# File lib/rqrcode/qrcode/qr_code.rb, line 269
    def to_s( *args )
      options                = args.extract_options!
      dark                   = options[:dark] || options[:true] || 'x'
      light                  = options[:light] || options[:false] || ' '
      quiet_zone_size        = options[:quiet_zone_size] || 0

      rows = []

      @modules.each do |row|
        cols = light * quiet_zone_size
        row.each do |col|
          cols += (col ? dark : light)
        end
        rows << cols
      end

      quiet_zone_size.times do
        rows.unshift(light * (rows.first.length / light.size))
        rows << light * (rows.first.length / light.size)
      end
      rows.join("\n")
    end