--- /dev/null
+/*
+* Copyright (c) 2003, the JUNG Project and the Regents of the University
+* of California
+* All rights reserved.
+*
+* This software is open-source under the BSD license; see either
+* "license.txt" or
+* http://jung.sourceforge.net/license.txt for a description.
+*/
+package edu.uci.ics.jung.algorithms.layout;
+
+import java.awt.geom.Point2D;
+
+/**
+ * Represents a point in polar coordinates: distance and angle from the origin.
+ * Includes conversions between polar and Cartesian
+ * coordinates (Point2D).
+ *
+ * @author Tom Nelson - tomnelson@dev.java.net
+ */
+public class PolarPoint
+{
+ double theta;
+ double radius;
+
+ /**
+ * Creates a new instance with radius and angle each 0.
+ */
+ public PolarPoint() {
+ this(0,0);
+ }
+
+ /**
+ * Creates a new instance with radius {@code radius} and angle {@code theta}.
+ */
+ public PolarPoint(double theta, double radius) {
+ this.theta = theta;
+ this.radius = radius;
+ }
+
+ /**
+ * Returns the angle for this point.
+ */
+ public double getTheta() { return theta; }
+
+ /**
+ * Returns the radius for this point.
+ */
+ public double getRadius() { return radius; }
+
+ /**
+ * Sets the angle for this point to {@code theta}.
+ */
+ public void setTheta(double theta) { this.theta = theta; }
+
+ /**
+ * Sets the radius for this point to {@code theta}.
+ */
+ public void setRadius(double radius) { this.radius = radius; }
+
+ /**
+ * Returns the result of converting <code>polar</code> to Cartesian coordinates.
+ */
+ public static Point2D polarToCartesian(PolarPoint polar) {
+ return polarToCartesian(polar.getTheta(), polar.getRadius());
+ }
+
+ /**
+ * Returns the result of converting <code>(theta, radius)</code> to Cartesian coordinates.
+ */
+ public static Point2D polarToCartesian(double theta, double radius) {
+ return new Point2D.Double(radius*Math.cos(theta), radius*Math.sin(theta));
+ }
+
+ /**
+ * Returns the result of converting <code>point</code> to polar coordinates.
+ */
+ public static PolarPoint cartesianToPolar(Point2D point) {
+ return cartesianToPolar(point.getX(), point.getY());
+ }
+
+ /**
+ * Returns the result of converting <code>(x, y)</code> to polar coordinates.
+ */
+ public static PolarPoint cartesianToPolar(double x, double y) {
+ double theta = Math.atan2(y,x);
+ double radius = Math.sqrt(x*x+y*y);
+ return new PolarPoint(theta, radius);
+ }
+
+ @Override
+ public String toString() {
+ return "PolarPoint[" + radius + "," + theta +"]";
+ }
+
+ /**
+ * Sets the angle and radius of this point to those of {@code p}.
+ */
+ public void setLocation(PolarPoint p) {
+ this.theta = p.getTheta();
+ this.radius = p.getRadius();
+ }
+}
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