075 *
076 * @param lowerBound the lower bound.
077 * @param upperBound the upper bound.
078 */
079 public GrayPaintScale(double lowerBound, double upperBound) {
080 if (lowerBound >= upperBound) {
081 throw new IllegalArgumentException(
082 "Requires lowerBound < upperBound.");
083 }
084 this.lowerBound = lowerBound;
085 this.upperBound = upperBound;
086 }
087
088 /**
089 * Returns the lower bound.
090 *
091 * @return The lower bound.
092 */
093 public double getLowerBound() {
094 return this.lowerBound;
095 }
096
097 /**
098 * Returns the upper bound.
099 *
100 * @return The upper bound.
101 */
102 public double getUpperBound() {
103 return this.upperBound;
104 }
105
106 /**
107 * Returns a paint for the specified value.
108 *
109 * @param value the value.
110 *
111 * @return A paint for the specified value.
112 */
113 public Paint getPaint(double value) {
114 double v = Math.max(value, this.lowerBound);
115 v = Math.min(v, this.upperBound);
116 int g = (int) ((value - this.lowerBound) / (this.upperBound
117 - this.lowerBound) * 255.0);
118 return new Color(g, g, g);
119 }
120
121 /**
122 * Tests this <code>GrayPaintScale</code> instance for equality with an
123 * arbitrary object. This method returns <code>true</code> if and only
124 * if:
125 * <ul>
126 * <li><code>obj</code> is not <code>null</code>;</li>
127 * <li><code>obj</code> is an instance of <code>GrayPaintScale</code>;</li>
128 * </ul>
129 *
130 * @param obj the object (<code>null</code> permitted).
131 *
132 * @return A boolean.
133 */
134 public boolean equals(Object obj) {
135 if (obj == this) {
136 return true;
137 }
138 if (!(obj instanceof GrayPaintScale)) {
139 return false;
140 }
141 GrayPaintScale that = (GrayPaintScale) obj;
142 if (this.lowerBound != that.lowerBound) {
143 return false;
144 }
145 if (this.upperBound != that.upperBound) {
146 return false;
147 }
148 return true;
149 }
150
151 /**
152 * Returns a clone of this <code>GrayPaintScale</code> instance.
153 *
154 * @return A clone.
155 *
156 * @throws CloneNotSupportedException if there is a problem cloning this
157 * instance.
158 */
159 public Object clone() throws CloneNotSupportedException {
160 return super.clone();
161 }
162
163 }