/*
 * matopt.java - revised 19 Apr 05 - width 601, height 301
 * matrix optics ray tracing program
 * rays traced from an object in H(-) to its image in H'(-)
 * @author jack@ord.ca
 */

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

public class matopt extends java.applet.Applet
                   implements ActionListener { 
  int kk=0; int cont=0; int opt=1; int first=0;        // Declarations
  int ncont=0; int nmat=0; int matn=0; int done=0; 
  double nleft=1; double nright=1; double r=1; double d=1;
  double a11, a12, a21, a22;
  double b11, b12, b21, b22;
  double x11, x12, x21, x22;
  double [] p=new double[10];
  TextField txtb;

  public void init() {
    txtb=new TextField(15);
    setBackground(new Color(211, 211, 211));
    txtb.setBackground(getBackground());
    add(txtb); txtb.addActionListener(this);
  }

  public void pin(Graphics g) {                        // Initialize Plot
    g.setColor(Color.black); g.drawRect(0, 0, 600, 300);
    if (first==0) {
      g.setFont(new Font("TimesRoman", Font.PLAIN, 14));
      txtb.setBounds(5, 25, 120, 20);
      txtb.setText("Click and hit Enter");
      first=1;
    }
    if (done==0) {
      g.drawString("1 Translation", 140, 15);
      g.drawString("2 Curved Surface", 140, 30);
      g.drawString("3 Plane Surface", 140, 45);
      g.drawString("4 Thin Lens", 140, 60);
    }
  }

  public void paint(Graphics g) {                      // Paint
    double d1, d2, f1, f2, m, det;
    double xmin, xmax, xsc;
    int q [] = new int[10];
    int cr;
    pin(g);
    if ((kk>3)&&(cont==0)) {                           // Print Matrices
      g.setColor(Color.blue);
      g.drawString("Matrix "+matn, 320, 15); 
      g.drawString(Float.toString((float)b11), 380, 15);
      g.drawString(Float.toString((float)b12), 480, 15);
      g.drawString(Float.toString((float)b21), 380, 30);
      g.drawString(Float.toString((float)b22), 480, 30);
      g.setColor(Color.red);
      g.drawString("System", 320, 45); g.drawString("Matrix", 320, 60);
      g.drawString(Float.toString((float)a11), 380, 45);
      g.drawString(Float.toString((float)a12), 480, 45);
      g.drawString(Float.toString((float)a21), 380, 60);
      g.drawString(Float.toString((float)a22), 480, 60);
    }
    if (done>0) {                                    
      det=a11*a22-a21*a12;                             // Determinant
      g.drawString("Determinant = "+(float)det, 380, 90);
      g.setColor(Color.black);
      if ((Math.abs(a21))<.000001) {                   // Telescopic system
        m=1/a22;
        g.drawString("Telescopic System", 140, 30);
        g.drawString("Angular M = "+(float)m, 140, 45);
      }
      else {                                           // Cardinal points
        d1=a11/a21; d2=a22/a21; f1=1/a21; f2=f1*det;       
        p[0]=-d1-f1; p[1]=-d1; p[2]=-d1+f1; p[3]=-d1+f2;   
        p[4]=p[9]+d2-f1; p[5]=p[9]+d2-f2; p[6]=p[9]+d2; p[7]=p[9]+d2+f2;
        g.drawString("Focal points relative to O-O'", 140, 15);
        g.drawString("OF = "+(float)d1, 160, 30);
        g.drawString("O'F' = "+(float)d2, 160, 45);
        g.drawString("The focal lengths f and f'", 140, 60);
        g.drawString("f = "+(float)f1, 160, 75);
        g.drawString("f' = "+(float)f2, 160, 90);
        g.drawString("Principal points relative to O-O'", 140, 105);
        g.drawString("OH = "+(float)(d1-f1), 160, 120);
        g.drawString("O'H' = "+(float)(d2-f2), 160, 135);
        xmin=p[0]; xmax=p[0];                          // p[0] H(-)
        for (int i=1; i<=9; i=i+1) {                   // p[1] F
          if (p[i]<xmin) {                             // p[2] H
            xmin=p[i];                                 // p[3] N
          }                                            // p[4] N'
          if (p[i]>xmax) {                             // p[5] H'
            xmax=p[i];                                 // p[6] F'
          }                                            // p[7] H'(-)
        }                                              // p[8] O
        xsc=500/(xmax-xmin);                           // p[9] O'
        for (int i=0; i<=9; i=i+1) {
          q[i]=50+(int)((p[i]-xmin)*xsc+.5);
        }
        g.setColor(Color.lightGray);
        g.fillRect(q[8], 140, q[9]-q[8], 159);
        g.setColor(Color.black); g.drawLine(25, 220, 575, 220);
        g.setColor(Color.blue);
        g.drawLine(q[2], 145, q[2], 295);
        g.drawLine(q[5], 145, q[5], 295);
        g.drawString("H", q[2]-12, 155);
        g.drawString("H'", q[5]+4, 155);
        g.setColor(Color.cyan);
        g.drawLine(q[0], 160, q[2], 280);
        g.drawLine(q[5], 280, q[7], 280);              //   object at H(-)
        g.setColor(Color.green);                       //   three rays to
        g.drawLine(q[0], 160, q[2], 160);              //   inverted image
        g.drawLine(q[5], 160, q[7], 280);              //   at H'(-)
        g.setColor(Color.yellow);
        g.drawLine(q[0], 160, q[3], 220);
        g.drawLine(q[4], 220, q[7], 280);
        g.setColor(Color.red);
        g.drawLine(q[0], 160, q[0], 220);
        g.drawLine(q[0], 160, q[0]-2, 170);
        g.drawLine(q[0], 160, q[0]-1, 170);
        g.drawLine(q[0], 160, q[0]+1, 170);
        g.drawLine(q[0], 160, q[0]+2, 170);
        g.drawLine(q[7], 280, q[7], 220);
        g.drawLine(q[7], 280, q[7]-2, 270);
        g.drawLine(q[7], 280, q[7]-1, 270);
        g.drawLine(q[7], 280, q[7]+1, 270);
        g.drawLine(q[7], 280, q[7]+2, 270);
        cr=3;
        g.fillArc(q[1]-cr, 220-cr, 2*cr, 2*cr, 0, 360);// F
        g.fillArc(q[3]-cr, 220-cr, 2*cr, 2*cr, 0, 360);// N
        g.fillArc(q[4]-cr, 220-cr, 2*cr, 2*cr, 0, 360);// N'
        g.fillArc(q[6]-cr, 220-cr, 2*cr, 2*cr, 0, 360);// F'
        g.drawString("F", q[1]-12, 235);
        g.drawString("F'", q[6]+4, 215);
        g.drawString("N", q[3]-12, 235);
        g.drawString("N'", q[4]+4, 215);
        g.setColor(Color.black);
      }
      txtb.setText("Incident Index"); txtb.selectAll();
      kk=1; p[8]=0; p[9]=0; done=0; cont=0; ncont=0; matn=0;
    }
  }

