Updating this with cleaned up code and a clearer example in four parts.
Realized a few things:
1) The context property changes are working as I expected and staves are
correctly hiding or showing. There is no need to use remove-layers here.
2) When keepAliveInterfaces is set to '() in the first moment of a system,
the new value only applies starting after the line break, so if the staff
was alive on the previous system it will be kept alive on this system. The
workaround is to apply changes to keepAliveInterfaces at a moment just
before they are meant to take effect. This makes for awkward user input,
but doing it automatically would require the engraver looking a moment into
the future. Is looking ahead a feasible thing for an engraver to do? Should
this be written as an iterator instead?
\version "2.19.82"
% From define-context-properties.scm
#(define (translator-property-description symbol type? description)
(if (not (and
(symbol? symbol)
(procedure? type?)
(string? description)))
(throw 'init-format-error))
(if (not (equal? #f (object-property symbol 'translation-doc)))
(ly:error (_ "symbol ~S redefined") symbol))
(set-object-property! symbol 'translation-type? type?)
(set-object-property! symbol 'translation-doc description)
(set! all-translation-properties (cons symbol
all-translation-properties))
symbol)
#(translator-property-description 'sharingParts list? "List of consecutive
ints, indices of parts sharing this staff.")
#(translator-property-description 'combineWithNext boolean? "Is it okay for
this music to share a staff with the music in the next staff?")
#(define (segment pred lst)
"Segments a list into sublists, such that all elements satisfy pred
except the last element of each sublist."
(fold-right
(lambda (x y)
(if (pred x)
(cons (cons x (car y)) (cdr y))
(cons (list x) y)))
'(() . ())
lst))
% #(display (segment cdr '((1 . #f) (2 . #t) (3 . #t))))
Staff_sharing_engraver = #(lambda (ctx)
(let* ((all-staves '())
(solo-staves '()))
(make-engraver
(acknowledgers
((hara-kiri-group-spanner-interface
engraver grob source-engraver)
; We need an alist of child contexts, but
getting them this way
; means the engraver can't operate on the
first measure.
; Not sure what the proper way to get them
is?
(let* (
(child-ctx (ly:translator-context
source-engraver))
(child-id (ly:context-id
child-ctx))
(child-parts (ly:context-property
child-ctx 'sharingParts))
)
(set! all-staves (assoc-set! all-staves
child-parts child-ctx))
; Build alist of just the staves for a
single part.
(if (and (eq? 1 (length child-parts))
(not (assoc child-parts
solo-staves)))
(set! solo-staves
(merge solo-staves
(acons child-parts child-ctx
'())
(lambda (x y) (< (caar x)
(caar y)))))))
))
((start-translation-timestep translator)
(let* (
; Build alist of index:
combineWithNext value for solo staves
(combine-which-parts (fold-right
(lambda (kv
result)
(acons (car
kv)
(ly:context-property (cdr kv) 'combineWithNext)
result))
'()
solo-staves))
; Split the list by which parts can
be combined
; Then just keep the part indices
(groups (map
(lambda (sublst)
(map caar sublst))
(segment cdr
combine-which-parts)))
; Use the index lists to select
staves
(live-ctxs (if (pair? (car groups))
(map
(lambda (k)
(assoc-get k all-staves))
groups)
'()))
)
; Set keepAliveInterfaces = '() for all
staves
(map (lambda (kv)
(ly:context-set-property! (cdr kv)
'keepAliveInterfaces '()))
all-staves)
; Set keepAliveInterfaces to the default
for just the staves
; Corresponding to the current part
combinations
(map (lambda (ctx)
(ly:context-unset-property ctx
'keepAliveInterfaces))
live-ctxs)
))
)))
\paper {
short-indent = 0.5\cm
}
\new StaffGroup \with {
\consists \Staff_sharing_engraver
combineWithNext = ##t
\override VerticalAxisGroup.remove-empty = ##t
\override VerticalAxisGroup.remove-first = ##t
} <<
\new Staff = "1+2" \with {
sharingParts = #'(1 2)
shortInstrumentName = "1 2"
keepAliveInterfaces = #'()
} \repeat unfold 8 {
c'8 8 8 8 8 8 8 8
}
\new Staff = "1+2+3" \with {
sharingParts = #'(1 2 3)
shortInstrumentName = "1 2 3"
keepAliveInterfaces = #'()
} \repeat unfold 8 {
c'8 8 8 8 8 8 8 8
}
\new Staff = "1+2+3+4" \with {
sharingParts = #'(1 2 3 4)
shortInstrumentName = "1 2 3 4"
keepAliveInterfaces = #'()
} {
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
c'8 8 8 8 8 8 8 8 \break
}
\new Staff = "1" \with {
sharingParts = #'(1)
shortInstrumentName = "1"
keepAliveInterfaces = #'()
} {
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
}
\new Staff = "2+3+4" \with {
sharingParts = #'(2 3 4)
shortInstrumentName = "2 3 4"
keepAliveInterfaces = #'()
} \repeat unfold 8 {
c'8 8 8 8 8 8 8 8
}
\new Staff = "2+3" \with {
sharingParts = #'(2 3)
shortInstrumentName = "2 3"
keepAliveInterfaces = #'()
} \repeat unfold 8 {
c'8 8 8 8 8 8 8 8
}
\new Staff = "2" \with {
sharingParts = #'(2)
shortInstrumentName = "2"
keepAliveInterfaces = #'()
} {
c'8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##t
c'8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8 8
c'8 8 8 8 8 8 8 8
}
\new Staff = "3+4" \with {
sharingParts = #'(3 4)
shortInstrumentName = "3 4"
keepAliveInterfaces = #'()
} \repeat unfold 8 {
c'8 8 8 8 8 8 8 8
}
\new Staff = "3" \with {
sharingParts = #'(3)
shortInstrumentName = "3"
keepAliveInterfaces = #'()
} {
c'8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##t
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##t
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##t
c'8 8 8 8 8 8 8 8
\set Staff.combineWithNext = ##f
c'8 8 8 8 8 8 8 8 8
}
\new Staff = "4" \with {
sharingParts = #'(4)
shortInstrumentName = "4"
keepAliveInterfaces = #'()
} \repeat unfold 8 { c'8 8 8 8 8 8 8 8 }
>>
On Sat, Dec 29, 2018 at 5:21 PM Saul Tobin <[email protected]>
wrote:
> Hi all,
>
> Attached is my latest attempt to make progress toward an automatic
> mechanism for n-parts that may share a staff or not.
>
> The idea is that if the context property combineNext = ##t, then that part
> can share a staff with the next part down. The engraver is supposed to set
> keepAliveInterfaces = '() for all the staves except the ones corresponding
> to the current part grouping. Then depending on line-breaking, staves will
> be hidden according to remove-layers.
>
> I have two issues currently:
> 1) How to initialize the engraver with a list of child staff contexts?
> Grabbing them by acknowledging hara-kiri-group-spanner grobs means this
> engraver can't affect which staves display on the first system, which isn't
> ideal. Is there a better way?
>
> 2) ly:context-set-property! seems to work in the sense that the changed
> value gets read back correctly, but it doesn't seem like it's affecting the
> music output as I'd expect. Should I be having the engraver broadcast a
> property change event or something? How would one even do that? Or is this
> something to do with the timing of property changes happening over line
> breaks?
>
> Apologies for the less than elegant Scheme code. I would love some
> feedback/assistance on how to improve this or approach it better.
>
> Happy new year!
>
_______________________________________________
lilypond-user mailing list
[email protected]
https://lists.gnu.org/mailman/listinfo/lilypond-user
