package multimediademo;import java.awt.*;import java.awt.event.*;import java.applet.*;import java.net.*;import java.awt.image.*;import multimediademo.ImageFilter;/** * <p>Title: </p> * <p>Description: </p> * <p>Copyright: Copyright (c) 2003</p> * <p>Company: </p> * @author not attributable * @version 1.0 */public class AppletDemo extends Applet implements Runnable{  private boolean isStandalone = false;  //變量申明  private URL m_imageURL;            //圖像的URL  private String m_imageName;        //圖像文件的名稱  Image sourceImage,filteredImage;    //圖像類變量  ImageFilter imageFilter;            //申明一個圖像過濾器  MediaTracker tracker;               //定義媒體跟蹤器  Thread thread = new Thread(); //定義一個空線程  //Get a parameter value  public String getParameter(String key, String def) {    return isStandalone ? System.getProperty(key, def) :      (getParameter(key) != null ? getParameter(key) : def);  }  //Construct the applet  public AppletDemo() {  }  //重載的構造函數  public AppletDemo(URL imageURL,String imageName){    m_imageURL = imageURL;    m_imageName = imageName;  }  //Initialize the applet  public void init() {    try {      jbInit();    }    catch(Exception e) {      e.printStackTrace();    }  }  //Component initialization  private void jbInit() throws Exception {    sourceImage = this.getImage(m_imageURL,m_imageName);    filteredImage = sourceImage;    ImageFilter imageFilter = new ImageFilter();  }  //Get Applet information  public String getAppletInfo() {    return "Applet Information";  }  //Get parameter info  public String[][] getParameterInfo() {    return null;  }  //定義paint函數  public void paint(Graphics g){    if(!tracker.checkAll(true)){      this.showStatus("Now,the images are loading...");    }    else{      this.showStatus("Loading images is over");      g.drawImage(filteredImage,50,50,150,150,this);    }  }  //線程開始函數  public void start(){    if(thread == null){      thread = new Thread(this,"DemoThread");      thread.start();    }  }  //Overriding stop function  public void stop(){    if(thread != null){      thread.stop();      thread = null;    }  }  //Overriding destroy function  public void destroy(){  }  //Overriding run function  public void run(){    while(true){      imageFilter.pixelValueChange();      filteringImage();      repaint();      try{        Thread.sleep(200);      }      catch(InterruptedException e)      {}    }  }  //定義過慮  private void filteringImage(){    ImageProducer producer = sourceImage.getSource();    producer = new FilteredImageSource(producer,imageFilter);    filteredImage = this.createImage(producer);    tracker.addImage(filteredImage,1);  }}