984794 - Tune and enable axis-locking on B2G

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[Chris Lord [:cwiiis]]

It would appear the APZC has no axis lock, making it very hard to scroll vertically when a page has horizontal scrolling (for example, after you've zoomed in slightly).

I think we should mimic the Android JPZC behaviour here.

Comment 1

[Botond Ballo [:botond]]

We have axis locking implemented (bug 892684), but it's off by default. It can be turned on using the "apz.axis_lock_mode" preference (see http://dxr.mozilla.org/mozilla-central/source/modules/libpref/src/init/all.js?from=all.js#324).

Comment 2

[Chris Lord [:cwiiis]]

(In reply to Botond Ballo [:botond] from comment #1)
> We have axis locking implemented (bug 892684), but it's off by default. It
> can be turned on using the "apz.axis_lock_mode" preference (see
> http://dxr.mozilla.org/mozilla-central/source/modules/libpref/src/init/all.
> js?from=all.js#324).

Well that's an interesting choice. I guess we can use this bug to track turning it on?

Comment 3

[Botond Ballo [:botond]]

(In reply to Chris Lord [:cwiiis] from comment #2)
> (In reply to Botond Ballo [:botond] from comment #1)
> > We have axis locking implemented (bug 892684), but it's off by default. It
> > can be turned on using the "apz.axis_lock_mode" preference (see
> > http://dxr.mozilla.org/mozilla-central/source/modules/libpref/src/init/all.
> > js?from=all.js#324).
> 
> Well that's an interesting choice. 

Kats said in https://bugzilla.mozilla.org/show_bug.cgi?id=892684#c11 that "with axis locking turned on it's pretty hard to do a pan that's not axis-locked, so that might need some tuning but we can do that if/when we turn it on on B2G by default." I'm not sure whether there is anything besides that tuning holding this up from being turned on by default.

> I guess we can use this bug to track turning it on?

Sure.

Comment 4

[Matt Brubeck (:mbrubeck)]

Using the "sticky" mode (apzc.axis_lock_mode = 2) helps avoid problems caused by unintended locking.  This is the mode we used in Firefox for Metro.

Comment 5

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

Attachment: Switch to sticky axis locking

Comment 6

[Chris Lord [:cwiiis]]

Comment on attachment 8397970 [details] [diff] [review]
Switch to sticky axis locking

Review of attachment 8397970 [details] [diff] [review]:
-----------------------------------------------------------------

LGTM, do we want to uplift this to Aurora too?

Comment 7

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

Maybe. Let's let it bake a bit on m-c first.

Comment 8

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/2fbe01ee3955

Comment 9

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/2fbe01ee3955

Comment 10

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

Comment on attachment 8397970 [details] [diff] [review]
Switch to sticky axis locking

[Approval Request Comment]
Bug caused by (feature/regressing bug #): none
User impact if declined: very easy to scroll on the secondary axis even when not desired. this also results in more painting which is bad for performance
Testing completed (on m-c, etc.): on m-c
Risk to taking this patch (and alternatives if risky): low risk, affects b2g only.
String or IDL/UUID changes made by this patch: none

Comment 11

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

https://hg.mozilla.org/releases/mozilla-aurora/rev/9d9ead7d6afa