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 * Changes
036 * -------
037 * 05-Jul-2006 : Version 1 (DG);
038 * 31-Jan-2007 : Renamed min and max to lowerBound and upperBound (DG);
039 * 26-Sep-2007 : Fixed bug 1767315, problem in getPaint() method (DG);
040 *
041 */
042
043 package org.jfree.chart.renderer;
044
045 import java.awt.Color;
046 import java.awt.Paint;
047 import java.io.Serializable;
048
049 import org.jfree.util.PublicCloneable;
050
051 /**
052 * A paint scale that returns shades of gray.
053 *
054 * @since 1.0.4
055 */
056 public class GrayPaintScale
057 implements PaintScale, PublicCloneable, Serializable {
058
059 /** The lower bound. */
060 private double lowerBound;
061
062 /** The upper bound. */
063 private double upperBound;
064
065 /**
066 * Creates a new <code>GrayPaintScale</code> instance with default values.
067 */
068 public GrayPaintScale() {
069 this(0.0, 1.0);
070 }
071
072 /**
073 * Creates a new paint scale for values in the specified range.
074 *
075 * @param lowerBound the lower bound.
076 * @param upperBound the upper bound.
077 *
078 * @throws IllegalArgumentException if <code>lowerBound</code> is not
079 * less than <code>upperBound</code>.
080 */
081 public GrayPaintScale(double lowerBound, double upperBound) {
082 if (lowerBound >= upperBound) {
083 throw new IllegalArgumentException(
084 "Requires lowerBound < upperBound.");
085 }
086 this.lowerBound = lowerBound;
087 this.upperBound = upperBound;
088 }
089
090 /**
091 * Returns the lower bound.
092 *
093 * @return The lower bound.
094 *
095 * @see #getUpperBound()
096 */
097 public double getLowerBound() {
098 return this.lowerBound;
099 }
100
101 /**
102 * Returns the upper bound.
103 *
104 * @return The upper bound.
105 *
106 * @see #getLowerBound()
107 */
108 public double getUpperBound() {
109 return this.upperBound;
110 }
111
112 /**
113 * Returns a paint for the specified value.
114 *
115 * @param value the value (must be within the range specified by the
116 * lower and upper bounds for the scale).
117 *
118 * @return A paint for the specified value.
119 */
120 public Paint getPaint(double value) {
121 double v = Math.max(value, this.lowerBound);
122 v = Math.min(v, this.upperBound);
123 int g = (int) ((v - this.lowerBound) / (this.upperBound
124 - this.lowerBound) * 255.0);
125 return new Color(g, g, g);
126 }
127
128 /**
129 * Tests this <code>GrayPaintScale</code> instance for equality with an
130 * arbitrary object. This method returns <code>true</code> if and only
131 * if:
132 * <ul>
133 * <li><code>obj</code> is not <code>null</code>;</li>
134 * <li><code>obj</code> is an instance of <code>GrayPaintScale</code>;</li>
135 * </ul>
136 *
137 * @param obj the object (<code>null</code> permitted).
138 *
139 * @return A boolean.
140 */
141 public boolean equals(Object obj) {
142 if (obj == this) {
143 return true;
144 }
145 if (!(obj instanceof GrayPaintScale)) {
146 return false;
147 }
148 GrayPaintScale that = (GrayPaintScale) obj;
149 if (this.lowerBound != that.lowerBound) {
150 return false;
151 }
152 if (this.upperBound != that.upperBound) {
153 return false;
154 }
155 return true;
156 }
157
158 /**
159 * Returns a clone of this <code>GrayPaintScale</code> instance.
160 *
161 * @return A clone.
162 *
163 * @throws CloneNotSupportedException if there is a problem cloning this
164 * instance.
165 */
166 public Object clone() throws CloneNotSupportedException {
167 return super.clone();
168 }
169
170 }