This weekend I made a thing called Portra. Take a photo, apply a filter, post to Twitter. It’s certainly been done before, but Portra is a proof-of-concept that combines iOS 6’s file uploads, HTML5 canvas and Twitter oAuth to do it in a web app. It’s being hosted on Heroku so you can try it out, and the code is up on GitHub.

It’s really only designed to run on iPod touches or iPhones with iOS 6 (obviously). Anything else will get redirected to an about page. There’s probably some bugs, I’m okay with that.


  • Canvas on mobile devices is really slow, always test directly on one.
  • Image orientation for photos directly from the camera is stored in metadata (i.e. the image probably isn’t right-side-up, mimicking the behaviour in Cocoa) so you need to handle this. I’ve done this, so take the code and run. There’s also a quick demo in a jsFiddle.
  • Weekend projects are fun.