gistfile1.rb

# getting more power out of Enumerable
# this is to convert an RGB data structure, into RGBA

require 'enumerator'
RGB_WIDTH = 3

raw_data = [1,1,1,2,2,2,3,3,3,4,4,4]

# returns an enumerable object with the raw data split up into chunks of 3
pixels = raw_data.enum_slice( RGB_WIDTH )

# give each pixel an extra alpha byte
rgba_result = pixels.inject([]){|result, pixel| result = result + pixel + [0] }

puts rgba_result.inspect
# [1,1,1,0,2,2,2,0,3,3,3,0,4,4,4,0]