in Snippets - LilyPond

Contexts and engravers 364
}
}
>>
}
}
\new Staff {
\once \override Staff.TimeSignature #'stencil = ##f
c1 | b
}
>>
c1
Centering markup on note heads automatically
For technical reasons, text scripts attached to note heads cannot easily be centered on a note
head’s width, unlike articulations.
Instead of using trial-and-error offset tweaks, this snippet uses a Scheme engraver to reset
the horizontal parent of each markup to a NoteColumn. This also allows text to follow note
heads which have been shifted via force-hshift.
#(define (Text_align_engraver ctx)
(let ((scripts '())
(note-column #f))
(make-engraver
(acknowledgers
((note-column-interface trans grob source)
;; cache NoteColumn in this Voice context
(set! note-column grob))
((text-script-interface trans grob source)
;; whenever a TextScript is acknowledged,
;; add it to `scripts' list
(set! scripts (cons grob scripts))))
((stop-translation-timestep trans)
;; if any TextScript grobs exist,
;; set NoteColumn as X-parent
(for-each (lambda (script)
(set! (ly:grob-parent script X) note-column))
scripts)
;; clear scripts ready for next timestep
(set! scripts '())))))
\layout {