自定义Decoration

大家都知道new PolygonDecoration就表示带箭头，但有的时候不想是箭头，想搞个圆圈，或者方块，那怎么做呢？那就只能自定义PolygonDecoration咯，我昨天自定义了一个圆圈，给大家看看吧

package com.netunit.workbench.parts;

import org.eclipse.draw2d.Ellipse; 
import org.eclipse.draw2d.RotatableDecoration; 
import org.eclipse.draw2d.geometry.Point; 
import org.eclipse.draw2d.geometry.Rectangle; 

public class CircleDecoration extends Ellipse implements RotatableDecoration { 
        private int myRadius = 5; 
        private Point myCenter = new Point(); 

        public void setRadius(int radius){ 
                erase(); 
                 myRadius = Math.abs(radius); 
                 bounds = null; 
                 repaint(); 
         } 

       public void setLineWidth(int width){ 
                 super.setLineWidth(width); 
         } 

         public Rectangle getBounds() { 
                if (bounds == null){ 
                        int diameter = myRadius * 2; 
                       bounds = new Rectangle(myCenter.x - myRadius, myCenter.y - myRadius, diameter, diameter); 
                      bounds.expand(lineWidth / 2, lineWidth / 2); 
              } 
                return bounds; 
       } 

         public void setLocation(Point p) { 
                 if (myCenter.equals(p)){ 
                         return; 
                 }        
                 myCenter.setLocation(p); 
                bounds = null; 
        } 

         public void setReferencePoint(Point p) { 
                //ignore, does not make sense to rotate circle 
         } 

} 

下面是效果图：