1705927 - Do not go into overscroll if prefers-reduced-motion is specified

Status: VERIFIED FIXED

(Core :: Panning and Zooming, enhancement)

Description

[MarjaE]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:87.0) Gecko/20100101 Firefox/87.0

Steps to reproduce:

Just saw video of new overscroll animations.

Actual results:

Got migraine, pain, nausea.

Expected results:

If prefers-reduced-motion is true, then Firefox should not use the new overscroll ui animations.

related to bug 1478597

bug 1605234

I have not been able to test with Nightly, with prefers-reduced-motion true and false, to compare the behavior.

This is something to check rather than a known defect or an enhancement.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Panning and Zooming' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 2

[Timothy Nikkel (:tnikkel)]

If my testing is correct then this is something that needs to be fixed. overscroll was still active when I set ui.prefersReducedMotion=true

Comment 3

[Botond Ballo [:botond]]

Thanks for the report. This is something we should fix before the release.

Comment 4

[Botond Ballo [:botond]]

Attachment: Bug 1705927 - Make GenericOverscrollEffect a no-op if prefers-reduced-motion is set. r=hiro

Comment 5

[Botond Ballo [:botond]]

Attachment: Bug 1705927 - Fix an include-what-you-use error in GeckoBindings.h. r=hiro

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/30af8f80e275
Make GenericOverscrollEffect a no-op if prefers-reduced-motion is set. r=hiro

Comment 7

[Iulian Moraru]

Backout changeset for causing failures at test_group_hittest-2.html.

Push with failures

Failure log

Backout link

Comment 8

[Hiroyuki Ikezoe (:hiro)]

Looks like the platform in question has set the prefers-reduced-motion pref by default.

Comment 9

[Pulsebot]

Backout by [e-mail]:
https://hg.mozilla.org/mozilla-central/rev/083f2a8fe4c5
Backed out changeset 30af8f80e275 for causing failures at test_group_hittest-2.html. a=backout

Comment 10

[Botond Ballo [:botond]]

(In reply to Hiroyuki Ikezoe (:hiro) from comment #8)

Looks like the platform in question has set the prefers-reduced-motion pref by default.

Thanks. It looks like the pref "ui.prefersReducedMotion" takes precedence over any system-level setting, so setting it to 0 in the test fixes the failure.

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1ea07fbb411c
Make GenericOverscrollEffect a no-op if prefers-reduced-motion is set. r=hiro

Comment 12

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/1ea07fbb411c

Comment 13

[Andrei Purice]

Verified fixed on the latest version of Nightly 90.0a1 (2021-04-21) (20210421095627) on MacOS 11.2.3 (MacBook Pro) and Mac Mini M1 11.0.1.
When the system option "reduce motion" is checked the overscroll effect is disabled.

Comment 14

[Botond Ballo [:botond]]

Comment on attachment 9216918 [details]
Bug 1705927 - Make GenericOverscrollEffect a no-op if prefers-reduced-motion is set. r=hiro

Beta/Release Uplift Approval Request

• User impact if declined: Overscroll effect would be shown even if prefers-reduced-motion is specified, causing avoidable motion

Required for MR1 / Proton

• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: Bug 1705826
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Patch is small and only affects rendering when the page is overscrolled and prefers-reduced-motion is specified
• String changes made/needed:

Comment 15

[Pascal Chevrel:pascalc]

Comment on attachment 9216918 [details]
Bug 1705927 - Make GenericOverscrollEffect a no-op if prefers-reduced-motion is set. r=hiro

Approved for 89 beta 3, thanks.

Comment 16

[Pascal Chevrel:pascalc]

https://hg.mozilla.org/releases/mozilla-beta/rev/a00f784cdf5d

Comment 17

[Andrei Purice]

Verified fixed on Beta 98.0b3 (20210422190146) on MacOS 11.2.3.

Comment 18

[Ethan]

Question, is this the official desired behaviour from Mozilla? It seems to be unique to Firefox — Safari, Chrome and Edge all still have overscrolling enabled when reduced motion is turned on in System Preferences on MacOS.

Comment 19

[MarjaE]

I really doubt I'm the only one to get migraines from overscroll, or any of the other common animations.

Comment 20

[Botond Ballo [:botond]]

(In reply to Ethan from comment #18)

Question, is this the official desired behaviour from Mozilla?

I think the overscroll animation is a good example of the sort of "non-essential motion" that prefers-reduced-motion is intended to avoid.

It seems to be unique to Firefox — Safari, Chrome and Edge all still have overscrolling enabled when reduced motion is turned on in System Preferences on MacOS.

My guess is that's likely an oversight.

If it turns out not to be an oversight -- for example, if someone files an issue similar to this one in one of these other browsers' issue trackers, and it gets closed as "wontfix" with a reason given -- please feel free to mention that reason here, and we can discuss it further.