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
044package org.jfree.chart.plot;
045
046import 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 */
052public 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}