1432021 - Improve scrolling by not firing scroll linked image reveals during scrolling, like Chromium seems to

Status: RESOLVED WORKSFORME

(Firefox for Android Graveyard :: General, enhancement, P3)

Description

[Mark]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_2) AppleWebKit/604.4.7 (KHTML, like Gecko) Version/11.0.2 Safari/604.4.7

Steps to reproduce:

When scrolling on some sites e.g. www.bikeradar.com, scrolling Firefox Android can become janky. I think it's because scroll-linked JavaScript images pop in during scrolling.

Chromium seems to NOT fire some classes of image pop ins during scrolling. It waits until scrolling stops.

I can see the difference on www.bikeradar.com:

- on Firefox Android as I scroll, the images pop in during the scroll leading to some jank

- on Chrome for Android it just shows a gray image placeholder until the scroll stops, then the images pop in.

It makes for a nicer scrolling experience on Chromium. Albeit I can't see the images til I stop scrolling!!

Comment 1

[James Willcox (:snorp) ([e-mail]) (he/him)]

Kats, what do you think?

Comment 2

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

Personally I'd prefer if we just did things fast enough that we didn't jank. I haven't tried loading these pages but profiling the jank would be a good first step. If it turns out it's something that's hard to fix we can consider mitigation strategies like what is suggested in comment 0. But even that seems like it wouldn't be easy to do. We'd have to schedule time for it and given our focus on WebRender right now it likely won't get done in the near/middle future.

Comment 3

[Mark]

I think I resolved my issue with www.bikeradar.com. The site seems to require some third party scripts to scroll smoothly. Both uBlock Origin and Firefox's Tracking Protection block those scripts which means I can't tap to move through some image sequences and the vertical flings get choppy. I allowed third party scripts in uBO and now the tap to move works and the scrolling seems much better. 

Same script blockage problem occurs on Desktop & on Safari desktop so I think it's a site issue not a Firefox issue. 

Not sure why it would cause choppy scrolling but happy to have it fixed.

Thanks for your time.

Comment 4

[Bogdan Surd, QA [:bsurd, NI]]

Thank's for your response Mark, based on Comment 3 I am closing this issue as a WORKSFORME since it seems to not be related to FF.