Re: rests colliding with beams when voice changes staves

[Mats Bengtsson]

If you explictly specify the stem directions of the notes
that the rest collides with, the rest collision handler will
move the rest in the opposite direction (which is what you
want, at least in this case). So, just change bar 17 of your
voice 1 to:

      \translator Staff = two   \stemUp fis, a cis
      \translator Staff = one   \stemBoth fis  e
      d8 r r
      r16
      \translator Staff = two \stemUp e, gis b
      \translator Staff = one \stemBoth e  d

It seems that Lilypond hasn't decided on the stem directions
at the moment when the rest collisions are handled, that's
why you have to specify them explicitly.

  /Mats

> take a look at measure 17 here:
> 
> http://jeffcovey.net/music/scores/bach/inventions/12-tmp/
> 
> when the upper voice moves into the lower staff, the eight rest in the
> lower voice jumps up and engraves itself over the beams of the upper
> voice.  it looks like it's trying to get out of the way and jumping in
> the wrong direction.
> 
> i was able to correct it with
> 
> \property Thread.Rest \override #'staff-position = #-11
> 
> here:
> 
> http://jeffcovey.net/music/scores/bach/inventions/12/
> 
> , but that's kludgey.  is there something else i should be doing, or
> is it just a bug in lily?