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simoncozens / feature-tags

A curated guide to the OpenType Specification feature tag repository
http://simoncozens.github.io/feature-tags
Apache License 2.0
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Comments on 'rphf' #5

Open dscorbett opened 3 years ago

dscorbett commented 3 years ago

In Devanagari, non-final ra+virama should be substituted by reph.

This is true of many Indic scripts; why specify one without saying it’s just an example? Reph only applies initially: “non-final” is too broad. Not every initial ra+virama should be substituted by reph: that’s just the default behavior in some scripts.

This feature replaces consonant+virama with the reph form of the consonant. [...] The context of application is restricted to a syllabic cluster.

In USE, the context of application is further restricted to the first three glyphs in a cluster. It doesn’t check whether the glyphs are for consonants or viramas.

simoncozens commented 3 years ago

Thanks for these - very helpful!

In USE, the context of application is further restricted to the first three glyphs in a cluster.

Looks like it's first three at most:

https://github.com/harfbuzz/harfbuzz/blob/e5bfd49ae5bc711a40e3fac9e3b8230f251e5d67/src/hb-ot-shape-complex-use.cc#L225