4 texidoc = "Use @code{define-event-class}, scheme engraver methods,
5 and grob creation methods to create a fully functional text spanner
9 #(define-event-class 'scheme-text-span-event
10 '(scheme-text-span-event
15 #(define (add-grob-definition grob-name grob-entry)
16 (let* ((meta-entry (assoc-get 'meta grob-entry))
17 (class (assoc-get 'class meta-entry))
18 (ifaces-entry (assoc-get 'interfaces meta-entry)))
19 (set-object-property! grob-name 'translation-type? list?)
20 (set-object-property! grob-name 'is-grob? #t)
21 (set! ifaces-entry (append (case class
22 ((Item) '(item-interface))
23 ((Spanner) '(spanner-interface))
24 ((Paper_column) '((item-interface
25 paper-column-interface)))
26 ((System) '((system-interface
28 (else '(unknown-interface)))
30 (set! ifaces-entry (uniq-list (sort ifaces-entry symbol<?)))
31 (set! ifaces-entry (cons 'grob-interface ifaces-entry))
32 (set! meta-entry (assoc-set! meta-entry 'name grob-name))
33 (set! meta-entry (assoc-set! meta-entry 'interfaces
35 (set! grob-entry (assoc-set! grob-entry 'meta meta-entry))
36 (set! all-grob-descriptions
37 (cons (cons grob-name grob-entry)
38 all-grob-descriptions))))
43 (bound-details . ((left . ((Y . 0)
47 (left-broken . ((end-on-note . #t)))
56 (left-bound-info . ,ly:line-spanner::calc-left-bound-info)
57 (outside-staff-priority . 350)
58 (right-bound-info . ,ly:line-spanner::calc-right-bound-info)
60 (stencil . ,ly:line-spanner::print)
63 (meta . ((class . Spanner)
64 (interfaces . (font-interface
66 line-spanner-interface
67 side-position-interface))))))
69 #(define scheme-event-spanner-types
72 . ((description . "Used to signal where scheme text spanner brackets
74 (types . (general-music scheme-text-span-event span-event event))
79 scheme-event-spanner-types
81 (set-object-property! (car x)
83 (cdr (assq 'description (cdr x))))
85 (set! lst (assoc-set! lst 'name (car x)))
86 (set! lst (assq-remove! lst 'description))
87 (hashq-set! music-name-to-property-table (car x) lst)
89 scheme-event-spanner-types))
91 #(set! music-descriptions
92 (append scheme-event-spanner-types music-descriptions))
94 #(set! music-descriptions
95 (sort music-descriptions alist<?))
97 #(define (add-bound-item spanner item)
98 (if (null? (ly:spanner-bound spanner LEFT))
99 (ly:spanner-set-bound! spanner LEFT item)
100 (ly:spanner-set-bound! spanner RIGHT item)))
102 #(define (axis-offset-symbol axis)
103 (if (eq? axis X) 'X-offset 'Y-offset))
105 #(define (set-axis! grob axis)
106 (if (not (number? (ly:grob-property grob 'side-axis)))
108 (set! (ly:grob-property grob 'side-axis) axis)
109 (ly:grob-chain-callback
112 ly:side-position-interface::x-aligned-side
113 side-position-interface::y-aligned-side)
114 (axis-offset-symbol axis)))))
116 schemeTextSpannerEngraver =
121 (event-drul '(() . ())))
123 (listeners ((scheme-text-span-event engraver event)
124 (if (= START (ly:event-property event 'span-direction))
125 (set-car! event-drul event)
126 (set-cdr! event-drul event))))
127 (acknowledgers ((note-column-interface engraver grob source-engraver)
128 (if (ly:spanner? span)
130 (ly:pointer-group-interface::add-grob span 'note-columns grob)
131 (add-bound-item span grob)))
132 (if (ly:spanner? finished)
134 (ly:pointer-group-interface::add-grob finished 'note-columns grob)
135 (add-bound-item finished grob)))))
136 ((process-music trans)
137 (if (ly:stream-event? (cdr event-drul))
139 (ly:warning "You're trying to end a scheme text spanner but you haven't started one.")
140 (begin (set! finished span)
141 (ly:engraver-announce-end-grob trans finished current-event)
143 (set! current-event '())
144 (set-cdr! event-drul '()))))
145 (if (ly:stream-event? (car event-drul))
146 (begin (set! current-event (car event-drul))
147 (set! span (ly:engraver-make-grob trans 'SchemeTextSpanner current-event))
149 (set-car! event-drul '()))))
150 ((stop-translation-timestep trans)
151 (if (and (ly:spanner? span)
152 (null? (ly:spanner-bound span LEFT)))
153 (set! (ly:spanner-bound span LEFT)
154 (ly:context-property context 'currentMusicalColumn)))
155 (if (ly:spanner? finished)
157 (if (null? (ly:spanner-bound finished RIGHT))
158 (set! (ly:spanner-bound finished RIGHT)
159 (ly:context-property context 'currentMusicalColumn)))
161 (set! event-drul '(() . ())))))
163 (if (ly:spanner? finished)
165 (if (null? (ly:spanner-bound finished RIGHT))
166 (set! (ly:spanner-bound finished RIGHT)
167 (ly:context-property context 'currentMusicalColumn)))
168 (set! finished '())))
169 (if (ly:spanner? span)
171 (ly:warning "I think there's a dangling scheme text spanner :-(")
172 (ly:grob-suicide! span)
173 (set! span '())))))))
175 schemeTextSpannerStart =
176 #(make-span-event 'SchemeTextSpanEvent START)
178 schemeTextSpannerEnd =
179 #(make-span-event 'SchemeTextSpanEvent STOP)
184 \grobdescriptions #all-grob-descriptions
188 \consists \schemeTextSpannerEngraver
193 a4 b\schemeTextSpannerStart c d |
194 \repeat unfold 20 { a4 b c d | }
195 a4 b c\schemeTextSpannerEnd d |
196 \override SchemeTextSpanner.to-barline = ##t
197 a4\schemeTextSpannerStart b d c |
198 \repeat unfold 20 { a4 b c d | }
199 a1\schemeTextSpannerEnd |