Sun 14 Jun 2009 12:12:57 PM UTC, original submission:
So far, have found very limited success in getting font features to work in the Musical Symbols range. This affects at least bug reports:
[https://savannah.gnu.org/bugs/index.php?26803
bug #26803: Musical Symbols: Begin/End Beam, Phrase, Slur, Tie]
[https://savannah.gnu.org/bugs/index.php?26801
bug #26801: Musical Symbols: combining articulations in text]
- In Linux, kerning and mark positioning works, but only in very
specific circumstances
(I think it's a bug in the text layout engine)
- Other features (Contextual Alternaties) I tried don't seem to be activated for the Musical Symbols range in Linux. I know these features work in the same font for other ranges. What's going on?
- I don't see any of the features I tried being used in Windows (in web browsers, anyway)
As to why:
- The question of what level of software is responsible for handling a feature is complicated and system-dependent.
On Linux, and in some free software such as FireFox, the level is the text-layout library Pango.
- The question of what feature should be turned on for what script is complex and messy.
- OpenType has a special script tag 'musc' to identify the Musical Symbols range.
OpenType Script Tags
- Unicode doesn't specify a special script for Music. This is
really too bad. So it gets labelled as "Common". Unfortunately, this is the way Pango determines its behaviour.
***ISO 15924
***Script database
***UCD
- Some font features are script-dependent: For example the 'calt' tag
'calt' feature description
says: "not applicable to ideographic scripts"
I think this results in text layout engines not knowing what specific features to apply to music, and only applying a very restricted, but inconsistent, set.
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