001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2008, 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 2004-2008, by Object Refinery Limited and Contributors.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes
036 * -------
037 * 08-Mar-2004 : Version 1 (DG);
038 * 18-Apr-2005 : Use StringBuffer (DG);
039 * 14-Jun-2007 : Now extends AbstractPieLabelDistributor (DG);
040 * 31-Mar-2008 : Fix bugs in label distribution (DG);
041 *
042 */
043
044 package org.jfree.chart.plot;
045
046 import java.util.Collections;
047
048 /**
049 * This class distributes the section labels for one side of a pie chart so
050 * that they do not overlap.
051 */
052 public class PieLabelDistributor extends AbstractPieLabelDistributor {
053
054 /** The minimum gap. */
055 private double minGap = 4.0;
056
057 /**
058 * Creates a new distributor.
059 *
060 * @param labelCount the number of labels (ignored).
061 */
062 public PieLabelDistributor(int labelCount) {
063 super();
064 }
065
066 /**
067 * Distributes the labels.
068 *
069 * @param minY the minimum y-coordinate in Java2D-space.
070 * @param height the available height (in Java2D units).
071 */
072 public void distributeLabels(double minY, double height) {
073 sort(); // sorts the label records into ascending order by baseY
074 // if (isOverlap()) {
075 // adjustInwards();
076 // }
077 // if still overlapping, do something else...
078 if (isOverlap()) {
079 adjustDownwards(minY, height);
080 }
081
082 if (isOverlap()) {
083 adjustUpwards(minY, height);
084 }
085
086 if (isOverlap()) {
087 spreadEvenly(minY, height);
088 }
089 }
090
091 /**
092 * Returns <code>true</code> if there are overlapping labels in the list,
093 * and <code>false</code> otherwise.
094 *
095 * @return A boolean.
096 */
097 private boolean isOverlap() {
098 double y = 0.0;
099 for (int i = 0; i < this.labels.size(); i++) {
100 PieLabelRecord plr = getPieLabelRecord(i);
101 if (y > plr.getLowerY()) {
102 return true;
103 }
104 y = plr.getUpperY();
105 }
106 return false;
107 }
108
109 /**
110 * Adjusts the y-coordinate for the labels in towards the center in an
111 * attempt to fix overlapping.
112 */
113 protected void adjustInwards() {
114 int lower = 0;
115 int upper = this.labels.size() - 1;
116 while (upper > lower) {
117 if (lower < upper - 1) {
118 PieLabelRecord r0 = getPieLabelRecord(lower);
119 PieLabelRecord r1 = getPieLabelRecord(lower + 1);
120 if (r1.getLowerY() < r0.getUpperY()) {
121 double adjust = r0.getUpperY() - r1.getLowerY()
122 + this.minGap;
123 r1.setAllocatedY(r1.getAllocatedY() + adjust);
124 }
125 }
126 PieLabelRecord r2 = getPieLabelRecord(upper - 1);
127 PieLabelRecord r3 = getPieLabelRecord(upper);
128 if (r2.getUpperY() > r3.getLowerY()) {
129 double adjust = (r2.getUpperY() - r3.getLowerY()) + this.minGap;
130 r3.setAllocatedY(r3.getAllocatedY() + adjust);
131 }
132 lower++;
133 upper--;
134 }
135 }
136
137 /**
138 * Any labels that are overlapping are moved down in an attempt to
139 * eliminate the overlaps.
140 *
141 * @param minY the minimum y value (in Java2D coordinate space).
142 * @param height the height available for all labels.
143 */
144 protected void adjustDownwards(double minY, double height) {
145 for (int i = 0; i < this.labels.size() - 1; i++) {
146 PieLabelRecord record0 = getPieLabelRecord(i);
147 PieLabelRecord record1 = getPieLabelRecord(i + 1);
148 if (record1.getLowerY() < record0.getUpperY()) {
149 record1.setAllocatedY(Math.min(minY + height
150 - record1.getLabelHeight() / 2.0,
151 record0.getUpperY() + this.minGap
152 + record1.getLabelHeight() / 2.0));
153 }
154 }
155 }
156
157 /**
158 * Any labels that are overlapping are moved up in an attempt to eliminate
159 * the overlaps.
160 *
161 * @param minY the minimum y value (in Java2D coordinate space).
162 * @param height the height available for all labels.
163 */
164 protected void adjustUpwards(double minY, double height) {
165 for (int i = this.labels.size() - 1; i > 0; i--) {
166 PieLabelRecord record0 = getPieLabelRecord(i);
167 PieLabelRecord record1 = getPieLabelRecord(i - 1);
168 if (record1.getUpperY() > record0.getLowerY()) {
169 record1.setAllocatedY(Math.max(minY
170 + record1.getLabelHeight() / 2.0, record0.getLowerY()
171 - this.minGap - record1.getLabelHeight() / 2.0));
172 }
173 }
174 }
175
176 /**
177 * Labels are spaced evenly in the available space in an attempt to
178 * eliminate the overlaps.
179 *
180 * @param minY the minimum y value (in Java2D coordinate space).
181 * @param height the height available for all labels.
182 */
183 protected void spreadEvenly(double minY, double height) {
184 double y = minY;
185 double sumOfLabelHeights = 0.0;
186 for (int i = 0; i < this.labels.size(); i++) {
187 sumOfLabelHeights += getPieLabelRecord(i).getLabelHeight();
188 }
189 double gap = height - sumOfLabelHeights;
190 if (this.labels.size() > 1) {
191 gap = gap / (this.labels.size() - 1);
192 }
193 for (int i = 0; i < this.labels.size(); i++) {
194 PieLabelRecord record = getPieLabelRecord(i);
195 y = y + record.getLabelHeight() / 2.0;
196 record.setAllocatedY(y);
197 y = y + record.getLabelHeight() / 2.0 + gap;
198 }
199 }
200
201 /**
202 * Sorts the label records into ascending order by y-value.
203 */
204 public void sort() {
205 Collections.sort(this.labels);
206 }
207
208 /**
209 * Returns a string containing a description of the object for
210 * debugging purposes.
211 *
212 * @return A string.
213 */
214 public String toString() {
215 StringBuffer result = new StringBuffer();
216 for (int i = 0; i < this.labels.size(); i++) {
217 result.append(getPieLabelRecord(i).toString()).append("\n");
218 }
219 return result.toString();
220 }
221
222 }