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.

Code Quality Rank: L5
Monthly Downloads: 1,146,382
Programming language: Ruby
License: MIT License
Tags: Misc     Graphics     QR Codes    
Latest version: v1.1.1

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RQRCode is a library for creating and rendering QR codes into various formats. It has a simple interface with all the standard QR code options. It was adapted from the Javascript library by Kazuhiko Arase.

  • QR code is trademarked by Denso Wave inc
  • Minimum Ruby version is >= 2.3
  • For rqrcode releases < 1.0.0 please use this README


Add this line to your application's Gemfile:

gem 'rqrcode'

or install manually:

gem install rqrcode

Basic usage example

require 'rqrcode'

qr = RQRCode::QRCode.new('https://kyan.com')

puts qr.to_s

xxxxxxx xxxxxxx  xxx  xxxxxxx
x     x  x  xxx   xx  x     x
x xxx x xx x x     xx x xxx x
x xxx x      xx xx xx x xxx x
x xxx x x x       xxx x xxx x
x     x  xxx x xx x x x     x

Advanced Options

These are the various QR Code generation options provided by rqrqcode_core.

string - the string you wish to encode

size   - the size of the qrcode (default 4)

level  - the error correction level, can be:
  * Level :l 7%  of code can be restored
  * Level :m 15% of code can be restored
  * Level :q 25% of code can be restored
  * Level :h 30% of code can be restored (default :h)

mode   - the mode of the qrcode (defaults to alphanumeric or byte_8bit, depending on the input data):
  * :number
  * :alphanumeric
  * :byte_8bit
  * :kanji


qrcode = RQRCodeCore::QRCode.new('hello world', size: 1, level: :m, mode: :alphanumeric)

Render types

You probably want to output your QR code in a specific format. We make this easy by providing a bunch of formats to choose from below, each with their own set of options:

as SVG

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


offset          - Padding around the QR Code in pixels
                  (default 0)
fill            - Background color e.g "ffffff" or :white
                  (default none)
color           - Foreground color e.g "000" or :black
                  (default "000")
module_size     - The Pixel size of each module
                  (defaults 11)
shape_rendering - SVG Attribute: auto | optimizeSpeed | crispEdges | geometricPrecision
                  (defaults crispEdges)
standalone      - whether to make this a full SVG file, or only an svg to embed in other svg
                  (default true)


require 'rqrcode'

qrcode = RQRCode::QRCode.new("http://github.com/")

# NOTE: showing with default options specified explicitly
svg = qrcode.as_svg(
  offset: 0,
  color: '000',
  shape_rendering: 'crispEdges',
  module_size: 11,
  standalone: true

[QR code with github url](./images/github-qrcode.svg)

as PNG

The will produce a PNG using the ChunkyPNG gem. The result will be a ChunkyPNG::Image instance.


fill  - Background ChunkyPNG::Color, defaults to 'white'
color - Foreground ChunkyPNG::Color, defaults to 'black'

When option :file is supplied you can use the following ChunkyPNG constraints:

color_mode  - The color mode to use. Use one of the ChunkyPNG::COLOR_* constants.
              (defaults to 'ChunkyPNG::COLOR_GRAYSCALE')
bit_depth   - The bit depth to use. This option is only used for indexed images.
              (defaults to 1 bit)
interlace   - Whether to use interlacing (true or false).
              (defaults to ChunkyPNG default)
compression - The compression level for Zlib. This can be a value between 0 and 9, or a
              Zlib constant like Zlib::BEST_COMPRESSION
              (defaults to ChunkyPNG default)

There are two sizing algorithms.

* Original that can result in blurry and hard to scan images
* Google's Chart API inspired sizing that resizes the module size to fit within the given image size.

The Google one will be used when no options are given or when the new size option is used.

*Google Sizing*

size            - Total size of PNG in pixels. The module size is calculated so it fits.
                  (defaults to 120)
border_modules  - Width of white border around the modules.
                  (defaults to 4).


*Original Sizing*

module_px_size  - Image size, in pixels.
border          - Border thickness, in pixels

It first creates an image where 1px = 1 module, then resizes.
Defaults to 120x120 pixels, customizable by option.


require 'rqrcode'

qrcode = RQRCode::QRCode.new("http://github.com/")

# NOTE: showing with default options specified explicitly
png = qrcode.as_png(
  bit_depth: 1,
  border_modules: 4,
  color_mode: ChunkyPNG::COLOR_GRAYSCALE,
  color: 'black',
  file: nil,
  fill: 'white',
  module_px_size: 6,
  resize_exactly_to: false,
  resize_gte_to: false,
  size: 120

IO.binwrite("/tmp/github-qrcode.png", png.to_s)

[QR code with github url](./images/github-qrcode.png)


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


light           - Foreground ANSI code
                  (default "\033[47m")
dark            - Background ANSI code
                  (default "\033[40m")
fill_character  - The written character
                  (default '  ')
quiet_zone_size - Padding around the edge
                  (default 4)


require 'rqrcode'

qrcode = RQRCode::QRCode.new("http://github.com/")

# NOTE: showing 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](./images/ansi-screen-shot.png)

API Documentation



You can run the test suite using:

$ ./bin/setup
$ rake      # runs specs and standard:fix
$ rake spec # just runs the specs

or try the lib from the console with:

$ ./bin/console


The project uses standardrb and can be used with:

$ ./bin/setup
$ rake standard # checks
$ rake standard:fix # fixes


The current plan moving forward is to move as_png, as_css, as_svg, as_ansi etc into their own gems so they can be managed independently -- ideally -- by people who are interested in maintaining a specific render type. This will leave me to look after rqrcode_core gem which I do have time for.

So for example if you only required a png rendering of a QR Code, you could simply use the gem rqrcode_png. This would eventually mean that the rqrcode gem will just become a bucket that pulls in all the existing renderings only and would have deprecated usage over time.

So, the motivation behind all this change is because the rendering side of this gem takes up the most time. It seems that many people want a slightly different version of a QR Code so supporting all the variations would be hard. The easiest way is to empower people to create their own versions which they can manage and share.

The work won't impact any current users of this gem. What this does mean though is that any contribution PR's should only be bug fixes rather than new functionality. Thanks D.

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


Original RQRCode author: Duncan Robertson

A massive thanks to all the contributors of the library over the years. It wouldn't exist if it wasn't for you all.

Oh, and thanks to my bosses at https://kyan.com for giving me time to maintain this project.



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

*Note that all licence references and agreements mentioned in the QR-code README section above are relevant to that project's source code only.