Multi-touch on the desktop

Craig Hockenberry wrote thought-provokingly about multi-touch interfaces on the desktop (via Gus Mueller).

This is a favorite topic of mine; as I've written before, I look forward to the day when multi-touch comes to desktop (or portable) computers.

One of his objections was the vertical orientation of traditional displays:

If you’re one of the people who think that a multi-touch monitor is a good idea, try this little experiment: touch the top and bottom of your display repeatedly for five minutes. Unless you’re able to beat the governor of California in an arm wrestling match, you’ll give up well before that time limit. Now can you imagine using an interface like this for an eight hour work day?

But he quickly counters that objection with what I feel is the obvious answer: a touch-based interface needs to be at a comfortable angle. I envision a desktop multi-touch surface at a 30-degree angle, or less, from the desktop: as he says, like a classic drafting table. Perhaps there won't be a distinction between desktop and notebook computers anymore, or perhaps the computer will be in two parts: a tablet-like mobile portion, which docks into and rests on a wedge-like stand on your desk, which adds additional functionality (kinda like the old PowerBook Duo and DuoDock).

The multi-touch screen would be the entire interface (other than perhaps some auxiliary buttons like brightness, volume, etc). It would obviously replace the mouse/trackpad, but would also replace the keyboard, using an onscreen keyboard instead. Yes, tactile feedback is an issue, but as many people have reported with their iPhones, it's possible to get used to typing without it; and there are ways to provide feedback, like the iPhone's magnified view of pressed keys, sounds, vibrations, and other ideas being worked on.

Hockenberry also raises a valid point regarding the precision of a mouse pointer vs a finger:

But even if there was a solution to the ergonomic issues, there would be problems mixing mouse-based applications (with small hit areas) with touch-based inputs (and large hit areas). Touch-based UI is not something you just bolt onto existing applications—it’s something that has to be designed in from the start.

Certainly an important consideration. However I would argue that most applications could be modified to support larger hit areas in sensible ways without too much difficulty - though in some cases major redesigns would be needed. Just have a look around the controls in your favorite apps, and think about how easy it would be to "click" on one with a finger, without activating a nearby control. In most cases, controls are spaced out enough for it to not be a problem, but some, like Photoshop, would require either optional support for a stylus (which Apple probably wouldn't be in favor of), or a finer on-screen control (perhaps like the iPhone's magnifying glass). I'm sure apps designed from the ground up with multi-touch in mind would be better... but migration is certainly possible. And yes, resolution independence should help. If you've got big fingers, you just scale everything up to a comfortable level.

I really believe that multi-touch is the way of the future, and will be coming for Macs in due course. But Apple being Apple, they will do it right, with as smooth a migration path for developers and users as possible.