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A Ruby library that encodes QR Codes

Merge pull request #31 from jlhonora/master

Fix output_file arg for .as_png in readme

rQRCode, Encode QRCodes

Build Status

Short changelog

0.7.0 (Aug 15, 2015)

  • Added shape_rendering option for as_svg

0.6.0 (Jun 2, 2015)

  • Improved png rendering. Previous png rendering could result in hard to scan qrcodes. Big thanks to Bart Jedrocha

0.5.5 (Apr 25, 2015)

  • Fixed major bug. The rs block data was missing resulting in qr codes failing to be generated. Upgrade highly recomended!!


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 standalone library It requires no other 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 ="")
image = qrcode.as_png
svg = qrcode.as_svg
html = qrcode.as_html
string = qrcode.to_s

Image Rendering


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

qrcode ="")
# With default options specified explicitly
svg = qrcode.as_svg(offset: 0, color: '000', 
                    shape_rendering: 'crispEdges', 
                    module_size: 11)


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

qrcode ="")
# 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

HTML Rendering

In your controller

@qr = '', :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; 
} { border-color: #000; }
td.white { border-color: #fff; }

On the console

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

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 (

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