StrokePointList.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 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;
}

}