An ugly extension to add text underneath the barcode image generated by Barby

swanand_rmagick_outputter.rb

module Barby
  class SwanandRmagickOutputter < RmagickOutputter
    register :to_jpg_2

    def to_jpg_2(*a)
      to_blob('jpg', *a)
    end
  
    #Returns a string containing a JPEG image
    def to_blob(format, *a)
      img = to_image(*a)
      add_text(img)
      blob = img.to_blob{|i| i.format = format }
    
      #Release the memory used by RMagick explicitly. Ruby's GC
      #isn't aware of it and can't clean it up automatically
      img.destroy! if img.respond_to?(:destroy!)
    
      blob
    end
  
    def add_text(canvas)
      text = Magick::Draw.new
      text.font_family = 'Courier'
      text.pointsize = 14
      text.gravity = Magick::SouthGravity
      text.undercolor = 'white'
      text.font_stretch = Magick::ExtraExpandedStretch
    
      text.annotate(canvas, 0, 0, 0, 8, " #{barcode.data} ")
      canvas
    end
  end
end

test.rb

# I put this in my controllers

require 'barby/barcode/code_39'
require 'barby/outputter/rmagick_outputter'
require 'lib/swanand_rmagick_outputter'


def barcode_test
  barcode = Barby::Code39.new(@key, true)
  send_data(barcode.to_jpg_2(:height => 60), 
    :type        => 'image/jpeg',
    :disposition => 'inline'
  )
end