Re: \autoBeamOff

[Carl Sorensen]

On 8/16/10 3:30 PM, "Patrick Schmidt" <address@hidden> wrote:

> Dear LilyPonders,
> 
> while trying to typeset some vocal music I encountered some
> difficulties with \autoBeamOff:
> 
> 1) \autoBeamOff has no effect on other voices when used in a global
> variable/ghost voice. It has to be turned on explicitly for each
> voice. This is probably intentional but AFAIK not mentioned in the docs.

This is probably an argument for eliminating \autoBeamOff.  As can be seen
in ly/property-init.ly, \autoBeamOff is an alias for

\set autoBeaming = ##f

If you want it to apply in a global voice, simply do

\set Score.autoBeaming = ##f

> 
> 2) \autoBeamoff shows strange effects in combination with 16th notes
> and \partcombine. \autoBeamOff only effects 16th notes when they
> happen to be in the first measure of a combined part. All following
> measures containing 16th notes are beamed automatically as if
> automatic beaming had been turned on again. This looks like a bug to
> me!? (No problems with \autoBeamOff in standard polyphonic notation)

This is a  *very* challenging bug.  Partcombine apparently works with 3
voices -- stem up single, stem down single, stem up combined.

An \autoBeamOff call in the first argument to partcombine will apply to the
voice that is active at the time the call is processed, either stem up
single or stem up combined.  An \autoBeamOff call in the second argument
will apply to the voice that is stem down single.

In order to use \autoBeamOff to stop all autobeaming, it will be necessary
to use *3* calls to \autoBeamOff.

A workaround is to \set Staff.autoBeaming = ##f

Note -- I do consider this to be a bug with partcombine.  There is a
workaround, however.

Here is a tiny example (you can uncomment and comment the various lines to
change the behavior):

\version "2.13"

{
  %\set Staff.autoBeaming = ##f % turns off all autobeaming
  \partcombine
      {   
        \autoBeamOff % applies to split up stems
        \repeat unfold 4 a'16
        %\autoBeamOff % applies to combined up stems
        \repeat unfold 4 a'8
        \repeat unfold 4 a'16
      }   
      {   
        \autoBeamOff % applies to down stems
        \repeat unfold 4 f'8
        \repeat unfold 8 f'16 |
      }   
}


> In combination with \autoBeamOff \partcombine seems to require some
> curly braces, e.g.:
> 
>      \partcombine { \autoBeamOff\MusicPartOne }  { \autoBeamOff
> \MusicPartTwo }
> 
> I didn't find this information in the docs.

This problem is not specific to \autoBeamOff.  \partcombine always works on
the next two music expressions.  Without the curly braces it would be
\autoBeamOff and \MusicPartOne that would be combined.

HTH,

Carl