/*
 * mw5.java - revised 23 Apr 07 - width 501, height 361
 * @author jackord@kw.igs.net
 * transmitted amplitude versus (k[in]/k[out])^2 (negative for tunneling)
 * the well/barrier width equals the incident wavelength  
 */

import java.applet.Applet;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class mw5 extends Applet
                 implements ActionListener {
  int kk=0;                                            // Declarations
  String bs="Plot"; Button b=new Button(bs);

  public void init() {
    setLayout(new FlowLayout(FlowLayout.LEFT));
    setBackground(new Color(211, 211, 211));
    add(b);
    b.addActionListener(this);
  }

  public void paint(Graphics g) {
    double c, s, a, k, x, t;
    int x1, y1, x2, y2; x1=0; y1=0;
    g.setFont(new Font("TimesRoman", Font.PLAIN, 16));
    g.setColor(Color.black);
    g.drawRect(88, 12, 400, 300);
    g.drawString("-1", 85, 332);
    g.drawString("9", 485, 332);
    g.drawString("(k[in]/k[out])^2", 240, 344);
    g.drawString("0", 76, 318);
    g.drawString("1", 76, 18);
    g.drawString("Transmitted", 4, 160);
    g.drawString("Amplitude", 8, 180);
    for (int i=1; i<=9; i=i+1) {
      g.drawLine(88+40*i, 12, 88+40*i, 312);
      g.drawLine(88, 12+30*i, 488, 12+30*i);
    }
    g.setColor(Color.blue);
    if (kk==1) {
      for (int i=-99; i<=299; i=i+1) {                   
        if (i==0) { i=i+1; }
        k=i*.01; a=2*k*Math.PI;
        if (i<0) {
          c=(Math.exp(-a)+Math.exp(a))/2;
          s=(Math.exp(-a)-Math.exp(a))/2;
          x=-k*k; t=1/Math.sqrt(c*c+s*s*(k-1/k)*(k-1/k)/4);
        }
        else {
          c=Math.cos(a); s=Math.sin(a); x=k*k;
          t=1/Math.sqrt(c*c+s*s*(k+1/k)*(k+1/k)/4);
        }
        
        if (i==-99) {
          x1=128+(int)(40*x); y1=312-(int)(300*t);
        }
        else {
          x2=128+(int)(40*x); y2=312-(int)(300*t);
          g.drawLine(x1, y1, x2, y2); x1=x2; y1=y2;
        }
      }
    }
    kk=0;
  }

  public void actionPerformed(ActionEvent e) {
    String tst;
    tst=e.getActionCommand();
    if (bs.equals(tst)) { kk=1; }
    repaint();
  }
}