Re: Getting beam subdivision working

[Jason Yip]

On 2023-06-17 06:27, David Kastrup - dak(a)gnu.org wrote:
> David Kastrup <dak@gnu.org> writes:
>
> > Dan Eble <dan@lyric.works> writes:
> >
> > > On Jun 16, 2023, at 19:13, Jason Yip <sripedia_getpgrp@slmail.me> wrote:
> > > > minSubdivideInterval and maxSubdivideInterval. They are both
> > > > Rationals. Their numerator and denominator must be a power of 2. For
> > > > each power of 2 (including negative powers of 2 of course)
> > That's redundant.  It just means minSubdivideInterval and
> > maxSubdivideInterval must be an integral power of 2 (including
> > negative).
> >
> > > > between those two values, the beam can be subdivided by that
> > > > interval. minSubdivideInterval can be 0 for no minimum limit,
> > > > maxSubdivideInterval can be infinity for no maximum limit.
> > > Setting the representation aside, is the following another way of
> > > describing what you have in mind?
> > >
> > > * These properties are independently optional.
> > > * The allowed values are integer powers of two (including negative powers).
> > That sounds like it would make more sense to specify those values in the
> > form of a "duration log", like the first argument to a ly:make-duration
> > call.
> Or just use a duration in the first place.  First iterations would
> likely only use the duration-log info while I consider it conceivable
> that in the context of tuplets, ultimately also the factor may get used.

I've went ahead and set the 2 new properties as Moments since I wasn't 
sure how to make them Durations from Scheme. I was able to get them to 
do as I wanted. I attached the compilation of this snippet:

```\relative c' {
  \time 1/4
  % \set subdivideBeams = ##t
  \set minSubdivideInterval = #(ly:make-moment 1 8)
  \set maxSubdivideInterval = #(ly:make-moment 1 16)
  c32 c
  \tuplet 3/2 {
    \repeat unfold 4 c64
    \tuplet 3/2 { \repeat unfold 12 c128 }
    \repeat unfold 4 c64
  }
  c32 c
  \break

  \tuplet 3/2 {
    \tuplet 3/2 { \repeat unfold 12 c128 }
    \repeat unfold 4 c64
    \repeat unfold 4 c64
  }
  c32 c
  c32 c
  \break

  c32 c
  c32 c
  \tuplet 3/2 {
    \repeat unfold 4 c64
    \repeat unfold 4 c64
    \tuplet 3/2 { \repeat unfold 12 c128 }
  }
}

```

In this example, I wanted just the eighth and 16th note levels to be 
subdivided. So minSubdivideInterval is a eighth note duration, 
maxSubdivideInterval is a 16th note duration. My results seem to 
correctly be what I want. Code is at 
https://gitlab.com/ljyip/lilypond/-/tree/new_scm .

To clarify the usage of these 2 variables, minSubdivideInterval must be 
less than or equal to eighth note length in order to have any effect. 
maxSubdivideInterval must less than or equal to minSubdivideInterval to 
have any effect also. The intervals to be subdivided are inclusive of 
the bounds, so if minSubdivideInterval and maxSubdivideInterval both 
equaled eighth note, it subdivides just the eighth note level. Adding 
dots or specifying a factor to the Moment/Duration does nothing, 
although a specified factor may have some sort of possible use case. I 
only came up with these constraints today as I worked on the code, not 
when I first suggested them.


--
- Jason Yip

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