1142286 - Touch event screenY value gets stuck when moving finger vertically

Status: RESOLVED INCOMPLETE

(Firefox for Android Graveyard :: Toolbar, defect)

Description

[:Margaret Leibovic]

Here's a testcase:
http://people.mozilla.org/~mleibovic/test/touchmove_test.html

It seems like this issue is caused by the dynamic toolbar.

I'm trying to track the vertical difference in a user's finger position while the page scrolls, and this issue seems to make that impossible :(

Comment 1

[Kartikaya Gupta (email:[e-mail])]

I don't think this is related to the dynamic toolbar. My hypothesis (unverified) is this is a result of async scrolling. Say you're moving your finger such that the page is scrolling. For a while the page will track your finger completely with async scroll. During this time we'll be sending touch events to content, but the screenY will be computed using a stale scroll offset (because gecko hasn't been updated with the new scroll position). And so the screenY might be wrong. After a repaint the screenY will snap to the right value. If you're at the edge of the page and pushing in the direction of overscroll, then the screenY value should be correct because the page isn't actually moving.

Not sure what the right fix here is.

Comment 2

[BMO Automation]

We have completed our launch of our new Firefox on Android. The development of the new versions use GitHub for issue tracking. If the bug report still reproduces in a current version of [Firefox on Android nightly](https://play.google.com/store/apps/details?id=org.mozilla.fenix) an issue can be reported at the [Fenix GitHub project](https://github.com/mozilla-mobile/fenix/). If you want to discuss your report please use [Mozilla's chat](https://wiki.mozilla.org/Matrix#Connect_to_Matrix) server https://chat.mozilla.org and join the [#fenix](https://chat.mozilla.org/#/room/#fenix:mozilla.org) channel.