blur3.rb

class Image
  def initialize(image_array)
    @image_array = image_array
  end

  def output
    @image_array.each do |row|
        puts row.join(' ')
    end
  end

  def rows
    rows = @image_array.count - 1
  end

  def columns
    columns = @image_array[0].count - 1
  end

  def blur!(n = 1)
    generate_blur_pixels(n).each do |index|
      @image_array[index[0]][index[1]] = 1 if
        index[0] >= 0 && index[0] <= rows && index[1] >= 0 && index[1] <= columns
    end

    return Image.new(@image_array)
  end

  private

  def generate_distance_pairs(n)
    distance_pair_array = []
    (1..n).each do |x|
      (0..x).each do |y|
        z = x - y
        distance_pair_array.push([y, z], [-y, -z])
        distance_pair_array.push([y, -z], [-y, z]) unless y == 0 || z == 0
      end
    end
    return distance_pair_array
  end

  def generate_blur_pixels(n)
    distance_pair_array = generate_distance_pairs(n)
    blur_pixel_array = []
    @image_array.each.with_index do |row, row_index|
      row.each.with_index do |pixel, column_index|
        if pixel == 1
          distance_pair_array.each do |delta|
            blur_pixel_array.push([row_index + delta[0], column_index + delta[1]])
          end
        end
      end
    end
    return blur_pixel_array
  end
end

image = Image.new([
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 1, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 0],
  [0, 0, 0, 0, 0, 0, 0, 0, 1]
])
image_blur = image.blur!(3)
image_blur.output