  public void actionPerformed(ActionEvent ev) {        
    String txt; int er=0;                                       
    txt=txtb.getText();
    if ((txt.equals("q"))||(txt.equals("Q"))) { kk=0; }
    if (kk==1) {
      try {
        nleft=Double.valueOf(txt).doubleValue();
      }
      catch(NumberFormatException e) {
        er=1; txtb.setText("ReTry Incident Index");
      }
      if (er==0) { txtb.setText("# of Matrices");       }
    }
    if (kk==2) {
      try {
        nmat=Integer.parseInt(txt);
      }
      catch(NumberFormatException e) {
        er=1; txtb.setText("ReTry # of Matrices");
      }
      if (er==0) { txtb.setText("Choose ->"); }
    }
    if (kk>2) {
      if (cont==0) {
        try {
          opt=Integer.parseInt(txt);
        }
        catch(NumberFormatException e) {
          er=1; txtb.setText("ReTry Choose ->");
        }
        if (er==0) {
          switch (opt) {
            case 1 :
              txtb.setText("Displacement (+)");
              break;
            case 2 :
              txtb.setText("Radius (+/-)");
              break;
            case 3 :
              txtb.setText("nright");
              break;
            case 4 :
              txtb.setText("f (+/-)");
              break;
          }
          ncont=1;
        }
      }
      if (cont>0) {
        try {
          d=Double.valueOf(txt).doubleValue();
        }
        catch(NumberFormatException e) {
          er=1; txtb.setText("Error - ReTry");
        }
      }
      if (er==0) {
        if (cont==1) {
          switch (opt) {
            case 1 :
              b11=1; b12=-d; b21=0; b22=1;
              ncont=0; p[9]=p[9]+d; break;
            case 2 :
              r=d;
              txtb.setText("nright");
              ncont=2; break;
            case 3 :
              nright=d;
              b11=1; b12=0; b21=0; b22=nright/nleft;
              nleft=nright;
              ncont=0; break;
            case 4 :
              b11=1; b12=0; b21=1/d; b22=1;
              ncont=0; break;
          }
        }
        if (cont==2) {
          nright=d;
          b11=1; b12=0; b21=(nright-nleft)/(nleft*r); b22=nright/nleft;
          nleft=nright;
          ncont=0;
        }
        cont=ncont;
        if ((cont==0)&&(kk>2)) {
          matn=matn+1;
          if (matn==1) {
            a11=b11; a12=b12; a21=b21; a22=b22;
          }
          else {
            x11=a11*b11+a12*b21; x12=a11*b12+a12*b22;
            x21=a21*b11+a22*b21; x22=a21*b12+a22*b22;
            a11=x11; a12=x12; a21=x21; a22=x22;
          }
          if (matn==nmat) {
            done=1;
          }
          else {
            txtb.setText("Choose ->");
          }
        }
      }
    }
    if (kk==0) {
      txtb.setText("Incident Index");
      p[8]=0; p[9]=0; done=0; cont=0; ncont=0; matn=0;
    }
    if (er==0) { kk=kk+1; }
    txtb.selectAll(); repaint();
  }
}