quarter tones in tablature - FretBoards

[Thomas Morley]

Hi all,

I'm working on "quarter tones in tablature"
https://sourceforge.net/p/testlilyissues/issues/4643/
I've locally some code which does it by modifying `determine-frets'
from translation-functions.scm

Though automatic fret-diagrams in FretBoards rely on it as well.
The problem arises how to print quarter-tones in fret-diagrams and how
to print/format a fret-label.

In the attached image you'll see that in first position the dot moves
within a fret.
In a higher position a fret-label would be needed, though, currently
it's impossible to display a non-integer.
But I could code to put out one of the listed possibilities.

Personally, I don't like any of those and lean towards excluding
quarter-tones from FretBoards at all and let output the warning about
"Missing fret for pitch ~a on string ~a" as before.
Letting only TabStaff display quarter-tones.

Opinions/suggestions?

Cheers,
  Harm

quarter-tone-fretboards.png
Description: PNG image