Thanks for implementing fortune's algo, I tried your code

When multiplying the number of point by 60 from 1024 to 60,000 is should go only about 80 times slower, since it is claimed a complexity of n log(n), but I waited 5mm and it did not complete.
Also I experiment a bug with the following set of points , it tries to go a get() on an optional which is empty

new Point(64.0,554.2562584220407),new Point(576.0,332.55375505322445),new Point(640.0,221.70250336881628),new Point(128.0,443.40500673763256),new Point(896.0,443.40500673763256),new Point(0.0,221.70250336881628),new Point(512.0,221.70250336881628),new Point(192.0,332.55375505322445),new Point(960.0,332.55375505322445),new Point(896.0,221.70250336881628),new Point(704.0,554.2562584220407),new Point(320.0,332.55375505322445),new Point(896.0,0.0),new Point(256.0,221.70250336881628),new Point(384.0,0.0),new Point(832.0,554.2562584220407),new Point(512.0,0.0),new Point(640.0,0.0),new Point(768.0,443.40500673763256),new Point(768.0,221.70250336881628),new Point(192.0,554.2562584220407),new Point(832.0,332.55375505322445),

I can't find any class/structure I could iterate over to draw cells

Example set of 9 points in a grid, 2 distance between each:
[(0.00,0.00), (0.00,2.00), (0.00,4.00), (2.00,0.00), (2.00,2.00), (2.00,4.00), (4.00,0.00), (4.00,2.00), (4.00,4.00)]

    @Test
    public void testColinear() {
    	List<Point> points = new ArrayList<Point>();
    	for (int x = 0; x <= 4; x +=2) {
    		for (int y = 0; y <= 4; y+= 2) {
    			points.add(new Point(x, y));
    		}
    	}

        Voronoi diagram = new Voronoi(points);
    }

When running this, I get:

java.util.NoSuchElementException: No value present
	at java.util.Optional.get(Optional.java:135)
	at de.alsclo.voronoi.event.VertexEvent.handle(VertexEvent.java:61)
	at de.alsclo.voronoi.Voronoi.<init>(Voronoi.java:50)
	at de.alsclo.voronoi.VoronoiTest.testColinear(VoronoiTest.java:30)

Let me know if I've made a mistake or misunderstood something.