Multi-touch test activity

Bert Freudenberg bert at
Sun Nov 4 17:48:31 EST 2012

Hi folks,

I made a simple Sugar activity to test the XO-4's multi-touch screen:

It works fine most of the time. Sometimes the touch contact ends unexpectedly without lifting the finger.

It also demonstrates that the Neonode sensor's two touch points are not independent: If you put down two fingers simultaneously, it does not know in which of the 4 possible positions the two fingers are (it only knows that 2 horizontal and 2 vertical beams got obstructed) and so it has to guess. Also, the tracking sometimes "switches over", e.g. when doing a pinch-zoom using your right hand.

For activity developers this means that pinch/zoom and rotation gestures will work fine, but we cannot rely on truly independent touch tracking.

Also, two-finger sweeps are not always recognized as two fingers if they are held close together.

Nonetheless, it is fun to play with if you happen to have an XO-4 Touch :)

Source code:

Patches welcome, but I want to keep the source simple, this is not going to become another Paint activity.

- Bert -

PS: Could some admin please delete the accidental non-mainline repo in ? Keep "mainline", remove "testmultitouch". Thanks.

More information about the Devel mailing list