import java.awt.*;
import java.applet.*;
import java.awt.image.*;
//author Carlos E. Yaguna
//e-mail pegasus@pegasus.udea.edu.co
//Departamento de Fisica
//Universidad de Antioquia
//Medellin-COLOMBIA

public class Inter extends Applet
{
  private InterCanva theCanvas;
  private Panel p1,p3,p4;
  private Button equi,bor;
  private Label l1,l2;
  private AudioClip sound;
  private Scrollbar s1,s2,s3;

  public void init()
  {
   sound=getAudioClip(getDocumentBase(), "drip.au");
   theCanvas=new InterCanva();
   theCanvas.resize(350,300);
   theCanvas.setBackground(Color.black);
   p1=new Panel();
   p3=new Panel();
   p4=new Panel();
   l1=new Label("Velocity");
   l2=new Label("Electric Field");
   equi=new Button("Start");
   bor=new Button("Stop");
   s1=new Scrollbar(Scrollbar.VERTICAL,150,0,0,300);
   s2=new Scrollbar(Scrollbar.HORIZONTAL,20,0,0,20);
   s3=new Scrollbar(Scrollbar.HORIZONTAL,5,0,0,18);
   p1.setLayout(new GridLayout(8,1));
   p3.setLayout(new BorderLayout());
   p4.setLayout(new GridLayout(1,2));
   p1.add(equi);
   p1.add(bor);
   p3.add("Center",p1);
   
   p4.add(s2);
   p4.add(s3);
   //p4.add(l1);
   //p4.add(l2);
   setLayout(new BorderLayout());
   add("East",p3);
   add("Center",theCanvas);
   add("South",p4);
   add("West",s1);
   
   theCanvas.init();
   theCanvas.start();
   theCanvas.repaint();
  }

   public boolean handleEvent(Event e){

      if(e.target instanceof Scrollbar){

        if(e.target==s1)
         theCanvas.lamb=(400.0+s1.getValue())/100.0;

        if(e.target==s2){
         theCanvas.num2=220+s2.getValue()*4;
          }

        if(e.target==s3){
          theCanvas.dist=2*s3.getValue();
          }
        theCanvas.repaint();
			
			return true;
		}
		
		return super.handleEvent(e);
        }


  public boolean action(Event e, Object o)
  {
   if(e.target instanceof Button){
   sound.play();
   if(e.target == equi){theCanvas.bb=1;
     theCanvas.repaint();
     return true;}

   if(e.target==bor){
     theCanvas.bb=0;
     theCanvas.repaint();
     return true;}
   return false;
   }
    return false;
   }
  /*public boolean mouseDown(Event e,int x,int y){
  if((x>theCanvas.pi)&&(x<theCanvas.pf)&&(y<120+theCanvas.h)&&(y>120-theCanvas.h))
  {
   //theCanvas.ss*=-1;
   //theCanvas.tt=0.0;
  theCanvas.repaint();
  }
  return true;
  }
    */
 }
 class InterCanva extends Canvas implements Runnable{
  public double tiem,lamb;
  int bb,num,num2,dist;
  double tt;
  Font fp,fn;
  Thread hilo;
  Image offScreenImage;
  Color c;


  public void init()
  {
   tiem=0.1;
   lamb=5.5;
   bb=0;
   num=3;
   num2=300;
   dist=10;
   fp=new Font("TimesRoman",Font.ITALIC,9);
   fn=new Font("TimesRoman",Font.BOLD,12);
   offScreenImage=createImage(size().width,size().height);
  }
    
  public void start()
  {
    if(hilo==null);
    {
     hilo=new Thread(this);
     hilo.start();
    }

  }
  public void stop()
  {
     if(hilo != null){
       hilo.suspend();
       hilo=null;
     }

  }
  public void run()
  {
    while(true){ if(bb==1)
                 repaint();

      try{ Thread.sleep(300);
		  
      }
      catch(InterruptedException e){ }
    
	 
	}           

  }

    public void update(Graphics g)
  { //To avoid flicker

    Graphics offScreenGraphics=offScreenImage.getGraphics();
    offScreenGraphics.setColor(getBackground());
    offScreenGraphics.fillRect(0,0,size().width,size().height);
    offScreenGraphics.setColor(g.getColor());
    paint(offScreenGraphics);
    g.drawImage(offScreenImage,0,0,this);

  }

 public void plot(Graphics g)
 {
  int i,var3,var4,var5,lamb2;
  double var,var2,yc,xc,ang;
  g.setColor(Color.white);
  var3=45;
  for(i=1;(i<20)&&(var3<150);i++){
  var3=40+10*i+5;
  g.drawLine(40+10*i,120,var3,120);
  }
  g.setColor(Color.magenta);
  g.fillArc(20,110,20,20,-30,60);
  g.setColor(Color.yellow);
  g.fillRect(160,80,3,120-80-dist);
  g.fillRect(160,120-dist+2,3,2*dist-2);
  g.fillRect(160,120+dist+2,3,40-dist);
  if(bb==1){
  g.setColor(Color.green);
  lamb2=(int)(20.0*lamb/5.0);
  //lamb2=20;
  for(i=1;i<20;i++){
    var=lamb2*tiem+lamb2*(i-3);
    var2=lamb2*tiem+lamb2*(i-6);
    var4=(int)(100+dist-var/2.0);
    var5=(int)(100-dist-var/2.0);
    if(80+var2<160)
    g.drawArc(40,(int)(110-10-var2/2),(int)(40+var2),(int)(40+var2),-45,90);
    g.drawArc(160,var4,(int)(40+var),(int)(40+var),-75,150);
    g.drawArc(160,var5,(int)(40+var),(int)(40+var),-75,150);
    }
   }
  g.setColor(Color.black);
  g.fillRect(num2,0,150,250);
  g.setColor(Color.gray);
  g.fillRect(num2,20,5,200);
 }
 public void diagrama(Graphics g)
 {
  double inten,pi;
  int i,j,var1,var2;
  pi=3.14159265358979323846;
  for(i=0;i<100;i+=2){
  inten=Math.cos(pi*dist*i/(num2*lamb));
  inten*=inten;
  j=(int)(inten*255);
  //lamb=6.9;
  if(lamb<4.6){
  c=new Color(j-(int)(j/0.6*(lamb-4.0)),0,j);
  g.setColor(c);
  }
  else if(lamb<5.2){
  g.setColor(new Color(0,(int)(j/0.6*(lamb-4.6)),j));
  }
  else if(lamb<5.8){
  g.setColor(new Color(0,j,j-(int)(j/0.6*(lamb-5.2))));
  }
  else if(lamb<6.4){
  g.setColor(new Color((int)(j/0.6*(lamb-5.8)),j,0));
  }
  else if(lamb<=7.0){
  g.setColor(new Color(j,j-(int)(j*(lamb-6.4)/0.6),0));
  }
  //g.setColor(new Color(j,0,0));
  g.fillRect(num2+5,120+i,40,2);
  g.fillRect(num2+5,120-i,40,2);
  }
  g.setColor(Color.gray);
  g.fillRect(num2+42,20,5,200);
  for(i=0;120-i*8>20;i++){
   g.drawLine(num2+47,120+i*8,num2+50,120+i*8);
   g.drawLine(num2+47,120-i*8,num2+50,120-i*8);
 }
}
 public void paint(Graphics g)
 {
  double del;
  del=0.1;
  if(bb==1)tiem+=del;
  if(tiem>=1){
  tiem=0.1;
  g.drawString("no",50,50);
  }
  plot(g);
  if(bb==1)diagrama(g);
 }

 }