// $AISD_VERSION:NumDemo.java@1.2/home/coei/arc/archive%shell3.ba.best.com$

//COPYRIGHT: Copyright (c) 1997 by Christopher K. Oei, Incorporated.
//COPYRIGHT: 
//COPYRIGHT: http://www.chrisoei.com
//COPYRIGHT: info@chrisoei.com
//COPYRIGHT: 
//COPYRIGHT: Permission to use, display, and modify this code
//COPYRIGHT: is hereby granted provided that:
//COPYRIGHT: 
//COPYRIGHT: 1) this notice is included in its entirety
//COPYRIGHT: 2) we are notified of the usage


import java.applet.*;
import java.awt.Graphics;
import java.awt.*;
import RKDemo;
import Rectangle;
import Line;
import Potential;
import Circle.*;

public class NumDemo extends Applet 
{
    int width=500; //real width is 200
    int height=700; // the real height is 200
    int offsetx=50;
    int offsety=50;
    double x1 = 225.0;
    double y1 = 140;
    int metery = 580;

    int x2 = 225;
    int y2 = 540;

    int dx = 45;

    double rada = 100.;

    int go = 0;

    int toggE = -1;
    int toggB = -1;

    double tim = 0;
    double dtim=0.01;

    int r1 = 15;
    int ri = 25;

    public double[] x;
    public double[] values;
    public double[][] graph;

    static double qvalue = 0.;
    static double betavalue = 10.;
    static double lambda = 2.;

    int maxtim = 5;
    int brectcx;
    int brectcy;

    long red;
    long green;
    long blue;

    double squarefunc;
    double squarefunc1;
    double squarefunc2;

    double dx11;
    double dy11;
    double dx12;
    double dy12;

    double dx21;
    double dx22;
    double dy21;
    double dy22;

    double dx1;
    double dx2;
    double dy1;
    double dy2;
    double r;

    double arrowlength;
    double arrowlength2 = 20;
    double arrowlength3 = 60;
    double angle = 20;
    double radangle = angle*(Math.PI/180);
    double sinangle = Math.sin(radangle);
    double cosangle = Math.cos(radangle);
    double max = .00000000000000001;


    double dist1;
    double dist2;
    double distt;
    double compx, compx1, compx2;
    double compy, compy1, compy2;
    double compz, compz1, compz2;
    double dummy = 0.;

    int numline = 2;

    int si = 0;
    int ki = 0;
    int nmax = 24;
    int sii = 0;
    int iv;
    double xolder;

    Circle cone, ctwo, cthr;    

    Scrollbar timeScroll = new Scrollbar(Scrollbar.HORIZONTAL,maxtim,1,10,300),betaScroll = new Scrollbar(Scrollbar.HORIZONTAL,(int)betavalue,1,0,200),qvalueScroll = new Scrollbar(Scrollbar.HORIZONTAL,(int)qvalue,1,0,100);

    public Label qvalueLabel = new Label("Resistance = " + qvalue), betaLabel = new Label("Dipole moment = " +betavalue), timeLabel = new Label("T = " +maxtim);

  Button restartbutton = new Button("Restart"), gobutton = new Button("Go");
  Button toggleEbutton = new Button("Toggle E Vector Field"), toggleBbutton = new Button("Toggle B Vector Field");

public void init()
    {

    restartbutton.setForeground(Color.black);
    restartbutton.setBackground(Color.lightGray);

    gobutton.setForeground(Color.black);
    gobutton.setBackground(Color.lightGray);

    toggleEbutton.setForeground(Color.black);
    toggleEbutton.setBackground(Color.lightGray);

    toggleBbutton.setForeground(Color.black);
    toggleBbutton.setBackground(Color.lightGray);

    timeScroll.setForeground(Color.black);
    timeScroll.setBackground(Color.lightGray);

    betaScroll.setForeground(Color.black);
    betaScroll.setBackground(Color.lightGray);

    qvalueScroll.setForeground(Color.black);
    qvalueScroll.setBackground(Color.lightGray);

    
    setLayout(new BorderLayout());

    Panel p = new Panel();
    p.setLayout(new FlowLayout(FlowLayout.CENTER));
    p.add(gobutton);
    p.add(restartbutton);
    p.add(toggleEbutton);
    p.add(toggleBbutton);
    add("North",p);

