Re: Modyfing bracketify-stencil

[Lukas-Fabian Moser]

Hi Marcin,

Am 01.09.21 um 02:11 schrieb Marcin Damianiak:
> Dear All,
>
> I have two questions regarding the bracketify-stencil function. When I 
> use the following snippet:
>
> \relative c' {
> \time 4/4
> \once\override Staff.MultiMeasureRest.stencil = #(lambda (grob)
> (bracketify-stencil (ly:multi-measure-rest::print grob) Y 0.1 0.2 0.1))
> R1
> }

Just an unrelated hint: By now, I prefer using grob-transformer as it 
enables me to use bracketify-stencil without having to resort to ::print 
routines, which means the routine can be used generically:

bracketizer =
#(grob-transformer 'stencil
                   (lambda (grob default)
                     (bracketify-stencil default Y 0.2 0.5 0.3)))
% usage:
% \once\override Rest.stencil = \bracketizer

bracketify =
#(define-music-function (grob-path) (key-list?)
   #{ \once\override $grob-path . stencil = \bracketizer #})

% usage:
% \bracketify Score.TimeSignature

> it creates brackets of the inner object's exact height. I'd like to 
> ask whether it is possible to:
> 1. make them longer on both ends, to extend beyond the parenthesized 
> object
> 2. disable one of the brackets (to keep only left or right)

I think it might be easiest to take the source code of 
bracketify-stencil and add the necessary options.

\version "2.22.0"

#(define (other-axis a)
   (remainder (+ a 1) 2))

#(define (flex-bracketify-stencil stil axis thick protrusion 
Y-protrusion padding left? right?)
   "Add brackets around @var{stil}, producing a new stencil."

   (let* ((ext (interval-widen (ly:stencil-extent stil axis) Y-protrusion))
          (lb (ly:bracket axis ext thick protrusion))
          (rb (ly:bracket axis ext thick (- protrusion))))
     (if right?
         (set! stil
               (ly:stencil-combine-at-edge stil (other-axis axis) 1 rb 
padding)))
     (if left?
         (set! stil
               (ly:stencil-combine-at-edge stil (other-axis axis) -1 lb 
padding)))
     stil))

{
  \once \override Rest.stencil =
  #(grob-transformer
    'stencil
    (lambda (grob default)
      (flex-bracketify-stencil default Y 0.1 0.2 0.3 0.1 #t #f)))
  r4
  \once \override Rest.stencil =
  #(grob-transformer
    'stencil
    (lambda (grob default)
      (flex-bracketify-stencil default Y 0.1 0.2 1.5 0.1 #f #t)))
  r4
}

Lukas