    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
    025 * Other names may be trademarks of their respective owners.]
    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}