examples.geometry.demos.TriangulationExample.java Source code

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Here is the source code for examples.geometry.demos.TriangulationExample.java

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/*******************************************************************************
 * Copyright (c) 2012 itemis AG 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:
 *     Matthias Wienand (itemis AG) - initial API and implementation
 *     
 *******************************************************************************/
package examples.geometry.demos;

import org.eclipse.gef4.geometry.planar.Line;
import org.eclipse.gef4.geometry.planar.Point;
import org.eclipse.gef4.geometry.planar.Polygon;
import org.eclipse.gef4.geometry.planar.Polygon.NonSimplePolygonException;

import com.google.gwt.canvas.client.Canvas;
import com.google.gwt.canvas.dom.client.Context2d;
import com.google.gwt.event.shared.EventBus;

import examples.geometry.AbstractExample;
import examples.geometry.ControllableShape;

public class TriangulationExample extends AbstractExample {

    public TriangulationExample(EventBus eventBus, Canvas canvas) {
        super(eventBus, canvas);
    }

    @Override
    protected ControllableShape[] createShapes(Canvas canvas, EventBus eventBus) {
        return new ControllableShape[] { new ControllableShape(canvas, eventBus) {
            {
                addControlPoints(new Point(300 / 2, 100 / 2), new Point(100 / 2, 200 / 2),
                        new Point(200 / 2, 300 / 2), new Point(100 / 2, 500 / 2), new Point(300 / 2, 400 / 2),
                        new Point(500 / 2, 600 / 2), new Point(600 / 2, 300 / 2), new Point(500 / 2, 400 / 2),
                        new Point(500 / 2, 200 / 2), new Point(300 / 2, 200 / 2));
            }

            @Override
            public Polygon getShape() {
                Polygon p = new Polygon(getPoints());
                return p;
            }

            @Override
            public void onDraw(Canvas canvas) {
                Context2d context = canvas.getContext2d();
                Polygon p = getShape();

                Polygon[] triangulation;
                try {
                    triangulation = p.getTriangulation();
                } catch (NonSimplePolygonException x) {
                    triangulation = new Polygon[] { p };
                }

                for (Polygon triangle : triangulation) {
                    context.beginPath();
                    context.setStrokeStyle("red");

                    for (Line s : triangle.getOutlineSegments()) {
                        Point p1 = s.getP1();
                        Point p2 = s.getP2();
                        context.moveTo(p1.x, p1.y);
                        context.lineTo(p2.x, p2.y);
                        context.stroke();
                    }
                    context.closePath();
                }

                double lineWidth = context.getLineWidth();
                context.setLineWidth(lineWidth + 2);
                context.setStrokeStyle("black");

                context.beginPath();
                for (Line s : p.getOutlineSegments()) {
                    Point p1 = s.getP1();
                    Point p2 = s.getP2();
                    context.moveTo(p1.x, p1.y);
                    context.lineTo(p2.x, p2.y);
                    context.stroke();
                }
                context.closePath();
                context.setLineWidth(lineWidth);
            }
        } };
    }

}