I just made Inkpad, my vector drawing app for the iPad, free software. I'm releasing it under the Mozilla Public License, v2.0. It requires iOS 7 and is currently "in review" at Apple.<p>I've spent the last few weeks updating it for iOS 7 and cleaning up the code for public release. There's a lot of code, however, so I'm sure there are still many untidy bits.<p>If you'd like to contribute, I'd appreciate bug fixes, new features, and localizations for your language of choice. Otherwise, I hope you can learn something from it, or find bits and pieces that are useful in your own apps.
I just want to say how much I love Inkpad. I am a heavy Illustrator user and Inkpad was super-easy to pick up and just start using without any prior experience or instruction. The multiple finger gestures are intuitive and the 'outline stroke' and pathfinder features are something I rely on heavily and are not common in vector-based iOS apps. I'm looking forward to reading some of your code!