Re: autochange with multiple voices

[David Kastrup]

Nik Repka <address@hidden> writes:

> I am attempting to make a scales sheet for piano.  I need to use autochange
> simultaneously in two voices.  
>
> I am using the syntax from this snippet page:
> http://www.lilypond.org/doc/v2.15/Documentation/snippets-big-page#keyboards-using-autochange-with-more-than-one-voice.
>
> The issue I am having is that autochange only works on the top voice, and it
> drags the lower voice up into the top staff.  Here is the code:
>
> \version "2.18.2"
>
> scaleRH = \relative c' {c d e f g a b c c b a g f e d c
> g a b c d e fis g g fis e d c b a g}
>
> scaleLH = \relative c {c d e f g a b c c b a g f e d c 
> g a b c d e fis g g fis e d c b a g}
>
>
> \score {
>    \new PianoStaff 
>     
>       << \new Staff = "up"
>          <<
>            \new Voice {
>            \voiceOne
>            \autochange
>     
>            \scaleRH 
>            
>            }
>
>            \new Voice {
>            \voiceTwo \autochange 
>
>            \scaleLH 
>            }
>          >>
>
>       \new Staff = "down" { 
>           \clef bass
>       }
>       >>
> }

Ok, disregard my previous reply.  It turns out that the whole
catastrophe happens _exclusively_ when the first note of the first voice
is c' (or probably one of cis' cisis' ces' ceses').

In every other situation, the outcome would appear to match
expectations.  It's not clear to me why (namely, it is not clear to me
why this problem would be restricted to melodies starting with c' as I'd
rather have expected it to occur always).

I have a patch that would appear to fix the problem but I'm somewhat
leery to propose it since I don't understand why the patch would not be
needed in general rather than just for the starts-with-c' situation.

-- 
David Kastrup