    Panel t = new Panel();
    t.setLayout(new FlowLayout(FlowLayout.CENTER));
    t.add(timeScroll);
    t.add(timeLabel);

    t.add(qvalueScroll);
    t.add(qvalueLabel);

    t.add(betaScroll);
    t.add(betaLabel);

    add("South",t);


    }


public void Reset()
    {
	x1 = 225.0;
	y1 = 140;
	go = 0;
	tim = 0;
	repaint();
    }

public void Settvalue(String m)
    {
  	maxtim = new Integer(m).intValue();
    }

public void Setqvalue(String m)
    {
	qvalue = new Double(m).doubleValue();
    }

public void Setbvalue(String m)
    {
	betavalue = new Double(m).doubleValue();
    }

public void SetGo()
    {
	go = 1;
	repaint();
    }
 
public void paint(Graphics g)
    {
	setBackground(java.awt.Color.white);
	
//      double values[] = {21.5,25.,30.};
//      double values[] = {19.5,25.,30.};
//      double values[] = {18.5,23.,28.};
        double values[] = {12.5,16.5,21.};
    
        x = new double[3];
        graph = new double[2][(nmax+1)];

	x[0]=4;
	x[1]=0;
	x[2]=0;

        double[] xold=new double[3];

	xold[0]=x[0];
	xold[1]=x[1]; 
	xold[2]=x[2];

	Rectangle rect = new Rectangle(15,10,(int)x1,(int)y1);
	RKDemo nint=new RKDemo(tim,x,.01);
	Line line=new Line(0.0,0.0,0.0,0.0);


	if(tim==0 && go==1)
	    {
		while(tim<maxtim && rect.cy < 1050)
		   {    
    			line.emag = 1;

			rect.cx = (int)x1;
			rect.cy = (int)y1;

//   draw magnet as it falls, as well as stationary ring

			y1 = 140.+(rada*(4.-xold[0]));

			g.setColor(java.awt.Color.white);
    			g.drawLine(rect.cx-rect.rw,rect.cy-rect.rh+2,rect.cx-rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy-rect.rh,(2*rect.rw),4);
    			g.drawLine(rect.cx+rect.rw,rect.cy-rect.rh+2,rect.cx+rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy+rect.rh,(2*rect.rw),4);

			g.setColor(java.awt.Color.black);

    			g.drawLine(rect.cx-rect.rw,rect.cy-rect.rh+2,rect.cx-rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy-rect.rh,(2*rect.rw),4);
    			g.drawLine(rect.cx+rect.rw,rect.cy-rect.rh+2,rect.cx+rect.rw,rect.cy+rect.rh+2);
			g.drawOval(rect.cx-rect.rw,rect.cy+rect.rh,(2*rect.rw),4);


// 	g.drawRect(25,350,450,100);

// draw the three field lines

            iv=0;
    	    while(iv < 3)
         	{
	    	    line.ang = values[iv]*(Math.PI/180.);

        	    line.sx = x1 - 10 * Math.sin(line.ang);
        	    line.sy = y1 - 10 * Math.cos(line.ang);

                    distt=100.;

        	    double delarc = 13.;
                    double intarc;
                    int ij;
                    double output1,output2;
                    intarc = delarc/3.;
                    double signx;

                    int ilinc = 0;

                    ij = 0;
		    si = 0;

//   draw field lines from magnet, at three different angles, including field due to ring

             	    while(ij < 150  && distt > 25.0)
                	{


                	    dist1 = Math.sqrt(Math.pow(line.sx-x1, 2) + Math.pow(line.sy - y1, 2));
                          if (ij > 3)
                             {
                              distt=dist1;
                             }
                          else
                             {
                             distt=100.;
                             }

 			//compute components of dipole field with unit magnetic dipole moment

                	    compx1 = -(3.*(line.sx-x1)*(line.sy-y1)/(4.*Math.PI))/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-y1,2),2.5) ;
                	    compy1 = -((2.*Math.pow(line.sy-y1,2)-Math.pow(line.sx-x1,2))/(4.*Math.PI))/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-y1,2),2.5);

 			//compute components of field due to ring, respectively
                        //  we compute curl numberically
  
