Re: brainstorming a really smart system engraver

[Janek Warchoł]

Hi Kieren,

2012-12-14 14:47 GMT+01:00 Kieren MacMillan <address@hidden>:
> Hello all,
>
> Like many people on this list, I engrave a number of choral works using 
> Lilypond. Like a smaller subset of those people, I engrave a number of large 
> and very large works (musicals, operas, extended choral works, etc.), which 
> require multiple editions (full score, pianovocal score, vocal book, etc.) 
> each with their own font sizes, system and page breaks, and so on.
>
> There are many times when two or more of my vocal or choral lines share 
> material — for example, in my "Wither's Carol", the entire first verse (with 
> the exception of a single two-measure chunk) is in "choral unison" (meaning 
> everyone singing the same notes and words in their own usual octave) — 
> whereas there are other very contrapuntal sections where material is totally 
> independent. Hence, there are sections where a score COULD be adequately 
> represented using only 1 choral staff, and other sections that require 2 or 3 
> or 4 (or even more) independent staves.
>
> Ultimately, I would like to have Lilypond choose the correct number of staves 
> so that horizontal and vertical spacing is optimal, using partcombine (or 
> 'partexplode'?), cueing, etc., to accomplish its task.
>
> I realize this is an AI nightmare and well outside Lilypond's current scope. 
> So as a half-measure, I would love to be able to tag certain sections as 
> "requires X staves", and then have Lilypond choose the least number of 
> required staves based on system/line breaking. As I [manually] change the 
> line breaks, the systems would automagically "expand" or "contract" as 
> necessary/possible to accommodate the new layout. Unfortunately, the current 
> tagging system is insufficient to do this, as far as I can tell.
>
> Can anyone think of a reasonably easy way to implement this feature?
> If so, I'll be happy to sponsor it.

I think that issue 3518 (pushed recently) does just this:
https://code.google.com/p/lilypond/issues/detail?id=3518