1014997 - [Vertical Homescreen] Bouncing continues after tapping the home button while flywheel scrolling

Status: VERIFIED FIXED

(Core :: Panning and Zooming, defect)

Description

[Johan Lorenzo [:jlorenzo]]

Build Information
Gaia      ef66efa34ed8a559c8998bde688fae88eb943a7a
Gecko     https://hg.mozilla.org/mozilla-central/rev/b40296602083
BuildID   20140522040230
Version   32.0a1
ro.build.version.incremental=94
ro.build.date=Tue May 20 09:29:20 CST 2014

Step to reproduce
With 3 column layout with more than 30 icons (eng build for instance), flick down twice to start flywheel scrolling
Immediately (before the end of scrolling), hit the home button
Let the homescreen finish the animation

Actual result
After tapping the home button, the vertical position is not set to the top because of the animation

Expected result
Tapping the home button should bring you to the top

Comment 1

[Cristian Rodriguez (:crdlc)]

I don't have idea how to stop the inertia of the scroll that is being performed. Any idea mates?

Comment 2

[Kevin Grandon :kgrandon]

The root cause of this is actually because we do not yet have the CSSOM smooth scrolling spec implemented yet (bug filed but that will not make 2.0).

In the meantime, we might be able to try to either delay the home button until after a scroll, or remove the animation all together. Even if we delay I feel it might still not be perfect though - racing APZ in client Js is never a good option :-/

Comment 3

[Vivien Nicolas (:vingtetun) (:21) - (NOT reading bugmails, needinfo? please)]

(In reply to Kevin Grandon :kgrandon from comment #2)
> The root cause of this is actually because we do not yet have the CSSOM
> smooth scrolling spec implemented yet (bug filed but that will not make 2.0).
> 
> In the meantime, we might be able to try to either delay the home button
> until after a scroll, or remove the animation all together. Even if we delay
> I feel it might still not be perfect though - racing APZ in client Js is
> never a good option :-/

Delaying seems painful. The CSSOM bits will solve that but the core issue is that setting scrollLeft/scrollTop from JS should just stop any APZ inertia. Which is a separate issue.

My understanding is that this should work with/without CSSOM smooth scrolling thing.

Kats, any opinion ?

Comment 4

[Kevin Grandon :kgrandon]

I suppose that could be an option, but ideally we would use an API to scroll to the top of the page, not manual scrollTop setting.

Comment 5

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

(In reply to Vivien Nicolas (:vingtetun) (:21) (NOT reading bugmails, needinfo? please) from comment #3)
> Delaying seems painful. The CSSOM bits will solve that but the core issue is
> that setting scrollLeft/scrollTop from JS should just stop any APZ inertia.
> Which is a separate issue.

As far as I know setting scrollLeft/scrollTop should abort APZ inertia. Is this not happening? If it isn't happening it's a bug.

Comment 6

[Cristian Rodriguez (:crdlc)]

Basically this is the algorithm:

https://github.com/mozilla-b2g/gaia/blob/master/dev_apps/home2/js/app.js#L73

and according to code we are using window.scrollBy(). Should it stop the inertia?

Thanks a lot

Comment 7

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

Yes, scrollTo, scrollBy, scrollLeft, scrollTop - all of them should abort the APZ inertia. If this bug is only about that issue then feel free to move it to Core::Panning & Zooming and I can take a look. If this bug includes other issues then please file a separate bug for this problem.

Comment 8

[Cristian Rodriguez (:crdlc)]

Done Kats. This bug does not include anything more, thanks a lot

Comment 9

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

Attachment: Patch

Pretty simple fix.

Comment 10

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/b81828b2dc18

Comment 11

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/b81828b2dc18

Comment 12

[Kevin Grandon :kgrandon]

Mass modify - set status-b2g-v2.0 fixed for fixed bugs under vertical homescreen dependency tree.

Comment 13

[Johan Lorenzo [:jlorenzo]]

https://moztrap.mozilla.org/manage/case/13745/