Polygon.java

/* -*- tab-width: 4 -*-
 *
 * Electric(tm) VLSI Design System
 *
 * File: Polygon.java
 *
 * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Electric(tm) is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * Electric(tm) 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Electric(tm); see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, Mass 02111-1307, USA.
 */
package com.sun.electric.api.minarea.geometry;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Immutable Polygon implementation
 * 
 * @author Felix Schmidt
 * 
 */
public class Polygon {

	public static interface PolygonUnionStrategy {
		public Polygon union(Polygon poly1, Polygon poly2);
	}

	public static interface PolygonIntersectStrategy {
		public Polygon intersect(Polygon poly1, Polygon poly2);

		public boolean intersectionTest(Polygon poly1, Polygon poly2);
	}

	protected List<Point> points;

	public Polygon(Point... points) {
		this.points = Arrays.asList(points);
	}

	public Rectangle getBoundingBox() {
		int lx = Integer.MAX_VALUE;
		int ly = Integer.MAX_VALUE;
		int hx = Integer.MIN_VALUE;
		int hy = Integer.MIN_VALUE;

		for (Point pt : points) {
			if (pt.getX() < lx)
				lx = pt.getX();
			if (pt.getY() < ly)
				ly = pt.getY();
			if (pt.getX() > hx)
				hx = pt.getX();
			if (pt.getY() > hy)
				hy = pt.getY();
		}

		return new Rectangle(new Point(lx, ly), new Point(hx, hy));
	}
	
	public List<Edge> extractEdges() {
		List<Edge> result = new ArrayList<Edge>();
		
		for(int i = 0; i < points.size(); i++) {
			result.add(new Edge(points.get(i), points.get((i+1) % points.size())));
		}
		
		return result;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder();
		builder.append("Polygon = (\n");
		for (Point pt : points) {
			builder.append("   ");
			builder.append(pt.toString());
		}
		builder.append(")");
		return builder.toString();
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#hashCode()
	 */
	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((points == null) ? 0 : points.hashCode());
		return result;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#equals(java.lang.Object)
	 */
	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		Polygon other = (Polygon) obj;
		if (points == null) {
			if (other.points != null)
				return false;
		} else if (!points.equals(other.points))
			return false;
		return true;
	}

	/**
	 * 
	 * @author Felix Schmidt
	 * 
	 */
	public static class Rectangle extends Polygon {

		/**
		 * 
		 * @param min
		 * @param max
		 */
		public Rectangle(Point min, Point max) {
			if (min.getX() >= max.getX() || min.getY() >= max.getY())
				throw new IllegalArgumentException();

			this.points = Arrays.asList(min, max);
		}

		public Rectangle(int minX, int minY, int maxX, int maxY) {
			this(new Point(minX, minY), new Point(maxX, maxY));
		}

		/**
		 * 
		 * @return
		 */
		public Point getMin() {
			return points.get(0);
		}

		/**
		 * 
		 * @return
		 */
		public Point getMax() {
			return points.get(1);
		}

		/**
		 * 
		 * @return
		 */
		public int width() {
			return Math.abs(points.get(1).getX() - points.get(0).getX());
		}

		/**
		 * 
		 * @return
		 */
		public int height() {
			return Math.abs(points.get(1).getY() - points.get(0).getY());
		}
		
		@Override
		public List<Edge> extractEdges() {
			return this.transformToPolygon().extractEdges();
		}

		public Polygon transformToPolygon() {
			Point top = new Point(getMax().getX(), getMin().getY());
			Point bottom = new Point(getMin().getX(), getMax().getY());
			return new Polygon(getMin(), bottom, getMax(), top);
		}

		public int[] toArray() {
			return new int[] { getMin().getX(), getMin().getY(), getMax().getX(), getMax().getY() };
		}

		/*
		 * (non-Javadoc)
		 * 
		 * @see com.sun.electric.api.minarea.geometry.Polygon#toString()
		 */
		@Override
		public String toString() {
			StringBuilder builder = new StringBuilder();
			builder.append("Rectangle = (\n");
			builder.append("  ");
			for (Point pt : points) {
				builder.append(" ");
				builder.append(pt.toString());
				builder.append(" ");
				builder.append("x");
			}

			builder.replace(builder.length() - 2, builder.length(), "");

			builder.append(")");
			return builder.toString();
		}

	}

	/**
	 * 
	 * @author Felix Schmidt
	 * 
	 */
	public static class PolygonHole extends Polygon {

		/**
		 * 
		 * @param points
		 */
		public PolygonHole(Point... points) {
			super(points);
		}
	}

}