Re: Setting up classical guitar fingerings

[Luca Fascione]

Hi Valentin, thank you this is super interesting. There's a lot of
information in there I want to read more carefully,
but for the moment I have one question: when is after-line-breaking invoke?
Or actually, better question: where do I go to discover when (and I guess
by what) after-line-breaking is invoked?

Another thing at the moment I don't follow is the 'engraver' variable in
the scheme engraver you wrote:
where does that come from? (I suspect it's some kind of name available
where the engraver is invoked, but again: how would I go at discovering
this?)

Many thanks, this is very helpful
Luca

On Sun, Feb 20, 2022 at 11:07 PM Valentin Petzel <valentin@petzel.at> wrote:

> Hello,
>
> our problem here is that such things like the positioning of beams are not
> known for quite some time. But we could use something like
> after-line-breaking
> to adjust the results. Somewhat like here.
>
> Valentin
>
> Am Sonntag, 20. Februar 2022, 21:17:31 CET schrieb Luca Fascione:
> > So... would anybody be able to lend a hand here please?
> >
> > Many thanks
> > Luca
> >
> > On Sat, Feb 12, 2022 at 7:49 PM Luca Fascione <l.fascione@gmail.com>
> wrote:
> > > Hello,
> > > sorry for the double-post, I'm unsure whether this should go to -user
> or
> > > -devel.
> > >
> > > I'm looking for some guidance to set up fingering on classical guitar
> > > sheets.
> > >
> > > I am attaching a simple piece of music, with two engraving sets
> (measures
> > > 1-5 and 6-10), one "as-is" from lilypond, the other using some trickery
> > > involving one-note chords, purely to show a sample of what the result
> I'm
> > > after (and it's an approximation), vs what I get at the moment.
> > >
> > > Measures 1-5 in the source look like what I am intending to type, but
> it
> > > has a number of engraving defects I don't understand (you can see the
> > > beams
> > > don't  avoid the fingerings, nor they are located correctly wrt the
> > > accidentals, the second beat of measure 5 illustrates this well. I'm
> not
> > > super in love with measure 10 either, but if I understand the docs
> > > correctly, the issue there is that the 'offset' correction is applied
> > > post-layout, and so naturally it won't back-affect the placement of the
> > > beams.
> > >
> > > I have made several other experiments, I'm just not wanting to waste
> > > people's time. But setting Fingering.side-axis = #X seems somewhat
> > > promising, but it seems unable to find any usable Y data about the
> > > parents,
> > > and smashes all numbers on the B line, as well as not dealing with
> > > accidentals.
> > >
> > > I have an engraving project in front of me, for which I'm more than
> happy
> > > to put in the time to contribute the code to a proper solution myself,
> and
> > > I really don't want to make poor use of time from folks busy with other
> > > work, but I feel I'll need some level of guidance as to what to do. For
> > > context I can do C++ and I can manage guile ok (I'm a software engineer
> > > for
> > > work, I'm mostly working in the field of computer graphics).
> > >
> > > I was looking into this problem several years ago also, and Han-Wen
> > > Nienhuys at the time suggested I should use a positioning callback
> > > attached
> > > to the Fingering grobs, but I couldn't find a way to do such a thing
> (in
> > > particular I can't find what property to use for this). So far I've
> traced
> > > the Fingering system to be an instance of the Articulations/Scripts
> > > system,
> > > but that's as far as I got.
> > >
> > > It seems to me what's needed would be to decide where the heads go,
> then
> > > the accidentals, at this stage deal with the fingering and only then
> there
> > > would be enough bboxes to reason about the beaming (this is the skyline
> > > concept I think). In reasoning about how Articulations are engraved,
> it's
> > > possible the order of events for fingering would be different from the
> > > order of events in other articulations (which I think are laid out
> after
> > > beams are in place, if I am not mistaken), warranting a bigger change,
> but
> > > I have no idea where that is located/managed.
> > >
> > > Many thanks for your time,
> > > Luca
>
>