I am setting Scarlatti's 'grace notes' and other ornamentation by
giving them real durations and smaller type size e.g.
n = {\property Voice.fontsize = "0"}
sm = {\property Voice.fontsize = "-1"}
...
\sm e''16 \n d''8.
or, for a 'true' grace note:
\sm e''16 \n \times 3/4 {d''4}
Two drawbacks are: 1. the gap between the notes is larger than it
should be. Attempting to narrow the gap with the \times construct
e.g. \times 1/4 {c''16 e''} \times 15/16 {d''4} doesn't significantly
narrow the c'' e'' d'' gaps, it primarily lengthens the gap after the
d''; 2. other simultaneous notes line up with the (first) gracenote,
rather than with the main note as is wanted to show the music
structure properly. An option with a single gracenote is to put the
main & grace notes in separate voices and use hshift, but hshift only
moves things to the right, not the left so again other notes line up
with the gracenote. Putting gracenote and mainnote in a chord can't
work with more than one gracenote, obviously, but it also doesn't
work when even a single gracenote is higher in pitch than the main
note because the higher pitch of a pair appears to the right of the
stem. (It also doesn't work currently because Lily applies properties
to all notes of a chord even when it is marked only for one note, but
Han-Wen has this in the TODO list to fix because I'll need it for the
two note shapes in Scarlatti.) I suspect that the cleanest permanent
solution might be similar to the one I use, but with spacing and
horizontal position corrected along with the notehead size...
