Re: A slur across a line break with change of clef in another staff generates bad output

[Richard Shann]

On Sat, 2015-05-30 at 22:23 +0200, Simon Albrecht wrote:
> Am 30.05.2015 um 18:10 schrieb Richard Shann:
> > Attached is a bit of LilyPond which has a slur over a line break. At the
> > same moment the clef is changing in the lower staff. The result is a
> > horribly broken slur start in the top staff.
> > I blindly applied the dragging-the-shape on this curve which generated
> > the commented out offsets. This results in something half-way
> > acceptable. The bug is sensitive to all sorts of things I think - this
> > was the most I managed to pare it down - reducing the font size made it
> > go away for example.
> > 
> > Questions:
> >     Is there special syntax for altering the shapes of the half-slurs at
> > the end and beginning of the line?
> Yes, look for \alterBroken in the docs.
> >     Is this a known bug?
> Yes, or at least partly so:
> <https://code.google.com/p/lilypond/issues/detail?id=3287> You may
> comment in there, in case you have something to add.

Well, it looks like you have it covered there. FWIW I further whittled
my example down and found that varying the global-staff-size I could
vary the response markedly. Which is what the bug report is alluding to
when it says "in tight spacing situations" I guess.
Here is my short example:


\version "2.18.2"
#(set-global-staff-size 36)
VoiceI = {
         fis''8 fis''8 fis''8 fis''8 fis''16( g'' a'' g'' fis''8) 
         fis''16( g''
         \break a''8) a''8 a''8 a''8 r2    
        }


VoiceII = {
         \clef bass r2 r4. a8(
         \clef treble d') <d' a'>8 <d' a'>8 <d' a'>8 r2
          }



\score {
 << 
   \new Staff \new Voice  \VoiceI             
   \new Staff \new Voice  \VoiceII  
 >>

      }