Generating a qrcode in a terminal window

.rvmrc

rvm use --create ruby-1.9.2-p180@grcode

Gemfile

# -*- ruby -*-
source 'http://rubygems.org'

gem 'term-ansicolor'
gem 'cheat'
gem 'pry'
gem 'highline'
gem 'rqrcode'

HOWTO.use

git clone git://gist.github.com/1972384.git
cd 1972384/
## ensure that rvm automagically uses the .rvmrc defined in the gist
gem install bundler
bundle
bundle exec ruby qrcode.rb

qrcode.rb

# -*- coding: utf-8 -*-
require 'rqrcode'
require 'term/ansicolor'
require 'highline/import'
require 'optparse'
require 'cgi'

@size     = 4
@quality  = 'q'
@password = false
@smsnum   = nil
@binary   = nil
@filename = nil
@tweet    = false

opts = OptionParser.new do |o|
  o.program_name = 'ruby qrcode.rb'
  o.separator 'Options:'
  o.on('--size NUM',  '-s', 'Size Default: %d' % @size) { |a| @size = a }
  o.on('--level NUM', '-l', 'Quality level: %s (possible values l,m,q,h)' % @quality) { |a| @quality = a }
  o.on('--password',  '-p', 'Password entry') { @password = true }
  o.on('--binary',    '-b', 'Use binary representation') { @binary = true }
  o.on('--file NAME', '-f', 'Read from file') { |a| @filename = a }

  o.on('--sms NUM',   '-t', 'Create an SMS code to given number') { |a| @smsnum = a }
  o.on('--tweet',      nil, 'Create twitter qrcode') { @tweet = true  }
  o.on_tail('--help', '-h', 'Show this message') do
    puts opts
    exit
  end
end
opts.parse!(ARGV)

class String
  include Term::ANSIColor

  # my terminal is black background, so space comes out as black and to have
  # white, need to have bright-white.
  def dark_if(yes_or_no)
    yes_or_no ? '  ' : on_white.white.bold
  end
end

ary = nil

pword = if ARGV.length > 0
          ARGV[0]
        elsif @filename
          File.open(@filename).read
        else
          ask("Enter the magic: "){ |q| q.echo = !@password }
        end

pword = "sms:#{@smsnum}?body=#{pword}" unless @smsnum.nil?
pword = "twitter://post?message=#{CGI.escape(pword).gsub(/[+]/,'%20')}" if @tweet

# Generate the qrcode but store it in an 2D array that is 2 pixels too bigger
# so that we can get a white border around the qrcode. this allows the
# scanner to pickup the code if the terminal window has a black (or dark) background.

qrcode = nil

3.times do
  begin
    qrcode = RQRCode::QRCode.
      new(pword, :size => @size.to_i, :level => @quality.to_sym)
  rescue RQRCode::QRCodeRunTimeError => e
    @size = (@size.to_i + 1).to_s
  end
end

ary_size =  qrcode.module_count + 2
ary = Array.new(ary_size) { |_| [false]*ary_size }

qrcode.modules.each_index do |x|
  qrcode.modules.each_index do |y|
    ary[x+1][y+1] = qrcode.dark?(x,y)
  end
end

def dump(yes_or_no)
  print '██'.dark_if(yes_or_no)
  STDERR.print(yes_or_no ? "1" : "0") if @binary
end

# because of the font setting on my terminal, to get a square qrcode, need to use
# ██ instead of just █ ...
(0...ary.size).to_a.tap do |loopidx|
  loopidx.each do |xidx|
    loopidx.each do |yidx|
      # print '██'.dark_if(ary[xidx][yidx])
      dump(ary[xidx][yidx])
    end
    puts ""
    STDERR.puts "" if @binary
  end
end