spriter.rb

#!/usr/bin/env ruby

# A quick and dirty image combiner for CSS sprites
# Name your files something along the lines of file_name_1.jpg (all with same extensions, 
# including casing if important on your OS) and this script will combine them in order,
# create a directory named 'sprites' and put the resulting CSS sprite image in that dir.
# Run this script in the directory that contains files that you want to combine. Takes
# one argument, specifying the highest number that the script will go up to. It defaults to 3.
# So if you have # 4 images for each sprite, simply pass the number 4 to the script like so:
# ./spriter.rb 4 
# Requires the Imagick libraries to be installed along with the rmagick gem. 


require 'RMagick'
include Magick

file_bases = {}
extensions = ['jpg', 'gif', 'png', 'jpeg']
num_in_sprite = ARGV[0] ? ARGV[0].to_i : 3

Dir.entries('.').each do |file|
  # Files that have a format of (filename_number.ext)
  if (file =~ %r"^(.*)_[1-9][0-9]*\.(#{extensions.join('|')})$"i)
    file_bases[$1] ||= $2
  end
end

Dir.mkdir('./sprites') unless File.directory?('./sprites')

file_bases.each do |base, format|
  sprite = ImageList.new
  1.upto(num_in_sprite) { |i| sprite << Image::read("#{base}_#{i}\.#{format}").first }
  sprite = sprite.append(true)
  sprite.write(File.join('./sprites',"#{base}.#{format}") )
end