leitu.java

一个applet程序

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
public class Leitu extends Applet implements MouseMotionListener 
{int dotSize=10;
 Point[] pts=new Point[10000];
 
 
 public void init()
 {
  for(int i=0;i<pts.length;i++)
  {pts[i]=new Point(0, 0);
  }
   setForeground(Color.red);
//   resize(300,300);
   addMouseMotionListener(this);
//   show();
 }
 
 
 public int random(int r)
 {r=Math.max(r,0);
  return(int)(Math.floor(Math.random()*r));
 }
 
  
  public void paint(Graphics g)
  {Insets insets=insets();
   int w=size().width-insets.left-insets.right;
   int h=size().height-insets.top-insets.bottom;
   for(int i=0;i<pts.length;i++)
   {pts[i].move(random(w-dotSize), random(h-dotSize));
   }
  }
  
  
  public void update(Graphics g)
  {for(int i=0;i<pts.length;i++)
   {if(pts[i].x<0)
    {g.fillOval(-pts[i].x,-pts[i].y,dotSize,dotSize);
    }
   }
  }
  
  
  public void mouseDragged(MouseEvent e){}
  public void mouseMoved(MouseEvent e)
  {int x=e.getX();
   int y=e.getY();
   Point p=new Point(x-dotSize/2,y-dotSize/2);
   for(int i=0;i<pts.length;i++)
   {if(p.equals(pts[i]))
    {pts[i].x=-pts[i].x;
     pts[i].y=-pts[i].y;
     repaint(); 
     break;
    }
   }
  }
}