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Re: [csswg-drafts] [css-text] [css-inline] Define how to deal with inline backgrounds whose boundary falls into a ligature (#5251)

From: jfkthame via GitHub <sysbot+gh@w3.org>
Date: Wed, 24 Jun 2020 12:38:56 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-648794428-1593002335-sysbot+gh@w3.org>
Fira Code has an unconventional implementation whereby it inserts extra "spacer" glyphs to maintain monospaced rendering in the presence of ligatures:

```
$ hb-shape --font-file FiraCode-Regular.ttf "<="
[less.spacer=0+1200|less_equal.liga=1+1200]
```

I haven't been through all the font lookups to confirm the exact sequence of operations, but what has happened here is not a ligation, but two substitutions: "<" replaced by the `less.spacer` glyph, and "=" replaced by `less_equal.liga` (which has its ink shifted left so that it is centered over the glyph origin rather than within the advance width, so it appears in the middle of the overall 2-char-wide space).

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Received on Wednesday, 24 June 2020 12:38:58 UTC

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