LGM: Unusual typography [LWN.net]

LGM: Unusual typography

Posted May 24, 2012 22:14 UTC (Thu) by behdad (subscriber, #18708)
In reply to: LGM: Unusual typography by micka
Parent article: LGM: Unusual typography

In these cases, from a Unicode and OpenType (and hence HarfBuzz) point of view, those are not really ligatures. Ie. fonts will not tell HarfBuzz to automatically convert 'oe' into 'œ'. To Unicode, 'œ' is a standalone character. Now, fonts *can* tell HarfBuzz to substitute such a ligaure, they can even say do it under French only. But if it's not mechanically decidable, then it shouldn't be in the font.

That said, the substitution mechanism in OpenType allows for contextual matches. So, if, say, a ligature should be formed only if followed by a certain string of characters, that can be expressed in the font.

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LGM: Unusual typography

Posted May 25, 2012 7:18 UTC (Fri) by micka (subscriber, #38720) [Link]

Well, a bit curious about it, I read on the subject, I found that there seems to be a distinction between different kinds of ligatures : typographic ligatures and linguistic ligatures.

If I understand correctly, Harfbuzz does the first kind, and I was talking about the second kind (thus my confusion).

I even read a bit about how TeX does ligatures, and I wish I didn't :) But maybe that's to be expected from a system usable in so many languages and writing systems.

LGM: Unusual typography

Posted May 27, 2012 1:58 UTC (Sun) by behdad (subscriber, #18708) [Link]

Thanks for the note. Yes, you are spot on. I've worked on the typographic side so much that I have had forgotten that the term 'ligature' is used in other contexts too.