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Algorithms for the JUNG project
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/*
 * Copyright (c) 2005, 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.
 *
 * Created on Jul 9, 2005
 */

package edu.uci.ics.jung.algorithms.layout;
import java.awt.Dimension;
import java.awt.geom.Point2D;
import java.util.HashMap;
import java.util.Map;

import edu.uci.ics.jung.graph.Forest;

/**
 * A radial layout for Tree or Forest graphs.
 * 
 * @author Tom Nelson 
 *  
 */
public class RadialTreeLayout extends TreeLayout {

    protected Map polarLocations;

    /**
     * Creates an instance for the specified graph with default X and Y distances.
     */
    public RadialTreeLayout(Forest g) {
    	this(g, DEFAULT_DISTX, DEFAULT_DISTY);
    }

    /**
     * Creates an instance for the specified graph and X distance with
     * default Y distance.
     */
    public RadialTreeLayout(Forest g, int distx) {
        this(g, distx, DEFAULT_DISTY);
    }

    /**
     * Creates an instance for the specified graph, X distance, and Y distance.
     */
    public RadialTreeLayout(Forest g, int distx, int disty) {
    	super(g, distx, disty);
    }
    
	@Override
    protected void buildTree() {
	    super.buildTree();
	    this.polarLocations = new HashMap();
        setRadialLocations();
    }

    @Override
    public void setSize(Dimension size) {
    	this.size = size;
        buildTree();
    }

    @Override
    protected void setCurrentPositionFor(V vertex) {
    	locations.get(vertex).setLocation(m_currentPoint);
    }

	@Override
    public void setLocation(V v, Point2D location)
    {
        Point2D c = getCenter();
        Point2D pv = new Point2D.Double(location.getX() - c.getX(), 
                location.getY() - c.getY());
        PolarPoint newLocation = PolarPoint.cartesianToPolar(pv);
        PolarPoint currentLocation = polarLocations.get(v);
        if (currentLocation == null)
        	polarLocations.put(v, newLocation);
        else
        	currentLocation.setLocation(newLocation);
     }
	
	/**
	 * Returns the map from vertices to their locations in polar coordinates.
	 */
	public Map getPolarLocations() {
		return polarLocations;
	}

	@Override
    public Point2D transform(V v) {
		PolarPoint pp = polarLocations.get(v);
		double centerX = getSize().getWidth()/2;
		double centerY = getSize().getHeight()/2;
		Point2D cartesian = PolarPoint.polarToCartesian(pp);
		cartesian.setLocation(cartesian.getX()+centerX,cartesian.getY()+centerY);
		return cartesian;
	}
	
	private Point2D getMaxXY() {
		double maxx = 0;
		double maxy = 0;
		for(Point2D p : locations.values()) {
			maxx = Math.max(maxx, p.getX());
			maxy = Math.max(maxy, p.getY());
		}
		return new Point2D.Double(maxx,maxy);
	}
	
	private void setRadialLocations() {
		Point2D max = getMaxXY();
		double maxx = max.getX();
		double maxy = max.getY();
		maxx = Math.max(maxx, size.width);
		double theta = 2*Math.PI/maxx;

		double deltaRadius = size.width/2/maxy;
		for(Map.Entry entry : locations.entrySet()) {
			V v = entry.getKey();
			Point2D p = entry.getValue();
			PolarPoint polarPoint = new PolarPoint(p.getX()*theta, (p.getY() - this.distY)*deltaRadius);
			polarLocations.put(v, polarPoint);
		}
	}
}