Initial clef change: Difference between revisions

This snippet handles initial clef changes with a custom engraver. This engraver checks whether there is a difference between the initial clef (as given by <code>\with { \clef ... }</code> and the clef at the first timestep. If any difference is encountered a new 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. See also [[Clef change at the beginning of a piece]] and [[Clef change at the beginning of a piece (alternative)]].

<span></span>

\version "2.24"

%%% 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.

<nowiki>#</nowiki>(define (initial-clef-change-engraver context)

<nowiki> </nowiki>  (let ((initial-clef-properties #f) (cclef #f) (keysigs '()))

<nowiki> </nowiki>   ; macro for checking if any clef property has changed

<nowiki> </nowiki>    (define (clef-changed)

<nowiki> </nowiki>      (>

<nowiki> </nowiki>      (length initial-clef-properties)

<nowiki> </nowiki>      (length

<nowiki> </nowiki>        (filter

<nowiki> </nowiki>        (lambda (x) (equal? (cdr x) (ly:context-property context (car x))))

<nowiki> </nowiki>        initial-clef-properties))))

<nowiki> </nowiki>    (make-engraver

<nowiki> </nowiki>     ; Record initials propertis

<nowiki> </nowiki>    ((initialize engraver)

<nowiki> </nowiki>      (set!

<nowiki> </nowiki>      initial-clef-properties

<nowiki> </nowiki>      `((clefGlyph . ,(ly:context-property context 'clefGlyph))

<nowiki> </nowiki>        (clefPosition  . ,(ly:context-property context 'clefPosition))

<nowiki> </nowiki>        (middleCClefPosition . ,(ly:context-property context 'middleCClefPosition))

<nowiki> </nowiki>        (clefTransposition . ,(ly:context-property context 'clefTransposition)))))

<nowiki> </nowiki>     ; Record the actual clef to adjust. Use details.muted to not acknowledge clef created by this engraver.

<nowiki> </nowiki>    (acknowledgers

<nowiki> </nowiki>      ((clef-interface engraver grob source-engraver)

<nowiki> </nowiki>      (if (not (assoc-get 'muted (ly:grob-property grob 'details) #f))

<nowiki> </nowiki>          (set! cclef grob)))

<nowiki> </nowiki>      ((key-signature-interface engraver grob source-engraver)

<nowiki> </nowiki>      (set! keysigs (cons grob keysigs))))

<nowiki> </nowiki>     ; Create a clef if necessary

<nowiki> </nowiki>    ((process-music engraver)

<nowiki> </nowiki>      (if (and initial-clef-properties (clef-changed))

<nowiki> </nowiki>          (let ((clef (ly:engraver-make-grob engraver 'Clef '())))

<nowiki> </nowiki>            (ly:grob-set-property! clef 'staff-position (assoc-get 'clefPosition initial-clef-properties))

<nowiki> </nowiki>            (ly:grob-set-property! clef 'glyph (assoc-get 'clefGlyph initial-clef-properties))

<nowiki> </nowiki>            (ly:grob-set-nested-property! clef '(details muted) #t)

<nowiki> </nowiki>            (if ((lambda (x) (and (number? x) (not (= 0 x))))

<nowiki> </nowiki>                (assoc-get 'clefTransposition initial-clef-properties 0))

<nowiki> </nowiki>                (let ((mod (ly:engraver-make-grob engraver 'ClefModifier '()))

<nowiki> </nowiki>                      (formatter (ly:context-property context 'clefTranspositionFormatter))

<nowiki> </nowiki>                      (style (ly:context-property context 'clefTranspositionStyle))

<nowiki> </nowiki>                      (dir (sign (assoc-get 'clefTransposition initial-clef-properties 0)))

<nowiki> </nowiki>                      (abs_trans (1+ (abs (assoc-get 'clefTransposition initial-clef-properties 0)))))

<nowiki> </nowiki>                  (if (procedure? formatter)

<nowiki> </nowiki>                      (ly:grob-set-property! mod 'text (formatter (number->string abs_trans) style)))

<nowiki> </nowiki>                  (ly:grob-set-object! mod 'side-support-elements (ly:grob-list->grob-array (list clef)))

<nowiki> </nowiki>                  (ly:grob-set-parent! mod X clef)

<nowiki> </nowiki>                  (ly:grob-set-parent! mod Y clef)

