QR Imager Library

This is a library to generate .png files from QR codes.

Dependencies

The library depends on the C library [https://github.com/fukuchi/libqrencode](libqrencode) which you will need to install separately, as well as the C library Zbar from here. You should also be able to get them from your distro.

Usage

The library exports three main functions - createQRCode, readQRString, and byteStringToQR - and their secured/signed versions. The first takes any object that is an instance of ToJSON and writes an image to file, while the second takes filepath pointing to an image and returns the text in the QR code. The third takes a (strict) bytestring and writes it to file.

Executable

Installation

For building haskell, the best tool is currently [http://haskellstack.org](stack). Install it, and then type

stack install --install-ghc

in the appropriate directory, and it will be installed to your path.

Use

Compiling will generate an executable called qrpipe which reads from stdin and outputs a file as the second argument, e.g.

echo 'My name is: Vanessa" | qrpipe write -v "nametag.png"

To then read the nametag:

qrpipe read "nametag.png"

Library

The library can be used via the exported functions createQRCode, byteStringToQR and readQRString, plus their signed counterparts.