From: James Edward Gray II <james@...>
Date: 2007-05-28T02:18:59+09:00
Subject: Fwd: Please Forward: Ruby Quiz Submission

--Apple-Mail-1-115650673
Content-Transfer-Encoding: 7bit
Content-Type: text/plain;
	charset=US-ASCII;
	delsp=yes;
	format=flowed

Begin forwarded message:

> From: Geoff Hulette <ghulette@cs.ucsd.edu>
> Date: May 25, 2007 6:19:24 PM CDT
> To: submission@rubyquiz.com
> Subject: Please Forward: Ruby Quiz Submission
>
> Hi, I am new to this group so I hope I am doing this right.  I  
> wrote a short ruby program that can render a Mandelbrot set to a  
> "MandelImage" object, which can then be printed as an ascii image  
> to the console.  You could imagine writing an RMagick routine to  
> render it to a GIF or something instead. This solution is more the  
> spirit than the letter for this week's quiz, since I don't process  
> any command line args (but you could reuse the classes), and  
> Mandelbrot sets, while fractal, don't really have integer  
> "levels".  If you run "ruby mandelbrot.rb", it should print first  
> the classic Mandelbrot set, and then similar-looking (but rotated)  
> cardioid, from deeper in the set.
> -geoff
>
>

--Apple-Mail-1-115650673
Content-Transfer-Encoding: 7bit
Content-Type: text/x-ruby-script;
	x-unix-mode=0644;
	x-mac-creator=54784D74;
	name=mandelbrot.rb
Content-Disposition: attachment;
	filename=mandelbrot.rb

require 'Complex'

class MandelbrotImage
  def initialize(data, max_iterations)
    @data = data
    @max_iterations = max_iterations
  end
  
  def to_s
    s = ""
    @data.each do |row|
      row.each do |i|
        case i
        when 0..5
          s << '  '
        when @max_iterations
          s << '##'
        else
          s << '..'
        end
      end
      s << "\n"
    end
    s
  end
end

class Mandelbrot
  def initialize(img_width, img_height)
    @img_width = img_width
    @img_height = img_height
  end

  def render(center, width, max_iterations=1000)
    from, to = convert_coords(center, width)
    pixel_size_y = (to.image - from.image)/@img_height
    pixel_size_x = (to.real - from.real)/@img_width
    image_data = []
    (from.image..to.image).step(pixel_size_y) do |yc|
      row = []
      (from.real..to.real).step(pixel_size_x) do |xc|
        c = Complex.new(xc, yc)
        z = Complex.new(0.0, 0.0)
        iteration = 0
        while z.abs < 2.0 and iteration < max_iterations
          z = z**2 + c
          iteration += 1
        end
        row << iteration
      end
      image_data << row
    end
    MandelbrotImage.new(image_data, max_iterations)
  end
  
  private
  
  def convert_coords(center, width)
    aspect = @img_height.to_f / @img_width.to_f
    height = width * aspect
    from = Complex.new(center.real - width/2.0, center.image - height/2.0)
    to = Complex.new(center.real + width/2.0, center.image + height/2.0)
    return from, to
  end
end

mandel = Mandelbrot.new(30, 20)
image = mandel.render(Complex.new(-0.7, 0.0), 3.0769)
puts image
image = mandel.render(Complex.new(-0.743643135, 0.131825963), 4.3884e-06, 2000)
puts image

--Apple-Mail-1-115650673
Content-Transfer-Encoding: 7bit
Content-Type: text/plain;
	charset=US-ASCII;
	format=flowed



--Apple-Mail-1-115650673--