White mensural ligatures

There is limited support for white mensural ligatures.

To engrave white mensural ligatures, in the layout block, replace the Ligature_bracket_engraver with the Mensural_ligature_engraver in the Voice context:

\layout {
  \context {
    \Voice
    \remove Ligature_bracket_engraver
    \consists Mensural_ligature_engraver
  }
}

There is no additional input language to describe the shape of a white mensural ligature. The shape is rather determined solely from the pitch and duration of the enclosed notes. While this approach may take a new user a while to get accustomed to, it has the great advantage that the full musical information of the ligature is known internally. This is not only required for correct MIDI output, but also allows for automatic transcription of the ligatures.

At certain places two consecutive notes can be represented either as two squares or as an oblique parallelogram (flexa shape). In such cases the default is the two squares, but a flexa can be required by setting the ligature-flexa property of the second note head. The length of a flexa can be set by the note head property flexa-width.

For example,

\score {
  \relative {
    \set Score.timing = ##f
    \set Score.measureBarType = #'()
    \override NoteHead.style = #'petrucci
    \override Staff.TimeSignature.style = #'mensural
    \clef "petrucci-g"
    \[ c''\maxima g \]
    \[ d'\longa
       \override NoteHead.ligature-flexa = ##t
       \once \override NoteHead.flexa-width = 3.2
       c\breve f e d \]
    \[ c\maxima d\longa \]
    \[ e1 a, g\breve \]
  }
  \layout {
    \context {
      \Voice
      \remove Ligature_bracket_engraver
      \consists Mensural_ligature_engraver
    }
  }
}

Without replacing Ligature_bracket_engraver with Mensural_ligature_engraver, the same music looks as follows:

There are also cases when a stem is not required to unambiguously encode the note length, but is also not forbidden:

• an initial breve (when lower than the next note) may or may not have a downward left stem;
• a maxima may or may not have a downward right stem;
• a final longa (when lower than the previous note) may or may not have a right stem.

For example,

\score {
  \relative {
    \set Score.timing = ##f
    \set Score.measureBarType = #'()
    \override NoteHead.style = #'petrucci
    \override Staff.TimeSignature.style = #'mensural
    \clef "petrucci-c4"
    \[ \once \override NoteHead.left-down-stem = ##t
       a\breve b
       \once \override NoteHead.right-down-stem = ##t
       g\longa \]
    \[ \once \override NoteHead.right-down-stem = ##t
       b\maxima
       \once \override NoteHead.right-up-stem = ##t
       g\longa \]
  }
  \layout {
    \context {
      \Voice
      \remove Ligature_bracket_engraver
      \consists Mensural_ligature_engraver
    }
  }
}

Without tweaking the same ligatures look like

\score {
  \relative {
    \set Score.timing = ##f
    \set Score.measureBarType = #'()
    \override NoteHead.style = #'petrucci
    \override Staff.TimeSignature.style = #'mensural
    \clef "petrucci-c4"
    \[ a\breve b g\longa \]
    \[ b\maxima g\longa \]
  }
  \layout {
    \context {
      \Voice
      \remove Ligature_bracket_engraver
      \consists Mensural_ligature_engraver
    }
  }
}

See also

Music Glossary: ligature.

Notation Reference: Gregorian square neume ligatures, Ligatures.

Known issues and warnings

Horizontal spacing of ligatures may be poor. Accidentals may collide with previous notes.