	                    Potential pinto=new Potential(dummy,rada,line.sx-x1, line.sy-y2);
	                    Potential pintx=new Potential(dummy,rada,line.sx + intarc-x1, line.sy-y2);
	                    Potential pinty=new Potential(dummy,rada,line.sx-x1 , line.sy + intarc-y2);

                        //note we are the dividing the dimensionless current by lambda beta radius radius where lambda is set to 2 above
                        //   see Force Memo #10, equation 10.28
                        //  the expressions below is the curl of the potential in cylindrical coordinates, with x = usual rho and y = usual z

                    signx= (line.sx-x1)/java.lang.Math.abs(line.sx-x1);
              	    compx2 = xold[1]*signx*( (pinty.Pota-pinto.Pota)/intarc  )/(betavalue*betavalue*lambda*rada*rada);
              	    compy2 = -xold[1]*signx*(   (pintx.Pota-pinto.Pota)/intarc + pinto.Pota/(line.sx-x1)  )/(betavalue*betavalue*lambda*rada*rada);

                            compx=compx1+compx2;
                            compy=compy1+compy2;

                	    line.emag = Math.sqrt(Math.pow(compx,2) + Math.pow(compy,2));

                	    line.ex = line.sx + delarc * (compx/line.emag);
                	    line.ey = line.sy + delarc * (compy/line.emag);


			    if(si != 0)
			        {
	    g.setColor(java.awt.Color.blue);
	    g.drawLine((int)line.sx, (int)line.sy, (int)line.ex, (int)line.ey);
	    g.drawLine(225-((int)line.sx-225),(int)line.sy,225-((int)line.ex-225),(int)line.ey);
			        }

//      draw arrow head on field line every once in awhile
                           ilinc++;

           if (ilinc>5) {
               double vey,vex;
              vey = line.sy ;
              vex = line.sx ;
               dy1 = 1*(arrowlength2*((sinangle*compx-cosangle*compy)/line.emag));
                dx1 = -1*(arrowlength2*((cosangle*compx+sinangle*compy)/line.emag));
                dy2 = 1*(arrowlength2*((-sinangle*compx-cosangle*compy)/line.emag));
                dx2 = -1*(arrowlength2*((cosangle*compx-sinangle*compy)/line.emag));
               g.drawLine((int)vex, (int)vey, (int)(vex + dx1/2.),(int)(vey + dy1/2.));
                g.drawLine((int)vex, (int)vey, (int)(vex + dx2/2.),(int)(vey + dy2/2.));
               g.drawLine(450-(int)vex, (int)vey,450- (int)(vex + dx1/2.),(int)(vey + dy1/2.));
                g.drawLine(450-(int)vex, (int)vey, 450-(int)(vex + dx2/2.),(int)(vey + dy2/2.));
               ilinc=0;
                       }


                	    line.sx = line.ex;
                	    line.sy = line.ey;


                            ij++;
			    si++;
                	}
			    sii++;
			
			if(sii==15)
			{	
			g.setColor(java.awt.Color.white);
			g.fillRect(0,0,width,height);
			sii=0;
			}
			g.setColor(java.awt.Color.black);
                    iv++;
        	}
//  begin cut here
//  draw vector field for magnetic field
        	    double delarc = 13.;
                    double intarc;
                    intarc = delarc/3.;
                    double signx;

    int ix=0;
    int iy=0;
    int numy;
    int numx;
    numx=2+ width/dx;
    numy=2+ height/dx;

      while(ix<numx)
        {
      while(iy<numy)
	{
          line.sx=(ix-1)*dx+22;
          line.sy=(iy-1)*dx;

                        //compute components of dipole field

                	    compx1 = -(3.*(line.sx-x1)*(line.sy-y1)/(4.*Math.PI))/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-y1,2),2.5) ;
                	    compy1 = -((2.*Math.pow(line.sy-y1,2)-Math.pow(line.sx-x1,2))/(4.*Math.PI))/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-y1,2),2.5);

 			//compute components of field due to ring, respectively
                        //  we compute curl numberically
  
	                    Potential pinto=new Potential(dummy,rada,line.sx-x1, line.sy-y2);
	                    Potential pintx=new Potential(dummy,rada,line.sx + intarc-x1, line.sy-y2);
	                    Potential pinty=new Potential(dummy,rada,line.sx-x1 , line.sy + intarc-y2);

