animatorapplet.java

一个带有背景卷动效果的精灵跑步Applet动画

import javax.swing.JApplet;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Graphics;
import java.awt.image.PixelGrabber;
import java.awt.image.MemoryImageSource;
import java.awt.Color;
public class AnimatorApplet extends JApplet implements Runnable{
	boolean startMoved=false;
	final int speedPixels=3;  //路边树木及精灵的移动象素速度
	final int speedDelay=200;  //路边树木及精灵的移动延时
	Image treeImage;	
	Image movedImage;
	Image stickImage;
	Image roadImage;  //道路图片
	Image spiritImage1,spiritImage2;  //精灵图片
	MediaTracker tracker;
	Thread bgThread;
	int win_w;
	int win_h;
	int treeImage_w;
	int treeImage_h;
	int stickImage_w;
	int stickImage_h;
	int spiritImage_w;
	int spiritImage_h;
	PixelGrabber pixelGrabber;
	PixelGrabber pixelGrabberPatch;  //打补丁的象素抓取器
	int[] pixels;
	boolean isReady=false;
	boolean treeWhileStop=false;  //将用这个标志终止线程内部的while循环
	int x=0;  //路边树木的移动横坐标
	SpiritThread spiritThread;  //精灵线程
	PixelGrabber pixelGrabberSpirit;  //抓取精灵将移到的位置处的背景象素
	boolean meetStatus=false;  //精灵碰到达标棒
	Image imageTreeBuffer;  //路边树木双缓冲区
	Image imageSpiritBuffer;  //精灵双缓冲区

	public void init(){
		tracker=new MediaTracker(this);
		treeImage=getImage(getCodeBase(),"image/tree.jpg");   //将被移动的路边树木图片
		stickImage=getImage(getCodeBase(),"image/stick.gif"); //达标棒图片
		roadImage=getImage(getCodeBase(),"image/road.jpg");
		spiritImage1=getImage(getCodeBase(),"image/spirit1.gif");
		spiritImage2=getImage(getCodeBase(),"image/spirit2.gif");
		tracker.addImage(treeImage,1);
		tracker.addImage(stickImage,2);
		tracker.addImage(roadImage,3);
		tracker.addImage(spiritImage1,4);
		tracker.addImage(spiritImage2,5);
		try{
			tracker.waitForAll(); //确保图象已被加载，否则treeImage_h等值仍为-1。
		}catch(InterruptedException e){
			System.out.println("加载图象文件失败");
		}
		win_w=getSize().width;
		win_h=getSize().height;
		treeImage_w=treeImage.getWidth(null);
		treeImage_h=treeImage.getHeight(null);
		//
		stickImage_w=stickImage.getWidth(null);
		stickImage_h=stickImage.getHeight(null);
		//
		spiritImage_w=spiritImage1.getWidth(null);
		spiritImage_h=spiritImage1.getHeight(null);
		//
		pixels = new int[win_w * win_h];
		//
		imageTreeBuffer=createImage(win_w,treeImage_h);  //双缓冲区,注意高度为treeImage_h.
		imageSpiritBuffer=createImage(win_w,win_h - treeImage_h);  //双缓冲区,高度为applet窗口下半部分.
	}
	
	public void start(){
		bgThread=new Thread(this);  //启动路边树木移动线程
		bgThread.start();
		spiritThread=new SpiritThread();  //启动精灵线程
		spiritThread.start();
	}
	public void paint(Graphics g){
		//动画开始
		if(imageTreeBuffer!=null){  //applet初始化后会调用一次paint,此时imageTreeBuffer为空.
			g.drawImage(imageTreeBuffer,0,0,null);  //显示路边树木缓冲区象素数据
		}
		if(imageSpiritBuffer!=null){  //绘制移动中的精灵
			g.drawImage(imageSpiritBuffer,0,treeImage_h,null);
		}
	}

	public void run(){  //背景图向左移动
		Graphics g1=imageTreeBuffer.getGraphics();  //取得缓冲区相应的Graphics对象
		while(!treeWhileStop){
			if(x >treeImage_w) x=0;
			if(treeImage_w  -x< win_w){  //从x处开始抓取的图片小于applet窗口宽度
				pixelGrabber=new PixelGrabber(treeImage,x,0,treeImage_w -x,treeImage_h,pixels,0,treeImage_w -x);
				try{
					pixelGrabber.grabPixels();
				}catch(InterruptedException e){
					System.err.println("interrupted waiting for pixels!");
				}
				movedImage=createImage(new MemoryImageSource(treeImage_w -x,treeImage_h,pixels,0,treeImage_w -x));
				g1.drawImage(movedImage,0,0,null);

