Automatic beaming

[Helge Kruse]

Hello,

I sent this mail yesterday with the graphics attached, but it did not 
appear in the mailing list. I resend it with an link to the graphic at a 
web server. Hope this passes the moderation.

I write a piece with where are a lot of triplets in one variation. It 
looks nice to have the beaming in the same length as the triplets as it 
is done in the hand writing original.

I found in the manual (1.2.4 Beams) that I can manually set beaming. But 
since the piece has a regulare structure (almost only triples), I wanted 
to use automatic beaming. Unfortunately I did get i working. I attach 
the samples in one file (tuplet.ly) with some samples. The handwritten 
original score is placed here: http://dj1na.gmxhome.de/pg-0009.JPG


Sample:1 got from the manual works, shows the use of beatGrouping.

Sample:2 I modified it using beatLength, shows that automatic beaming 
works with triplets.

Sample:3 This is an excerpt of the "real score", but using manual 
beaming. The object is to setup automatic beaming, that it produces the 
same output.

Sample:4 My Playground, where no combination of beatLength and 
beatGrouping gave any acceptible result.


Can you tell we, what must I do to fix this?


Best Regards,
Helge

\version "2.11.63"
\include "deutsch.ly"

% sample:1
% from snippet repository, two explicit voices, works fine
\score {
  \new Staff <<
    \time 7/8
    \new Voice {
      \relative c'' {
        \set Staff.beatGrouping = #'(2 3 2)
        a8 a a a a a a
      }
    }
    \new Voice {
      \relative c' {
        \voiceTwo
        \set Voice.beatGrouping = #'(1 3 3)
        f8 f f f f f f
      }
    }
  >>
%  \layout { \context { \Staff \consists "Measure_grouping_engraver" } }
}

% sample:2
% based on snippet repository shows beatGrouping with triplets, works fine
% but give unexpected behavior, when the \time is changed to 4/8 or 2/4
\score {
  \new Staff <<
    \time 7/8
    \new Voice {
      \relative c'' {
        \voiceTwo
        \set Staff.beatLength = #(ly:make-moment 1 8)
        \times 2/3 { a16 a a } \times 2/3 { a a a } 
      }
    }
  >>
%  \layout { \context { \Staff \consists "Measure_grouping_engraver" } }
}   

% sample:3
% "real score", manual beaming, works
% but this requires manual beaming for all measures
\score {
  \relative c'' {
    \clef treble \key as \minor \time 2/4
    
    << { r8 ces r ces } 
       \\
       { \times 2/3 { r16 as[ b] }
         \times 2/3 { ces[ b as] }
         \times 2/3 { s as[ b] }
         \times 2/3 { ces[ b as] }
       } 
     >>
    }
  \layout { \context { \Staff \consists "Measure_grouping_engraver" } }
}

% "real score", automatic beaming, does NOT work 
\score {
  \relative c'' {
    \clef treble \key as \minor \time 2/4

%    \set Staff.beatLength = #(ly:make-moment 1 8)
%    \set Staff.beatGrouping = #'(2 2 2 2 2 2 2 2 )
    \set Staff.beatGrouping = #'(8 8 8 8)
    
    << { r8 ces r ces } 
       \\
       { \times 2/3 { r16 as b }
         \times 2/3 { ces b as }
         \times 2/3 { s as b }
         \times 2/3 { ces b as }
       } 
     >>
  }
  \layout { \context { \Staff \consists "Measure_grouping_engraver" } }
}