Codebrawl #2 Entry

output.png

solution.rb

# Basic requirements for pixelator
require 'chunky_png'
include ChunkyPNG::Color

# Pixelator - a quick script to pixelate PNGs.
#
# @author Timmy Christensen
class Pixelator 

  # Initialize attributes
  attr_accessor :file_name, :pixel_size
 
  ####################################################################
  # Initialize
  ####################################################################

  # Create a new instance of Pixelator.
  #
  # @param [String] file_name The name of the image file in the current directory.
  # @param [Integer] pixel_size The square dimensions of the pixelation.
  def initialize(file_name, pixel_size)
    @file_name = file_name
    @pixel_size = pixel_size
  end

  ####################################################################
  # Pixelate
  ####################################################################

  # Create a pixelated copy of the image file.
  #
  # The pixelated image is saved as `output.png` in the current directory.
  def pixelate
    image = ChunkyPNG::Image.from_file(@file_name)
    hex = from_hex('#ffffffff')

    x = 0
    y = 0

    while y < image.height
      while x < image.row(y).length

        hex = to_hex image[x,y]

        0.upto(@pixel_size - 1) { |i|      
          0.upto(@pixel_size - 1) { |j|
            if (x+i < image.width && y+j < image.height)
              image[x+i,y+j] = from_hex(hex) 
            end
          }
        }

        x += @pixel_size
      end
      x = 0
      y += @pixel_size
    end

    image.save('output.png') # Overwrites the file.
  end

end

####################################################################
# Usage
####################################################################

# Call the script from the command using `ruby pixelator.rb <filename> <pixelsize>`
p = Pixelator.new(ARGV[0] || 'input.png', ARGV[1].to_i < 2 ? 10 : ARGV[1].to_i)
p.pixelate