Bug 258137

Summary:

Layer-backed GIF image animate improperly or flicker on Intel macOS 14 machines when bitmap-backend based ImageBuffer is used.

Product:

WebKit

Reporter:

Ethan Wong <bunnnywong>

Component:

Layout and Rendering

Assignee:

Nobody <webkit-unassigned>

Status:

NEW ---

Severity:

Normal

CC:

bfulgham, kkinnunen, sabouhallawa, simon.fraser, webkit-bug-importer, zalan

Priority:

Keywords:

InRadar

Version:

Safari 17

Hardware:

Mac (Intel)

OS:

Other

Attachments:

Description	Flags
A web page to reproduce this issue	none
The screen recording for this issue	none

Description Ethan Wong 2023-06-15 08:15:17 PDT

Created attachment 466703 [details]
A web page to reproduce this issue

Layer-backed GIF images may animate improperly or flicker.


See the attached page and screen recording for this issue, the GIF image with rabbit ears animates in a wrong frame rate and may even flicker.


This issue: 

* happens only on Intel-based machines running macOS 14 beta.

* happens only when the layer's backing store is small enough so that `ImageBufferShareableMappedIOSurfaceBitmapBackend` is used. (Introduced in: https://commits.webkit.org/264004@main.)

* happens when WebKit is built with both macOS 13 & 14 SDK.


I'm not sure if issue is WebKit specific or it's a CoreGraphics issue.

Comment 1 Ethan Wong 2023-06-15 08:17:08 PDT

Created attachment 466704 [details]
The screen recording for this issue

Comment 2 Radar WebKit Bug Importer 2023-06-22 08:16:15 PDT

<rdar://problem/111161156>

Comment 3 Ethan Wong 2023-06-24 23:13:58 PDT

This issue could still be reproduced in macOS 14.0 Developer Beta 2 (23A5276g).