This split from bug 160634. When a font has a “morx” table, HarfBuzz will use it for glyph substitution, so if the font has also “GSUB” table it will not be used. Font Features dialog will list the “GSUB” features in the font, but they will have no effect which is misleading, so it should not list such features. attachment 193636 [details] (from bug 160634) has a font that has both “morx” and “GSUB” and can be used for testing.
-> NEW
Totally disagree. Harfbuzz should be patched to re-enable OpenType features instead. See https://bugs.documentfoundation.org/show_bug.cgi?id=160634
OpenType and AAT have different features that complete each other: Some features are only available in OT, some only in AAT, some in both. It's up to the software to enable individual features. Disabling them all is not a good approach. According to FontForge's OT->AAT equivalence for glyph substitution: Single -> Non-Contextual Glyph Multiple -> N/A N/A -> Glyph Insertion Alternate -> N/A Ligature -> Ligature N/A -> Contextual Glyph Chaining / Chaining Context -> N/A Reverse Chaining Context -> N/A N/A -> Indic Rearrangement
Hey Y. Kawara, next time you change the status, I will ban you.
This is a Harfbuzz bug. The UI is acting correctly.
Is there any real advantage to majority of LibreOffice users to have mixed AAT and OpenType features, even if complementary? Seems very much a corner case of interest only to those font designers making it a practice in their offerings. The HarfBuzz community does not seem enthusiastic of mixing smart type features, one or the other is fine--but not in combination. So why would we for an office suite. Suppressing OTF feature when an AAT feature takes precedence seems reasonable, especially if the OTF feature is disabled as implemented in HarfBuzz libs. If HarfBuzz moves the mark, sure. Until then just suppress the feature on the LibreOffice Character dialog. +1
I gave it a try here: https://gerrit.libreoffice.org/c/core/+/174294
Julien Nabet committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/0679a5cee16ae96c0d11e7d4fc1e59fb0f9cc591 tdf#163213: do not show OpenType features if the font has "morx" table It will be available in 25.2.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
I'm not sure it worths it to cherry-pick this on 24.8 but if someone thinks it does, don't hesitate to cherry-pick it! :-)
Y. Kawara: I think I understand your point of view. The patch may be reverted quite quickly (since I put the tdf in comment and it's only a 2 lines patch) if Harfbuzz changes about this point. I'm not an expert about fonts but I suppose first step would be to discuss again about this with Harfbuzz community and then propose them a patch. Let's put this one to FIXED.