Re: \textLengthOn - choosing which note to lengthen

[Carl D. Sorensen]

On 8/14/08 7:25 AM, "Chris Snyder" <address@hidden> wrote:

>
> Here ya go. This is for section 1.8.1.1. I'd recommend that it be placed
> between the current \textLengthOn example and the Predefined commands
> header.

Chris, thanks for the specific location recommendation.  This makes it
easy for the doc team to assess your contribution and change the docs.
>
> -- begin documentation snippet --
>
> Note that \textLengthOn does not necessarily increase the spacing of
> the note that the text is attached to. Rather, the shortest moment in
> time when the text occurs will get the added space (even if it is
> in another voice).
>
Your proposed text shows that you don't quite understand how
\textLengthOn works from a LilyPond point of view.  Your terminology
is not quite right, so we'll need to change the text a bit before
we put it in the manual.  I hope you'll not mind that.

\textLengthOn applies to a musical moment, not a note.  A musical
moment starts at an instant in time of the score, and includes all
events that occur at that instant.  A musical moment ends when
the next musical moment begins, or when the first event occurs
is not simultaneous with the current moment.

So, in the example, the first musical moment contains the c4 in
the treble cleff, the c1 in the bass clef, and the markup.  The
second musical moment contains the e in the treble clef.  The
effect of \textLengthOn is to make the first musical moment
take as much horizontal space as the markup.

While it appears that \textLengthOn adds space to the shortest
note, this is incorrect.  It is not the duration of the note in
the current moment that matters, but the timing of the first
note to follow the current moment.

> \score {
>    \new ChoirStaff <<
>      \new Staff \relative c' {
>        \clef treble
>        c4 e g e
>      }
>      \new Staff \relative c {
>        \clef bass
>        \textLengthOn
>        c1_\markup \column {
>          "The space is inserted between the first"
>          "and second beat, even though this text"
>          "is attached to the whole-note."
>        }
>      }
> }
>
Thanks for the small example -- it's very helpful.  Again, we'll
need to change it a bit some to better show the LilyPond
behavior.

Perhaps this modified version of your example helps to
explain the concept.

\score {
   \new ChoirStaff <<
     \new Staff \relative c' {
       \clef treble
       c4 e g e
     }
     \new Staff \relative c {
       \clef bass
       \textLengthOn
       c8 e2._\markup \column {
         "The musical moment extends from the"
         "e in the bass clef to the e in the"
         "treble clef, so the e in the treble"
         "clef is pushed right to fit this text."
       }
      g8
     }
   >>
}


Please let me know if this explanation has helped you
understand \textLengthOn.  If not, I'll need to better
understand the source of your confusion.

Thanks for your contributions to the documentation process!

Carl