Re: Access a stem’s notehead

[Simon Albrecht]

On 22.01.2016 16:11, Simon Albrecht wrote:
> The feature is designed for a very specific case: Renaissance vocal 
> music, one voice per staff, no chords, no dynamics etc. With this 
> callback, I crop those stems which protrude beyond the staff, such as 
> to allow for still closer vertical spacing. 

Oops, there was an else-statement missing. Here again:

%%%%%%%%%%%%%%
\version "2.19.35"
#(define crop-outside-staff-stem
   (lambda (grob)
     (let* ((note-col (ly:grob-parent grob 0))
            (note-heads (ly:grob-object note-col 'note-heads)) ; is a 
Grob array
            (note-head (ly:grob-array-ref note-heads 0)) ; we don’t 
have chords anyway
            (staff-pos (ly:grob-staff-position note-head))
            (stem-len (ly:grob-property grob 'length))
            (delta (case (abs staff-pos)
                     ((3) -0.3)
                     ((2) -1)
                     ((1) -1.5)
                     ((0) -1.8)
                     (else 0))))
       (ly:grob-set-property! grob 'length (+ stem-len delta)))))
mus = {
  a'4 b' c'' d'' e'' f'' g''
}
{
  \time 7/4
  \mus
  \override Stem.before-line-breaking = #crop-outside-staff-stem
  \mus
}
%%%%%%%%%%%%%%%

Best, Simon