Re: 3/2 unusual writing

[Aaron Hill]

On 2018-10-04 2:09 am, Jacques Menu wrote:
> Hello folks,
>
> I’ve found this in Charpentier’s Te Deum, as engraved by the
> Centre de Musique Baroque de Versailles, which I had never seen
> before:
>
> It’s quite readable indeed, maybe more than using the modern
> notation with quarters, and I’ve wondered if there a way to obtain
> that with Lily.

Simplest option is to use a note scaling fraction:

d2*1/2

This produces a "half note" but it has been scaled in half so it only 
lasts as long as a quarter note.  The note head, however, will still 
render as a half.

The problem is that this does not let you do beaming:

d2*1/2[ e f g]

You will get an error because half notes do not support beams.

One way to get around this is to use something like an eighth note 
(which does support beams) and then scale it so it lasts as long as a 
quarter (which is what the music in question needs):

d8*2[ e f g]

But now we are back at the problem where the note heads are showing as 
solid.  Graham has provided a way to force the note head to render 
however you want.  Allow me to provide an alternative:

%%%%
\version "2.19.82"

\relative d {
  \clef bass \key d \major
  \time 3/2
  \override NoteHead.stencil = #(lambda (grob)
    (let* ((dur (ly:event-property (event-cause grob) 'duration))
           (dur? (and (eqv? (ly:duration-log dur) 3) (eqv? 
(ly:duration-scale dur) 2))))
      (if dur? (ly:grob-set-property! grob 'text (markup #:musicglyph 
"noteheads.s1")))
      (if dur? ly:text-interface::print ly:note-head::print)))
  d1. | e1. | fis2 b,8*2[ cis d b] |
  e1. | fis2. gis8*2 ais2 | b2 b,8*2 cis d2 |
  e2. d8*2 cis2
}
%%%%

What I am doing here is providing a function that checks to see if you 
are using the 8*2 duration specifically and only then adjusting the way 
the note head is displayed.

-- Aaron Hill