Below is a demonstration of an odd behavior I noticed.
When using a context like MarkLine for tempo marks, if the staff immediately below the MarkLine is hidden but contains rhythmic activity, and if BOTH Y-offset and extra-spacing-width are overridden for MetronomeMark, the first rhythmic column will stretch to the width of the tempo mark.
\version "2.19.82"
\layout {
\context {
\name "MarkLine"
\type "Engraver_group"
\consists Axis_group_engraver
\override VerticalAxisGroup.staff-affinity = #DOWN
\consists Metronome_mark_engraver
%% If either of the below lines is removed, the music spaces correctly
\override MetronomeMark.extra-spacing-width = #'(0 . 0)
\override MetronomeMark.Y-offset = #0
}
\context {
\Score
\remove Mark_engraver
\remove Metronome_mark_engraver
\accepts MarkLine
}
}
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\new MarkLine { \tempo "Testing testing" 4=123 }
\new Staff \with {
\override VerticalAxisGroup.remove-empty = ##t
\override VerticalAxisGroup.remove-first = ##t
keepAliveInterfaces = #'()
} {
c'8 8 8 8 8 8 8 8
}
\new Staff {
c'8 8 8 8 8 8 8 8
}
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