Re: Remove all occurrencies of "0" fingerings

[Thomas Morley]

2017-08-08 11:46 GMT+02:00 Marc Hohl <address@hidden>:
> Hi Malte,
>
> Am 08.08.2017 um 10:30 schrieb Malte Meyn:
>>
>>
>>
>> Am 08.08.2017 um 10:23 schrieb Marc Hohl:
>>>
>>>
>>> I wanted to write a little callback to remove all occurrencies
>>> of "0" fingerings.
>>
>>
>> This doesn’t empty the stencil but removes the Fingering grobs completely
>> (by suicide):
>
>
> thanks for this solution!
>
> In my real-life example, I got
>
> lilypond: ../flower/include/drul-array.hh:35: T&
> Drul_array<T>::at(Direction) [with T = scm_unused_struct*]: Zusicherung >>d
> == 1 || d == -1<< nicht erf?llt.music = {
  \set fingeringOrientations = #'(left)
  c'4-333333333333 d'-0 e'-2 <f'-333333333333> | g'1_0 a'^0
}

\score {
  \new Staff
  \with {
    \override Fingering.after-line-breaking =
    #(lambda (grob)
          (if (equal? (ly:grob-property grob 'text) "333333333333")
              (ly:grob-suicide! grob)))
  }
  { \music }
}
> Aborted (core dumped)
>
> but changing before-line-breaking to after-line-breaking did the trick.
>
> I do not fully understand why, but it works.
>
> Thanks,
>
> Marc
>
>>
>>      \override Fingering.before-line-breaking =
>>      #(lambda (grob)
>>         (if (equal? (ly:grob-property grob 'text) "0")
>>             (ly:grob-suicide! grob)))

Hi Marc,

your initial code had two problems, comments inline:

\override Fingering.stencil =
  #(lambda (grob)
     (let* ((text (ly:grob-property grob 'text))
            (stencil (if (equal? text "0")
                         ;; to avoid the warning go for point-stencil
                         ;; not empty-stencil
                         point-stencil
                         ;; return a stencil yourself, don't call the
                         ;; property which is created by the stencil-prop
                         ;; it's a cycle and I'm somewhat surprised it failed
                         ;; not more spectaculary
                         (ly:text-interface::print grob))))
           stencil))

In certain cases going for after-line-break will be too late and
leaves you with bad spacing:

music = {
  \set fingeringOrientations = #'(left)
  c'4-333333333333 d'-0 e'-2 <f'-333333333333> | g'1_0 a'^0
}

\score {
  \new Staff
  \with {
    \override Fingering.after-line-breaking =
    #(lambda (grob)
          (if (equal? (ly:grob-property grob 'text) "333333333333")
              (ly:grob-suicide! grob)))
  }
  { \music }
}

Ofcourse it's far less likely that a single-digit like will cause such badness.
Nevertheless I'd research why/where your real-life code gives that
assertion failure.


Cheers,
  Harm