Re: GSoC 2020 update, July 18

[Owen Lamb]

Thanks for the tip, Benkő!

At the moment, I think these sort of double stems are outside of my
project's scope. A two-stemmed black dragma is present in SMuFL as a
pre-composed note (mensuralBlackDragma), but Emmentaler does not have a
glyph for it and LilyPond does not specifically support double-stemming
single notehead grobs. All I am in charge of at the moment is taking how
LilyPond currently handles glyphs and adapting it to the SMuFL
specification, and that's keeping my hands full enough at the moment.

If you need it, I think the basic version of such a glyph can currently be
simulated by using two notehead grobs, something like this:

dragma =
#(define-music-function (music)
   (ly:music?)
   #{
     \override Staff.Stem.length = 4
     <<
       \override NoteColumn.direction = #UP
       #music
       \\
       \override NoteColumn.direction = #DOWN
       #music
     >>
     \revert Staff.Stem.length
   #})

\score {
  \new Staff {
    \override Staff.NoteHead.style = #'petrucci
    \dragma { g'4 a'2 }
    b'4 \dragma b' a' c''
  }
}

I can't vouch for the flags looking right, but it's something.

If you want to use the precomposed glyph as it is found in another SMuFL
font, you should be able to find it via something like OLL's
\smuflglyph command once I'm done with GSoC. Otherwise, this would probably
be a good idea for a separate feature request.

Hope this helps,
Owen

On Tue, Jul 21, 2020 at 3:28 AM Benkő Pál <benko.pal@gmail.com> wrote:

> Thanks. Lukas, that's what I looked for!  On the next page there are
> dragmas with flags on both stem and ones with flags only on the down
> stem.
>
> Lukas-Fabian Moser <lfm@gmx.de> ezt írta (időpont: 2020. júl. 21., K,
> 11:32):
> >
> > Hi Pál,
> >
> > > in ancient (ars subtilior) notation there actually are noteheads with
> > > two stems (which may also be flagged differently), called "dragma".
> > > a picture search for "dragma ars subtilior" returned poor images; one
> > > not entirely useless is
> > >
> https://www.last.fm/music/Philippus+de+Caserta/+images/f82a66af9573ba3cf431b0b1986f07e8
> > > (staff three, the black block between two red block in the first half
> > > of the staff); or see the youtube video
> > > https://www.youtube.com/watch?v=wd3ouxA9p-o
> >
> > See also the examples given in Apel, the first of which being
> >
> > https://archive.org/details/notationofpolyph1953apel/page/392/mode/2up
> >
> > Best
> > Lukas
> >
>