                        //note we are the dividing the dimensionless current by lambda beta radius radius where lambda is set to 2 above
                        //   see Force Memo #10, equation 10.28
                        //  the expressions below is the curl of the potential in cylindrical coordinates, with x = usual rho and y = usual z

                    signx= (line.sx-x1)/java.lang.Math.abs(line.sx-x1);
              	    compx2 = xold[1]*signx*( (pinty.Pota-pinto.Pota)/intarc  )/(betavalue*betavalue*lambda*rada*rada);
              	    compy2 = -xold[1]*signx*(   (pintx.Pota-pinto.Pota)/intarc + pinto.Pota/(line.sx-x1)  )/(betavalue*betavalue*lambda*rada*rada);

                            compx=compx1+compx2;
                            compy=compy1+compy2;


		squarefunc = Math.sqrt(Math.pow(compx,2) + Math.pow(compy,2));
                line.emag = squarefunc;
		r = Math.sqrt((5e11)*line.emag);

		red = (long)(255-r);
		blue = (long)(255);
		green = (long)(255-r);

		if(red>255)      {red=255;}
		if(green>255)    {green=255;}
		if(blue>255)     {blue=255;}
	
		if(red<0)      {red=0;}
		if(green<0)    {green=0;}
		if(blue<0)     {blue=0;}
	
		arrowlength = dx/6;

                line.ey = line.sy + (compy/line.emag) * dx/2.;
                line.ex = line.sx + dx*(compx/line.emag)/2.;

                dy1 = 1*(arrowlength*((sinangle*compx-cosangle*compy)/squarefunc));
                dx1 = -1*(arrowlength*((cosangle*compx+sinangle*compy)/squarefunc));
                dy2 = 1*(arrowlength*((-sinangle*compx-cosangle*compy)/squarefunc));
                dx2 = -1*(arrowlength*((cosangle*compx-sinangle*compy)/squarefunc));

     if (toggB > 0 )
      {
		g.setColor(new Color((int)red,(int)green,(int)blue));
                g.drawLine((int)line.sx, (int)line.sy, (int)line.ex, (int)line.ey);
		g.drawLine((int)line.ex, (int)line.ey, (int)(line.ex + dx1),(int)(line.ey + dy1));
		g.drawLine((int)line.ex, (int)line.ey, (int)(line.ex + dx2),(int)(line.ey + dy2));
      }

//  draw vector field for electric field
      if ( toggE > 0 )
         {

//     compute electric field due to magnetic dipole:  this is just v x B, where v is in the y-direction
//     so it picks out the x component of the B field due to the magnetic dipole

                            compz1 = compx1*xold[2]*rada;

       //compute electric field due to ring
       //  from B = curl A and curl E = - dB/dt,  we get E = - dA/dt, so this devolves into dI/dt times
       //   the spatial parts of the potential A  (see Force Memo #6, equation 1)  

                double Ider = RKDemo.Ideriv;
//    Ider is the time derivative of our dimensionless current wrt to our dimensionless time (see Force Memo #10)
//              System.out.println("Ider " +Ider );
                    compz2 = signx*Ider*pinto.Pota/(betavalue*betavalue*lambda*rada*rada);
//  above converts to real current, leaves time dimensionless
                    compz=compz1+compz2;


		squarefunc = Math.sqrt(Math.pow(compz,2) + Math.pow(compz,2));
                line.emag = squarefunc;
		r = line.emag/1.e-8;
//             System.out.println("r = " +r);

		red = (long)(255-r);
		green = (long)(255);
		blue = (long)(255-r);

		if(red>255)      {red=255;}
		if(green>255)    {green=255;}
		if(blue>255)     {blue=255;}
	
		if(red<0)      {red=0;}
		if(green<0)    {green=0;}
		if(blue<0)     {blue=0;}
		g.setColor(new Color((int)red,(int)green,(int)blue));

    if(compz<0)
        {
    g.drawOval((int)line.sx-r1/2,(int)line.sy-r1/2,r1,r1);
    g.drawLine((int)line.sx-(r1*71/200),(int)line.sy-(r1*71/200),(int)line.sx+(r1*71/200),(int)line.sy+(r1*71/200));
    g.drawLine((int)line.sx-(r1*71/200),(int)line.sy+(r1*71/200),(int)line.sx+(r1*71/200),(int)line.sy-(r1*71/200));
        }
      else
        {
    g.drawOval((int)line.sx-r1/2,(int)line.sy-r1/2,r1,r1);
    g.fillOval((int)line.sx-r1/6,(int)line.sy-r1/6,r1/3,r1/3);
        }
       }

            iy++;
           }
        ix++;
        iy=0;
}
//  end cut here

//   draw current in ring
		r = 22.5*java.lang.Math.abs(xold[1]);