<nowiki> </nowiki>                  (ly:grob-set-property! mod 'direction dir))))))

<nowiki> </nowiki>     ; Adjust the actual clef and key signatures

<nowiki> </nowiki>    ((process-acknowledged engraver)

<nowiki> </nowiki>      (if (and cclef initial-clef-properties (clef-changed))

<nowiki> </nowiki>          (begin

<nowiki> </nowiki>           ; Key signatures need to be handled if they appear before the cue-clef

<nowiki> </nowiki>           ; This requires the break alignment information, so this only sets a

<nowiki> </nowiki>           ; hook which will be processed during `before-line-breaking` of the

<nowiki> </nowiki>           ; BreakAlignGroups

<nowiki> </nowiki>          (for-each

<nowiki> </nowiki>            (lambda (keysig)

<nowiki> </nowiki>              (let ((det (ly:grob-property keysig 'details))

<nowiki> </nowiki>                    (initial-clef-properties initial-clef-properties))

<nowiki> </nowiki>                (ly:grob-set-property!

<nowiki> </nowiki>                keysig

<nowiki> </nowiki>                'details

<nowiki> </nowiki>                (acons

<nowiki> </nowiki>                  'break-alignment-handler

<nowiki> </nowiki>                  (lambda (grob break-alignment)

<nowiki> </nowiki>                    (let ((start-of-line

<nowiki> </nowiki>                          (vector-ref

<nowiki> </nowiki>                            (ly:grob-property break-alignment 'break-align-orders)

<nowiki> </nowiki>                            2)))

<nowiki> </nowiki>                      (if (member 'cue-clef (or (member 'key-signature start-of-line) '()))

<nowiki> </nowiki>                          (ly:grob-set-property!

<nowiki> </nowiki>                          grob 'c0-position

<nowiki> </nowiki>                          (assoc-get 'middleCClefPosition initial-clef-properties)))))

<nowiki> </nowiki>                  det))))

<nowiki> </nowiki>            keysigs)

<nowiki> </nowiki>          (ly:grob-set-property! cclef 'non-default #t)

<nowiki> </nowiki>          (ly:grob-set-property! cclef 'break-align-symbol 'cue-clef)

<nowiki> </nowiki>          (if (not (eq? #t (ly:grob-property cclef 'full-size-change)))

<nowiki> </nowiki>              (ly:grob-set-property! cclef 'glyph-name

<nowiki> </nowiki>                                    (format #f "~a_change" (ly:grob-property cclef 'glyph)))))))

<nowiki> </nowiki>     ; Unset parameters

<nowiki> </nowiki>    ((stop-translation-timestep engraver)

<nowiki> </nowiki>      (set! initial-clef-properties #f)

<nowiki> </nowiki>      (set! clef #f)

<nowiki> </nowiki>      (set! keysigs '())))))

\layout {

<nowiki> </nowiki> \context {

<nowiki> </nowiki>  \Staff

<nowiki> </nowiki>  \consists #initial-clef-change-engraver

<nowiki> </nowiki> }

<nowiki> </nowiki> \context {

<nowiki> </nowiki>  \Score

<nowiki> </nowiki>  \override BreakAlignGroup.before-line-breaking =

<nowiki> </nowiki>  #(lambda (grob)

<nowiki> </nowiki>      (let ((grobs (ly:grob-object grob 'elements))

<nowiki> </nowiki>            (break-alignment (ly:grob-parent grob X)))

<nowiki> </nowiki>        (if (not (null? grobs))

<nowiki> </nowiki>            (set! grobs (ly:grob-array->list grobs)))

<nowiki> </nowiki>        (for-each

<nowiki> </nowiki>        (lambda (grob)

<nowiki> </nowiki>          (let* ((det (ly:grob-property grob 'details))

<nowiki> </nowiki>                  (handler (assoc-get 'break-alignment-handler det)))

<nowiki> </nowiki>            (if (procedure? handler)

<nowiki> </nowiki>                (handler grob break-alignment))))

<nowiki> </nowiki>        grobs)))

<nowiki> </nowiki> }

}

\new Staff \with { \clef "bass^15" } {

<nowiki> </nowiki> \key bes\major

<nowiki> </nowiki> \clef "treble_8"

