1731138 - Animated gif with mask-image not playing unless user is actively dragging mouse

Status: VERIFIED FIXED

(Core :: Layout, defect)

Description

[Nicolas]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

1. Use the mask-image property with a url to an animated GIF

Snippet used:
#content {
width: 200px;
height: 200px;
background-color: aqua;
-webkit-mask-clip: border-box;
-webkit-mask-size: 100% 100%;
-webkit-mask-image: url("./myGif.gif")
}
2) Or viewing the following codepen: https://codepen.io/NicolasNewman/pen/WNOdJMa

Actual results:

The animation only plays if I am actively holding down left click and dragging my mouse across the screen.

Expected results:

Since Chromium doesn't exhibit this behavior and the animation plays as expected, I'm assuming this isn't intended behavior.

Comment 1

[Peter Magyari (Desktop QA)]

Hi Nicolas,

I was able to reproduce the issue on Firefox Nightly 94.0a1 and Firefox 92.0

I'm setting a component in order to get the development team involved in reviewing it.

Thank you for reporting!

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: test-case from reporter (kinda, with a different image)

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1731138 - Invalidate WebRender mask data from css::ImageLoader. r=aosmond,tnikkel

Otherwise we don't properly repaint animated images.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/3aa4f09a896e
Invalidate WebRender mask data from css::ImageLoader. r=tnikkel

Comment 5

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/3aa4f09a896e

Comment 6

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

The patch landed in nightly and beta is affected.
:emilio, is this bug important enough to require an uplift?
If not please set status_beta to wontfix.

For more information, please visit auto_nag documentation.

Comment 7

[Emilio Cobos Álvarez (:emilio)]

It's a very old regression, so I think it can probably ride the trains.

Comment 8

[Cristian Fogel [:cfogel]]

Confirmed issue with 94.0a1Build ID 20210916214506 on Win10 using TC from Emilio.
Fix verified with 94.0b2.

Comment 9

[Mihai Boldan, Desktop QA [:mboldan]]

Based on Comment 8, I'm marking this issue as Verified Fixed.