Re: vertical shift of trill

[Jean Abou Samra]

Hi Valentin,


Le 06/08/2022 à 15:05, Valentin Petzel a écrit :
> But we can in fact implement a simple function that tries to fit the
> TrillSpanner  (or in fact any spanner) to the notes. Consult the appended file
> for details.


FYI, the bulk of this function can be simplified using
ly:relative-group-extent. That said, there's a much simpler
way. Your function is essentially reimplementing part of
the side-position-interface. TrillSpanner has its Y offset
computed by side-position-interface::y-aligned-side, so apart
from outside-staff-priority handling, it will avoid objects
in its side-support-elements array. The problem here is that
by default, LilyPond doesn't fill in this array. On the other
hand, Trill_spanner_engraver fills a note-columns array
which contains exactly what you want, so you can just use that:


    \override TrillSpanner.meta.object-callbacks.side-support-elements =
      #(lambda (grob)
         (ly:grob-object grob 'note-columns))

Add \override TrillSpanner.staff-padding = ##f and
side-position-interface::y-aligned-side will no longer
push the object out of the staff.

Also, instead of defining functions tweaking the direction,
I'd suggest allowing the syntax with _ and ^ by looking
at the event's direction property.

Giving:


\version "2.22.0"

\layout {
  \context {
    \Score
    \override TrillSpanner.outside-staff-priority = ##f
    \override TrillSpanner.staff-padding = ##f
    \override TrillSpanner.meta.object-callbacks.side-support-elements =
      #(lambda (grob)
         (ly:grob-object grob 'note-columns))
    \override TrillSpanner.direction =
      #(lambda (grob)
         (let ((ev (event-cause grob)))
           (ly:event-property ev 'direction UP)))
  }
}

mus = \relative c'' {
  <<{ \pitchedTrill
   c'1~^\f
   \startTrillSpan
   des c1*7/8 s8 \stopTrillSpan }\\{\pitchedTrill
   a1~\f
   \startTrillSpan bes a1*7/8 s8 \stopTrillSpan}>>
}

{
  \clef treble
  \mus
  \transpose c a, \mus
  \transpose c fis, \mus
  \transpose c c, \mus
  \transpose c a,, \mus
  \transpose c fis,, \mus
  \transpose c c,, \mus
}

% Using TrillSpanner.padding to correct distance
{
  f''1_\startTrillSpan ~ 1 \stopTrillSpan
  1\tweak padding 0 _\startTrillSpan ~ 1 \stopTrillSpan
  1\tweak padding 2 _\startTrillSpan ~ 1 \stopTrillSpan
  1\tweak padding -1 _\startTrillSpan ~ 1 \stopTrillSpan
}


Best,
Jean