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JFreeChart is a class library, written in Java, for generating charts.
Utilising the Java2D APIs, it currently supports bar charts, pie charts,
line charts, XY-plots and time series plots.
/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2013, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jfreechart/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* ------------------------
* PieLabelDistributor.java
* ------------------------
* (C) Copyright 2004-2008, by Object Refinery Limited and Contributors.
*
* Original Author: David Gilbert (for Object Refinery Limited);
* Contributor(s): -;
*
* Changes
* -------
* 08-Mar-2004 : Version 1 (DG);
* 18-Apr-2005 : Use StringBuffer (DG);
* 14-Jun-2007 : Now extends AbstractPieLabelDistributor (DG);
* 31-Mar-2008 : Fix bugs in label distribution (DG);
*
*/
package org.jfree.chart.plot;
import java.util.Collections;
/**
* This class distributes the section labels for one side of a pie chart so
* that they do not overlap.
*/
public class PieLabelDistributor extends AbstractPieLabelDistributor {
/** The minimum gap. */
private double minGap = 4.0;
/**
* Creates a new distributor.
*
* @param labelCount the number of labels (ignored).
*/
public PieLabelDistributor(int labelCount) {
super();
}
/**
* Distributes the labels.
*
* @param minY the minimum y-coordinate in Java2D-space.
* @param height the available height (in Java2D units).
*/
@Override
public void distributeLabels(double minY, double height) {
sort(); // sorts the label records into ascending order by baseY
// if (isOverlap()) {
// adjustInwards();
// }
// if still overlapping, do something else...
if (isOverlap()) {
adjustDownwards(minY, height);
}
if (isOverlap()) {
adjustUpwards(minY, height);
}
if (isOverlap()) {
spreadEvenly(minY, height);
}
}
/**
* Returns true if there are overlapping labels in the list,
* and false otherwise.
*
* @return A boolean.
*/
private boolean isOverlap() {
double y = 0.0;
for (int i = 0; i < this.labels.size(); i++) {
PieLabelRecord plr = getPieLabelRecord(i);
if (y > plr.getLowerY()) {
return true;
}
y = plr.getUpperY();
}
return false;
}
/**
* Adjusts the y-coordinate for the labels in towards the center in an
* attempt to fix overlapping.
*/
protected void adjustInwards() {
int lower = 0;
int upper = this.labels.size() - 1;
while (upper > lower) {
if (lower < upper - 1) {
PieLabelRecord r0 = getPieLabelRecord(lower);
PieLabelRecord r1 = getPieLabelRecord(lower + 1);
if (r1.getLowerY() < r0.getUpperY()) {
double adjust = r0.getUpperY() - r1.getLowerY()
+ this.minGap;
r1.setAllocatedY(r1.getAllocatedY() + adjust);
}
}
PieLabelRecord r2 = getPieLabelRecord(upper - 1);
PieLabelRecord r3 = getPieLabelRecord(upper);
if (r2.getUpperY() > r3.getLowerY()) {
double adjust = (r2.getUpperY() - r3.getLowerY()) + this.minGap;
r3.setAllocatedY(r3.getAllocatedY() + adjust);
}
lower++;
upper--;
}
}
/**
* Any labels that are overlapping are moved down in an attempt to
* eliminate the overlaps.
*
* @param minY the minimum y value (in Java2D coordinate space).
* @param height the height available for all labels.
*/
protected void adjustDownwards(double minY, double height) {
for (int i = 0; i < this.labels.size() - 1; i++) {
PieLabelRecord record0 = getPieLabelRecord(i);
PieLabelRecord record1 = getPieLabelRecord(i + 1);
if (record1.getLowerY() < record0.getUpperY()) {
record1.setAllocatedY(Math.min(minY + height
- record1.getLabelHeight() / 2.0,
record0.getUpperY() + this.minGap
+ record1.getLabelHeight() / 2.0));
}
}
}
/**
* Any labels that are overlapping are moved up in an attempt to eliminate
* the overlaps.
*
* @param minY the minimum y value (in Java2D coordinate space).
* @param height the height available for all labels.
*/
protected void adjustUpwards(double minY, double height) {
for (int i = this.labels.size() - 1; i > 0; i--) {
PieLabelRecord record0 = getPieLabelRecord(i);
PieLabelRecord record1 = getPieLabelRecord(i - 1);
if (record1.getUpperY() > record0.getLowerY()) {
record1.setAllocatedY(Math.max(minY
+ record1.getLabelHeight() / 2.0, record0.getLowerY()
- this.minGap - record1.getLabelHeight() / 2.0));
}
}
}
/**
* Labels are spaced evenly in the available space in an attempt to
* eliminate the overlaps.
*
* @param minY the minimum y value (in Java2D coordinate space).
* @param height the height available for all labels.
*/
protected void spreadEvenly(double minY, double height) {
double y = minY;
double sumOfLabelHeights = 0.0;
for (int i = 0; i < this.labels.size(); i++) {
sumOfLabelHeights += getPieLabelRecord(i).getLabelHeight();
}
double gap = height - sumOfLabelHeights;
if (this.labels.size() > 1) {
gap = gap / (this.labels.size() - 1);
}
for (int i = 0; i < this.labels.size(); i++) {
PieLabelRecord record = getPieLabelRecord(i);
y = y + record.getLabelHeight() / 2.0;
record.setAllocatedY(y);
y = y + record.getLabelHeight() / 2.0 + gap;
}
}
/**
* Sorts the label records into ascending order by y-value.
*/
public void sort() {
Collections.sort(this.labels);
}
/**
* Returns a string containing a description of the object for
* debugging purposes.
*
* @return A string.
*/
@Override
public String toString() {
StringBuilder result = new StringBuilder();
for (int i = 0; i < this.labels.size(); i++) {
result.append(getPieLabelRecord(i).toString()).append("\n");
}
return result.toString();
}
}