package jmslexamples;
import java.awt.*;
import com.softsynth.jmsl.util.Bessel;

/** 	
	BesselDemo.java
	
	Graph integer order Bessel functions, superimposed on one canvas. 
	
 * @author Phil Burk and Nick Didkovsky
 */
/*
 * (C) 1997 Phil Burk and Nick Didkovsky, All Rights Reserved
 * JMSL is based upon HMSL (C) Phil Burk, Larry Polansky and David Rosenboom.
 */
 
public class BesselDemo extends java.applet.Applet {


public void init() {
	BesselCanvas canvas = new BesselCanvas();
	canvas.setSize(BesselCanvas.WIDTH,BesselCanvas.HEIGHT);
	add(canvas);
}

	public static void main(String args[]) {
		BesselDemo applet = new BesselDemo();
		Frame f = new Frame("Bessel Demo");
		f.addWindowListener( 
			new java.awt.event.WindowAdapter() {
				public void windowClosing(java.awt.event.WindowEvent e) {
					System.exit(0);
				}
			});
		f.add(applet, BorderLayout.CENTER);
		applet.init();
		applet.start();
		f.setSize(1024,300);
		f.setVisible(true);
	}

}

class BesselCanvas extends Canvas {
	public static final int WIDTH=1000;
	public static final int HEIGHT=200;
	public static final double RANGE=10.0;
	Color[] colors = {Color.black, Color.blue, Color.green, Color.red, Color.orange};
	
	public void paint(Graphics g) {
		int newY;
		for (int n=0; n<5; n++) { // order
			for (int step=0; step<WIDTH; step++) { // range over x
				double x = step * RANGE/WIDTH*2;
				if (n==0)	newY = (int)(HEIGHT-(HEIGHT/2 * Bessel.bessj0(x) + HEIGHT/2));
				else if (n==1) newY = (int)(HEIGHT-(HEIGHT/2 * Bessel.bessj1(x) + HEIGHT/2));
				else newY = (int)(HEIGHT-(HEIGHT/2 * Bessel.bessj(n, x) + HEIGHT/2));
				g.setColor(colors[n]);
				g.drawLine(step, newY, step, newY);
			}
			g.drawString("J"+n, 10, 120 + 15*n);
		}
	
	}
	
}