Hello,
I grabbed this snippet a while ago from somewhere™ which puts a box around music (an "improvisation box"). It works perfectly in Lilypond 2.22.1, but not in Lilypond 2.23.3+. Does somebody know how to make it work in more recent versions? This is the snippet:
\version "2.19.15"
\header {
tagline = ##f
}
#(define-event-class 'music-boxer-event 'span-event)
#(define-event-class 'box-event 'music-event)
#(define (add-grob-definition grob-name grob-entry)
(let* ((meta-entry (assoc-get 'meta grob-entry))
(class (assoc-get 'class meta-entry))
(ifaces-entry (assoc-get 'interfaces meta-entry)))
;; change ly:grob-properties? to list? to work from 2.19.12 back to at least 2.18.2
(set-object-property! grob-name 'translation-type? ly:grob-properties?)
(set-object-property! grob-name 'is-grob? #t)
(set! ifaces-entry (append (case class
((Item) '(item-interface))
((Spanner) '(spanner-interface))
((Paper_column) '((item-interface
paper-column-interface)))
((System) '((system-interface
spanner-interface)))
(else '(unknown-interface)))
ifaces-entry))
(set! ifaces-entry (uniq-list (sort ifaces-entry symbol<?)))
(set! ifaces-entry (cons 'grob-interface ifaces-entry))
(set! meta-entry (assoc-set! meta-entry 'name grob-name))
(set! meta-entry (assoc-set! meta-entry 'interfaces
ifaces-entry))
(set! grob-entry (assoc-set! grob-entry 'meta meta-entry))
(set! all-grob-descriptions
(cons (cons grob-name grob-entry)
all-grob-descriptions))))
#(define (make-box thick padding xext yext)
(let ((xext (interval-widen xext padding))
(yext (interval-widen yext padding)))
(ly:stencil-add
(make-filled-box-stencil xext (cons (- (car yext) thick) (car yext)))
(make-filled-box-stencil xext (cons (cdr yext) (+ (cdr yext) thick)))
(make-filled-box-stencil (cons (cdr xext) (+ (cdr xext) thick)) yext)
(make-filled-box-stencil (cons (- (car xext) thick) (car xext)) yext))))
#(define (music-boxer-stencil grob)
(let* ((elts (ly:grob-object grob 'elements))
(refp-X (ly:grob-common-refpoint-of-array grob elts X))
(X-ext (ly:relative-group-extent elts refp-X X))
(refp-Y (ly:grob-common-refpoint-of-array grob elts Y))
(Y-ext (ly:relative-group-extent elts refp-Y Y))
(padding (ly:grob-property grob 'padding 0.3))
(stil (make-box 0.1 padding X-ext Y-ext))
(offset (ly:grob-relative-coordinate grob refp-X X)))
(ly:stencil-translate-axis stil (- offset) X)))
#(define box-stil music-boxer-stencil)
#(add-grob-definition
'Box
`(
(stencil . ,box-stil)
(meta . ((class . Item)
(interfaces . ())))))
#(add-grob-definition
'MusicBoxer
`(
(stencil . ,music-boxer-stencil)
(meta . ((class . Spanner)
(interfaces . ())))))
#(define box-types
'(
(BoxEvent
. ((description . "A box encompassing music at a single timestep.")
(types . (general-music box-event music-event event))
))
))
#(define music-boxer-types
'(
(MusicBoxerEvent
. ((description . "Used to signal where boxes encompassing music start and stop.")
(types . (general-music music-boxer-event span-event event))
))
))
#(set!
music-boxer-types
(map (lambda (x)
(set-object-property! (car x)
'music-description
(cdr (assq 'description (cdr x))))
(let ((lst (cdr x)))
(set! lst (assoc-set! lst 'name (car x)))
(set! lst (assq-remove! lst 'description))
(hashq-set! music-name-to-property-table (car x) lst)
(cons (car x) lst)))
music-boxer-types))
#(set!
box-types
(map (lambda (x)
(set-object-property! (car x)
'music-description
(cdr (assq 'description (cdr x))))
(let ((lst (cdr x)))
(set! lst (assoc-set! lst 'name (car x)))
(set! lst (assq-remove! lst 'description))
(hashq-set! music-name-to-property-table (car x) lst)
(cons (car x) lst)))
box-types))
#(set! music-descriptions
(append music-boxer-types music-descriptions))
#(set! music-descriptions
(append box-types music-descriptions))
#(set! music-descriptions
(sort music-descriptions alist<?))
#(define (add-bound-item spanner item)
(if (null? (ly:spanner-bound spanner LEFT))
(ly:spanner-set-bound! spanner LEFT item)
(ly:spanner-set-bound! spanner RIGHT item)))
musicBoxerEngraver =
#(lambda (context)
(let ((span '())
(finished '())
(current-event '())
(event-start '())
(event-stop '()))
`((listeners
(music-boxer-event .
,(lambda (engraver event)
(if (= START (ly:event-property event 'span-direction))
(set! event-start event)
(set! event-stop event)))))
(acknowledgers
(note-column-interface .
