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 * 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 *
041 */
042
043 package org.jfree.chart.plot;
044
045 import java.util.Collections;
046
047 /**
048 * This class distributes the section labels for one side of a pie chart so
049 * that they do not overlap.
050 */
051 public class PieLabelDistributor extends AbstractPieLabelDistributor {
052
053 /** The minimum gap. */
054 private double minGap = 4.0;
055
056 /**
057 * Creates a new distributor.
058 *
059 * @param labelCount the number of labels (ignored).
060 */
061 public PieLabelDistributor(int labelCount) {
062 super();
063 }
064
065 /**
066 * Distributes the labels.
067 *
068 * @param minY the minimum y-coordinate in Java2D-space.
069 * @param height the available height (in Java2D units).
070 */
071 public void distributeLabels(double minY, double height) {
072 sort(); // sorts the label records into ascending order by baseY
073 if (isOverlap()) {
074 adjustInwards();
075 }
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 /**
093 * Returns <code>true</code> if there are overlapping labels in the list,
094 * and <code>false</code> otherwise.
095 *
096 * @return A boolean.
097 */
098 private boolean isOverlap() {
099 double y = 0.0;
100 for (int i = 0; i < this.labels.size(); i++) {
101 PieLabelRecord plr = getPieLabelRecord(i);
102 if (y > plr.getLowerY()) {
103 return true;
104 }
105 y = plr.getUpperY();
106 }
107 return false;
108 }
109
110 /**
111 * Adjusts the y-coordinate for the labels in towards the center in an
112 * attempt to fix overlapping.
113 */
114 protected void adjustInwards() {
115 int lower = 0;
116 int upper = this.labels.size() - 1;
117 while (upper > lower) {
118 if (lower < upper - 1) {
119 PieLabelRecord r0 = getPieLabelRecord(lower);
120 PieLabelRecord r1 = getPieLabelRecord(lower + 1);
121 if (r1.getLowerY() < r0.getUpperY()) {
122 double adjust = r0.getUpperY() - r1.getLowerY()
123 + this.minGap;
124 r1.setAllocatedY(r1.getAllocatedY() + adjust);
125 }
126 }
127 PieLabelRecord r2 = getPieLabelRecord(upper - 1);
128 PieLabelRecord r3 = getPieLabelRecord(upper);
129 if (r2.getUpperY() > r3.getLowerY()) {
130 double adjust = (r2.getUpperY() - r3.getLowerY()) + this.minGap;
131 r3.setAllocatedY(r3.getAllocatedY() + adjust);
132 }
133 lower++;
134 upper--;
135 }
136 }
137
138 /**
139 * Any labels that are overlapping are moved down in an attempt to
140 * eliminate the overlaps.
141 *
142 * @param minY the minimum y value (in Java2D coordinate space).
143 * @param height the height available for all labels.
144 */
145 protected void adjustDownwards(double minY, double height) {
146 for (int i = 0; i < this.labels.size() - 1; i++) {
147 PieLabelRecord record0 = getPieLabelRecord(i);
148 PieLabelRecord record1 = getPieLabelRecord(i + 1);
149 if (record1.getLowerY() < record0.getUpperY()) {
150 record1.setAllocatedY(Math.min(minY + height,
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, record0.getLowerY()
170 - this.minGap - record1.getLabelHeight() / 2.0));
171 }
172 }
173 }
174
175 /**
176 * Labels are spaced evenly in the available space in an attempt to
177 * eliminate the overlaps.
178 *
179 * @param minY the minimum y value (in Java2D coordinate space).
180 * @param height the height available for all labels.
181 */
182 protected void spreadEvenly(double minY, double height) {
183 double y = minY;
184 double sumOfLabelHeights = 0.0;
185 for (int i = 0; i < this.labels.size(); i++) {
186 sumOfLabelHeights += getPieLabelRecord(i).getLabelHeight();
187 }
188 double gap = Math.max(0, height - sumOfLabelHeights);
189 if (this.labels.size() > 1) {
190 gap = gap / (this.labels.size() - 1);
191 }
192 for (int i = 0; i < this.labels.size(); i++) {
193 PieLabelRecord record = getPieLabelRecord(i);
194 y = y + record.getLabelHeight() / 2.0;
195 record.setAllocatedY(y);
196 y = y + record.getLabelHeight() / 2.0 + gap;
197 }
198 }
199
200 /**
201 * Sorts the label records into ascending order by y-value.
202 */
203 public void sort() {
204 Collections.sort(this.labels);
205 }
206
207 /**
208 * Returns a string containing a description of the object for
209 * debugging purposes.
210 *
211 * @return A string.
212 */
213 public String toString() {
214 StringBuffer result = new StringBuffer();
215 for (int i = 0; i < this.labels.size(); i++) {
216 result.append(getPieLabelRecord(i).toString()).append("\n");
217 }
218 return result.toString();
219 }
220
221 }