LayoutUnrooted.java

package org.phylowidget.render;

import java.util.List;

import org.phylowidget.PhyloWidget;
import org.phylowidget.tree.PhyloNode;

import processing.core.PGraphics;

/**
 * An unrooted radial layout based on the equal-angle algorithm.
 * @author Greg
 *
 */
public class LayoutUnrooted extends LayoutBase
{
	static final float STARTING_ANGLE = (float)-Math.PI/2;
	
	@Override
	public void layoutImpl()
	{
		float angle = STARTING_ANGLE + context.config().layoutAngle / 360f * (float)Math.PI*2f;
		layoutNode((PhyloNode)tree.getRoot(),angle, angle + 2*Math.PI);
	}

	@Override
	public void drawLine(PGraphics canvas, PhyloNode p, PhyloNode c)
	{
		canvas.line(c.getX(), c.getY(), p.getX(),p.getY());
	}
	
	void layoutNode(PhyloNode n, double loAngle, double hiAngle)
	{
		if (tree.isRoot(n)) // Set the root to (0,0).
		{
			setPosition(n,0,0);
		}
		if (tree.isLeaf(n)) // Leaves need no more laying out!
			return;
		
		float numEnclosed = tree.getNumEnclosedLeaves(n); // Total enclosed leaves for this node.
		double curX = n.getLayoutX();
		double curY = n.getLayoutY();
		
		List<PhyloNode> children = tree.getChildrenOf(n);
		double curAngle = loAngle;
		for (int i=0; i < children.size(); i++)
		{
			PhyloNode child = children.get(i);
			
			// Get the % of leaves under this child.
			float childEnclosed = tree.getNumEnclosedLeaves(child);
			double childRatio = childEnclosed / numEnclosed;
			double arcSize = childRatio * (hiAngle-loAngle);
			
			// Place this child in the middle of its given arc.
			double length = child.getBranchLength() * 10;
			double midAngle = curAngle+arcSize/2;
			
			double newX = curX + Math.cos(midAngle)*length;
			double newY = curY + Math.sin(midAngle)*length;
			
			setPosition(child, (float)newX, (float)newY);
			setAngle(child,(float)midAngle);
			
			layoutNode(child,curAngle,curAngle+arcSize);
			
			curAngle += arcSize;
		}
	}
	
	
}