Bug 259081

Summary:	`background-blend-mode` not applied for some background image sizes / repeat
Product:	WebKit	Reporter:	strarsis
Component:	Layout and Rendering	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	bfulgham, jjones1000, paco, simon.fraser, webkit-bug-importer, zalan
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	iPhone / iPad
OS:	Unspecified

Description strarsis 2023-07-10 16:23:02 PDT

`background-blend-mode` is not applied when the background image has a specific size relative to the DOM element.
This only occurs in iOS/iPad OS Safari.
Empirically, it appears that the background image size has to be smaller than 256 pixel on one side, 
the issue is sometimes also caused by repeating the background in the direction where the background image dimension is smaller than 256 pixels.

A variety of examples that use `background-blend-mode` which do work and do not work in iOS / iPad OS Safari:
https://codepen.io/strarsis/pen/poQWPOX

Minimal, reproducible sample:
https://codepen.io/strarsis/pen/ZEmXyxL

Feature (or rather bug) detection:
https://codepen.io/strarsis/pen/YzRrbaZ


MDN browser compat data issue:
https://github.com/mdn/browser-compat-data/issues/20308

Comment 1 Radar WebKit Bug Importer 2023-07-17 16:23:17 PDT

<rdar://problem/112435175>