Re: Parenthensize a horizontal group?

[Aaron Hill]

On 2021-06-30 9:07 pm, Aaron Hill wrote:
> On 2021-06-30 9:00 pm, Mark Probert wrote:
> > Hi.
> >
> > I've looked through docs and snippets and can't seem to find a way to
> > place parens around a horizontal group of notes (an "optional"
> > indicator for leadsheets). I've tried
> >
> >  \parenthesize { a8 bes }
> >
> > but nope. Is there a simple way? I want to do something like:
> >
> >  \mark "(" a8 bes \mark ")"
> >
> > and have the parens aligned on the center of the staff.
>
> Does LSR 902 [1] help?
>
> [1]: https://lsr.di.unimi.it/LSR/Item?id=902

Or perhaps this which might be easier to use if this sort of thing 
occurs often:

%%%%
\version "2.22.0"

parenthesizeMusic =
#(define-music-function (music) (ly:music?)
  (define ((stencils which) grob)
   (let* ((stens (parentheses-item::calc-parenthesis-stencils grob))
          (sten (which stens)))
    (if (eq? which first) (list sten point-stencil) (list point-stencil 
sten))))
  (define (add-tweak event tweak)
   (ly:music-set-property! event 'tweaks
    (cons tweak (ly:music-property event 'tweaks '()))))
  (let ((evs (extract-typed-music music 'rhythmic-event)))
   (ly:music-set-property! (first evs) 'parenthesize #t)
   (add-tweak (first evs) `((ParenthesesItem . stencils) . ,(stencils 
first)))
   (ly:music-set-property! (last evs) 'parenthesize #t)
   (add-tweak (last evs) `((ParenthesesItem . stencils) . ,(stencils 
second))))
  music)

{
  \override ParenthesesItem.font-size = 5
  \override ParenthesesItem.extra-offset =
    #(lambda (grob) (cons 0 (* -1/2 (ly:grob-staff-position grob))))
  \parenthesizeMusic { <c' c''> d' e' f' g' }
}
%%%%


-- Aaron Hill

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