Re: [csswg-drafts] [css-text-4] text-spacing-trim and classes of closing punctuation (#9504)

Well, re-reading the spec, I think you're right. Avoiding glyph collisions is the top priority for me, so I guess I misread the spec.

There are two places in the spec. The [8.5.2. Text Spacing Character Classes](https://drafts.csswg.org/css-text-4/#fullwidth-collapsing) requires it only for colon and dots, but not for other types.

In antother place, [8.5.1. Fullwidth Punctuation Collapsing](https://drafts.csswg.org/css-text-4/#fullwidth-collapsing) says:
> trim (kern) the blank half of the glyphs, if they are given full-width and must be set half-width

This may read impls need to check inks as it says it can trim only "blank half", but it can improve, such as what to do if the glyph doesn't have "blank half".

For the latter, it says "must be set half-width". We apply `halt`, which doesn't guarantee to set half-width. This happens with [U+FF5D FULLWIDTH RIGHT CURLY BRACKET](https://codepoints.net/U+ff5d) in extra-bold fonts when ink fills a bit more than half, and thus font designers set its `halt` a bit wider than half-width.

/cc @nt1m @vitorroriz @clqsin45

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Received on Monday, 23 October 2023 08:31:06 UTC