import java.*;
import java.awt.*;


public class Ninept extends java.applet.Applet implements Runnable {
   Thread nineptdemo;
   NineptControl mycontrol;
   int state;  
   Font font;  
   int fsize;

   DPoint a,b,c;
   DPoint l,m,n;
   DPoint p,q,r;
   DPoint h;
   DPoint d,e,f;
   DLine sideab,sidebc,sideca,altap,altbq,altcr;
   DPoint center;
   double radius;
   public void init() {

      setLayout(new BorderLayout());
      font = new Font("TimesRoman", Font.PLAIN, 12);
      fsize = font.getSize();
  
      mycontrol = new NineptControl(this);
      mycontrol.addcontinuebutton();
      mycontrol.addrestartbutton();
      add("South",mycontrol);
      state = 0;      
      a = new DPoint(40.0,20.0,"A");
      b = new DPoint(270.0,20.0,"B");
      c = new DPoint(120.0,150.0,"C");
      sideab = new DLine(a,b);
     repaint();
   }

   public void draw0(Graphics g) {
      g.setColor(Color.black);
      g.setFont(font);
      g.drawString("Click any point above this text and below line AB.",10,180);
      sideab.Show(g);
      a.Show(g,7);
      b.Show(g,1);
   }

   public void draw1(Graphics g) {
      g.setColor(Color.black);
      g.setFont(font);
      g.drawString("Take any triangle ABC.",10,180);
      sideab.Show(g);
      sidebc.Show(g);
      sideca.Show(g);
      a.Show(g,7);
      b.Show(g,1);
      c.Show(g,4);
   }

   public void draw2(Graphics g){
      draw1(g);
      g.setColor(Color.red);
      g.drawString("The midpoints of the sides, ",10,180+fsize);            
      l.Show(g,0);
      m.Show(g,3);
      n.Show(g,5);
   }

   public void draw3(Graphics g){
      draw2(g);
      int width2 = g.getFontMetrics().stringWidth("The midpoints of the sides, ");
      g.setColor(Color.green);
      g.drawString("the feet of the altitudes ",10+width2, 180+fsize);
      p.Show(g,3);
      q.Show(g,5);
      r.Show(g,0);
      altap.Show(g);
      altbq.Show(g);
      altcr.Show(g);
      g.setColor(Color.blue);
      h.Show(g,7);
      g.drawString("(H, the point where the altitudes meet, is the orthocenter), ",10,180+2*fsize);
 
   }
   
   public void draw4(Graphics g){
      draw3(g);
      g.setColor(Color.cyan);
      d.Show(g,1);
      e.Show(g,7);
      f.Show(g,3);
      g.drawString("and the midpoints of AH, BH and CH ",10,180+3*fsize);
  
   }

   public void draw5(Graphics g){
      draw4(g);
      g.setColor(Color.magenta);
      int width2 = g.getFontMetrics().stringWidth("and the midpoints of AH, BH and CH ");
      g.drawString("all lie on a circle.",10+width2,180+3*fsize);
      g.drawOval( (int)(center.x-radius),(int)(center.y-radius),(int)(2.0*radius),(int)(2.0*radius));      

   }

   public void paint(Graphics g) {
      switch (state) {
         case 0: {
            draw0(g);
            break;
         }
         case 1: {
            draw1(g); 
            break;          
            }
         case 2: {
            draw2(g);
            break;
            }
         case 3: {
            draw3(g);
            break;         
            }
         case 4: {
            draw4(g);
            break;
            }
         default: {
            draw5(g);
            break;
            }
 
       }      

             
   }

   public boolean mouseUp(Event evt, int x, int y){
      if((state == 0) && (y > 20) && (y < 180)){
         c.x = (double) x;
         c.y = (double) y;
         state = 1;
      sidebc = new DLine(b,c);
      sideca = new DLine(c,a);
      l = sideab.midpoint();
      m = sidebc.midpoint();
      n = sideca.midpoint();
      l.label = "L";
      m.label = "M";
      n.label = "N";
      r = sideab.footalt(c);
      p = sidebc.footalt(a);
      q = sideca.footalt(b);
      p.label = "P";
      q.label = "Q";
      r.label = "R";
      altap = new DLine(a,p);
      altbq = new DLine(b,q);
      altcr = new DLine(c,r);
      h = altap.intersect(altbq);
      h.label = "H";
      d = new DLine(a,h).midpoint();
      e = new DLine(b,h).midpoint();
      f = new DLine(c,h).midpoint();
      d.label = "D";
      e.label = "E";
      f.label = "F";
      center = l.circumcenter(m,n);
      center.label = "CENTER";
      radius = center.dist(l);
          repaint();
      }
      return true;
   }

