图形自动随窗口缩放的java小程序

import java.awt.*;
import java.applet.*;
 import java.awt.event.*;
 import java.awt.Window;

public class autoSize extends Applet
{

int width,height,a=200,b=200; 
 public void init() { 
      //addWindowStateListener(new Mouse()); 
   this.addComponentListener(new ComponentAdapter() {
           public void componentResized(ComponentEvent evt) {
              width = getWidth(); 
              height = getHeight(); 
     // repaint();
           }
      });

   setSize(300,300);

   }
 public void paint(Graphics g){
 
   //g.drawOval((width-a)/2,(height-b)/2,a,b);//定中心位置
  
    
  
   //g.drawOval((width-a)/2,(height-b)/2,(a*width)/300,(b*width)/300);计算长宽缩放
 g.drawOval((width-(a*width)/300)/2,(height-(b*width)/300)/2,(a*width)/300,(b*width)/300)；
 //计算圆心保持中心位置

 }

 //class Mouse extends WindowAdapter { 
     // public void windowStateChanged(WindowEvent e) { 
   
       //  width = size().width; 
       //  height = size().height; 
       //  repaint();  
     // } //end mousePressed   
    //end Mouse 
  

}