1 % DO NOT EDIT this file manually; it is automatically
2 % generated from Documentation/snippets/new
3 % Make any changes in Documentation/snippets/new/
4 % and then run scripts/auxiliar/makelsr.py
6 % This file is in the public domain.
7 %% Note: this file works from version 2.15.31
11 %% Translation of GIT committish: 30339cb3706f6399c84607426988b25f79b4998c
13 Cet exemple démontre comment définir son propre graveur de tessiture à
16 Il s'agit d'une réécriture en Scheme du code contenu dans le fichier
17 @file{lily/ambitus-engraver.cc}.
20 doctitlefr = "Définition d'un graveur en Scheme : graveur d'ambitus"
23 lsrtags = "contexts-and-engravers"
26 texidoc = "This example demonstrates how the ambitus engraver may be
27 defined on the user side, with a Scheme engraver.
29 This is basically a rewrite in Scheme of the code from
30 @file{lily/ambitus-engraver.cc}.
33 doctitle = "Defining an engraver in Scheme: ambitus engraver"
37 #(use-modules (oop goops))
42 %%% These are literal rewrites of some C++ methods used by the ambitus engraver.
44 #(define (ly:separation-item::add-conditional-item grob grob-item)
45 "Add @var{grob-item} to the array of conditional elements of @var{grob}.
46 Rewrite of @code{Separation_item::add_conditional_item} from @file{lily/separation-item.cc}."
47 (ly:pointer-group-interface::add-grob grob 'conditional-elements grob-item))
49 #(define (ly:accidental-placement::accidental-pitch accidental-grob)
50 "Get the pitch from the grob cause of @var{accidental-grob}.
51 Rewrite of @code{accidental_pitch} from @file{lily/accidental-placement.cc}."
52 (ly:event-property (ly:grob-property (ly:grob-parent accidental-grob Y) 'cause)
55 #(define (ly:accidental-placement::add-accidental grob accidental-grob)
56 "Add @var{accidental-grob}, an @code{Accidental} grob, to the
57 list of the accidental grobs of @var{grob}, an @code{AccidentalPlacement}
59 Rewrite of @code{Accidental_placement::add_accidental} from @file{lily/accidental-placement.cc}."
60 (let ((pitch (ly:accidental-placement::accidental-pitch accidental-grob)))
61 (set! (ly:grob-parent accidental-grob X) grob)
62 (set! (ly:grob-property accidental-grob 'X-offset)
63 ly:grob::x-parent-positioning)
64 (let* ((accidentals (ly:grob-object grob 'accidental-grobs))
65 (handle (assq (ly:pitch-notename pitch) accidentals))
66 (entry (if handle (cdr handle) '())))
67 (set! (ly:grob-object grob 'accidental-grobs)
68 (assq-set! accidentals
69 (ly:pitch-notename pitch)
70 (cons accidental-grob entry))))))
73 %%% Ambitus data structure
76 %%% The <ambitus> class holds the various grobs that are created
77 %%% to print an ambitus:
78 %%% - ambitus-group: the grob that groups all the components of an ambitus
80 %%% - ambitus-line: the vertical line between the upper and lower ambitus
81 %%% notes (AmbitusLine grob);
82 %%% - ambitus-up-note and ambitus-down-note: the note head and accidental
83 %%% for the lower and upper note of the ambitus (see <ambitus-note> class
85 %%% The other slots define the key and clef context of the engraver:
86 %%% - start-c0: position of middle c at the beginning of the piece. It
87 %%% is used to place the ambitus notes according to their pitch;
88 %%% - start-key-sig: the key signature at the beginning of the piece. It
89 %%% is used to determine if accidentals shall be printed next to ambitus
92 #(define-class <ambitus> ()
93 (ambitus-group #:accessor ambitus-group)
94 (ambitus-line #:accessor ambitus-line)
95 (ambitus-up-note #:getter ambitus-up-note
96 #:init-form (make <ambitus-note>))
97 (ambitus-down-note #:getter ambitus-down-note
98 #:init-form (make <ambitus-note>))
99 (start-c0 #:accessor ambitus-start-c0
101 (start-key-sig #:accessor ambitus-start-key-sig
104 %%% Accessor for the lower and upper note data of an ambitus
105 #(define-method (ambitus-note (ambitus <ambitus>) direction)
106 "If @var{direction} is @code{UP}, then return the upper ambitus note
107 of @var{ambitus}, otherwise return the lower ambitus note."
