Re: slurs between pairs of notes horizontally close and vertically distant

[Flaming Hakama by Elaine]

---------- Forwarded message ----------
From: Mason Hock <address@hidden>
To: lilypond-user <address@hidden>

Subject: slurs between pairs of notes horizontally close and vertically distant

I'm working on a score with many pairs of notes a sixth or seventh apart slurred together. When the stem of the second note of a pair is down, the slur intersects the accidental. If I increase 'Slur.details.accidental-collision' the slur avoids the accidental, but is not as well-shaped. For most pairs Lilypond acheives a good compromise, but sometimes the slur is quite distant from the notes and the endpoints of the slur are close to the same height, making it unclear that the curve represents a slur between the two pitches.

It seems that the bad slurs occur when there is not a lot of horizontal space between the two notes. In the example below, the slur between the half notes in the second bar looks much better than the slur between the same two pitches as eighth notes in the first bar. Even the third and fourth slurs look much better than the first and second because the accidentals add just a tiny bit more horizontal space.

From reading this <http://lilypondblog.org/2013/11/engraving-challenges-slurs-and-ties> it sounds like slurs are very difficult to shape well automatically. It's impressive that Lilypond does this well before manual tweaking. However, this issue occurs so many times in this score that it would take way too long for me to fix each one manually with \shape.

Since Lilypond really only seems to have trouble when the notes are very close to each other horizontally, perhaps a way to fix the slurs globally would be to set a minimum horizontal space between notes. However, Lilypond's horizontal spacing is not the issue and I'd rather not override something that it is doing well. Also, I expect that the horizontal space needed to fix the slur depends on the vertical distance and stem direction of the first note

I would prefer a solution that only affects the slurs. Perhaps the issue would be fixed by allowing greater curvature for slurs. For example, if the first slur began close to the staff, looped all the way around the flat, then came back down and ended close to the second notehead, it would look a little odd but would be a large improvement. Some of the more adequate slurs might also be improved by this, and I don't see any that it would break. I would have no idea how to implement this though.

Does anyone have any suggestions?

Thanks,

Mason

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\version "2.18.2"

\language "english"

% slurs are shaped well but intersect accidentals

\relative c' {

  \accidentalStyle neo-modern

  c'8( af') cqs,( aqf') cs,( a') ctqs,( aqs') |  c,2( af') |

  \tuplet 3/2 {f,4( e') fqs,(} \tuplet 3/2 {eqs') gf,( f')} |

  g,( ef') gqs,8( eqf') gs,( e') |

}

% slurs avoid accidentals but are not well-shaped

\relative c' {

  \accidentalStyle neo-modern

  \override Slur.details.accidental-collision = #30

  c'8( af') cqs,( aqf') cs,( a') ctqs,( aqs') |  c,2( af') |

  \tuplet 3/2 {f,4( e') fqs,(} \tuplet 3/2 {eqs') gf,( f')} |

  g,( ef') gqs,8( eqf') gs,( e') |

}

Here is an approach that yields something hopefully more acceptable.

I suspect this may cause some side effects, exaggerating other slurs that were ok before, since it is a global adjustment.

\score {

\relative c' {

  \accidentalStyle neo-modern

  <>^"9"

  c'8( af') cqs,( aqf') cs,( a') ctqs,( aqs') |  c,2( af') |

  \tuplet 3/2 {f,4( e') fqs,(} \tuplet 3/2 {eqs') gf,( f')} |

  g,( ef') gqs,8( eqf') gs,( e') |

}

\layout {

    \context {

        \Voice

        \override Slur.height-limit = 9

        \override Slur.ratio = 0.5

    }

}

}

HTH, 

David Elaine Alt

415 . 341 .4954                                           "Confusion is highly underrated"

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