// 程序：連續圖像繪制
// 范例文件：SerialImage.java

import java.awt.*;
import java.applet.*;
import java.awt.image.*;

public class SerialImage extends Applet implements Runnable
{
   int          AppletWidth,AppletHeight,currentImage;          
   Image        Animation[],SerialImage,OffScreen;
   Thread       newThread;      
   Graphics     drawOffScreen;
   MediaTracker MT;

   ImageProducer       Source;  
   CropImageFilter     CutImage; 
    
   public void init()
   {
      MT            = new MediaTracker(this);
      Animation     = new Image[8];   
      currentImage  = 0;             

      AppletWidth   = getSize().width;   
      AppletHeight  = getSize().height;   

      OffScreen     = createImage(AppletWidth,AppletHeight);
      drawOffScreen = OffScreen.getGraphics();

      SerialImage = getImage(getDocumentBase(),"Images/serial.gif");
      MT.addImage(SerialImage,0);
      try
      {
         showStatus("圖像載入中...");
         MT.waitForAll();
      }
      catch(InterruptedException E)
      { 
         E.printStackTrace();      
      }

      Source = SerialImage.getSource();
      for(int i=0;i<8;i++)
      {
         CutImage = new CropImageFilter(i*250,0,250,250);

         Animation[i] 
         = createImage(new FilteredImageSource(Source,CutImage));

         drawOffScreen.drawImage(Animation[i],0,0,this);
      }
   }

   public void start()        
   {
      newThread = new Thread(this); 
      newThread.start();
   }

   public void stop()         
   {
      newThread = null;     
   }

   public void paint(Graphics g)
   {
      drawOffScreen.clearRect(0,0,AppletWidth,AppletHeight);
  
      drawOffScreen.drawImage(Animation[currentImage],0,0,this);
      
      g.drawImage(OffScreen,0,0,this); 
   }

   public void update(Graphics g)     
   {
      paint(g);                      
   }

   public void run()
   {
      while(newThread != null)     
      {
         repaint();               

         try
         {
            Thread.sleep(80);    
         }
         catch(InterruptedException E){ }
       
         currentImage = (++currentImage) % 8; 
      }  
   }
}