Re: change custom notehead for different stem direction

[Lukas-Fabian Moser]

Hi Orm,

>   for flute pizzicato in contemporary music, it is quite common to use
> a ">" as a notehead. With a stem down, the ">" should be changed to a
> "<" as visible in the attached png.
>
> I know how to change the notehead by overriding the NoteHead stencil
> with an eps file, but can't find any information about automatically
> changing the glyph depending on stem direction. Is that possible in
> lilypond and does anybody have advice?
>
> It's cumbersome to do this by hand each time stem direction is
> changed.

Unfortunately you didn't provide a working example, hence my cumbersome 
and ugly choice of > or < for "note-heads".

\version "2.22.0"

\relative
{
  \override NoteHead.stencil = #ly:text-interface::print
  \override NoteHead.text =
  #(lambda (grob)
     (let*
      ((notecolumn (ly:grob-parent grob X))
       (stem (ly:grob-object notecolumn 'stem))
       (direction (ly:grob-property stem 'direction)))
      (markup #:general-align
              Y CENTER
              (if (positive? direction) ">" "<"))))
  c'4 d e f g a b c d e f
}

Of course, one might adapt the general logic to either use glyphs better 
suited than ">"/"<", or even conditionally rotate/mirror _any_ note-head 
depending on the direction. (One might use grob-transformer for that.)

Lukas