//              System.out.println("r = " + r );

		green = (long)(255-r);
		red = (long)(255);
		blue = (long)(255-r);

		if(red>255)      {red=255;}
		if(green>255)    {green=255;}
		if(blue>255)     {blue=255;}
	
		if(red<0)      {red=0;}
		if(green<0)    {green=0;}
		if(blue<0)     {blue=0;}
		g.setColor(new Color((int)red,(int)green,(int)blue));


            line.sy=y2-12;   
            line.sx=125.;
if(xold[1]<0)
        {
    g.drawOval((int)line.sx,(int)line.sy,ri,ri);
    g.drawLine((int)line.sx-(ri*71/200)+ri/2,(int)line.sy-(ri*71/200)+ri/2,(int)line.sx+(ri*71/200)+ri/2,(int)line.sy+(ri*71/200)+ri/2
);
    g.drawLine((int)line.sx-(ri*71/200)+ri/2,(int)line.sy+(ri*71/200)+ri/2,(int)line.sx+(ri*71/200)+ri/2,(int)line.sy-(ri*71/200)+ri/2
);
        }
      else
        {
    g.drawOval((int)line.sx,(int)line.sy,ri,ri);
    g.fillOval((int)line.sx+ri/2-ri/6,(int)line.sy+ri/2-ri/6,ri/3,ri/3);
        }
           line.sx = 300.;
if(xold[1]>0)
        {
    g.drawOval((int)line.sx,(int)line.sy,ri,ri);
    g.drawLine((int)line.sx-(ri*71/200)+ri/2,(int)line.sy-(ri*71/200)+ri/2,(int)line.sx+(ri*71/200)+ri/2,(int)line.sy+(ri*71/200)+ri/2
);
    g.drawLine((int)line.sx-(ri*71/200)+ri/2,(int)line.sy+(ri*71/200)+ri/2,(int)line.sx+(ri*71/200)+ri/2,(int)line.sy-(ri*71/200)+ri/2
);
        }
      else
        {
    g.drawOval((int)line.sx,(int)line.sy,ri,ri);
    g.fillOval((int)line.sx+ri/2-ri/6,(int)line.sy+ri/2-ri/6,ri/3,ri/3);
        }


  	    brectcx = rect.cx;
	    brectcy = rect.cy;

	    nint.iterate();
	    xold[0]=nint.x[0]; xold[1]=nint.x[1];xold[2]=nint.x[2];

	    tim+=dtim;

	    xolder = xold[1] * 9;
		if(xolder > 45)
			{
			xolder = 45;
			}
		if(xolder < -45)
			{
			xolder = -45;
			}

	    g.setColor(java.awt.Color.red);
     g.drawLine(438,metery+68,(438+(int)xolder),metery+15);
	    g.setColor(java.awt.Color.black);

//  do line plot at bottom
	    graph[0][ki] = 25.+(tim*40);
//          graph[1][ki] = 449. - Math.pow(xold[1],2);
            graph[1][ki] = 400. - 4.*xold[1];

	    g.setColor(Color.red);
	    g.setColor(Color.white);
//	    g.fillOval((int)graph[0][ki],(int)graph[1][ki],3,3);
	    ki++;

	    //System.out.println("ki = " +ki );
	    //System.out.println("Xcoord = " +(int)(25.+(tim*40)));
	    g.setColor(java.awt.Color.black);
// draw meter
	    g.setColor(java.awt.Color.black);
	    g.drawArc(390,metery,100,40,0,180);
	    g.drawLine(390,metery+20,420,metery+70);
	    g.drawLine(490,metery+20,460,metery+70);
	    g.drawLine(420,metery+70,460,metery+70);
	    g.fillOval(435,metery+65,6,6);

	    g.drawOval(125,y2-20,(2*(int)rada),20);
	    g.drawOval(125,y2,(2*(int)rada),20);

	    g.drawLine(125,y2-10,125,y2+10);
	    g.drawLine(325,y2-10,325,y2+10);

	    g.drawOval(150,y2-20,((2*(int)rada)-50),20);
	    g.drawOval(150,y2,((2*(int)rada)-50),20);

	    g.drawLine(150,y2-10,150,y2+10);
            g.drawLine(300,y2-10,300,y2+10);

