import java.awt.*;
import java.applet.Applet;
import java.math.*;

/*
**        --- Spiral.java ---
** 
** (c) 2000 Stefan Robl <stefan@qdev.de>
**
**      Web:  https://www.qdev.de
*/


public class Spiral extends Applet implements Runnable
{
	Image img;
	Graphics gfx;
	Thread thread;

	int width, height, mx, my, x, y, ox, oy; 
	double ww=0.0, f=0.0, b=20.0;

	public void init() 
	{
		width=this.size().width;
		height=this.size().height;
		img=createImage(width,height);
		gfx=img.getGraphics();
		mx=width>>1;
		my=height>>1;
	}
	

	public void start()
	{
		if (thread == null)
		{
			thread = new Thread(this);
			thread.start();
		}
	}
	
	public void stop()
	{
		if (thread != null)
		{
			thread.stop();
			thread = null;
		}
	}
	
	public void run()
	{
		while (true)
		{
			repaint();
			try { Thread.sleep(25); }
			catch(InterruptedException e) {}
		}
	}

	
	public void paint( Graphics g )
	{
		double w=ww;
		
		gfx.setColor(new Color(0,0,0));
		gfx.fillRect(0, 0, width, height);
		gfx.setColor(new Color(255,255,255));
		x=mx;y=my;
		
		for(f=0; f<300; f+=b)
		{   
			for(int l=0; l<62; l++)
			{
				double ff=f+(((double) l/62.0)*b);
				ox=x; oy=y;
				x=mx+(int) (Math.sin(w)*ff);
				y=my+(int) (Math.cos(w)*ff);
				gfx.drawLine(ox,oy,x,y);
				gfx.drawLine(ox,oy+1,x,y+1);
				gfx.drawLine(ox+1,oy,x+1,y);
				w-=0.1;
			}    
		}
		g.drawImage(img,0,0,this);
		
		ww+=0.3;
	}
	
	public void update(Graphics g)
	{
		paint(g);
	}
}