import java.applet.Applet;
import java.awt.*;
import java.net.MalformedURLException;
import java.net.URL;

//圖片倒影

public class ReflectionApplet extends Applet implements Runnable {

	Thread lakeThread; //圖片倒影線程
	Graphics graphics; //該Applet的Graphics對象
	Graphics waveGraphics; //倒影的Graphics對象
	Image image; //Applet的Image對象
	Image waveImage; //倒影的Graphics對象
	int currentImage,imageWidth,imageHeight; 
	boolean imageLoaded; //圖片是否裝載
	String imageName; //圖片名稱
	
	public void init() {
		imageName= getParameter("image"); //得到圖片名稱
	}

	public void start() {
		if (lakeThread == null) {
			lakeThread= new Thread(this); //實例化線程
			lakeThread.start(); //運行線程
		}
	}

	public void run() {
		currentImage= 0;
		if (!imageLoaded) { //如果圖片未裝載
			repaint(); //得繪屏幕
			graphics= getGraphics(); //得到Graphics對象
			MediaTracker mediatracker= new MediaTracker(this); //實例化MediaTracker對象
			image= getImage(getDocumentBase(), imageName); //得到Image實例
			mediatracker.addImage(image, 0); //增加待加載的圖片
			try {
				mediatracker.waitForAll();  //裝載圖片
				imageLoaded= !mediatracker.isErrorAny();  //是否有錯誤發生
			} catch (InterruptedException ex) {
			}
			if (!imageLoaded) {  //加載圖片失敗
				stop(); //Applet停止運行
				graphics.drawString("加載圖片錯誤", 10, 40); //輸出錯誤信息
				return;
			}
			imageWidth= image.getWidth(this); //得到圖像寬度
			imageHeight= image.getHeight(this);  //得到圖像高度
			createAnimation(); //創建動畫效果
		}
		repaint();  //重繪屏幕
		try {
			while (true) {
				repaint(); //得繪屏幕
				currentImage++;
				if (currentImage == 12) 
					currentImage= 0;
				Thread.sleep(50); //線程休眠
			}
		} catch (InterruptedException ex) {
				stop();
		}
	}
	
	public void createAnimation() {
		Image img= createImage(imageWidth, imageHeight);  //以圖像高度創建Image實例
		Graphics g= img.getGraphics(); //得到Image對象的Graphics對象
		g.drawImage(image, 0, 0, this);  //繪制Image
		for (int i= 0; i < imageHeight ; i++) {
			g.copyArea(0,imageHeight-1-i,imageWidth,1,0,-imageHeight+1+(i*2)); //拷貝圖像區域
		}

		waveImage= createImage(13 * imageWidth, imageHeight); //得到波浪效果的Image實例
		waveGraphics= waveImage.getGraphics(); //得到波浪效果的Graphics實例
		waveGraphics.drawImage(img, 12 * imageWidth, 0, this); //繪制圖像
		int j= 0;
		while (j<12){
			makeWaves(waveGraphics, j);
			j++;
		}
		g.drawImage(image, 0, 0, this);  //繪制圖像
	}

	public void makeWaves(Graphics g, int i) { //波浪效果模擬
		double d= (6.2831853071795862 * i) / 12;
		int j= (12 - i) * imageWidth;
		int waveHeight=imageHeight / 16;
		for (int l= 0; l < imageHeight; l++) {			
			int k=(int) ((waveHeight* (l + 28)* Math.sin(waveHeight * (imageHeight - l)/ (l + 1)+ d))/imageHeight);
			if (l < -k)
				g.copyArea(12 * imageWidth, l, imageWidth, 1, -j, 0); //拷貝圖像區域,形成波浪
			else
				g.copyArea(12 * imageWidth, l + k, imageWidth, 1, -j, -k);
		}
	}

	public void paint(Graphics g) {
		update(g);
	}
	
	public void update(Graphics g){
		if (waveImage != null) {
			g.drawImage(waveImage,-currentImage * imageWidth,imageHeight-1,	this);  //繪制圖像
			g.drawImage(waveImage,(12 - currentImage) * imageWidth,	imageHeight-1,this);
		}
		g.drawImage(image, 0, 1, this);
	}
}