bundles/org.eclipse.gef/src/org/eclipse/gef/editpolicies/StrokePointList.java

/*******************************************************************************
 * Copyright (c) 2000, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.gef.editpolicies;

import java.awt.BasicStroke;
import java.awt.Shape;
import java.awt.geom.Area;
import java.awt.geom.GeneralPath;
import java.awt.geom.PathIterator;

import org.eclipse.draw2d.geometry.Point;
import org.eclipse.draw2d.geometry.PointList;

/**
 * @author hudsonr
 * @since 2.0
 */
public class StrokePointList {

	static float segment[] = new float[6];

	static PointList strokeList(PointList list, int offset) {
		GeneralPath path = new GeneralPath(GeneralPath.WIND_NON_ZERO);

		Point p = list.getPoint(0);
		path.moveTo(p.x, p.y);
		for (int i = 1; i < list.size(); i++)
			path.lineTo((p = list.getPoint(i)).x, p.y);
		BasicStroke stroke = new BasicStroke(offset * 2,
				BasicStroke.CAP_SQUARE, BasicStroke.JOIN_MITER, 10.0f);
		Shape stroked = stroke.createStrokedShape(path);
		Area area = new Area(stroked);
		PathIterator iter = area.getPathIterator(null, 10.0f);

		PointList currentSegment = null;
		PointList result = null;
		int largestSegmentSize = 0;

		while (!iter.isDone()) {
			if (currentSegment == null)
				currentSegment = new PointList(list.size() * 2);
			int type = iter.currentSegment(segment);
			currentSegment.addPoint(Math.round(segment[0]),
					Math.round(segment[1]));
			iter.next();
			if (type == PathIterator.SEG_CLOSE) {
				if (currentSegment.size() > largestSegmentSize) {
					result = currentSegment;
					largestSegmentSize = currentSegment.size();
					currentSegment = null;
				}
			}
		}

		return result;
	}

}