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 * PieLabelDistributor.java
029 * ------------------------
030 * (C) Copyright 2004-2007, by Object Refinery Limited and Contributors.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * $Id: PieLabelDistributor.java,v 1.5.2.2 2007/06/14 15:04:21 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 08-Mar-2004 : Version 1 (DG);
040 * 18-Apr-2005 : Use StringBuffer (DG);
041 * 14-Jun-2007 : Now extends AbstractPieLabelDistributor (DG);
042 *
043 */
044
045 package org.jfree.chart.plot;
046
047 import java.util.Collections;
048
049 /**
050 * This class distributes the section labels for one side of a pie chart so
051 * that they do not overlap.
052 */
053 public class PieLabelDistributor extends AbstractPieLabelDistributor {
054
055 /** The minimum gap. */
056 private double minGap = 4.0;
057
058 /**
059 * Creates a new distributor.
060 *
061 * @param labelCount the number of labels (ignored).
062 */
063 public PieLabelDistributor(int labelCount) {
064 super();
065 }
066
067 /**
068 * Distributes the labels.
069 *
070 * @param minY the minimum y-coordinate in Java2D-space.
071 * @param height the available height (in Java2D units).
072 */
073 public void distributeLabels(double minY, double height) {
074 sort(); // sorts the label records into ascending order by baseY
075 if (isOverlap()) {
076 adjustInwards();
077 }
078
079 // if still overlapping, do something else...
080 if (isOverlap()) {
081 adjustDownwards(minY, height);
082 }
083
084 if (isOverlap()) {
085 adjustUpwards(minY, height);
086 }
087
088 if (isOverlap()) {
089 spreadEvenly(minY, height);
090 }
091
092 }
093
094 /**
095 * Returns <code>true</code> if there are overlapping labels in the list,
096 * and <code>false</code> otherwise.
097 *
098 * @return A boolean.
099 */
100 private boolean isOverlap() {
101 double y = 0.0;
102 for (int i = 0; i < this.labels.size(); i++) {
103 PieLabelRecord plr = getPieLabelRecord(i);
104 if (y > plr.getLowerY()) {
105 return true;
106 }
107 y = plr.getUpperY();
108 }
109 return false;
110 }
111
112 /**
113 * Adjusts the y-coordinate for the labels in towards the center in an
114 * attempt to fix overlapping.
115 */
116 protected void adjustInwards() {
117 int lower = 0;
118 int upper = this.labels.size() - 1;
119 while (upper > lower) {
120 if (lower < upper - 1) {
121 PieLabelRecord r0 = getPieLabelRecord(lower);
122 PieLabelRecord r1 = getPieLabelRecord(lower + 1);
123 if (r1.getLowerY() < r0.getUpperY()) {
124 double adjust = r0.getUpperY() - r1.getLowerY()
125 + this.minGap;
126 r1.setAllocatedY(r1.getAllocatedY() + adjust);
127 }
128 }
129 PieLabelRecord r2 = getPieLabelRecord(upper - 1);
130 PieLabelRecord r3 = getPieLabelRecord(upper);
131 if (r2.getUpperY() > r3.getLowerY()) {
132 double adjust = (r2.getUpperY() - r3.getLowerY()) + this.minGap;
133 r3.setAllocatedY(r3.getAllocatedY() + adjust);
134 }
135 lower++;
136 upper--;
137 }
138 }
139
140 /**
141 * Any labels that are overlapping are moved down in an attempt to
142 * eliminate the overlaps.
143 *
144 * @param minY the minimum y value (in Java2D coordinate space).
145 * @param height the height available for all labels.
146 */
147 protected void adjustDownwards(double minY, double height) {
148 for (int i = 0; i < this.labels.size() - 1; i++) {
149 PieLabelRecord record0 = getPieLabelRecord(i);
150 PieLabelRecord record1 = getPieLabelRecord(i + 1);
151 if (record1.getLowerY() < record0.getUpperY()) {
152 record1.setAllocatedY(Math.min(minY + height,
153 record0.getUpperY() + this.minGap
154 + record1.getLabelHeight() / 2.0));
155 }
156 }
157 }
158
159 /**
160 * Any labels that are overlapping are moved up in an attempt to eliminate
161 * the overlaps.
162 *
163 * @param minY the minimum y value (in Java2D coordinate space).
164 * @param height the height available for all labels.
165 */
166 protected void adjustUpwards(double minY, double height) {
167 for (int i = this.labels.size() - 1; i > 0; i--) {
168 PieLabelRecord record0 = getPieLabelRecord(i);
169 PieLabelRecord record1 = getPieLabelRecord(i - 1);
170 if (record1.getUpperY() > record0.getLowerY()) {
171 record1.setAllocatedY(Math.max(minY, record0.getLowerY()
172 - this.minGap - record1.getLabelHeight() / 2.0));
173 }
174 }
175 }
176
177 /**
178 * Labels are spaced evenly in the available space in an attempt to
179 * eliminate the overlaps.
180 *
181 * @param minY the minimum y value (in Java2D coordinate space).
182 * @param height the height available for all labels.
183 */
184 protected void spreadEvenly(double minY, double height) {
185 double y = minY;
186 double sumOfLabelHeights = 0.0;
187 for (int i = 0; i < this.labels.size(); i++) {
188 sumOfLabelHeights += getPieLabelRecord(i).getLabelHeight();
189 }
190 double gap = Math.max(0, height - sumOfLabelHeights);
191 if (this.labels.size() > 1) {
192 gap = gap / (this.labels.size() - 1);
193 }
194 for (int i = 0; i < this.labels.size(); i++) {
195 PieLabelRecord record = getPieLabelRecord(i);
196 y = y + record.getLabelHeight() / 2.0;
197 record.setAllocatedY(y);
198 y = y + record.getLabelHeight() / 2.0 + gap;
199 }
200 }
201
202 /**
203 * Sorts the label records into ascending order by y-value.
204 */
205 public void sort() {
206 Collections.sort(this.labels);
207 }
208
209 /**
210 * Returns a string containing a description of the object for
211 * debugging purposes.
212 *
213 * @return A string.
214 */
215 public String toString() {
216 StringBuffer result = new StringBuffer();
217 for (int i = 0; i < this.labels.size(); i++) {
218 result.append(getPieLabelRecord(i).toString()).append("\n");
219 }
220 return result.toString();
221 }
222
223 }