109 (ambitus-up-note ambitus)
110 (ambitus-down-note ambitus)))
112 %%% The <ambitus-note> class holds the grobs that are specific to ambitus
113 %%% (lower and upper) notes:
114 %%% - head: an AmbitusNoteHead grob;
115 %%% - accidental: an AmbitusAccidental grob, to be possibly printed next
116 %%% to the ambitus note head.
118 %%% - pitch is the absolute pitch of the note
119 %%% - cause is the note event that causes this ambitus note, i.e. the lower
120 %%% or upper note of the considered music sequence.
122 #(define-class <ambitus-note> ()
123 (head #:accessor ambitus-note-head
125 (accidental #:accessor ambitus-note-accidental
127 (cause #:accessor ambitus-note-cause
129 (pitch #:accessor ambitus-note-pitch
133 %%% Ambitus engraving logics
135 %%% Rewrite of the code from @file{lily/ambitus-engraver.cc}.
137 #(define (make-ambitus translator)
138 "Build an ambitus object: initialize all the grobs and their relations.
140 The Ambitus grob contain all other grobs:
143 |- AmbitusNoteHead for upper note
144 |- AmbitusAccidental for upper note
145 |- AmbitusNoteHead for lower note
146 |- AmbitusAccidental for lower note
148 The parent of an accidental is the corresponding note head,
149 and the accidental is set as the 'accidental-grob of the note head
150 so that is printed by the function that prints notes."
151 ;; make the ambitus object
152 (let ((ambitus (make <ambitus>)))
153 ;; build the Ambitus grob, which will contain all other grobs
154 (set! (ambitus-group ambitus) (ly:engraver-make-grob translator 'Ambitus '()))
155 ;; build the AmbitusLine grob (line between lower and upper note)
156 (set! (ambitus-line ambitus) (ly:engraver-make-grob translator 'AmbitusLine '()))
157 ;; build the upper and lower AmbitusNoteHead and AmbitusAccidental
158 (for-each (lambda (direction)
159 (let ((head (ly:engraver-make-grob translator 'AmbitusNoteHead '()))
160 (accidental (ly:engraver-make-grob translator 'AmbitusAccidental '()))
161 (group (ambitus-group ambitus)))
162 ;; The parent of the AmbitusAccidental grob is the
163 ;; AmbitusNoteHead grob
164 (set! (ly:grob-parent accidental Y) head)
165 ;; The AmbitusAccidental grob is set as the accidental-grob
166 ;; object of the AmbitusNoteHead. This is later used by the
167 ;; function that prints notes.
168 (set! (ly:grob-object head 'accidental-grob) accidental)
169 ;; both the note head and the accidental grobs are added
170 ;; to the main ambitus grob.
171 (ly:axis-group-interface::add-element group head)
172 (ly:axis-group-interface::add-element group accidental)
173 ;; the note head and the accidental grobs are added to the
175 (set! (ambitus-note-head (ambitus-note ambitus direction))
177 (set! (ambitus-note-accidental (ambitus-note ambitus direction))
180 ;; The parent of the ambitus line is the lower ambitus note head
181 (set! (ly:grob-parent (ambitus-line ambitus) X)
182 (ambitus-note-head (ambitus-note ambitus DOWN)))
183 ;; the ambitus line is added to the ambitus main grob
184 (ly:axis-group-interface::add-element (ambitus-group ambitus) (ambitus-line ambitus))
187 #(define-method (initialize-ambitus-state (ambitus <ambitus>) translator)
188 "Initialize the state of @var{ambitus}, by getting the starting
189 position of middle C and key signature from @var{translator}'s context."
190 (if (not (ambitus-start-c0 ambitus))
192 (set! (ambitus-start-c0 ambitus)
193 (ly:context-property (ly:translator-context translator)
196 (set! (ambitus-start-key-sig ambitus)
197 (ly:context-property (ly:translator-context translator)
200 #(define-method (update-ambitus-notes (ambitus <ambitus>) note-grob)
201 "Update the upper and lower ambitus pithes of @var{ambitus}, using
203 ;; Get the event that caused the note-grob creation
204 ;; and check that it is a note-event.
