Initial clef change
Implements initial clef changes using a custom engraves. This engraves will upon encountering a difference between initial clef (as given by \with { \clef ... } and the clef at first timestep. If any difference is encountered a now clef (spaced like a cue clef) is created, while the original clef and any key signatures are modified to look like the initial clef values.
\version "2.24.0"
%%% This engraver records the initial clef properties (e.g. what is set by \with { \clef ... })
%%% If in the first timestep these changed, engrave the original clef, and change formatting and break
%%% alignment of the actual clef to mimic a clef change clef. Duplicates some procedure from clef engraver
%%% and could easily be integrated.
#(define (initial-clef-change-engraver context)
(let ((initial-clef-properties #f) (cclef #f) (keysigs '()))
; macro for checking if any clef property has changed
(define (clef-changed)
(>
(length initial-clef-properties)
(length
(filter
(lambda (x) (equal? (cdr x) (ly:context-property context (car x))))
initial-clef-properties))))
(make-engraver
; Record initials propertis
((initialize engraver)
(set!
initial-clef-properties
`((clefGlyph . ,(ly:context-property context 'clefGlyph))
(clefPosition . ,(ly:context-property context 'clefPosition))
(middleCClefPosition . ,(ly:context-property context 'middleCClefPosition))
(clefTransposition . ,(ly:context-property context 'clefTransposition)))))
; Record the actual clef to adjust. Use details.muted to not acknowledge clef created by this engraver.
(acknowledgers
((clef-interface engraver grob source-engraver)
(if (not (assoc-get 'muted (ly:grob-property grob 'details) #f))
(set! cclef grob)))
((key-signature-interface engraver grob source-engraver)
(set! keysigs (cons grob keysigs))))
; Create a clef if necessary
((process-music engraver)
(if (and initial-clef-properties (clef-changed))
(let ((clef (ly:engraver-make-grob engraver 'Clef '())))
(ly:grob-set-property! clef 'staff-position (assoc-get 'clefPosition initial-clef-properties))
(ly:grob-set-property! clef 'glyph (assoc-get 'clefGlyph initial-clef-properties))
(ly:grob-set-nested-property! clef '(details muted) #t)
(if ((lambda (x) (and (number? x) (not (= 0 x))))
(assoc-get 'clefTransposition initial-clef-properties 0))
(let ((mod (ly:engraver-make-grob engraver 'ClefModifier '()))
(formatter (ly:context-property context 'clefTranspositionFormatter))
(style (ly:context-property context 'clefTranspositionStyle))
(dir (sign (assoc-get 'clefTransposition initial-clef-properties 0)))
(abs_trans (1+ (abs (assoc-get 'clefTransposition initial-clef-properties 0)))))
(if (procedure? formatter)
(ly:grob-set-property! mod 'text (formatter (number->string abs_trans) style)))
(ly:grob-set-object! mod 'side-support-elements (ly:grob-list->grob-array (list clef)))
(ly:grob-set-parent! mod X clef)
(ly:grob-set-parent! mod Y clef)
(ly:grob-set-property! mod 'direction dir))))))
; Adjust the actual clef and key signatures
((process-acknowledged engraver)
(if (and cclef initial-clef-properties (clef-changed))
(begin
; Key signatures need to be handled if they appear before the cue-clef
; This requires the break alignment information, so this only sets a
; hook which will be processed during `before-line-breaking` of the
; BreakAlignGroups
(for-each
(lambda (keysig)
(let ((det (ly:grob-property keysig 'details))
(initial-clef-properties initial-clef-properties))
(ly:grob-set-property!
keysig
'details
(acons
'break-alignment-handler
(lambda (grob break-alignment)
(let ((start-of-line
(vector-ref
(ly:grob-property break-alignment 'break-align-orders)
2)))
(if (member 'cue-clef (or (member 'key-signature start-of-line) '()))
(ly:grob-set-property!
grob 'c0-position
(assoc-get 'middleCClefPosition initial-clef-properties)))))
det))))
keysigs)
(ly:grob-set-property! cclef 'non-default #t)
(ly:grob-set-property! cclef 'break-align-symbol 'cue-clef)
(if (not (eq? #t (ly:grob-property cclef 'full-size-change)))
(ly:grob-set-property! cclef 'glyph-name
(format #f "~a_change" (ly:grob-property cclef 'glyph)))))))
; Unset parameters
((stop-translation-timestep engraver)
(set! initial-clef-properties #f)
(set! clef #f)
(set! keysigs '())))))
\layout {
\context {
\Staff
\consists #initial-clef-change-engraver
}
\context {
\Score
\override BreakAlignGroup.before-line-breaking =
#(lambda (grob)
(let ((grobs (ly:grob-object grob 'elements))
(break-alignment (ly:grob-parent grob X)))
(if (not (null? grobs))
(set! grobs (ly:grob-array->list grobs)))
(for-each
(lambda (grob)
(let* ((det (ly:grob-property grob 'details))
(handler (assoc-get 'break-alignment-handler det)))
(if (procedure? handler)
(handler grob break-alignment))))
grobs)))
}
}
\new Staff \with { \clef "bass^15" } {
\key bes\major
\clef "treble_8"
c'1 c'1
\clef bass
c'1
}
\score {
\layout {
\context {
\Score
\override BreakAlignment.break-align-orders =
##((staff-ellipsis
left-edge
cue-end-clef
ambitus
breathing-sign
optional-material-end-bracket
signum-repetitionis
clef
cue-clef
staff-bar
key-cancellation
key-signature
time-signature
optional-material-start-bracket
custos)
(staff-ellipsis
left-edge
optional-material-end-bracket
cue-end-clef
ambitus
breathing-sign
signum-repetitionis
clef
cue-clef
staff-bar
key-cancellation
key-signature
time-signature
optional-material-start-bracket
custos)
(staff-ellipsis
left-edge
optional-material-end-bracket
ambitus
breathing-sign
signum-repetitionis
clef
cue-clef
key-cancellation
key-signature
time-signature
staff-bar
optional-material-start-bracket
custos))
}
}
\new Staff \with { \clef "bass^15" } {
\key bes\major
\clef "treble_8"
c'1 c'1
\clef bass
c'1
}
}
