Bug 240871

Summary:

REGRESSION (r252945): accelerated animations prevent videos from taking up entire screen in fullscreen mode

Product:

WebKit

Reporter:

Liam DeBeasi <ldebeasi>

Component:

Animations

Assignee:

Nobody <webkit-unassigned>

Status:

RESOLVED CONFIGURATION CHANGED

Severity:

Normal

CC:

dino, fred.wang, graouts, jer.noble, simon.fraser, webkit-bug-importer

Priority:

Keywords:

InRadar

Version:

Safari 15

Hardware:

Unspecified

OS:

Unspecified

Bug Depends on:

Bug Blocks:

276855

Attachments:

Description	Flags
Code reproduction	none
CSS only reproduction	none
testcase with a different video	none

Liam DeBeasi

Reported 2022-05-24 07:29:09 PDT

Created attachment 459722 [details] Code reproduction Running an accelerated animation on an element prevents the containing <video> element from taking up the entire screen when in fullscreen mode. Steps to reproduce: 1. Open attached code reproduction in Safari for macOS. 2. Click the fullscreen button on the video. Observe that the video goes fullscreen and takes up the entire screen. 3. Exit fullscreen. 4. Click "Add Animation" 5. Click the fullscreen button on the video. Observe that the video goes fullscreen but does not take up the entire screen. Expected Behavior: I expect that the video takes up the entire screen when in fullscreen mode. Actual Behavior: The video does not take up the entire screen when in fullscreen mode. Other Information: - I reproduced this on both Safari 15.5 and STP 145. - This issue does not reproduce on Chrome or Firefox.

Attachments
Code reproduction (962 bytes, text/html) 2022-05-24 07:29 PDT, Liam DeBeasi	no flags	Details
CSS only reproduction (868 bytes, text/html) 2022-05-24 09:59 PDT, Liam DeBeasi	no flags	Details
testcase with a different video (997 bytes, text/html) 2026-10-30 04:44 PDT, Frédéric Wang Nélar	no flags	Details
View All Add attachment proposed patch, testcase, etc.

Antoine Quint

Comment 1 2022-05-24 07:45:16 PDT

Thanks for filing this Liam. Do you have any indication that this behavior could have regressed?

Radar WebKit Bug Importer

Comment 2 2022-05-24 07:45:26 PDT

<rdar://problem/93831877>

Liam DeBeasi

Comment 3 2022-05-24 09:09:19 PDT

Thanks for taking a look. This does appear to have regressed. Safari 12.1 does not reproduce the issue, but Safari 13.1+ does.

Jer Noble

Comment 4 2022-05-24 09:40:25 PDT

The current fullscreen implementation works by forcibly removing/overriding all styles that create a stacking context between the root and the fullscreen element. In this case, the animation is creating a stacking context that limits the width and height of the video element in fullscreen to the size of the .wrapper div.

Antoine Quint

Comment 5 2022-05-24 09:47:47 PDT

(In reply to Liam DeBeasi from comment #3) > Thanks for taking a look. > > This does appear to have regressed. Safari 12.1 does not reproduce the > issue, but Safari 13.1+ does. Are you sure that it wasn't the case that the repro you create uses the Web Animations API which wasn't available in Safari 12.1 and thus no animation is added?

Liam DeBeasi

Comment 6 2022-05-24 09:59:49 PDT

Created attachment 459727 [details] CSS only reproduction Ah, good point! I attached a reproduction that only uses CSS Animations. However, I get the same results as before: Safari 12.1 does not reproduce the issue, but Safari 13.1+ does.

Antoine Quint

Comment 7 2022-05-24 10:30:50 PDT

This regressed when we enabled Web Animations for CSS-originated animations in r252945.

Frédéric Wang Nélar

Comment 8 2026-10-30 04:44:16 PDT

Created attachment 482068 [details] testcase with a different video The link to the video seems broken, here is the testcase with the video URL tweaked.

Frédéric Wang Nélar

Comment 9 2026-10-30 04:47:32 PDT

I cannot reproduce in Safari 27.0.1, so tentatively closing this. Feel free to reopen if you still see it.

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