//   g.drawRect(25,350,450,100);

	    if (ki <= nmax)
		{

	    int bki = ki;
	    ki = 0;

	    while (ki < bki)
		{
			if(graph[1][ki] < 350) {g.setColor(java.awt.Color.white);}
			else if(graph[1][ki] > 350) {g.setColor(java.awt.Color.white);}
  	            g.fillOval((int)graph[0][ki],(int)graph[1][ki],3,3);
		    
		    ki++;
		}
	    ki = bki;
 	    }
		    
	    if(ki == nmax)
		{
		ki = 0;
		while (ki < nmax)
		    {
		    graph[0][ki] = graph[0][(ki+1)]-1;
		    graph[1][ki] = graph[1][(ki+1)];
		    ki++;
		    }
		ki = nmax -1;
    	 	}  	   
    	    }
    }

	g.setColor(java.awt.Color.black);

// draw meter
	    g.setColor(java.awt.Color.black);
	    g.drawArc(390,metery,100,40,0,180);
	    g.drawLine(390,metery+20,420,metery+70);
	    g.drawLine(490,metery+20,460,metery+70);
	    g.drawLine(420,metery+70,460,metery+70);
	    g.fillOval(435,metery+65,6,6);

// draw the three field lines

            iv=0;
    	    while(iv < 3)
         	{
	    	    line.ang = values[iv]*(Math.PI/180.);

        	    line.sx = x1 - 10 * Math.sin(line.ang);
        	    line.sy = y1 - 10 * Math.cos(line.ang);

                    distt=100.;

        	    double delarc = 13.;
                    double intarc;
                    int ij;
                    double output1,output2;
                    intarc = delarc/3.;
                    double signx;
                    int ilinc = 0;

                    ij = 0;
		    si = 0;

//   draw field lines from magnet, at three different angles, including field due to ring

             	    while(ij < 150  && distt > 25.0)
                	{


                	    dist1 = Math.sqrt(Math.pow(line.sx-x1, 2) + Math.pow(line.sy - y1, 2));
                          if (ij > 3)
                             {
                              distt=dist1;
                             }
                          else
                             {
                             distt=100.;
                             }

 			//compute components of dipole field with unit magnetic dipole moment

                	    compx1 = -(3.*(line.sx-x1)*(line.sy-y1)/(4.*Math.PI))/Math.pow(Math.pow(line.sx-x1,2)+Math.pow(line.sy-y1,2),2.5) ;
                	    compy1 = -((2.*Math.pow(line.sy-y1,2)-Math.pow(line.sx-x1,2))/(4.*Math.PI))/Math.pow(Math.pow(line.sx-x1,2) + Math.pow(line.sy-y1,2),2.5);

 			//compute components of field due to ring, respectively
                        //  we compute curl numberically
  
	                    Potential pinto=new Potential(dummy,rada,line.sx-x1, line.sy-y2);
	                    Potential pintx=new Potential(dummy,rada,line.sx + intarc-x1, line.sy-y2);
	                    Potential pinty=new Potential(dummy,rada,line.sx-x1 , line.sy + intarc-y2);

                        //note we are the dividing the dimensionless current by lambda beta radius radius where lambda is set to 2 above
                        //   see Force Memo #10, equation 10.28
                        //  the expressions below is the curl of the potential in cylindrical coordinates, with x = usual rho and y = usual z

                    signx= (line.sx-x1)/java.lang.Math.abs(line.sx-x1);
              	    compx2 = xold[1]*signx*( (pinty.Pota-pinto.Pota)/intarc  )/(betavalue*betavalue*lambda*rada*rada);
              	    compy2 = -xold[1]*signx*(   (pintx.Pota-pinto.Pota)/intarc + pinto.Pota/(line.sx-x1)  )/(betavalue*betavalue*lambda*rada*rada);

