Matt Gemmell

TOLL is available now!

An action-thriller novel — book 2 in the KESTREL series.

★★★★★ — Amazon

iPad Multi-Touch

development, interface & source 1 min read

A friend of mine recently asked how many simultaneous touch events the iPad supported; I wasn’t sure, so I promised to write some code to conduct an experiment and find the answer. I got around to doing so, and the answer is: eleven.

I’m sure you can imagine the response from certain colleagues regarding that number (not just “this one goes up to eleven”, but also “ten fingers and a…”, well, quite.) I thought you might want to see it in action, or play with it yourself. There’s a screenshot below:

iPad multi-touch test screenshot

Colourful touches galore (click for a bigger version).

You can also see a video on YouTube, which is embedded below. Please note that the videos show only ten touches, but I previously established (with Lauren’s help) that the iPad supports exactly 11. You can reproduce the result yourself using ten fingers and the pads of your thumbs, or lowest knuckle-joints of your index fingers, or your nose and chin (or just ask a friend, which will look less odd).


And here’s a video showing the new touch animations. It’s just not sci-fi until you have Spinning Arrows From Space:


And finally, of course, you can get the source code from my github repository (requires iPhone SDK 3.2, etc). Trivial but fun!

I’ll hopefully be posting a few more experiments in coming weeks/months, so feel free to follow me on Twitter to stay up to date. I will also whorishly link you to my Amazon wishlist if you’re feeling grateful.

(Footnote: We went to see Iron Man 2 the other night, and the touch-tracking appearance was definitely loosely inspired by all of Tony Stark’s nifty holographic computer UI toys.)