Re: Possible bug with multiple voices, slurup and rests?

[Mats Bengtsson]

> Hi all,
>
> I seem to be having trouble with rest alignment. The specific case I have is
> pretty specific:
>
> 1. I have a multiple-voice section
> 2. I have /slurUp
> 3. I have a rest, with no rests before this point
>
> In this case, the rest seems to still be high rather than centered, as if
> another voice still existed. If there is a rest anywhere before the /slurUp
> command, the problem does not exist. Is this a known issue or am I doing
> something stupid?
>
>
> \version "2.14.2"
> {
>    % Problem here
>    <<  { f' e' g' g' } \\ { e' d' d' d' }>>  \slurUp d' r4
> }
> {
>    % This is fine
>    r4<<  { e' g' g' } \\ { d' d' d' }>>  \slurUp d' r4
> }
> {
>    % This is fine
>    <<  { f' e' g' g' } \\ { e' d' d' d' }>>  r4 \slurUp r4
> }

This is one example of the problems that are related to the "A word of 
warning" in the Learning Manual, Sect. 3.1.1 "Introduction to the 
LilyPond file structure". If you explicitly tell LilyPond that you want 
to create a voice of music, then the problem disappears:
\new Voice {
<< { f' e' g' g' } \\ { e' d' d' d' } >> \slurUp d' r4
}

What happens with the <<{...} \\ {...}>> construct is that LilyPond 
creates two Voice contexts, called "1" and "2" and then goes back to the 
main Voice that existed before the polyphonic part. However, if this 
happens at the start of the score, then LilyPond has not had any 
opportunity to create a main Voice context and then it keeps the "1" 
Voice also for the following music. The simple solution is, as shown in 
my example, to explicitly create a Voice context before the <<...\\...>> 
section.

    /Mats

--
=============================================
        Mats Bengtsson
        Signal Processing
        School of Electrical Engineering
        Royal Institute of Technology (KTH)
        SE-100 44  STOCKHOLM
        Sweden
        Phone: (+46) 8 790 8463                         
        Fax:   (+46) 8 790 7260
        Email: address@hidden
        WWW: http://www.ee.kth.se/~mabe
=============================================