<nowiki> </nowiki> c'1 c'1

<nowiki> </nowiki> \clef bass

<nowiki> </nowiki> c'1

}

\score {

<nowiki> </nowiki> \layout {

<nowiki> </nowiki>  \context {

<nowiki> </nowiki>    \Score

<nowiki> </nowiki>    \override BreakAlignment.break-align-orders =

<nowiki> </nowiki>    ##((staff-ellipsis

<nowiki> </nowiki>        left-edge

<nowiki> </nowiki>        cue-end-clef

<nowiki> </nowiki>        ambitus

<nowiki> </nowiki>        breathing-sign

<nowiki> </nowiki>        optional-material-end-bracket

<nowiki> </nowiki>        signum-repetitionis

<nowiki> </nowiki>        clef

<nowiki> </nowiki>        cue-clef

<nowiki> </nowiki>        staff-bar

<nowiki> </nowiki>        key-cancellation

<nowiki> </nowiki>        key-signature

<nowiki> </nowiki>        time-signature

<nowiki> </nowiki>        optional-material-start-bracket

<nowiki> </nowiki>        custos)

<nowiki> </nowiki>        (staff-ellipsis

<nowiki> </nowiki>        left-edge

<nowiki> </nowiki>        optional-material-end-bracket

<nowiki> </nowiki>        cue-end-clef

<nowiki> </nowiki>        ambitus

<nowiki> </nowiki>        breathing-sign

<nowiki> </nowiki>        signum-repetitionis

<nowiki> </nowiki>        clef

<nowiki> </nowiki>        cue-clef

<nowiki> </nowiki>        staff-bar

<nowiki> </nowiki>        key-cancellation

<nowiki> </nowiki>        key-signature

<nowiki> </nowiki>        time-signature

<nowiki> </nowiki>        optional-material-start-bracket

<nowiki> </nowiki>        custos)

<nowiki> </nowiki>        (staff-ellipsis

<nowiki> </nowiki>        left-edge

<nowiki> </nowiki>        optional-material-end-bracket

<nowiki> </nowiki>        breathing-sign

<nowiki> </nowiki>        signum-repetitionis

<nowiki> </nowiki>        clef

<nowiki> </nowiki>        cue-clef

<nowiki> </nowiki>        key-cancellation

<nowiki> </nowiki>        key-signature

<nowiki> </nowiki>        time-signature

<nowiki> </nowiki>        staff-bar

<nowiki> </nowiki>        optional-material-start-bracket

<nowiki> </nowiki>        custos))

<nowiki> </nowiki>   }

<nowiki> </nowiki> \new Staff \with { \clef "bass^15" } {

<nowiki> </nowiki>  \key bes\major

<nowiki> </nowiki>  \clef "treble_8"

<nowiki> </nowiki>  c'1 c'1

<nowiki> </nowiki>  \clef bass

<nowiki> </nowiki>  c'1

<nowiki> </nowiki> }

}

% Basic usage:

\score {

<nowiki> </nowiki> <<

<nowiki> </nowiki>   % Just the treble clef

<nowiki> </nowiki>  \new Staff {

<nowiki> </nowiki>    \key bes \major

<nowiki> </nowiki>    c<nowiki>''</nowiki>1

<nowiki> </nowiki>  }

<nowiki> </nowiki>      

<nowiki> </nowiki>  \new Staff \with { \clef bass  } {

<nowiki> </nowiki>    \key bes \major

<nowiki> </nowiki>     c1

<nowiki> </nowiki>  }

<nowiki> </nowiki>   % Initial treble clef, then bass clef

<nowiki> </nowiki>  \new Staff {

<nowiki> </nowiki>    \key bes \major

<nowiki> </nowiki>    \clef bass  

<nowiki> </nowiki>    c1

<nowiki> </nowiki>   % Initial bass clef, then treble clef

<nowiki> </nowiki>  \new Staff \with { \clef bass  } {

<nowiki> </nowiki>    \key bes \major

<nowiki> </nowiki>    \clef treble  

<nowiki> </nowiki>    c<nowiki>''</nowiki>1

<nowiki> </nowiki> >>

<nowiki> </nowiki> \layout {

<nowiki> </nowiki>  \context {

<nowiki> </nowiki>    \Staff

<nowiki> </nowiki>    \consists #initial-clef-change-engraver

<nowiki> </nowiki>  }

<nowiki> </nowiki> }

}

<span></span>