Re: Text Spanner auto expand to end of duration

[Dimitris Marinakis]

Thanks a lot!

Could this be forwarded to the devs? I think such functions are really needed in "vanilla" Lilypond. The current behaviour isn't wrong per se but in most contexts I think the extension of the spanners until the end of the duration is the standard rule. 

They may be able to make something that works even better, that's all I'm saying. No problems with your solution.

Best,

Dimitris

On Mon, Feb 8, 2021 at 1:01 AM Thomas Morley <thomasmorley65@gmail.com> wrote:

Am Sa., 6. Feb. 2021 um 20:07 Uhr schrieb Dimitris Marinakis
<dtsmarin02@gmail.com>:
>
> Aha! Found the culprit. As you can see if other staves have different durations (shorter than the span that needs to be covered), the spanner terminates at the first next duration it finds. Could you make the spanner to see only the relevant duration of the context it is applied to? Voice, Staff etc.?
> Apologies for the redundant erroneous mails.
> Dimitris
> %%%%%%%%%%%%%%%%%%%%%
> \version "2.23.0"
[...]

I don't know any method to do so by amending the current coding.
An engraver could likely work:

\version "2.22.0"

Test_engraver =
#(lambda (context)
  (let* ((rhythmic-events '())
         (bar-line #f)
         (end-spanner #f)
         (trill-spanner #f))
    (make-engraver
      (listeners
        ((rhythmic-event this-event event)
          ;; store moments for all rhythmic events
          ;; NB this will include skip-events
          (set! rhythmic-events
                (cons (ly:context-current-moment context) rhythmic-events))))

      (acknowledgers
        ((bar-line-interface this-engraver grob source-engraver)
          ;; keep track of BarLine
          (set! bar-line (cons (ly:context-current-moment context) grob)))
        ((trill-spanner-interface this-engraver grob source-engraver)
          (set! end-spanner #t)
          ;; keep track of TrillSpanner
          (if (ly:grob-property grob 'full-length-to-extent #f)
              (set! trill-spanner grob))))

      ((stop-translation-timestep this-engraver)
        (if (ly:grob? trill-spanner)
            (let ((right-bound (ly:spanner-bound trill-spanner RIGHT)))
              (if (and (ly:grob? right-bound) (>= (length rhythmic-events) 2))
                  (let* ((curr-moment (ly:context-current-moment context))
                         (to-barline?
                           (ly:grob-property trill-spanner 'to-barline #f)))
                    (if (and (equal? (grob::when right-bound)
                                     (second rhythmic-events))
                             end-spanner)
                      (begin
                        ;; set right bound of the TrillSpanner to the BarLine
                        ;; if 'to-barline is enabled, otherwise to current
                        ;; PaperColumn
                        (ly:spanner-set-bound! trill-spanner RIGHT
                          (if (and to-barline?
                                   (equal? (car bar-line) curr-moment))
                              (cdr bar-line)
                              (ly:context-property
                                context 'currentMusicalColumn)))
                        (set! end-spanner #f))))))))

      ((finalize this-engraver)
        ;; house keeping
        (set! trill-spanner #f)
        (set! rhythmic-events '())
        (set! bar-line #f)))))

instrumentOne = \relative c' {
  \override TrillSpanner.to-barline = ##f
  \override TrillSpanner.full-length-to-extent = ##t
  c4 d\startTrillSpan e f |
  R1 |
  d'2\stopTrillSpan\startTrillSpan c | b a |
  b2  g2 | f2 f2\stopTrillSpan |
  e e e e |
}

instrumentTwo = \relative g' {
  R1 |
  R1 |
  R1 |
  R1 |
  R1 |
  R1 |
  R1 |
}

instrumentThree = \relative g' {
  a4 b c d e f d e c b a d g f e d c b c d e f e d c1
}

\layout {
  \context {
      \Staff
      \consists \Test_engraver
  }
}

<<
  \new Staff \instrumentTwo
  \new Staff \instrumentOne
>>

<<
  \new Staff \instrumentThree
  \new Staff \instrumentOne
>>


You can switch it of by setting
  \override TrillSpanner.full-length-to-extent = ##f

'full-length-to-extent is a property stolen from
'tuplet-bracket-interface. Meaning it is an established grob-property,
but will issue:
    programming error: Grob `TrillSpanner' has no interface for
property `full-length-to-extent'
if you compile with the check-internal-types option.

Cheers,
  Harm