Java Mandelbrot test

Complex.java

package test;

public class Complex {
  public final double real;
  public final double imaginary;

  public Complex(double r, double i) {
    real = r;
    imaginary = i;
  }

  public final double abs() {
    return Math.sqrt(real * real + imaginary * imaginary);
  }

  public final double absSquared() {
    return real * real + imaginary * imaginary;
  }

  public final Complex plus(Complex that) {
    return new Complex(real + that.real, imaginary + that.imaginary);
  }

  public final Complex times(Complex that) {
    return new Complex(real * that.real - imaginary * that.imaginary, real * that.imaginary + imaginary * that.real);
  }

  public final Complex minus(Complex that) {
    return new Complex(real - that.real, imaginary - that.imaginary);
  }

  public final Complex divide(Complex that) {
    double denom = that.real * that.real + that.imaginary * that.imaginary;
    return new Complex((real * that.real + imaginary * that.imaginary) / denom,
                       (imaginary * that.real - real * that.imaginary) / denom);
  }

  public final Complex plus(double that) {
    return new Complex(real + that, imaginary);
  }

  public final Complex times(double that) {
    return new Complex(real * that, imaginary * that);
  }

  public final Complex minus(double that) {
    return new Complex(real - that, imaginary);
  }

  public final Complex divide(double that) {
    return new Complex(real / that, imaginary / that);
  }
}

Drawing.java

package gr;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Color;
import java.awt.Point;
import java.awt.BasicStroke;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
import javax.swing.JPanel;

public abstract class Drawing extends JPanel {

  private static final String DEFAULT_NAME = "Main";
  private static final int DEFAULT_WIDTH = 500;
  private static final int DEFAULT_HEIGHT = 500;

  private JFrame frame;

  private String name;

  private Color background;

  private KeyListener kl;

  private int currentX = 0;

  private int currentY = 0;

  public void run() {
    javax.swing.SwingUtilities.invokeLater(new Runnable() {
      public void run() { startWindow(); }
    });
  }

  protected Drawing() {
    this(DEFAULT_NAME, DEFAULT_WIDTH, DEFAULT_HEIGHT, null);
  }

  protected Drawing(String name) {
    this(name, DEFAULT_WIDTH, DEFAULT_HEIGHT, null);
  }

  protected Drawing(int width, int height) {
    this(DEFAULT_NAME, width, height, null);
  }

  protected Drawing(String name, int width, int height) {
    this(name, width, height, null);
  }

  protected Drawing(Color background) {
    this(DEFAULT_NAME, DEFAULT_WIDTH, DEFAULT_HEIGHT, background);
  }

  protected Drawing(String name, Color background) {
    this(name, DEFAULT_WIDTH, DEFAULT_HEIGHT, background);
  }

  protected Drawing(int width, int height, Color background) {
    this(DEFAULT_NAME, width, height, background);
  }

  protected Drawing(String name, int width, int height, Color background) {
    this.name = name;
    setPreferredSize(new Dimension(width, height));
    this.background = background;
  }

  protected void startWindow() {
    frame = new JFrame(name);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().add(this);
    frame.pack();
    frame.setBackground(background);
    kl = new KL();
    frame.addKeyListener(kl);
    frame.setVisible(true);
  }

  public void addKeyListener(KeyListener l) {
    frame.removeKeyListener(kl);
    frame.addKeyListener(l);
  }

  public Drawing setBG(Color c) {
    background = c;
    if (frame != null) frame.setBackground(c);
    return this;
  }

  public void setPos(int x, int y) {
    currentX = x;
    currentY = y;
  }

  public void plot(Graphics g, int x, int y) {
    currentX = x;
    currentY = y;
    g.fillRect(x, y, 1, 1);
  }

  public void plot(Graphics g, int x, int y, Color c) {
    Color lc = g.getColor();
    g.setColor(c);
    plot(g, x, y);
    g.setColor(lc);
  }

  public void plot(Graphics g, double x, double y) {
    plot(g, (int)x, (int)y);
  }

  public void plot(Graphics g, double x, double y, Color c) {
    plot(g, (int)x, (int)y, c);
  }

  public void lineto(Graphics g, int x, int y) {
    g.drawLine(currentX, currentY, x, y);
    currentX = x;
    currentY = y;
  }

  public void lineto(Graphics g, int x, int y, Color c) {
    Color lc = g.getColor();
    g.setColor(c);
    lineto(g, x, y);
    g.setColor(lc);
  }

  public void lineto(Graphics g, double x, double y) {
    lineto(g, (int)x, (int)y);
  }

  public void lineto(Graphics g, double x, double y, Color c) {
    lineto(g, (int)x, (int)y, c);
  }

  public Point getCenter() {
    return new Point(getWidth() / 2, getHeight() / 2);
  }

  private class KL implements KeyListener {
    public void keyPressed(KeyEvent e) {
      if (e.getKeyChar() == 'q') System.exit(0);
    }
    public void keyReleased(KeyEvent e) {
    }
    public void keyTyped(KeyEvent e) {
    }
  }
}

Mand.java

package test;

import gr.Drawing;
import java.awt.*;
import java.awt.event.KeyEvent;

public class Mand extends Drawing {

  public static void main(String[] args) {
    new Mand(INITIAL_WIDTH, INITIAL_HEIGHT).setBG(Color.WHITE).run();
  }

  private static final int R = 100;
  private static final double TAU = 2 * Math.PI;
  private static final double INC = TAU / 100.0;

  private static final double INITIAL_MIN_X = -2.0;
  private static final double INITIAL_MAX_X = 1.0;
  private static final double INITIAL_MIN_Y = -1.0;
  private static final double INITIAL_MAX_Y = 1.0;

  private double minX = INITIAL_MIN_X;
  private double maxX = INITIAL_MAX_X;
  private double minY = INITIAL_MIN_Y;
  private double maxY = INITIAL_MAX_Y;

  private static final int INITIAL_WIDTH = 300;
  private static final int INITIAL_HEIGHT = 200;

  private static int limit = 1000;

  private double mathWidth = maxX - minX;
  private double mathHeight = maxY - minY;
  private int gWidth = 0;
  private int gHeight = 0;

  public Mand(int w, int h) {
    super(w, h);
  }

  public void paint(Graphics g) {
    setExtents();
    System.out.println("Rendering: " + gWidth + "x" + gHeight);
    long time = System.currentTimeMillis();
    for (int x = 0; x < gWidth; x++) {
      for (int y = 0; y < gHeight; y++) {
        g.setColor(mandelbrotColor(coord2Math(x, y)));
        plot(g, x, y);
      }
    }
    System.out.println("Render: " + (System.currentTimeMillis() - time) + "ms");
  }

  private final void setExtents() {
    gWidth = getWidth();
    gHeight = getHeight();
    mathWidth = maxX - minX;
    mathHeight = maxY - minY;
  }

  private final Complex coord2Math(int x, int y) {
    double mx = x * mathWidth / gWidth + minX;
    double my = maxY - y * mathHeight / gHeight;
    return new Complex(mx, my);
  }

  private static final int scaled(int count) {
    return (int)(Math.log(count + 1) * 37);
  }

  private static final Color mandelbrotColor(Complex c) {
    Complex z = new Complex(0, 0);
    int count = 0;
    do {
      z = z.times(z).plus(c);
      if (count++ >= limit) return Color.blue;
    } while (z.absSquared() < 4.0);
    return new Color(scaled(count), 0, 0);
  }
}