Shameless plug, but I coded up http://www.crimesagainstcode.com a little while back as a learning exercise that lets you manipulate QR code pixels like this. No logo image injection but you can "draw" whatever you want
As long as you keep it within the error correction you can do whatever you want.
(it's admittedly not very robust, I have a lot more ideas for it, but my time is scarce and my site metrics haven't really shown there's enough interest to put a bunch of time into it -- feedback is welcome though).
Do you have Github for this project? I'm interested in building my own QrCode encoder in JavaScript, what resources do you recommend to get me started?
The RQRCode gem does all of the QR Code generation magic. I manipulate all the code with some CoffeeScript and jQuery. RQRCode itself is a port of a JavaScript library: http://www.d-project.com/qrcode/
I've written some stuff locally that'll render the QR Code into canvas and provide a download link using a dataURI but it's fundamentally different than the table/css manipulations I'm doing right now...and well, I have an infant at home, so the site's being neglected ;) PM me on github if you want that chunk.
(it's admittedly not very robust, I have a lot more ideas for it, but my time is scarce and my site metrics haven't really shown there's enough interest to put a bunch of time into it -- feedback is welcome though).