--- /dev/null
+\version "2.13.36"
+
+\header {
+ texidoc = "Use @code{define-event-class}, scheme engraver methods,
+and grob creation methods to create a fully functional text spanner
+in scheme."
+}
+
+#(define-event-class 'scheme-text-span-event
+ '(scheme-text-span-event
+ span-event
+ music-event
+ StreamEvent))
+
+#(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)))
+ (set-object-property! grob-name 'translation-type? list?)
+ (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))))
+
+#(add-grob-definition
+ 'SchemeTextSpanner
+ `(
+ (bound-details . ((left . ((Y . 0)
+ (padding . 0.25)
+ (attach-dir . ,LEFT)
+ ))
+ (left-broken . ((end-on-note . #t)))
+ (right . ((Y . 0)
+ (padding . 0.25)
+ ))
+ ))
+ (dash-fraction . 0.2)
+ (dash-period . 3.0)
+ (direction . ,UP)
+ (font-shape . italic)
+ (left-bound-info . ,ly:line-spanner::calc-left-bound-info)
+ (outside-staff-priority . 350)
+ (right-bound-info . ,ly:line-spanner::calc-right-bound-info)
+ (staff-padding . 0.8)
+ (stencil . ,ly:line-spanner::print)
+ (style . dashed-line)
+
+ (meta . ((class . Spanner)
+ (interfaces . (font-interface
+ line-interface
+ line-spanner-interface
+ side-position-interface))))))
+
+#(define scheme-event-spanner-types
+ '(
+ (SchemeTextSpanEvent
+ . ((description . "Used to signal where scheme text spanner brackets
+start and stop.")
+ (types . (general-music scheme-text-span-event span-event event))
+ ))
+ ))
+
+#(set!
+ scheme-event-spanner-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)))
+ scheme-event-spanner-types))
+
+#(set! music-descriptions
+ (append scheme-event-spanner-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)))
+
+#(define (axis-offset-symbol axis)
+ (if (eq? axis X) 'X-offset 'Y-offset))
+
+#(define (set-axis! grob axis)
+ (if (not (number? (ly:grob-property grob 'side-axis)))
+ (begin
+ (set! (ly:grob-property grob 'side-axis) axis)
+ (ly:grob-chain-callback
+ grob
+ (if (eq? axis X)
+ ly:side-position-interface::x-aligned-side
+ ly:side-position-interface::y-aligned-side)
+ (axis-offset-symbol axis)))))
+
+schemeTextSpannerEngraver =
+#(lambda (context)
+ (let ((span '())
+ (finished '())
+ (current-event '())
+ (event-drul '(() . ())))
+ (list (cons 'listeners
+ (list (cons 'scheme-text-span-event
+ (lambda (engraver event)
+ (if (= START (ly:event-property event 'span-direction))
+ (set-car! event-drul event)
+ (set-cdr! event-drul event))))))
+ (cons 'acknowledgers
+ (list (cons 'note-column-interface
+ (lambda (engraver grob source-engraver)
+ (if (ly:spanner? span)
+ (begin
+ (ly:pointer-group-interface::add-grob span 'note-columns grob)
+ (add-bound-item span grob)))
+ (if (ly:spanner? finished)
+ (begin
+ (ly:pointer-group-interface::add-grob finished 'note-columns grob)
+ (add-bound-item finished grob)))))))
+ (cons 'process-music
+ (lambda (trans)
+ (if (ly:stream-event? (cdr event-drul))
+ (if (null? span)
+ (ly:warning "You're trying to end a scheme text spanner but you haven't started one.")
+ (begin (set! finished span)
+ (ly:engraver-announce-end-grob trans finished current-event)
+ (set! span '())
+ (set! current-event '())
+ (set-cdr! event-drul '()))))
+ (if (ly:stream-event? (car event-drul))
+ (begin (set! current-event (car event-drul))
+ (set! span (ly:engraver-make-grob trans 'SchemeTextSpanner current-event))
+ (set-axis! span Y)
+ (set-car! event-drul '())))))
+ (cons 'stop-translation-timestep
+ (lambda (trans)
+ (if (and (ly:spanner? span)
+ (null? (ly:spanner-bound span LEFT)))
+ (set! (ly:spanner-bound span LEFT)
+ (ly:context-property context 'currentMusicalColumn)))
+ (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 '())
+ (set! event-drul '(() . ()))))))
+ (cons '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 "I think there's a dangling scheme text spanner :-(")
+ (ly:grob-suicide! span)
+ (set! span '()))))))))
+
+schemeTextSpannerStart =
+#(make-span-event 'SchemeTextSpanEvent START)
+
+schemeTextSpannerEnd =
+#(make-span-event 'SchemeTextSpanEvent STOP)
+
+\layout {
+ \context {
+ \Global
+ \grobdescriptions #all-grob-descriptions
+ }
+ \context {
+ \Voice
+ \consists \schemeTextSpannerEngraver
+ }
+}
+
+\relative c' {
+ a4 b\schemeTextSpannerStart c d |
+ \repeat unfold 20 { a4 b c d | }
+ a4 b c\schemeTextSpannerEnd d |
+ \override SchemeTextSpanner #'to-barline = ##t
+ a4\schemeTextSpannerStart b d c |
+ \repeat unfold 20 { a4 b c d | }
+ a1\schemeTextSpannerEnd |
+}
projects / lilypond.git / commitdiff