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PlantUML is a component that allows to quickly write : * sequence diagram, * use case diagram, * class diagram, * activity diagram, * component diagram, * state diagram * object diagram

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/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
 *
 * (C) Copyright 2009-2013, Arnaud Roques
 *
 * Project Info:  http://plantuml.sourceforge.net
 * 
 * This file is part of PlantUML.
 *
 * PlantUML 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.
 *
 * PlantUML 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 this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * Original Author:  Arnaud Roques
 * 
 * Revision $Revision: 5183 $
 *
 */
package net.sourceforge.plantuml.svek.image;

import java.awt.geom.Point2D;
import java.util.ArrayList;
import java.util.List;

public class SmallestEnclosingCircle {

	private final List all = new ArrayList();
	private Circle lastSolution;

	public void append(Point2D pt) {
		all.add(pt);
		this.lastSolution = null;
	}

	public Circle getCircle() {
		if (lastSolution == null) {
			lastSolution = findSec(all.size(), all, 0, new ArrayList(all));
		}
		return lastSolution;
	}

	private Circle findSec(int n, List p, int m, List b) {
		Circle sec = new Circle();

		// Compute the Smallest Enclosing Circle defined by B
		if (m == 1) {
			sec = new Circle(b.get(0));
		} else if (m == 2) {
			sec = new Circle(b.get(0), b.get(1));
		} else if (m == 3) {
			return Circle.getCircle(b.get(0), b.get(1), b.get(2));
		}

		// Check if all the points in p are enclosed
		for (int i = 0; i < n; i++) {
			if (sec.isOutside(p.get(i))) {
				// Compute B <--- B union P[i].
				b.set(m, p.get(i));
				// Recurse
				sec = findSec(i, p, m + 1, b);
			}
		}

		return sec;
	}

}