Re: "Controlled aleatorism" notation

[Han-Wen Nienhuys]

Andrzej Kopec wrote:
>     //         \\
> ----||--|-------||                    |-----
> ----||.-|---|--.||                    |-----
> ----||.-|---|--.||~~~~~~~~~~~~~~~~~~~~|-----
> ----||--o---|---||                    |-----
> ----||------o---||                    |-----
>     \\         //
>
> This notation was broadly used by Witold Lutosławski and Kazimierz
> Serocki (the greatest XX-cent. polish composers), and I suppose, that
> it isn't something strange to many other western Europe composers)
>
> To achieve that I've prepared stencils (as callbacks for print function, BTW 
> method seen on this
> list) repOn-callback and repOff-callback. And then I insert them to Rest's
> print-function. Why rest? maybe because I couldn't find any better object. But 
> rest isn't
> perfect frame for such things. Nevertheless this works in limited range, but
> works. Difficulties start if there is more than one voice/instrument. 
> Also wavy line made with TrillSpanner, and it is very hard to exactly determine start and
> stop points, and exact vertical positioning in consecutive systems.
>
> So I have some questions: 
>
> 1. is there any more suitable grob for this purpose? 

for what? Brackets or the wavy line?

> this means: some object which don't
>    take place in "musical time" but can be ideally vertically and horizontally 
> (in latter
>    rests used to have obstacles) positioned to staff. This is similar to 
> BarLine, and in
>    past I had used BarLines (ie. |: and :|, with Timing_engraver in Staff 
> context) for
>    that, but if I put patterns with a little shift in subsequent staves I get 
> lots of
>    empty spaces on each staff (place for barlines in other staffs). Ideal would 
> be some
>    object with no X-extent. Any ideas?
>
> 2. Is there any way to typeset spanner exactly from one place to another, in 
> manner that
>    it starts at \stopStaff and stops at \startStaff ?

why don't you change the number of stafflines to 1 and start a new 
staff?  ie.

  \stopStaff
  \override Staff.StaffSymbol #'line-count = #1
  \startStaff
   ...
  \stopStaff
  \revert Staff.StaffSymbol #'line-count
  \startStaff
   ...

Another option is to override the stencil callback for StaffSymbol.

If you have problems with this, I can cook up a sponsored aleatoric 
example .ly , but I guess there will be lots of people eager to 
demonstrate their elite L1l33P0nd ski11z :)

--
 Han-Wen Nienhuys - address@hidden - http://www.xs4all.nl/~hanwen