Re: uniform-stretching

[Trevor Bača]

On 12/4/06, Trevor Bača <address@hidden> wrote:
> On 12/4/06, Trevor Bača <address@hidden> wrote:
> > On 12/4/06, Orm Finnendahl <address@hidden> wrote:
> > > Hi,
> > >
> > > I tried the uniform-stretching property but couldn't get it to work as
> > > expected. If I understand this property correctly, it should stretch
> > > out bars according to their time-signature regardless of skips or
> > > rests within.
> > >
> > > This fails (e.g. the first measure should be much wider than the
> > > second, the last and the one before the last measure should have the
> > > same width ...):
> > >
> > > \version "2.11.0"
> > >
> > > \score {
> > >     \new Staff {
> > >         \relative {
> > >             \override Score.SpacingSpanner #'uniform-stretching = ##t
> > >             \set Score.proportionalNotationDuration = #(ly:make-moment 8 50)
> > >             \time 4/4 r1
> > >             \time 3/8 r4.
> > >             \time 5/4 r1 r4
> > >             \time 5/16 r4 r16
> > >             \time 5/8 s2 s8
> > >             \time 5/8 r2 r8
> > >         }
> > >     }
> > >     \layout {
> > >         ragged-right = ##t
> > >     }
> > > }
> > >
> > > Can someone help? Trevor?
> >
> > Hi Orm,
> >
> > OK, I'm spinning out some combinations of different settings, and
> > getting closer.
> >
> > We definitely need uniform-stretching = ##t (as you have here in your 
> example).
> >
> > I think we also need \remove Separating_line_group_engraver, as
> > Han-Wen mentioned in a mail yesterday. (Separating_line_group_engraver
> > lives in the Staff context, BTW; make sure to place the \remove there
> > or else Lily will silently pass over your incorrect engraver removal,
> > never letting you know that you've failed to remove what you thought
> > you were removing.)
> >
> > So I've put together four score pairs; each pair comprises first notes
> > and then rests.
> >
> > The first pair has no tweaks and shows that notes and rests of like
> > duration space differently by default.
> >
> > The second pair removes Separating_line_group_engraver from the Staff context.
> >
> > The third pair sets uniform-stretching = ##t.
> >
> > The fourth pair performs both tweaks.
> >
> > These examples provide a couple of useful conclusions but don't yet
> > solve the problem. The conclusions are:
> >
> > 1. Notes and rests of like duration space differently by default (as
> > mentioned above)
> >
> > 2. uniform-stretching = ##t spaces notes and rests of like duration
> > identically (which is what we want)
> >
> > 3. removing Separating_line_group_engraver by itself is not enough to
> > cause even spacing; but I'm including the examples with removing
> > Separating_line_group_engraver because other testfiles seem to show
> > that the removal is necessary to get true proportional spacing
> >
> >
> > More tests coming later today ...
>
> AHA. There *is* a genuine bug as relates to spaces screwing up
> proportional notation under the circumstance that a skip *appears as
> the first item in a measure*. I'll crosspost to the bug list.

Hi Orm,

So, in the meantime you can use replace skips with transparent rests
as a workaround to the measure-initial skip bug. The last two measures
in 5/8 are uneven with skips (in the first score) and completely even
with transparent rests (in the second score).

%%% BEGIN %%%

\version "2.11.0"

\layout {
  ragged-right = ##t
}

\score {
  \new Staff \with {
     \remove Separating_line_group_engraver
  } {
      \relative {
          \override Score.SpacingSpanner #'uniform-stretching = ##t
          \set Score.proportionalNotationDuration = #(ly:make-moment 8 50)
          \time 4/4 r1
          \time 3/8 r4.
          \time 5/4 r1 r4
          \time 5/16 r4 r16
          \time 5/8 s2 s8 % Uneven
          \time 5/8 r2 r8   % Uneven
      }
  }
}

\score {
  \new Staff \with {
     \remove Separating_line_group_engraver
  } {
      \relative c' {
          \override Score.SpacingSpanner #'uniform-stretching = ##t
          \set Score.proportionalNotationDuration = #(ly:make-moment 8 50)
          \time 4/4 r1
          \time 3/8 r4.
          \time 5/4 r1 r4
          \time 5/16 r4 r16
          \override Rest #'transparent = ##t
          \time 5/8 r2 r8
          \revert Rest #'transparent
          \time 5/8 r2 r8
      }
  }
}

%%% END %%%

So the transparent rest workaround should help until we can fix the
measure-initial skip bug.

What's odd, though, is how short that first measure in 4/4 is ... can
we get a minimal (one- or two-measure) example that shows that overly
shortened first measure?


--
Trevor Bača
address@hidden

transparent-rests.png
Description: PNG image