				//显示补丁
				pixelGrabberPatch=new PixelGrabber(treeImage,0,0,win_w -(treeImage_w-x),treeImage_h,pixels,0,win_w -(treeImage_w -x));
				try{
					pixelGrabberPatch.grabPixels();
				}catch(InterruptedException e){
					System.err.println("interrupted waiting for pixels!");
				}
				movedImage=createImage(new MemoryImageSource(win_w -(treeImage_w -x),treeImage_h,pixels,0,win_w -(treeImage_w -x)));
				g1.drawImage(movedImage,(treeImage_w -x)-1,0,null);
			}
			else{
				pixelGrabber=new PixelGrabber(treeImage, x, 0, win_w, treeImage_h, pixels, 0, win_w);
				try {
     					pixelGrabber.grabPixels();
				} catch (InterruptedException e){
    					System.err.println("interrupted waiting for pixels!");
 				}

				movedImage=createImage(new MemoryImageSource(win_w,treeImage_h,pixels,0,win_w));
				g1.drawImage(movedImage,0,0,null);

			}
			repaint();
			try{
				Thread.sleep(speedDelay);
			}catch(Exception e){}
			isReady=true;
			x+=speedPixels;  //改变路边树背景取图位移
		}
		
	}
	
	public void destroy(){  //当applet被摧毁时才停止线程,调换页面时的stop()不作处理.
		if(bgThread!=null){
			treeWhileStop=true;  //使该线程的内部while循环终止
			bgThread=null;
		}
		if(spiritThread!=null){
			meetStatus=true;  //使该线程的内部while循环终止
			spiritThread=null;
		}
	}

	class SpiritThread extends Thread {  //Thread已声明Runnable接口
		Graphics g2=imageSpiritBuffer.getGraphics();  //取得缓冲区相应的Graphics对象
		Image oldBgImage;
		int[] pixels=new int[spiritImage_w * spiritImage_h];
		int stick_x=win_w -30;  //初始化达标棒的显示位置
		int stick_y=(win_h - treeImage_h)/2;
		int spirit_x=-10;  //精灵的开始起跑位置,负数使精灵从左边框渐现.
		int spirit_y=(win_h - treeImage_h)/2;
		public void run(){
			g2.drawImage(roadImage,0,0,null);  //绘制道路背景
			g2.drawImage(stickImage,stick_x,stick_y,null);  //显示达标棒
			while(!meetStatus){  //精灵碰到达标棒
				//精灵未碰到达标棒,起跑.
				pixelGrabberSpirit=new PixelGrabber(roadImage,spirit_x,spirit_y,spiritImage_w,spiritImage_h,pixels,0,spiritImage_w);
				try{
					pixelGrabberSpirit.grabPixels();
				}catch(InterruptedException e){
					System.err.println("interrupted waiting for pixels!");	
				}
				oldBgImage=createImage(new MemoryImageSource(spiritImage_w,spiritImage_h,pixels,0,spiritImage_w));
				spirit_x+=speedPixels;  //增加精灵的移动位置
				if(Math.abs(spirit_x)%2==1){  //奇数,显示spiritImage1图片
					g2.drawImage(oldBgImage,spirit_x-speedPixels,spirit_y,null);  //先恢复前一精灵位置处的背景
					g2.drawImage(spiritImage1,spirit_x,spirit_y,null);
				}
				else if(Math.abs(spirit_x)%2==0){  //偶数，显示spiritImage2图片
					g2.drawImage(oldBgImage,spirit_x-speedPixels,spirit_y,null);
					g2.drawImage(spiritImage2,spirit_x,spirit_y,null);
				}
				if(spirit_x +spiritImage_w > stick_x){  //检测精灵碰到达标棒
					meetStatus=true;
					g2.drawImage(stickImage,stick_x,stick_y,null);
				}
				repaint();
				try{
					Thread.sleep(speedDelay); //延时,决定精灵的步速.
				}catch(Exception e){}
			}
			treeWhileStop=true;  //使路边树木移动线程内部的while终止
			bgThread=null;  //停止路边树木移动线程
		}
	}
}