/**

 * MandelBrot: Plots Mandelbrot set and displays in Web Browser

 *

 * @version 1.0, DATE: 10.31.97

 * @author Paul Santa Maria

 */

import java.applet.*;

import java.awt.*;              // User Interface components



//

// MandelPlot: Implements Mandelbrot plot

//

class MandelPlot extends Canvas

{

  private int maxcol = 399, maxrow = 399, max_colors = 8,

        max_iterations = 512, max_size = 4;

  private Color cmap[];



/**

 * Plot a single point in Mandelbrot set

 */

  private void plot (Graphics g, int x, int y, int color_index)

  {

    g.setColor (cmap[color_index]);

    g.drawLine (x,y, x,y);

  }



/**

 * Constructor: initialize color table for drawing

 */

  public MandelPlot ()

  {

     cmap = new Color[max_colors];



     cmap[0] = Color.black;

     cmap[1] = Color.red;

     cmap[2] = Color.green;

     cmap[3] = Color.blue;

     cmap[4] = Color.cyan;

     cmap[5] = Color.magenta;

     cmap[6] = Color.yellow;

     cmap[7] = Color.white;

  }



/**

 * Actually draws the Mandelbrot set

 */

  public void paint (Graphics g)

  {



     float Q[] = new float[400];

     double Pmax = 1.75,Pmin = -1.75, Qmax = 1.5, Qmin = -1.5,

        P, deltaP, deltaQ, X, Y, Xsquare, Ysquare;

     int color, row, col;



     deltaP = (Pmax - Pmin)/(double)(maxcol - 1);

     deltaQ = (Qmax - Qmin)/(double)(maxrow - 1);

     for (row=0; row<=maxrow; row++) {

       Q[row] = (float)(Qmin + row*deltaQ);

     }

     for (col=0; col<=maxcol; col++) {

       P = Pmin + col*deltaP;

       for (row=0; row<=maxrow; row++) {

         X = Y = 0.0;

         color = 0;

         for (color=0; color<max_iterations; color++) {

           Xsquare = X*X;

           Ysquare = Y*Y;

           if ((Xsquare+Ysquare) > max_size)

             break;

           Y = 2*X*Y+Q[row];

           X = Xsquare-Ysquare+P;

         }

         plot (g, col, row, (int)(color % max_colors));

       }

     }

  }

}



/**

 * Create/display main window

 */

public class MandelBrot extends Applet

{

  private MandelPlot canvas;



  // MandelBrot: Frame constructor

  public void init ()

  {

     setLayout (new BorderLayout());

     canvas = new MandelPlot ();

     add ("Center", canvas);

   }



  // handleEvent: give us a way to gracefully exit the program

  public boolean handleEvent (Event evt)

  { if (evt.id == Event.WINDOW_DESTROY)

        System.exit (0);

     return false;

  }

}