[smufl-discuss] Re: Tuplets in SMuFL Text

[Knut Nergaard]

I’ve been trying to educate myself a bit more on the GPOS features not natively available in FontLab. As I understand it,  the mark and mkmk features used in e.g. arabic fonts, could be very useful in handling the more complicated tasks of music notation in a text editor, especially since they greatly reduce the need for composite glyphs, which would be essential for situations like tuplets, chords, chord symbols and function theory).

On the downside, these feature require both certain dedicated scripts and external software (some font editors may support them for all I know, but FontLab doesn’t). I have no thorough understanding of these features by any means, but I feel that they have the potential to greatly enhance SMuFL Text.

I’ve also looked into one of the more full-featured text based music fonts out there, the Cavatina font. Like most other musical text fonts, Cavatina makes extensive use of negative spacing and zero width side bearings. I remember Daniel saying something about why such spacing is generally avoided in SMuFL, but I can't remember what. 

Apart from this, Cavatina, like SMuFL, handles the more complex situations with OT ligatures and composite glyphs. Cavatina also covers some situations that seem basic enough to justify similar support in SMuFL, namely intervals and chords (including seconds), slanted beam pairs and notes on multiple ledger lines.

The avoidance of negative and zero width side bearings certainly presents a challenge in implementing the features mentioned above into a text based music font, but it seems possible with a more extensive use of advanced OT features. I may have missed prior discussions about this, but I feel this is certainly something to consider.

Lastly, I've fiddled around a bit further with the kerning of the Beamed groups of notes range, and with the use of space or continuing beam characters, basic triplets for stemmed notes are certainly possible within the current limitations of this range. However, decent spacing of characters will require some modifications to the current guidelines: 

1. The left tuplet bracket should be entered prior to the first note of a tuplet, and kerned accordingly. That way, the bracket does not affect the spacing of following characters.

2. (In Bravura) the right bracket should be kerned so that the hook is centered above the stem of the last note, not to the right of it, as is currently the case.

2. Space or continuing beam characters should both precede and follow the tuplet number to achieve an even spacing.

Knut Nergaard

3. jun. 2015 kl. 11.10 skrev Knut Nergaard <[hidden email]>:

Is SMuFL supposed to be able to handle tuplets in text based applications? 

After attempting to work out the kerning for the Beamed groups of notes range (U+E1F0–U+E20F), I’ve found that even the simple example in the manual (p. 97) is not possible without additional spaces on each side of the number. (The suggested sequence renders the brackets to close to the triplet number.) As I see it, the Beamed groups range is too limited and/or the guidelines too non-specific to handle even some of the most basic triplets, let alone more complex ones or tuplets of other ratios. 

I realize that, similarly to chords and function theory, this is complicated and may be difficult, if not impossible, to handle at the font level. Even so, musically, it is pretty basic, and a music font for text based applications should ideally be able to handle it.

Knut Nergaard