// The copyright of this program is reserved by �N�L.
/* 
Hilbert�Ȑ�
*/ 

/* <applet code="Ex061010f.class" width=410 height=410> </applet> */

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Ex061010f extends JApplet implements ActionListener{
	boolean flag=false;
	int order;
	double leng;
	dTurtle t;
	JComboBox cb;
	String cbl[]={"n=1","n=2","n=3","n=4","n=5","n=6","n=7"};	
	public void init(){
		Container cp = getContentPane();
		JPanel pl = new JPanel();
		pl.setBackground(Color.black);
		t = new dTurtle(5,405);
		t.setColor(Color.yellow);
    pl.setLayout(null);
    cb = new JComboBox(cbl);
    cb.setBounds(0,0,60,20);
    cb.setSelectedIndex(0);
    cb.addActionListener(this);
		pl.add(cb);
		cp.add(pl);
	}
	
	public void actionPerformed(ActionEvent event){
		order = cb.getSelectedIndex()+1;
		t.setPos(5,405);
		t.setAng(0);
		flag=true;
		leng=400.0/(Math.pow(2.0,order)-1.0);
		repaint();
	}
	
	public void paint(Graphics g){
		super.paint(g);
		if(flag==true)
			Hilbert(order,90.0,g);
	}
	
	public void Hilbert(int order, double th, Graphics g){
		if(order>0){
			t.turn(th);
			Hilbert(order-1,-th,g);
			t.move(leng,g);
			t.turn(-th);
			Hilbert(order-1,th,g);
			t.move(leng,g);
			Hilbert(order-1,th,g);
			t.turn(-th);
			t.move(leng,g);
			Hilbert(order-1,-th,g);
			t.turn(th);
		}
	}
}