Re: DurationLine avoiding RehearsalMarks

[Thomas Morley]

Hi Jean,

thanks for all your work and explanations.
I'll split my answer into different mails.
This one is about the design

Am Mo., 11. Apr. 2022 um 18:04 Uhr schrieb Jean Abou Samra <jean@abou-samra.fr>:
>
> Le 11/04/2022 à 17:20, Thomas Morley a écrit :
> > Well, your example prints as I would wish it should.
> > Alas, there are obviously different opinions. Look at:
> > \layout {
> >     \context {
> >       \Voice
> >       \consists Duration_line_engraver
> >     }
> > }
> >
> > <<
> >     \new Staff {
> >           \override Glissando.breakable = ##t
> >           c'1(\-\startTextSpan\glissando \break s1 c''1)\stopTextSpan
> >     }
> >     \new Staff { s1 \key cis \major s1 s1 }
> > >>
> > Not all spanners start/end equal.
> > Imho, it's a mess which needs design decisions.
>
>
>
> Hm. That's right. Let's consider another example:
>
> \version "2.23.8"
>
> \layout {
>    \context {
>      \Voice
>      \consists Duration_line_engraver
>    }
> }
>
> \paper {
>    ragged-right = ##t
> }
>
> <<
>    \new Staff { c'1\- \break c'1 }
>    \new Staff { c'1 \breathe c'1 }
>  >>
>
>
> Well, maybe it doesn't make sense anyway -- I don't think I've
> ever seen a breathing sign in one staff and not another.
>
> Though, if this is something we want to support, I think we'll
> agree that the duration line in the upper staff should not be
> affected by the breathing sign, as the breathing sign doesn't
> apply to that staff.

I slightly disagree.

In many details DurationLine was tailored after Glissando and
Glissando _is_ effected by the breathing sign. See:

\layout {
   \context {
     \Voice
     \consists Duration_line_engraver
   }
}

\paper {
   ragged-right = ##t
}

<<
   \new Staff {
          \override Glissando.breakable = ##t
          \override Glissando.after-line-breaking = ##t
          \override DurationLine.after-line-breaking = ##t
          \override Score.RehearsalMark.break-visibility = ##(#t #t #t)
          c'1\-\glissando
          %\mark \default
          \break c''1
   }
   \new Staff {
          c'1
          \breathe
          c'1
   }
 >>

Thus any design decision should affect both, DurationLine and Glissando, imho.


> Making the DurationLine affected only by breakable items in
> its staff is easy to define (implementation: see below). If
> we decide that we want different behaviors for different breakable
> items, like KeySignature vs. BreathingSign, a definition is
> going to be trickier ...

If you uncomment \mark above then DurationLine is affected and Glissando not.
That's the bug at hand, imho.
I have a fix for it in a local branch, explicitely removing
RehearsalMark from items to consider.
Isn't it sufficient here?

If you agree I'll do some polish and probably add a regtest and open a MR.

Thanks,
  Harm