Re: touch events

[Peter Hutterer <peter hutterer who-t net>]

On Thu, Feb 09, 2012 at 12:06:01AM +0100, Jernej Simončič wrote:
> On Thu, 9 Feb 2012 08:31:42 +1000, Peter Hutterer wrote:
> 
> > note that depending on how recent your laptop is, it may support multitouch.
> > I've got a x220t and the touchpad in it works fine*.
> 
> From what I can see, multitouch is pretty much a driver feature. At least
> on Windows if you install a recent Synaptics driver, the laptop gains
> multitouch support (I verified this on several older laptops, eg. my own
> Acer TravelMate 4272WLMi bought in 2006).

for touchpads, there is no single definition of multitouch, largely blurred
by the driver features. Taken the xf86-input-synaptics driver for example,
we have some multitouch features like two-finger-scrolling that work on
devices that are decidedly single-touch only. We just take the width of the
finger and if it exceeds a threshold we assume that it's a two-finger
interaction. Even though the hardware can't detect two fingers.

Newer touchpads will actually tell you the position of each finger
separately, allowing for more complex gestures. The x220 has one of these,
and having this fine-grained detail obviously allows for more complex
interaction than other guesswork.
Having said that, I don't know how far back "newer touchpads" go, it
certainly isn't just the last round, these touchpads have been around for a
bit now.

Cheers,
  Peter