Inconsistent contextualization of Tibetan vowel signs above tsa ’phru

[dscorbett]

Font

NotoSerifTibetan-Regular.ttf

Where the font came from, and when

Site: https://github.com/googlefonts/noto-fonts/blob/96e3d51ab4ad78e74a4cb0752dc25d010d6946de/unhinted/NotoSerifTibetan/NotoSerifTibetan-Regular.ttf Date: 2020-01-02

Font version

Version 2.001

Issue

Above letters like tsa with built-in U+0F39s, vowel signs take their narrow forms. Above other letters followed by separately encoded U+0F39s, vowel signs do not take their narrow forms.

Character data

ཙོ ངོ༹ ཙ U+0F59 TIBETAN LETTER TSA ོ U+0F7C TIBETAN VOWEL SIGN O U+0020 SPACE ང U+0F44 TIBETAN LETTER NGA ོ U+0F7C TIBETAN VOWEL SIGN O ༹ U+0F39 TIBETAN MARK TSA -PHRU

Screenshot

[marekjez86]

corrected Prod-report_NotoSerifTibetan_857328.pdf

[dscorbett]

This issue has not been addressed. That PDF discusses ⟨ཙོངོ༹⟩, but this report is about ⟨ཙོ ངོ༹⟩. That’s two clusters separated by a space: the first cluster as an example of a cluster with a narrow vowel sign, and the second as an example of a cluster with a wide vowel sign. The point is that they are inconsistent so I showed both.

The problematic cluster is <U+0F44, U+0F7C, U+0F39>. This is still true in version 2.101.

[simoncozens]

I think I've fixed it. Everything with a tsa-phru (whether built-in or separately encoded) now gets narrow top vowels, and also so do top vowels on the following syllable. (I think part of the purpose of narrowing is to stop the top mark bumping into the flag of the tsa-phru.)