serialimage.java

《java游戏设计》范例源代码及程序执行结果

// 程序：连续图像绘制
// 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;                          //新线程
   Graphics     drawOffScreen;
   MediaTracker MT;

   ImageProducer       Source;             //连续图像来源         
   CropImageFilter     CutImage;           //用来剪裁图像
    
   public void init()
   {
      MT            = new MediaTracker(this);
      Animation     = new Image[8];        //8张图像
      currentImage  = 0;                   //目前图像为第一张

      AppletWidth   = getSize().width;     //Applet的宽度
      AppletHeight  = getSize().height;    //Applet的高度

      //次画面及绘制工具
      OffScreen     = createImage(AppletWidth,AppletHeight);
      drawOffScreen = OffScreen.getGraphics();

      //获得连续图像
      SerialImage = getImage(getDocumentBase(),"Images/serial.gif");
      MT.addImage(SerialImage,0);
      try
      {
         showStatus("图像加载中...");  //在状态列显示信息
         MT.waitForAll();
      }
      catch(InterruptedException E)
      { 
         E.printStackTrace();          //打印错误信息
      }

      //剪裁连续图像
      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()                    //start()函数  
   {
      newThread = new Thread(this);       //建立与启动新线程
      newThread.start();
   }

   public void stop()                     //stop()函数
   {
      newThread = null;                   //将线程设为null
   }

   public void paint(Graphics g)
   {
      //下面这行的作用为清除次画面
      drawOffScreen.clearRect(0,0,AppletWidth,AppletHeight);
  
      //下面这行的作用为在次画面上绘制目前图像
      drawOffScreen.drawImage(Animation[currentImage],0,0,this);
      
      //将次画面贴到主画面上
      g.drawImage(OffScreen,0,0,this); 
   }

   public void update(Graphics g)         //update()函数
   {
      paint(g);                           //只单纯调用paint()函数
   }

   public void run()
   {
      while(newThread != null)            //动画循环
      {
         repaint();                       //重新绘制图像

         try
         {
            Thread.sleep(80);             //暂停程序执行80毫秒
         }
         catch(InterruptedException E){ }
       
         currentImage = (++currentImage) % 8;  //指定目前图像
      }  
   }
}