1651149 - 2 finger touchpad scrolling stops working with desktop zooming

Status: RESOLVED INVALID

(Core :: Panning and Zooming, defect, P3)

Description

[Kris Taeleman (:ktaeleman)]

Unknown repro steps

Sometimes 2 finger scrolling stops working. After pinch zooming in/out scrolling starts working again.

Comment 1

[Timothy Nikkel (:tnikkel)]

I wonder if the direct manipulation state machine is getting confused?

I can try adding some logging using moz_log for that, or you could try setting the direct manip pref to false again and see if it happens. Although that will of course disable pinch zooming on your touchpad.

Comment 2

[Kris Taeleman (:ktaeleman)]

I haven't seen it happen again in the last couple of days. I'll let you know if I see it again.
If I see it again I can attach the debugger and check some states if you point me to some potential spots this could go wrong.

Comment 3

[Timothy Nikkel (:tnikkel)]

When you start a two finger pan this is the sequence I would expect:

1. A call to DManipEventHandler::OnViewportStatusChanged with the direct manipulation status as DIRECTMANIPULATION_RUNNING

2. A call to DManipEventHandler::OnContentUpdated with a new xoffset and yoffset so that we call TransitionToState(State::ePanning), and then hit the mShouldSendPanStart case and call SendPan(Phase::eStart...)

3. A call to DManipEventHandler::TransitionToState to be called to move us from mState == eNone to ePanning.

4. Further calls to DManipEventHandler::OnContentUpdated that call SendPan in the !mShouldSendPanStart case

5. DManipEventHandler::OnViewportStatusChanged with status DIRECTMANIPULATION_INERTIA

6. DManipEventHandler::OnViewportStatusChanged with status DIRECTMANIPULATION_READY

Comment 4

[Kris Taeleman (:ktaeleman)]

Can't reproduce this anymore and only saw this once.