A Ruby library that encodes QR Codes
Clone or download
bjornblomqvist Merge pull request #53 from nickgnd/add-support-for-ruby2.3.3
Update travis rubies version (ruby v2.3.3)
Latest commit 31f14b6 Apr 16, 2018


rQRCode, Encode QRCodes

Build Status

All users of rqrcode are highly recomended to upgrade to version 0.5.5 ore later!

Short changelog

0.10.1 (Feb 11, 2016)

  • Changed so that gem wont include images and tests.

0.10.0 (Feb 11, 2016)

0.9.0 (Jan 3, 2016)

  • Added support for auto selecting qrcode size up to level 40. (only worked up to level 10 before)
  • Added numeric support during auto selection of qrcode mode.

0.8.1 (Jan 3, 2016)

  • Remove active support specific present?.
  • Fix so that all tests are run.

0.8.0 (Dec 18, 2015)

  • Added numeric QR code support
  • Dropped Ruby v1.8 support


rQRCode is a library for encoding QR Codes in Ruby. It has a simple interface with all the standard qrcode options. It was adapted from the Javascript library by Kazuhiko Arase.

Let's clear up some rQRCode stuff.

  • rQRCode is a ruby only library It requires no native libraries. Just Ruby!
  • It is an encoding library. You can't decode QR codes with it.
  • The interface is simple and assumes you just want to encode a string into a QR code
  • QR code is trademarked by Denso Wave inc


You may get the latest stable version from Rubygems.

gem install rqrcode

Using rQRCode

require 'rqrcode'

qrcode = RQRCode::QRCode.new("http://github.com/")
image = qrcode.as_png
svg = qrcode.as_svg
html = qrcode.as_html
string = qrcode.as_ansi
string = qrcode.to_s

Image Rendering


The SVG renderer will produce a stand-alone SVG as a String

qrcode = RQRCode::QRCode.new("http://github.com/")
# With default options specified explicitly
svg = qrcode.as_svg(offset: 0, color: '000', 
                    shape_rendering: 'crispEdges', 
                    module_size: 11)

QR code with github url


The ANSI renderer will produce as a string with ANSI color codes.

qrcode = RQRCode::QRCode.new("http://github.com/")
# With default options specified explicitly
svg = qrcode.as_ansi_(light: "\033[47m", dark: "\033[40m",
                    fill_character: '  ',
                    quiet_zone_size: 4)

QR code with github url


The library can produce a PNG. Result will be a ChunkyPNG::Image instance.

qrcode = RQRCode::QRCode.new("http://github.com/")
# With default options specified explicitly
png = qrcode.as_png(
          resize_gte_to: false,
          resize_exactly_to: false,
          fill: 'white',
          color: 'black',
          size: 120,
          border_modules: 4,
          module_px_size: 6,
          file: nil # path to write
IO.write("/tmp/github-qrcode.png", png.to_s)

QR code with github url

HTML Rendering

In your controller

@qr = RQRCode::QRCode.new( 'https://github.com/whomwah/rqrcode', :size => 4, :level => :h )

In your view

<%= raw @qr.as_html %>


table {
  border-width: 0;
  border-style: none;
  border-color: #0000ff;
  border-collapse: collapse;

td {
  border-left: solid 10px #000;
  padding: 0; 
  margin: 0; 
  width: 0px; 
  height: 10px; 

td.black { border-color: #000; }
td.white { border-color: #fff; }

On the console

qr = RQRCode::QRCode.new( 'my string to generate', :size => 4, :level => :h )
puts qr.to_s


xxxxxxx x  x x   x x  xx  xxxxxxx
x     x  xxx  xxxxxx xxx  x     x
x xxx x  xxxxx x       xx x xxx x
... etc 

Doing your own rendering

qr = RQRCode::QRCode.new( 'my string to generate', :size => 4, :level => :h )
qr.modules.each do |row|
    row.each do |col| 
        print col ? "X" : " "
    print "\n"

Specifying QR code mode

Sometimes you may want to specify the QR code mode explicitly.

It is done via the mode option. Allowed values are: number, alphanumeric and byte_8bit.

qr = RQRCode::QRCode.new( '1234567890', :size => 2, :level => :m, :mode => :number )

API Documentation




Original author: Duncan Robertson

Special thanks to the following people for submitting patches:


  • Fork the project
  • Send a pull request
  • Don't touch the .gemspec, I'll do that when I release a new version


MIT License (http://www.opensource.org/licenses/mit-license.html)