/* Java Applet "Mandel" is a standard Mandelbrot set explorer.
   Copyright Danny Calegari; source code released under GPL license */

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

public class mandel extends Applet 
    implements MouseListener, MouseMotionListener, ActionListener{
    
    double xc,yc,xz,yz,x,y;
    double xleft,xright;
    double yleft,yright;
    int xileft,yileft,xiright,yiright;
    int col[][];
    int bwcol[][];
    double scale;
    double xcenter,ycenter;
    int iterate,detail,i,j,k;
    int a,b,m,n;
    int f,g;
    int dragbox, bw;
    Button moredetail, lessdetail, resetbut, BWbut;
    
    
    public void init() {
	
	setLayout(new FlowLayout(10));
	moredetail = new Button("detailed");
	lessdetail = new Button("coarse");
	resetbut = new Button("reset");
	BWbut = new Button("B/W");
	add(moredetail);
	add(lessdetail);
	add(resetbut);
	add(BWbut);
	moredetail.addActionListener(this);
	lessdetail.addActionListener(this);
	resetbut.addActionListener(this);
	BWbut.addActionListener(this);
	col = new int[501][501];
	bwcol = new int[501][501];
	addMouseListener(this);
	addMouseMotionListener(this);
	xcenter=-1.0;
	ycenter=0.0;
	scale=0.01;
	detail=100;
	compute();
	dragbox=0;
	bw=0;

    }
    
    public void paint( Graphics graphics ) {

	m=0;
	if(dragbox==0){
	    for (xc=xcenter-(200.0*scale);xc<xcenter+(200.0*scale);xc=xc+scale){
		m++;
		n=0;
		for (yc=ycenter-(200.0*scale);yc<ycenter+(200.0*scale);yc=yc+scale){
		    n++;
		    iterate=col[m][n];
		    graphics.setColor( Color.black);
		    if (iterate!=detail-1){
			if (bw==0){
			    i = iterate*255/detail;
			    j = (iterate*511/detail) % 256;
			    k = (iterate*1023/detail) % 256;
			    graphics.setColor(new Color(i,j,k));		    
			    graphics.drawLine(m,n,m,n);
			} else {
			    if (bwcol[m][n]==0){
				graphics.drawLine(m,n,m,n);
			    };
			};
		    } else {
			graphics.drawLine(m,n,m,n);
		    };
		};
	    };
	};
	if(dragbox==1){
	    for (xc=xcenter-(200.0*scale);xc<xcenter+(200.0*scale);xc=xc+(scale*4)){
		m=m+4;
		n=0;
		for (yc=ycenter-(200.0*scale);yc<ycenter+(200.0*scale);yc=yc+(scale*4)){
		    n=n+4;
		    iterate=col[m][n];
		    graphics.setColor( Color.black);
		    if (iterate!=detail-1){
			if (bw==0){
			    i = iterate*255/detail;
			    j = (iterate*511/detail) % 256;
			    k = (iterate*1023/detail) % 256;
			    graphics.setColor(new Color(i,j,k));
			    graphics.fillRect(m,n,4,4);
			} else {
			    if (bwcol[m][n]==0){
				graphics.fillRect(m,n,4,4);
			    };
			};
		    } else {
			graphics.fillRect(m,n,4,4);
		    };
		};
	    };
	    graphics.setColor( Color.white);
	    graphics.drawRect(xileft,yileft,xiright-xileft,xiright-xileft);
	};
    };

    public void compute() {
	m=0;
	for (xc=xcenter-(200.0*scale);xc<xcenter+(200.0*scale);xc=xc+scale){
	    m++;
	    n=0;
	    for (yc=ycenter-(200.0*scale);yc<ycenter+(200.0*scale);yc=yc+scale){
		n++;
		    iterate = 0;
		    xz=xc;
		    yz=yc;
		    while(iterate < detail){
			bwcol[m][n]=0;
			col[m][n]=iterate;
			x = xz*xz - yz*yz + xc;
			yz = (2*xz*yz) + yc;
			xz = x;
			if ((xz*xz + yz*yz)>4.0){
			    if (yz>0){
				bwcol[m][n]=0;
			    } else {
				bwcol[m][n]=1;
			    };
			    iterate=detail;
			};
			iterate++;
		    };
		    
	    };
	};
    };

    public void actionPerformed( ActionEvent e) {
	if (e.getSource() == moredetail){
	    detail = (int) (detail*1.2);
	    compute();
	    repaint();
	};
	if (e.getSource() == lessdetail){
	    detail = (int) (detail*0.8);
	    compute();
	    repaint();
	};
	if (e.getSource() == resetbut){
	    xcenter=-1.0;
	    ycenter=0.0;
	    scale=0.01;
	    detail=100;
	    bw=0;
	    compute();
	    repaint();
	};
	if (e.getSource() == BWbut){
	    if(bw==0){
		bw=1;
	    } else {
		bw=0;
	    };
	    repaint();
	};
    };

    public void mouseMoved( MouseEvent e) {
    };

    public void mousePressed( MouseEvent e ) {
	if ((e.getY()>38) || e.getX()>326){
	    xleft = xcenter+(e.getX()-200)*scale;
	    yleft = ycenter+(e.getY()-200)*scale;
	    xileft = e.getX();
	    yileft = e.getY();
	    dragbox=1;
	};
    };
    public void mouseDragged( MouseEvent e ){
	xiright = e.getX();
	yiright = e.getY();
	repaint();
    };
    public void mouseReleased( MouseEvent e ) { 
	if ((e.getY()>38) || e.getX()>326){
	    xright = xcenter+(e.getX()-200)*scale;
	    yright = ycenter+(e.getY()-200)*scale;
	    xcenter = (xleft+xright)/2.0;
	    ycenter = (yleft+yright)/2.0;
	    scale=(xright-xleft)/400.0;
	    dragbox=0;
	    compute();
	    repaint();
	};
    };
    public void mouseClicked( MouseEvent e ) { };
    public void mouseEntered( MouseEvent e ) { };
    public void mouseExited( MouseEvent e ) { };
    
}