QR scanner

Ruby Gem which wraps ZXing QR decoder library (C++) and ImageMagick



First, gem install 'qrscanner'. This also provides you with a command-line tool (“qrscanner”) for testing.

require 'qrscanner'

QrScanner.decode '/path/to/hellworld.png'
=> "Hello, world"

The parameter accepts any image format that ImageMagick supports, which should include PDF for scanned documents as well as PNG/JPG/TIFF/etc.

Returns nil if it can't find a qr code or other error. It currently prints the error to STDERR.


  • Python (for ZXing build script)

  • ImageMagick: libMagick++, libMagickWand, libMagickCore

  • gcc, g++, libstd++

  • Operating system with a PREFIX of “/usr”.

This last one means it really only works on Linux eg. Ubuntu, and not OSX or BSD, because the ZXing CPP build script has hard coded paths for include files etc. :-(

Contact the author

Andrew Snow <andrew@modulus.org> Andys^ on irc.freenode.net