QR Code generator in clojure/clojurescript that outputs to HTML5 canvas.
Check it out at http://nherzing.github.io/qrcloj/.
Supports numeric, alphanumeric, and byte encoding for all versions (1-40) and error correction levels. Currently no Kanji support.
It takes quite a long time. 99% of that time is spent figuring out which mask to use. Maybe I'll get around to figuring out why that is.