>From the attachment you can see that mir giving a bogus event stream.
When you lay two fingers on the screen at roughly the same time (like when 
doing a pinch gesture) it's common for mir to not generate or send the "down" 
event for the first touch point.

qtmir has a basic event stream sanity check and validation. It detects
this problem and transforms the action=change for the first touch event
with id=0 into a action=down instead. But then we end up with an input
event with *two* pressed touch points, which at least makes sense but I
think Qt does not like that. It probably expects a single touch up/down
per event, like android. I could make qtmir's event stream validator
more sophisticated and have it split those two touch down actions into
two separate input events, but mir should really send us a clean event
stream in the first place.

** Attachment added: "Typical qtmir log output on an unsuccessful pinch gesture"
   
https://bugs.launchpad.net/ubuntu/+source/qtmir/+bug/1531517/+attachment/4545169/+files/qtmir-mir-input.log

** Also affects: mir (Ubuntu)
   Importance: Undecided
       Status: New

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/1531517

Title:
  pinch to zoom not working reliably

To manage notifications about this bug go to:
https://bugs.launchpad.net/canonical-devices-system-image/+bug/1531517/+subscriptions

-- 
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to