Translate Let it Snow in the Terminal from Ruby to Ruby

snow.rb

# Translate Let it Snow in the Terminal from Ruby to Ruby
#
# Original code:
#   ruby -e 'C=`stty size`.scan(/\d+/)[1].to_i;S=["2743".to_i(16)].pack("U*");a={}; \
#   puts "\e[2J";loop{a[rand(C)]=0;a.each{|x,o|;a[x]+=1;print "\e[#{o};#{x}H \
#   \e[#{a[x]};#{x}H#{S} \e[0;0H"};$stdout.flush;sleep 0.1}'
#
# Let it Snow in the Terminal of Mac OS X with This Command
# http://osxdaily.com/2013/12/06/snow-terminal-mac-os-x-command/
#
# Macのターミナルで雪が降る ～ 最後のホワイトクリスマス - #RyoAnnaBlog
# http://d.hatena.ne.jp/RyoAnna/20131211/1386769871

class Snow
  MARK = ["2743".to_i(16)].pack("U*")

  def self.run(x, colorize=false, mark=MARK)
    new(x, colorize, mark).run
  end

  def initialize(x, colorize, mark)
    @x = x
    @colorize = colorize
    @mark = mark
    @screen = {}
    $stdout.sync = true
  end

  def run
    clear_screen
    loop_on(0.1) do
      print_snows
    end
  end

  private
  def clear_screen
    print "\e[2J"
  end

  def loop_on(interval)
    loop do
      yield
      sleep interval
    end
  end

  def print_snows
    @screen[rand @x] = 0
    @screen.each do |x, y|
      @screen[x] += 1
      clear_prev_snow(x, y)
      color = @colorize ? [*31..37].sample : 37
      draw_snow(x, @screen[x], color)
    end
  end
  
  def clear_prev_snow(x, y)
    draw_mark(x, y, " ")
  end

  def draw_snow(x, y, color)
    draw_mark(x, y, @mark, color)
  end

  def draw_mark(x, y, mark, color=37)
    print "\e[%dm \e[%d;%dH%s \e[0;0H \e[0m" % [color, y, x, mark]
  end
end

if __FILE__ == $0
  # $ ruby snow.rb c
  #   or
  # ruby -e 'C=`stty size`.scan(/\d+/)[1].to_i;S=["2743".to_i(16)].pack("U*");a={};puts "\e[2J";loop{a[rand(C)]=0;a.each{|x,o|;a[x]+=1;print "\e[#{o};#{x}H \e[#{[*31..37].sample}m \e[#{a[x]};#{x}H#{S} \e[0;0H \e[0m"};$stdout.flush;sleep 0.1}'

  columns = `stty size`.scan(/\d+/)[1].to_i
  colorize = ARGV[0].to_s.match(/^c/i) ? true : false
  Snow.run(columns, colorize)
end