[csswg-drafts] [css-values-4] `round(line-width, ...)` specification is confusing (#13794)

romainmenke has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-values-4] `round(line-width, ...)` specification is confusing ==
see: https://github.com/w3c/csswg-drafts/commit/f63d90ecd8b444eee8a69567e548f8b43241b41a

> Otherwise, identical to nearest, except that if A is positive (non-zero) and one of lower B or upper B is zero, choose the non-zero one, then snap as a border width.

Can be read as:

- `line-width` is almost identical to `nearest`
- has an exception when lower/upper B is zero and ...
- always snaps to border width

or:

- `line-width` is almost identical to `nearest`
- has an exception when lower/upper B is zero and ... only when in this exception snap to border width

-----

> If <rounding-strategy> is line-width, B may also be omitted and has special behavior (defined above) essentially defaulting it to one device pixel. In all other cases, omitting B is invalid.

Can be read as:

- `line-width` allows `B` to be omitted
- always has special behavior -> snapping to border width

or:

- `line-width` allows `B` to be omitted
- only when `B` is omitted the value is snapped to border width

----

@tabatkins I assume the intention is to always have the border width snapping behavior?
It might help to split into a bit more sentences :)

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/13794 using your GitHub account


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Received on Sunday, 12 April 2026 08:47:11 UTC