学步园

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;  //包含有Graphics2D类 这个类（画笔）可以设置旋转
public class Ellipse extends Applet implements Runnable
{
 int AppletWidth,AppletHeight;
 Ellipse2D E2D;  //椭圆画笔
 AffineTransform tans; //用于旋转
 Thread thread;
 Image OffScreen;//子画面 把子画面放在主画面上可以消去闪烁缺点
 Graphics2D drawOffScreen;
 
 public void inint()
 {
  this.setBackground(Color.black);
  AppletWidth=getSize().width;
  AppletHeight=getSize().height;
  E2D=new Ellipse2D.Double(30,30,80,30);
  tans=new AffineTransform();
  OffScreen=createImage(AppletWidth,AppletHeight);
  drawOffScreen=(Graphics2D)OffScreen.getGraphics();
 }
 public void start()
 {
  thread=new Thread(this);
  thread.start();
 }
 public void stop()
 {
  thread=null;
 }
 public void update(Graphics g)
 {
  paint(g);
 }
 public void paint(Graphics g)
 {
  g.drawImage(OffScreen, 0, 0, this);
 }
 public void run()
 {
  while(true)
  {
   drawOffScreen.clearRect(0, 0, AppletWidth, AppletHeight);
   drawOffScreen.setColor(Color.white);
   tans.rotate(15.0*Math.PI/180, 70, 45);
   drawOffScreen.setTransform(tans);
   drawOffScreen.draw(E2D);
   
   repaint();
   try{
    Thread.sleep(33);
   }
   catch(InterruptedException e){}
  }
 }

}