how does hildon detect if a tap is from the finger or stylus? eg: the left app menu is
large if tapped with whole thumb vs fingernail.

Is there some way to detect amount of surface area being pressed?

Something I've wondered too - whether you could poll various areas of the touchscreen at will.

In that case it'd be simple to check multiple touch, or surface area touch.

Anyone out there know more about this?

download maemopad+ and use your finger on the screen, then use a stylus.

You'll see the difference.

Can't instakl it, download keeps failing om app man and maemo.org, server must be down :/

i believe it has to do with the pressure area. the stylus is a small confined contact/pressure zone. with your finger, the pressure/contact zone is much greater.

by determining the area of contact, you can set the logic around which menu to show.

The question is - can you poll specific areas of the touchscreen at will?

i.e. I sense touch at X1, Y1 - I can query X2, Y2 and X3, Y3 locations and henceforth determine the larger area for myself.

If you can do this then multitouch would be a non-issue. Just divvy up the screen into quadrants and hone into the locations of said contacts.

Without knowing anything - my guess is the touchscreen hardware itself does this and reports back to the OS whether a larger or small area was touched. You won't programmatically have the ability to poll multiple areas of the screen to determine area/multiple touch.