Re: Whole-note tremolo beams

[Thomas Morley]

Am Do., 19. März 2020 um 11:12 Uhr schrieb Leo Correia de Verdier
<address@hidden>:
>
> For the sake of clarity, a MWE:
>
> %%%%%%%%%%%
>
> \version "2.20.0"
> \repeat tremolo 16 {dis'32 dis’’}
>
> %%%%%%%%%%%
>
> > 19 mars 2020 kl. 11:01 skrev Leo Correia de Verdier <address@hidden>:
> >
> > Dear list!
> >
> > I’m working on a piece with a lot of whole note tremolos and was wondering 
> > if any of you have a nice workaround for the beams (issues 318 and 704). I 
> > would like them slanted (with the same slope as a regular beam), centered 
> > between the noteheads and avoiding accidentals on the second note column, 
> > but if you have code producing any of these results it would be welcome. 
> > Harm’s code from this tread does unfortunately not seem to work any longer 
> > http://lilypond.1069038.n5.nabble.com/Tremolos-between-two-whole-notes-tt57577.html#a57580
> >  . I’ll start hacking something together, but if any of you already have 
> > invented this wheel it would be nice not to reinvent it.
> >
> > Thanks a lot!
> > /Leo
>
>

Hi,

here an updated version of my ancient code, along with a function to
supress warnings.

\version "2.20.0"

\paper { line-width = 120 }

tweakWholeNoteTremolo =
#(define-music-function (parser location gap y-off-pair)((number? 0.8) pair?)
#{
  \once \override Beam.gap = $gap
  \once \override Beam.positions =
    #(lambda (grob)
      (let* ((pos (beam::place-broken-parts-individually grob)))
        (cons
          (+ (car pos) (car y-off-pair))
          (+ (cdr pos) (car y-off-pair) (cdr y-off-pair)))))
#})

%--- test

suppressWarning =
#(define-void-function (amount message)(number? string?)
  (for-each
    (lambda (warning) (ly:expect-warning message))
    (iota amount 1 1)))

\suppressWarning 3 "weird stem size"

\score {
  \relative c'' {
  \tweakWholeNoteTremolo #'(-2.4 . 1.2)
  \repeat tremolo 16  { gis32 dis' }
  %\break

  \tweakWholeNoteTremolo #'(-3.6 . 1.7)
  \repeat tremolo 32  { <e, gis b>64 d' }

  \tweakWholeNoteTremolo #1.3 #'(4.4 . -3.0)
  \repeat tremolo 16  { a'32 a, }

  }
}


\new PianoStaff <<
  \new Staff = "right" {
    \repeat tremolo 16  {

    \tweakWholeNoteTremolo #'(11.2 . -19)
     e'''32
    \change Staff = "left"
     a,,
    }
  }
  \new Staff = "left" {
    \clef bass
    s1
  }
>>

It will not avoid possible accidentals at right NoteColumn, though.
Not saying it would be impossible, rather I've not the time to dive
into it deeper...

Cheers,
  Harm