mandelbrot.rb

java_import java.awt.image.BufferedImage
java_import javax.swing.JFrame
 
class Mandelbrot < JFrame
  MAX_ITER = 570;
  ZOOM = 150.0;

  def initialize
    super("Mandelbrot Set")
    setBounds(100, 100, 800, 600);
    setResizable(false);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    @image = BufferedImage.new(getWidth(), getHeight(), BufferedImage::TYPE_INT_RGB);
    height.times do |y|
      width.times do |x|
        zx = 0.0;
        zy = 0.0;
        cX = (x - 400) / ZOOM;
        cY = (y - 300) / ZOOM;
        iter = MAX_ITER;
        while (zx * zx + zy * zy < 4 && iter > 0)
          tmp = zx * zx - zy * zy + cX
          zy = 2.0 * zx * zy + cY
          zx = tmp
          iter -= 1
        end
        @image.setRGB(x, y, iter | (iter << 8))
      end
    end
  end
 
  def paint(g)
    g.drawImage(@image, 0, 0, self);
  end
end
      
 Mandelbrot.new.setVisible(true);