/* Java Applet "Julia" computes the
   invariant lamination for a connected Julia set
   on the boundary of the Mandelbrot set with
   variable external angle. This program is released
   under the GNU GPL; copyright is retained by
   the author, Danny Calegari. See http://www.gnu.org */

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.lang.Math;



public class julia extends Applet {

    int angle=20;
    int count,i,j,k,l,m,n;
    int x1,x2,y1,y2,radius;
    double leaf[][] = new double [10000][2];
    double a,b,c,d,e,f;
    double alpha,beta,gamma,delta;
   
    Scrollbar exterior_angle = new Scrollbar(Scrollbar.HORIZONTAL,20,10,1,209);
    
    public void init() {
	
	setLayout( new GridLayout( 15, 2));
	add( "North", exterior_angle);
	exterior_angle.setUnitIncrement(1); 
	exterior_angle.setBlockIncrement(5);
	add(exterior_angle);
	ScrAdj sa = new ScrAdj();
	exterior_angle.addAdjustmentListener(sa);
	
    }
    
    public void paint( Graphics graphics ) {
	graphics.setColor( Color.black );

	leaf[1][0] = angle/200.0;
	leaf[1][1] = leaf[1][0]+0.5;
	
	if (leaf[1][1]>1.0){
	    leaf[1][0] = leaf[1][1]-1.0;
	    leaf[1][1] = leaf[1][1]-0.5;
	};

	e = leaf[1][0];
	f = leaf[1][1];
	
	j=1;
	k=1;
	
	for (count=0;count<10;count++){
	    n=0;
	    for (i=j;i<=k;i++){
		
		leaf[k+(2*(i-j))+1][0] = leaf[i][0]/2.0;
		leaf[k+(2*(i-j))+1][1] = leaf[i][1]/2.0;
		leaf[k+(2*(i-j))+2][0] = (leaf[i][0]/2.0) + 0.5;
		leaf[k+(2*(i-j))+2][1] = (leaf[i][1]/2.0) + 0.5;
		
		n=n+2;
		
		
		a = leaf[k+(2*(i-j))+1][0];
		b = leaf[k+(2*(i-j))+1][1];
		c = leaf[k+(2*(i-j))+2][0];
		d = leaf[k+(2*(i-j))+2][1];
		
		
		if(  ((a<e) && (e<b) && (b<f)) ||
		     ((a<f) && (f<b) && (b<e)) ||
		     ((b<e) && (e<a) && (a<f)) ||
		     ((b<f) && (f<a) && (a<e)) ||
		     ((c<e) && (e<d) && (d<f)) ||
		     ((c<f) && (f<d) && (d<e)) ||
		     ((d<e) && (e<c) && (c<f)) ||
		     ((d<f) && (f<c) && (c<e)) ){
		    leaf[k+(2*(i-j))+1][1] = d;
		    leaf[k+(2*(i-j))+2][1] = b;
		};
	    }
	    
	    l=n+k;
	    j=k+1;
	    k=l;
	};
	
	
	for(i=1;i<j;i++){
	    alpha = leaf[i][0]*6.2831852;
	    beta = leaf[i][1]*6.2831852;

	    if (alpha>6.2831852){
		alpha=alpha-6.2831852;
	    };
	    if (alpha<0){
		alpha=alpha+6.2831852;
	    };
	    if (beta>6.2831852){
		beta=beta-6.2831852;
	    };
	    if (beta<0){
		beta=beta+6.2831852;
	    };

	    gamma = (alpha+beta)/2.0;
	    delta = (alpha-beta)/2.0;

	    x1 = (int) (100.0 + (75.0*(Math.cos(gamma))/(Math.cos(delta))));
	    x2 = (int) (110.0 + (75.0*(Math.sin(gamma))/(Math.cos(delta))));
	    radius = (int) (75.0*Math.tan(delta));

	    graphics.drawOval(x1-radius,x2-radius,radius*2,radius*2);
	};
    }
    
    
    class ScrAdj implements AdjustmentListener {
	public void adjustmentValueChanged(AdjustmentEvent ae) {
	    Scrollbar s = (Scrollbar) ae.getAdjustable();
	    angle=(ae.getValue());
	    repaint();
	}
    }
}