                            compx=compx1+compx2;
                            compy=compy1+compy2;

                	    line.emag = Math.sqrt(Math.pow(compx,2) + Math.pow(compy,2));

                	    line.ex = line.sx + delarc * (compx/line.emag);
                	    line.ey = line.sy + delarc * (compy/line.emag);


			    if(si != 0)
			        {
	    g.setColor(java.awt.Color.blue);
	    g.drawLine((int)line.sx, (int)line.sy, (int)line.ex, (int)line.ey);
	    g.drawLine(225-((int)line.sx-225),(int)line.sy,225-((int)line.ex-225),(int)line.ey);
			        }

//      draw arrow head on field line every once in awhile
                           ilinc++;

           if (ilinc>5) {
               double vey,vex;
              vey = line.sy ;
              vex = line.sx ;
               dy1 = 1*(arrowlength2*((sinangle*compx-cosangle*compy)/line.emag));
                dx1 = -1*(arrowlength2*((cosangle*compx+sinangle*compy)/line.emag));
                dy2 = 1*(arrowlength2*((-sinangle*compx-cosangle*compy)/line.emag));
                dx2 = -1*(arrowlength2*((cosangle*compx-sinangle*compy)/line.emag));
               g.drawLine((int)vex, (int)vey, (int)(vex + dx1/2.),(int)(vey + dy1/2.));
                g.drawLine((int)vex, (int)vey, (int)(vex + dx2/2.),(int)(vey + dy2/2.));
               g.drawLine(450-(int)vex, (int)vey,450- (int)(vex + dx1/2.),(int)(vey + dy1/2.));
                g.drawLine(450-(int)vex, (int)vey, 450-(int)(vex + dx2/2.),(int)(vey + dy2/2.));
               ilinc=0;
                       }


                	    line.sx = line.ex;
                	    line.sy = line.ey;

                            ij++;
			    si++;
                	}
			    sii++;
			
			if(sii==15)
			{	
			g.setColor(java.awt.Color.white);
			g.fillRect(0,0,width,height);
			sii=0;
			}
			g.setColor(java.awt.Color.black);
                    iv++;
        	}

	g.drawLine(125,y2-10,125,y2+10);
	g.drawLine(325,y2-10,325,y2+10);

//draw ring
	g.drawOval(125,y2-20,(2*(int)rada),20);
	g.drawOval(125,y2,(2*(int)rada),20);

	g.drawLine(150,y2-10,150,y2+10);
	g.drawLine(300,y2-10,300,y2+10);

	g.drawOval(150,y2-20,((2*(int)rada)-50),20);
	g.drawOval(150,y2,((2*(int)rada)-50),20);

    	g.drawLine(rect.cx-rect.rw,rect.cy-rect.rh+2,rect.cx-rect.rw,rect.cy+rect.rh+2);
	g.drawOval(rect.cx-rect.rw,rect.cy-rect.rh,(2*rect.rw),4);
    	g.drawLine(rect.cx+rect.rw,rect.cy-rect.rh+2,rect.cx+rect.rw,rect.cy+rect.rh+2);
	g.drawOval(rect.cx-rect.rw,rect.cy+rect.rh,(2*rect.rw),4);

//	g.drawRect(25,350,450,100);
    }

public boolean handleEvent(Event e)
    {
    Object target=e.target;

    if(target==timeScroll)
        {
        maxtim = timeScroll.getValue();
        timeLabel.setText("T =  " + maxtim);
        }
    if(target==qvalueScroll)
        {
        qvalue = qvalueScroll.getValue();
        qvalueLabel.setText("Resistance = " + qvalue);
        }
    if(target==betaScroll)
        {
        betavalue = betaScroll.getValue();
        betaLabel.setText("Dipole moment =  " + betavalue);
        }

    if (e.id==Event.ACTION_EVENT)
        {
       if(target==restartbutton)
            {
		x1 = 225.0;
		y1 = 140;
		go = 0;
		tim = 0;
		go = 0;
		repaint();
            }

        else if(target==gobutton)
            {
            	go = 1;
            	repaint();
            }

        else if(target==toggleEbutton)
            {
            	toggE = -1*toggE;
            	repaint();
            }

        else if(target==toggleBbutton)
            {
            	toggB = -1*toggB;
            	repaint();
            }
        }
    return super.handleEvent(e);
    }

}