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 negativePoint 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 connectionPolylineConnection 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 Triangleextends Shapeimplements Orientable
?
?