[csswg-drafts] [css-inline] Define how to synthesize `ideographic-over` and `ideographic-under` (#10850)

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

== [css-inline] Define how to synthesize `ideographic-over` and `ideographic-under` ==
The [`text-box-edge`](https://drafts.csswg.org/css-inline-3/#propdef-text-box-edge)  property has [text-edge](https://drafts.csswg.org/css-inline-3/#typedef-text-edge) as its value.

It defines that:
* `ideographic`: Use the [ideographic-over baseline](https://drafts.csswg.org/css-inline-3/#ideographic-over-baseline)/[ideographic-under baseline](https://drafts.csswg.org/css-inline-3/#ideographic-under-baseline) as the [over](https://drafts.csswg.org/css-writing-modes-4/#over)/[under](https://drafts.csswg.org/css-writing-modes-4/#under) edge.
* `ideographic-ink`: Use the [ideographic-ink-over baseline](https://drafts.csswg.org/css-inline-3/#ideographic-ink-over-baseline)/[ideographic-ink-under baseline](https://drafts.csswg.org/css-inline-3/#ideographic-ink-under-baseline) as the [over](https://drafts.csswg.org/css-writing-modes-4/#over)/[under](https://drafts.csswg.org/css-writing-modes-4/#under) edge.

Which goes to these definitions:
* ideographic-over: Corresponds to the line-over design edge of CJK (Han/Hangul/Kana) text. Assigned to idtp in OpenType.
* ideographic-under: Corresponds to the line-under design edge of CJK (Han/Hangul/Kana) text. Assigned to ideo in OpenType.
* ideographic-ink-over: Corresponds to the line-over ink edge of CJK (Han/Hangul/Kana) text. Assigned to icft in OpenType.
* ideographic-ink-under: Corresponds to the line-under ink edge of CJK (Han/Hangul/Kana) text. Assigned icfb in OpenType.

Questions:
1. Most fonts, including many CJK fonts, don't have these tables. How should this be synthesized when these are missing?
2. When the first font in the cascade doesn't have these tables but the second one does, should UA synthesize from the first font, or use the table from the second font?

@fantasai @nt1m @vitorroriz @clqsin45 @bfgeek @kidayasuo

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/10850 using your GitHub account


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Received on Saturday, 7 September 2024 09:53:01 UTC