Bug 248220

Summary:	[css-text] word-spacing does not allow calculated values
Product:	WebKit	Reporter:	Antoine Quint <graouts>
Component:	Animations	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	dino, graouts, karlcow, mmaxfield, webkit-bug-importer
Priority:	P2	Keywords:	BrowserCompat, InRadar
Version:	Safari Technology Preview
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=248218
Bug Depends on:
Bug Blocks:	235768

Description Antoine Quint 2022-11-22 06:10:01 PST

While we support both fixed and percentage values for word-spacing, we do not support calculated values. The custom BuilderConverter::convertWordSpacing() does not account for calculated values and RenderStyle::setWordSpacing() computes a canned value when dealing with a calculated length. While we added support for blending between percentage and fixed values in bug 248218, this still causes failures in three animation tests where the keyframes use calc()` values:

web-animations/animation-model/animation-types/accumulation-per-property-002.html
web-animations/animation-model/animation-types/addition-per-property-002.html
web-animations/animation-model/animation-types/interpolation-per-property-002.html

Comment 1 Antoine Quint 2022-11-22 06:17:53 PST

I must say I am a bit confused here. The spec for word-spacing (https://w3c.github.io/csswg-drafts/css-text/#word-spacing-property) says percentages are *not* supported. However, both Safari and Firefox clearly have support for percentages and there are several WPT tests for this on the animation side. BUT, also, the WPT parsing tests explicitly call out percentages as non-supported (see https://github.com/web-platform-tests/wpt/blob/master/css/css-text/parsing/word-spacing-invalid.html).

Comment 2 Radar WebKit Bug Importer 2022-11-29 06:10:15 PST

<rdar://problem/102763017>