1287185 - Disable paint-skipping for elements with background-attachment:local

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

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

This is similar to bug 1284586, but for background-attachment:local. Again, APZ doesn't properly handle background-attachment:local and with paint-skipping enabled the visual effect can get very laggy. With paint-skipping turned off on these elements it's much better. Bug 1267656 tracks fixing this properly, by implementing support for background-attachment:local that works with async scrolling.

Comment 1

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

Attachment: Bug 1287185 - Disable paint skipping for scrollframes with background-attachment:local.

Review commit: https://reviewboard.mozilla.org/r/64644/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/64644/

Comment 2

[Markus Stange [:mstange]]

Comment on attachment 8771516 [details]
Bug 1287185 - Disable paint skipping for scrollframes with background-attachment:local.

https://reviewboard.mozilla.org/r/64644/#review61694

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1a50ebf3ebab
Disable paint skipping for scrollframes with background-attachment:local. r=mstange

Comment 4

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/1a50ebf3ebab

Comment 5

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

Comment on attachment 8771516 [details]
Bug 1287185 - Disable paint skipping for scrollframes with background-attachment:local.

Approval Request Comment
[Feature/regressing bug #]: APZ
[User impact if declined]: Pages with background-attachment:local have the background visibly lag when the scrollframe is scrolled. The URL in the bug URL field has an example. This is similar to the fix we did in bug 1284586, disabling APZ in specific cases to make the behaviour less bad
[Describe test coverage new/current, TreeHerder]: tested locally
[Risks and why]: low risk, it's a pretty small patch
[String/UUID change made/needed]: none

Comment 6

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

(Note also that bug 1267656 tracks fixing this properly)

Comment 7

[Gerry Chang [:gchang]]

Hi Kartikaya,
May I know when/how the bug is introduced?

Comment 8

[Sylvestre Ledru [:Sylvestre]]

Comment on attachment 8771516 [details]
Bug 1287185 - Disable paint skipping for scrollframes with background-attachment:local.

Too late in the 48 cycle.

Comment 9

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

(In reply to Gerry Chang [:gchang] from comment #7)
> Hi Kartikaya,
> May I know when/how the bug is introduced?

The bug was introduced by turning on APZ, which doesn't properly support background-attachment:local. It was made worse by enabling paint-skipping in bug 1253860 and bug 1257641. This patch turns off paint-skipping for these scrollframes and improves the situation considerably.

Comment 10

[Gerry Chang [:gchang]]

Comment on attachment 8771516 [details]
Bug 1287185 - Disable paint skipping for scrollframes with background-attachment:local.

As mentioned in comment #9, this patch turns off paint-skipping can improve the situation considerably. Take it in 49 aurora.

Comment 11

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/68f7a96e9277