el-qrencode 1.0-alpha

This is a QR code generator for Emacs, written in Emacs Lisp. It's a CommonLISP-to-EmacsLISP port of the cl-qrencode package by jnjcc, see Copyright and License at bottom for more details.

Please consider this EmacsLISP version as an alpha-quality hobby project: future version may add, rename or remove functions.

If you like it and have bugfixes or enhancements to contribute, please do! Patches and forks are more than welcome, please read also the Proposed/Needed Future Enhancements section below.

Usage example

In the following the Emacs keyboard notation will be used: for example RET means press Return, M-x means press Alt+x, C-x means press Ctrl+x. For further details see the Emacs manual, section User Input.

Here's a basic usage example:

• start Emacs
• M-x cd RET <qrencode directory here> RET
• M-x load-file RET load.el RET
• put the cursor in an empty buffer (like *scratch*) and type some example text like hello qrencode!.
• mark the hello qrencode! with the mouse and type M-x qrencode-region RET: a QRcode has been generated in results buffer *qrcode* using ASCII characters
• view the results buffer by typing C-x b *qrcode*, maybe use zoom-out (C-x C-+) to make it fit in your window

Configuration

You may tweak the (defvar ...) statements at top of emacs-commands.el. Most variables are rather self-explanatory, except the ones used for ASCII representation of the single black/white QR cell.

Every cell is qrencode-hzoom characters large and qrencode-vzoom characters tall. I've set a default of qrencode-hzoom=2 because my default fonts are rather tall.

Dependencies

I tried to keep them to the bare minimum. You need to have at least the cl package. It works properly on Emacs 24.4, it's untested on other versions.

Proposed/Needed Future Enhancements

• better documentation of both the private and interactive functions
• code refactoring: decorate private functions and classes with the qrencode-- prefix
• code refactoring: remove recursive functions (they forced me to tweak max-specpdl-size and max-lisp-eval-depth in load.el)
• code refactoring: turn this into an Emacs package, so it might work with M-x list-packages RET and Emacs repositories (maybe Melpa or Marmalade)
• enhancement: generate an image containing the QR code; start with XPM format (built-in support in Emacs), add other formats if possible and not too hard (SVG?)
• enhancement: build a separate module for Org mode that turns a timestamped Org task into a QRcode calendar event
• (other suggestions welcome)

Copyright and License

Original Common Lisp version: Copyright (c) 2011-2014 jnjcc, Yste.org

Port to Emacs Lisp: Copyright (c) 2015 Andrea Rossetti (http://andrear.altervista.org)

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. Refer to the COPYING file in this same directory.