New snippet: remove staff if another is alive (for wind divisi)

[Saul Tobin]

Hi all,

I just put together a snippet to make managing shared wind staves more
automatic, particularly with triple winds that may be combined in different
ways.

\version "2.19.82"

#(define remove-if-sibling
   (lambda (offsets)
     (lambda (grob)
       (let* (
               ;; The parent of a VerticalAxisGroup is a VerticalAlignment
               (parent (ly:grob-parent grob 1))
               ;; Get the children VerticalAxisGroups of the parent
               (siblings (ly:grob-object parent 'elements))
               (siblings-list
                (if (ly:grob-array? siblings)
                    (ly:grob-array->list siblings)
                    '()))
               ;; Find the siblings above or below me by offsets
               (my-vindex (ly:grob-get-vertical-axis-group-index grob))
               (enemy-indices (map (lambda (offset) (+ offset my-vindex))
offsets))
               (enemy-vaxis? (lambda (v) (member
(ly:grob-get-vertical-axis-group-index v)
                                           enemy-indices)))
               (enemy-vaxes
                (filter enemy-vaxis? siblings-list))
               )
         ;; Suicide if an enemy sibling is alive
         (map
          (lambda (enemy-vaxis)
            (ly:pointer-group-interface::add-grob grob 'make-dead-when
enemy-vaxis))
          enemy-vaxes)
         )
       )
     )
   )

%% Two Staff Example

global = {
  s1
  \break
  s1
  \break
  s1*2
}

I = {
  c'''1
  \context Staff = "1" { \set Staff.keepAliveInterfaces = #'() }
  c'''1
  c'''1
  \context Staff = "1" { \unset Staff.keepAliveInterfaces }
  c'''1
}

II = {
  e''1
  e''1
  e''1
  e''1
}

<<
  \new Staff = "1+2" \with {
    \override VerticalAxisGroup.before-line-breaking = #(remove-if-sibling
'(1))
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \partcombine \I \II >>
  \new Staff = "1" \with {
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \I >>
  \new Staff = "2" \with {
    \override VerticalAxisGroup.before-line-breaking = #(remove-if-sibling
'(-2))
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \II >>
>>

%% Three Staff Example

global = {
  s1
  \break
  s1
  \break
  s1
  \break
  s1*2
}

I = {
  c'''1
  \context Staff = "1" { \set Staff.keepAliveInterfaces = #'() }
  c'''1
  c'''1
  c'''1
  \context Staff = "1" { \unset Staff.keepAliveInterfaces }
  c'''1
}

II = {
  e''1
  e''1
  e''1
  e''1
  e''1
}

III = {
  a'1
  a'1
  \context Staff = "3" { \set Staff.keepAliveInterfaces = #'() }
  a'1
  a'1
  a'1
}

<<
  \new Staff = "1+2+3" \with {
    \override VerticalAxisGroup.before-line-breaking = #(remove-if-sibling
'(2 5))
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \I \II \III >>
  \new Staff = "1+2" \with {
    \override VerticalAxisGroup.before-line-breaking = #(remove-if-sibling
'(1 -1))
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \partcombine \I \II >>
  \new Staff = "1" \with {
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \I >>
  \new Staff = "2+3" \with {
    \override VerticalAxisGroup.before-line-breaking = #(remove-if-sibling
'(2 -3))
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \partcombine \II \III >>
  \new Staff = "2" \with {
    \override VerticalAxisGroup.before-line-breaking = #(remove-if-sibling
'(-1 -3 -4))
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \II >>
  \new Staff = "3" \with {
    \override VerticalAxisGroup.remove-empty = ##t
    \override VerticalAxisGroup.remove-first = ##t
  } << \global \III >>
>>

_______________________________________________
lilypond-user mailing list
lilypond-user@gnu.org
https://lists.gnu.org/mailman/listinfo/lilypond-user