laserpic.java

Java Applet实例讲解 N多例子

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

public class LaserPic extends Applet{

   private Image image;
   private int x = 25,y = 25;
   private Random random;
   private int width,height,w,h,image_size,pixels[];

   public void init() {
      random=new Random();
      String imageName=getParameter("Image");
      image=getImage(getDocumentBase(),imageName);
      MediaTracker imageTracker=new MediaTracker(this);
      imageTracker.addImage(image,0);
      try {
         imageTracker.waitForID(0);
      }catch (InterruptedException e){}
   }

   public void start(){

      width=getSize().width;
      height=getSize().height;
      w=image.getWidth(this);
      h=image.getHeight(this);
      x = (width - w)/2;
      y = (height - h)/2; 
      image_size=w*h;
      pixels=new int[image_size];
      PixelGrabber pg=new PixelGrabber(image,0,0,w,h,pixels,0,w);
      try {
         while (!pg.grabPixels()){}
      } catch (InterruptedException e){}
   }

   public void paint(Graphics g) {
      g.setColor(Color.white);
      g.fillRect(0,0,getSize().width,getSize().height);
      drawImage(g,image,x,y);
   }

   private void drawImage(Graphics g,Image image,int x,int y){
      while(true){     
         g.setColor(Color.white);
         g.fillRect(0,0,getSize().width,getSize().height);
         try {
            int one_time=w;
            int S_x=0,S_y=0;
            S_x=(int)(random.nextFloat()*width);
   	    S_y=(int)(random.nextFloat()*height);
	    Laser[] nextlot=new Laser[one_time];
            int k=0,l=0;
            int step=1,start=0;
            float f=random.nextFloat();
            step=(f<0.8)?34759:(f<0.9?1:image_size-1);
            start=(int)(random.nextFloat()*image_size);
            f=random.nextFloat();
            start=(f<0.5)?image_size:0;
            int sofar=0;
            for (k=start;l<image_size;l++,k+=step){
               if (k<0) k+=image_size;
                  k%=image_size;
               int row=k/w;
               int col=k%w;
               Color colr=new Color(pixels[k]);
               int finishx=x+col;
               int y1=y+row;
               nextlot[sofar]=new Laser(colr,new Point(S_x,S_y),new Point(finishx,y1));
               sofar++;
               if (sofar==one_time){
                  Track(g,nextlot);
                   sofar=0;
               }
            }

         } catch (Exception e){}
         g.setPaintMode();
         g.drawImage(image,x,y,this);
         try{
            Thread.sleep(2000);
         }catch (InterruptedException e){}
      }
   }

   private synchronized void Track(Graphics g,Laser[] nextlot){
      Color back=Color.white;
      g.setXORMode(back);
      for (int pass=0;pass<2;pass++){
         for (int pixnr=0;pixnr<nextlot.length;pixnr++){
            Laser p=nextlot[pixnr];
            if (!close(p.c,back)){
		g.setColor(p.c);
		g.drawLine(p.start.x,p.start.y,p.finish.x,p.finish.y);

            }
            if (pass==1) {
               g.setColor(p.c);
               g.drawLine(p.finish.x,p.finish.y,p.finish.x,p.finish.y);
            }
         }
      }
      Thread.yield();
   }

   private boolean close(Color c1,Color c2){
      return (Math.abs(c1.getRed()-c2.getRed()) + Math.abs(c1.getGreen()-c2.getGreen()) + 
                                                           Math.abs(c1.getBlue()-c2.getBlue()))<0xff;
   }

}
class Laser{
	public Color c;
	public Point start,finish;

	public Laser(Color c,Point start,Point finish){
		this.c=c;
		this.start=start;
		this.finish=finish;
	}
}