   public void start(){
      nineptdemo = new Thread(this);
      nineptdemo.start();
   }

   public void stop(){
      nineptdemo.stop();
   }

   public void run()
   {
     
   }
}

class DPoint{
   
   double x, y;
   String label;
   public DPoint(double first, double second, String name){
      x = first;
      y = second;
      label = name;
   }
   public DPoint(double first, double second){
      x = first;
      y = second;
      label = "";
   }
   public void Show(Graphics g, int where){
      int first = (int) x;
      int second = (int) y;
      // where tells us where to place the character
      // relative to the point --- 0 = north, 1 = northeast,
      // 2 = east, ..., 7 = northwest.
       
      int xoffs[] = {0,3,5,6,-3,-10,-12,-10};
      int yoffs[] = {-5,-3,0,10,13,10,0,-3};
      int offsetx = xoffs[where];
      int offsety = yoffs[where];    
      g.drawOval(first-1,second-1,2,2);
      g.drawString(label,first+offsetx,second+offsety);
   }

   public double dist(DPoint q){
      return Math.sqrt((q.x - x)*(q.x - x) + (q.y - y)*(q.y - y));
   }

   public DPoint orthocenter(DPoint m, DPoint n){
   // orthocenter of triangle
      DLine sidemn = new DLine(m,n);
      DLine sidelm = new DLine(this,m);
      DPoint foot1 = sidemn.footalt(this);
      DPoint foot2 = sidelm.footalt(n);
      DLine alt1 = new DLine(this, foot1);
      DLine alt2 = new DLine(n, foot2);
      return alt1.intersect(alt2);
   }
      
   public DPoint circumcenter(DPoint b, DPoint c){
   // circumcenter of triangle formed by the 3 points
      DPoint l = new DLine(this,b).midpoint();
      DPoint m = new DLine(this,c).midpoint();
      DPoint n = new DLine(b,c).midpoint();
      return l.orthocenter(m,n);
   }      

}

class DLine{
   DPoint p,q;
   public DLine(DPoint first, DPoint second){
      p = first;
      q = second;
   }
   public void Show(Graphics g){
      int x1 = (int) p.x;
      int y1 = (int) p.y;
      int x2 = (int) q.x;
      int y2 = (int) q.y;
      g.drawLine(x1,y1,x2,y2);
   }
   public DPoint lambdapoint(double lambda){
      // The result is the point a fraction lambda 
      // of the way from point p to point q. For example,
      // if lambda == 0.5, we get the midpoint. In
      // vector notation, r = p*(1-lambda) + q*lambda.
      return(new DPoint(q.x*lambda + p.x*(1.0-lambda),
                    q.y*lambda + p.y*(1.0-lambda)));
   }
   public DPoint midpoint(){
      return lambdapoint(0.5);
   }
   public DPoint intersect(DLine m){
      double numerator = (m.q.x-q.x)*(m.q.y-m.p.y) - (m.q.x-m.p.x)*(m.q.y-q.y);
      double denominator = (p.x-q.x)*(m.q.y-m.p.y) - (m.q.x-m.p.x)*(p.y-q.y);
      double lambda = 1.0 - numerator / denominator;
      return( lambdapoint(lambda));
   }

   public DPoint footalt(DPoint c){
      // foot of the altitude from point c to this line
      // determine lambda so that 
      // lambdapoint h on line qp satisfies
      // dot product ch.pq == 0.
      double lambda = ( (q.x-p.x)*(q.x-c.x)
          + (q.y-p.y)*(q.y-c.y) )
          /
          ( (q.x-p.x)*(q.x-p.x) + (q.y-p.y)*(q.y-p.y) );
      return lambdapoint(1.0-lambda);
   }
}

class NineptControl extends Panel{
   Button continuebutton, restartbutton;
   Ninept applet;

   public NineptControl(Ninept app){
       applet = app;
   }

   public void addcontinuebutton(){
       add(continuebutton = new Button("Continue"));
   }

   public void addrestartbutton(){
       add(restartbutton = new Button("Restart"));
   }

   public boolean action(Event ev, Object arg){
       if(ev.target instanceof Button  && applet.state > 0){
          if("Continue".equals(arg)){
             applet.state++;
          }
          if("Restart".equals(arg)){
             applet.state = 0;
          }
          applet.repaint();
          return true;
       }
       return false;
   }

}