Class: Fractals::Mandelbrot

Inherits:
Object
  • Object
show all
Defined in:
lib/fractal.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(image) ⇒ Mandelbrot

Returns a new instance of Mandelbrot.



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# File 'lib/fractal.rb', line 16

def initialize image
  @width, @height = image.width, image.height
  @image = image
end

Instance Attribute Details

#colorType ⇒ Object

Returns the value of attribute colorType.



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# File 'lib/fractal.rb', line 14

def colorType
  @colorType
end

Instance Method Details

#calculate(a, b, c_arr) ⇒ Object 



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# File 'lib/fractal.rb', line 21

def calculate a, b, c_arr
  ca, cb = c_arr
  left = a * a - b * b
  right = 2 * a * b
  a = left  + ca
  b = right + cb

  return [a, b]
end

#draw(definition = 255, scale = 2) ⇒ Object 



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# File 'lib/fractal.rb', line 31

def draw definition=255, scale=2
  scaleWidth  = scale.to_f
  scaleHeight = scale.to_f * (@height.to_f / @width.to_f)
  definition = definition.to_f
  (0..@width - 1).each do |x|
    (0..@height - 1).each do |y|
      a = ca = drag(x, 0, @width,  -scaleWidth, scaleWidth)
      b = cb = drag(y, 0, @height, -scaleHeight, scaleHeight)

      snap = 0
      while snap < definition
        a, b = calculate(a, b, [ca, cb])
        if a * a + b * b > 16
          break
        end
        snap += 1
      end
      # TODO: Use colorType as option non-monochromatic images
      #       (allow colourful fractals), currently only greyscale
      shade = drag(snap, 0, definition, 0, 1)
      shade = drag(Math.sqrt(shade), 0, 1, 0, 255)

      colours = [shade.round.to_i] * 3
      hex = String.new
      colours.each { |component| hex << component.to_s(16) }
      @image[x, y] = ChunkyPNG::Color.from_hex hex
    end
  end
  return @image
end