Sneaky Abstractions

Barby 0.2 has support for two-dimensional barcodes, and all existing outputters have been updated to work with 2D. The first supported 2D symbology is QR Code which is quite popular for mobile phone implementations and big in Japan. It uses the excellent RQRCode library by Duncan Robertson.

require 'barby'
require 'barby/outputter/png_outputter'

qrcode = Barby::QrCode.new('2D power')

File.open('qrcode.png', 'w') do |f|
  f << qrcode.to_png
end

To update or install:

sudo gem install barby

The implementation of 2D support is pretty simple: 2D barcodes are considered to be 1D barcodes on top of each other. So if you’re writing a class for a 2D symbology, the difference is that your encoding method must return an array of strings instead if a single string:

class My2DBarcode < Barby::Barcode2D

  def endoding
    ['010011', '011001', '110001']
  end

end

If you’re writing an outputter that is capable of handling 2D barcodes, you just have to keep this in mind. You can use the two_dimensional? method to check if a barcode is 2D:

class MyOutputter < Barby::Outputter

  def to_something
    if barcode.two_dimensional?
      encoding.inject(""){|s,line| s + do_something_with(line) }
    else
      do_something_with(encoding)
    end
  end

end