Draw2d 连线三 锚点 TriangleAnchor

关键字：Draw2d、锚点、TriangleAnchor

 

连线的时候能不能连接到画的图中去，在连线二中已经提到了，简单的跟图形连在一起，但是对于特殊的图是有不同的需求的。

如三角形，怎样连接端点。

 

public class TriangleAnchor extends ChopboxAnchor {

	public TriangleAnchor(Triangle triangle) {
		super(triangle);
	}
	
	public Point getLocation(Point reference) {
		Rectangle r = Rectangle.SINGLETON;
		r.setBounds(getBox());
		r.resize(-1, -1);
		
		int size;
		size = Math.min(r.height, r.width / 2);
		r.y += (r.height - size) / 2;
		size = Math.max(size, 1); //Size cannot be negative

		Point head, p2, p3;
		int d1,d2,d3;
		head = new Point(r.x + r.width / 2, r.y);
		p2   = new Point (head.x - size, head.y + size);
		p3   = new Point (head.x + size, head.y + size);

		Point p;
		if(Math.abs(reference.x-p2.x)+Math.abs(reference.y-p2.y) > 
		Math.abs(reference.x-p3.x)+Math.abs(reference.y-p3.y)) {
			p = p3;
		} else {
			p = p2;
		}
		d1 = distance(reference,head);
		d2 = distance(reference,p2);
		d3 = distance(reference,p3);
		
		p = head;
		if(d1<d2 && d1<d3) {
			p = head;
		}
		if(d2<d1 && d2<d3) {
			p = p2;
		}
		if(d3<d1 && d3<d2) {
			p = p3;
		}
		
		return p;
	}

	private int distance(Point p1, Point p2) {
		return Math.abs(p1.x-p2.x)+Math.abs(p1.y-p2.y);
	}

}

 

 

public class HelloWorld2 {
	public static void main(String args[]) {
		Shell shell = new Shell();
		shell.setText("Draw2d Hello World");
		shell.setSize(400, 400);
		shell.open();
		
		// create content 4 shell.
		createContent4Shell(shell);
		
		while (!shell.isDisposed ()) {
			if (!Display.getDefault().readAndDispatch ())
				Display.getDefault().sleep ();
		}
	}

	private static void createContent4Shell(Shell shell) {
		Panel rootFigure = new Panel();
		rootFigure.setLayoutManager(new XYLayout());
		
		IFigure figure1 = new Ellipse();
//		Label figure2 = new Label("ddddddddddddddddd");
		Triangle figure2 = new Triangle();
		
		// --------------------------------------------------------
		// add connection
		PolylineConnection connection = new PolylineConnection();
		connection.setSourceAnchor(new ChopboxAnchor(figure1));
	    
		connection.setTargetAnchor(new TriangleAnchor(figure2));
		// add connection
		// --------------------------------------------------------

		rootFigure.add(figure1,new Rectangle(10,10,60,30));
		rootFigure.add(figure2,new Rectangle(80,90,90,190));
		rootFigure.add(connection);
		
		LightweightSystem lws = new LightweightSystem(shell);
		lws.setContents(rootFigure);
	}
}

 

 

 

这个端点的求法，没有考虑三角形的方向，计算方法参考：

package org.eclipse.draw2d;

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

/**
 * A triangular graphical figure.
 */
public final class Triangle
	extends Shape
	implements Orientable