,(lambda (engraver grob source-engraver)
(if (ly:spanner? span)
(begin
(ly:pointer-group-interface::add-grob span 'elements grob)
(add-bound-item span grob)))
(if (ly:spanner? finished)
(begin
(ly:pointer-group-interface::add-grob finished 'elements grob)
(add-bound-item finished grob)))))
(inline-accidental-interface .
,(lambda (engraver grob source-engraver)
(if (ly:spanner? span)
(begin
(ly:pointer-group-interface::add-grob span 'elements grob)))
(if (ly:spanner? finished)
(ly:pointer-group-interface::add-grob finished 'elements grob))))
(script-interface .
,(lambda (engraver grob source-engraver)
(if (ly:spanner? span)
(begin
(ly:pointer-group-interface::add-grob span 'elements grob)))
(if (ly:spanner? finished)
(ly:pointer-group-interface::add-grob finished 'elements grob))))
(finger-interface .
,(lambda (engraver grob source-engraver)
(if (ly:spanner? span)
(begin
(ly:pointer-group-interface::add-grob span 'elements grob)))
(if (ly:spanner? finished)
(ly:pointer-group-interface::add-grob finished 'elements grob))))
;; add additional interfaces to acknowledge here
)
(process-music .
,(lambda (trans)
(if (ly:stream-event? event-stop)
(if (null? span)
(ly:warning "No start to this box.")
(begin
(set! finished span)
(ly:engraver-announce-end-grob trans finished event-start)
(set! span '())
(set! event-stop '()))))
(if (ly:stream-event? event-start)
(begin
(set! span (ly:engraver-make-grob trans 'MusicBoxer event-start))
(set! event-start '())))))
(stop-translation-timestep .
,(lambda (trans)
(if (and (ly:spanner? span)
(null? (ly:spanner-bound span LEFT)))
(ly:spanner-set-bound! span LEFT
(ly:context-property context 'currentMusicalColumn)))
(if (ly:spanner? finished)
(begin
(if (null? (ly:spanner-bound finished RIGHT))
(ly:spanner-set-bound! finished RIGHT
(ly:context-property context 'currentMusicalColumn)))
(set! finished '())
(set! event-start '())
(set! event-stop '())))))
(finalize
(lambda (trans)
(if (ly:spanner? finished)
(begin
(if (null? (ly:spanner-bound finished RIGHT))
(set! (ly:spanner-bound finished RIGHT)
(ly:context-property context 'currentMusicalColumn)))
(set! finished '())))
(if (ly:spanner? span)
(begin
(ly:warning "unterminated box :-(")
(ly:grob-suicide! span)
(set! span '()))))))))
boxEngraver =
#(lambda (context)
(let ((box '())
(ev '()))
`((listeners
(box-event .
,(lambda (engraver event)
(set! ev event))))
(acknowledgers
(note-column-interface .
,(lambda (engraver grob source-engraver)
(if (ly:grob? box)
(begin
; (set! (ly:grob-parent box X) grob) ;; ??
(set! (ly:grob-parent box Y) grob)
(ly:pointer-group-interface::add-grob box 'elements grob)))))
(inline-accidental-interface .
,(lambda (engraver grob source-engraver)
(if (ly:item? box)
(ly:pointer-group-interface::add-grob box 'elements grob))))
(script-interface .
,(lambda (engraver grob source-engraver)
(if (ly:item? box)
(ly:pointer-group-interface::add-grob box 'elements grob))))
(finger-interface .
,(lambda (engraver grob source-engraver)
(if (ly:item? box)
(ly:pointer-group-interface::add-grob box 'elements grob))))
;; add additional interfaces to acknowledge here
)
(process-music .
,(lambda (trans)
(if (ly:stream-event? ev)
(begin
(set! box (ly:engraver-make-grob trans 'Box ev))
(set! ev '())))))
(stop-translation-timestep .
,(lambda (trans)
(set! box '()))))))
musicBoxerStart =
#(make-span-event 'MusicBoxerEvent START)
musicBoxerEnd =
#(make-span-event 'MusicBoxerEvent STOP)
box = #(make-music 'BoxEvent)
\layout {
\context {
\Global
\grobdescriptions #all-grob-descriptions
}
\context {
\Score
\consists \musicBoxerEngraver % for spans
\consists \boxEngraver
}
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% EXAMPLE %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
melody = \relative c'' {
\set fingeringOrientations = #'(left)
%1
\repeat volta 2 {
%\once\override Score.Box.padding = 1
\box <g-3 c-2 f-1>1
\musicBoxerStart d8-4 g,-0 d' g, d'-4 g,-0 d' \musicBoxerEnd g,
}
%2
\repeat volta 2 {
\box <d'-4 c'-2 f-1>1\f\fermata
\musicBoxerStart g8-3 d-0 g d g8-4 d-0 g \musicBoxerEnd d\accent
}
}
\score {
\new Staff \melody
}
It should produce:
It produces instead: fatal error: meta.classes must be non-empty list, found #f
Something seems to have changed in the meanwhile. It would be nice to update this snippet to work in more recent versions.
Regards,
Martín.
--
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