Re: Issue 1043 in lilypond: Cross-staff beams confuse skyline calculations

[David Kastrup]

address@hidden writes:

> Comment #11 on issue 1043 by address@hidden: Cross-staff beams
> confuse skyline calculations
> http://code.google.com/p/lilypond/issues/detail?id=1043
>
> Now I see that placement of outside-staff grobs uses a series of
> skyline calculations. Knowing that, the 'Summary:' makes sense.  Sorry
> for my  objection earlier.
>
> I would categorize the behavior:
>
> 2) Cross-staff beams do not expand skylines. This makes sense so these
> beams do not push the staves apart, but then these beams can overlap
> outside-staff grobs, notably dynamics.  Same as issue 439, and issue
> 36;  see also issue 721.

How would cross-staff beams push staves apart when their respective
stems apparently don't?  The thing that I can imagine is that the
cross-staff beam is part of both skylines, and Lilypond tries pushing it
away from itself.

Is it something like that?

> 1) An automatic beam ending just before a staff change fails to expand
> skylines, resulting in similar collisions.  Explicit [ ] beams are a
> workaround.  First described in this issue, comments 2 and following.

That sounds like something that could be addressed without something
else caving in.

-- 
David Kastrup