import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Line2D;
import java.util.ArrayList;
import java.util.Random;

import javax.swing.JFrame;

/**
 * Snowflake / coastline printer
 * 
 * For snowflake, set the shape variable below to 3 or more.  The best value is probably 6.
 * For coastline, set shape to 1 and set size to 600.
 **/
public class Tri extends JFrame
{
    private final double sq2 = Math.sqrt(2);
    private final int shape = 3;
    private final int siz=200;
    private class Limb{
    double sx;
    double sy;
    double len;
    double angle;
    public Limb(double ssx, double ssy, double llen, double aangle)
    {
	this.sx=ssx;
	this.sy=ssy;
	this.len=llen;
	this.angle=aangle;
    }
    public double ex()
    {
	return this.sx+Math.cos(angle)*len;
    }
    public double ey()
    {
	return this.sy+Math.sin(angle)*len;
    }
    }
    private Random random;
    private ArrayList<Limb> ls;
    public Tri(){
	ls = new ArrayList<>();
        setSize(820, 820);
        random = new Random();
        setTitle("JFrame");
        setBackground(Color.WHITE);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
        
        double interiorAngle = 180-(180.0*(shape-2))/shape;
        Limb p = new Limb(150, 150, siz, 0);
	ls.add(p);
	for (int i=1; i<shape; i++)
	{
	    p = new Limb(p.ex(), p.ey(), p.len, p.angle+Math.PI*interiorAngle/180);
	    ls.add(p);
	}
	repaint();
        setVisible(true);
    }
    
    public void addL()
    {
	Limb l = ls.remove(0);
	//System.out.println(l.len);
	if (l.len<2)
	    return;
	Limb l25 = new Limb(l.sx, l.sy, l.len*0.25, l.angle);
	Limb l75 = new Limb(l.sx, l.sy, l.len*0.75, l.angle);
	Limb l1 = new Limb(l.sx, l.sy, l.len*0.25, l.angle);
	Limb l2 = new Limb(l75.ex(), l75.ey(), l.len*0.25, l.angle);
	
	ls.add(l1);
	int pm = random.nextBoolean() ? 1 : -1;
	if (siz>1)
	    pm=1;
	ls.add(new Limb(l25.ex(), l25.ey(), l.len*0.25*sq2, l.angle+pm*Math.PI/4));
	ls.add(new Limb(l75.ex(), l75.ey(), l.len*0.25*sq2, l.angle-pm*(1.25*Math.PI)));

	ls.add(l2);
	if (ls.size()%20==0)	
	    repaint();
	try { Thread.sleep(20); } catch (Exception e) {}
	addL();
		
    }
    
    public String toString()
    {
	return "";
    }

    
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Tri m = new Tri();
        m.repaint();
        m.addL();
   }

   public void paint(Graphics g) 
   {
       Graphics2D g2 = (Graphics2D) g;
       g2.clearRect(0, 0, 820, 800);
       g2.setStroke(new BasicStroke(1));
       for (Limb l:ls)
       {
           g2.draw(new Line2D.Float((int)l.sx, (int)l.sy, (int)l.ex(), (int)l.ey()));
       }
   }

 
}