205 (let ((note-event (ly:grob-property note-grob 'cause)))
206 (if (ly:in-event-class? note-event 'note-event)
207 ;; get the pitch from the note event
208 (let ((pitch (ly:event-property note-event 'pitch)))
209 ;; if this pitch is lower than the current ambitus lower
210 ;; note pitch (or it has not been initialized yet),
211 ;; then this pitch is the new ambitus lower pitch,
212 ;; and conversely for upper pitch.
213 (for-each (lambda (direction pitch-compare)
214 (if (or (not (ambitus-note-pitch (ambitus-note ambitus direction)))
216 (ambitus-note-pitch (ambitus-note ambitus direction))))
218 (set! (ambitus-note-pitch (ambitus-note ambitus direction))
220 (set! (ambitus-note-cause (ambitus-note ambitus direction))
223 (list ly:pitch<? (lambda (p1 p2)
224 (ly:pitch<? p2 p1))))))))
226 #(define-method (typeset-ambitus (ambitus <ambitus>) translator)
227 "Typeset the ambitus:
228 - place the lower and upper ambitus notes according to their pitch and
229 the position of the middle C;
230 - typeset or delete the note accidentals, according to the key signature.
231 An accidental, if it is to be printed, is added to an AccidentalPlacement
232 grob (a grob dedicated to the placement of accidentals near a chord);
233 - both note heads are added to the ambitus line grob, so that a line should
234 be printed between them."
235 ;; check if there are lower and upper pitches
236 (if (and (ambitus-note-pitch (ambitus-note ambitus UP))
237 (ambitus-note-pitch (ambitus-note ambitus DOWN)))
238 ;; make an AccidentalPlacement grob, for placement of note accidentals
239 (let ((accidental-placement (ly:engraver-make-grob
242 (ambitus-note-accidental (ambitus-note ambitus DOWN)))))
243 ;; For lower and upper ambitus notes:
244 (for-each (lambda (direction)
245 (let ((pitch (ambitus-note-pitch (ambitus-note ambitus direction))))
246 ;; set the cause and the staff position of the ambitus note
247 ;; according to the associated pitch
248 (set! (ly:grob-property (ambitus-note-head (ambitus-note ambitus direction))
250 (ambitus-note-cause (ambitus-note ambitus direction)))
251 (set! (ly:grob-property (ambitus-note-head (ambitus-note ambitus direction))
253 (+ (ambitus-start-c0 ambitus)
254 (ly:pitch-steps pitch)))
255 ;; determine if an accidental shall be printed for this note,
256 ;; according to the key signature
257 (let* ((handle (or (assoc (cons (ly:pitch-octave pitch)
258 (ly:pitch-notename pitch))
259 (ambitus-start-key-sig ambitus))
260 (assoc (ly:pitch-notename pitch)
261 (ambitus-start-key-sig ambitus))))
262 (sig-alter (if handle (cdr handle) 0)))
263 (cond ((= (ly:pitch-alteration pitch) sig-alter)
264 ;; the note alteration is in the key signature
265 ;; => it does not have to be printed
267 (ambitus-note-accidental (ambitus-note ambitus direction)))
268 (set! (ly:grob-object (ambitus-note-head (ambitus-note ambitus direction))
272 ;; otherwise, the accidental shall be printed
273 (set! (ly:grob-property (ambitus-note-accidental
274 (ambitus-note ambitus direction))
276 (ly:pitch-alteration pitch)))))
277 ;; add the AccidentalPlacement grob to the
278 ;; conditional items of the AmbitusNoteHead
279 (ly:separation-item::add-conditional-item
280 (ambitus-note-head (ambitus-note ambitus direction))
281 accidental-placement)
282 ;; add the AmbitusAccidental to the list of the
283 ;; AccidentalPlacement grob accidentals
284 (ly:accidental-placement::add-accidental
286 (ambitus-note-accidental (ambitus-note ambitus direction)))
287 ;; add the AmbitusNoteHead grob to the AmbitusLine grob
288 (ly:pointer-group-interface::add-grob
289 (ambitus-line ambitus)
291 (ambitus-note-head (ambitus-note ambitus direction)))))
293 ;; add the AccidentalPlacement grob to the main Ambitus grob
294 (ly:axis-group-interface::add-element (ambitus-group ambitus) accidental-placement))
295 ;; no notes ==> suicide the grobs
297 (for-each (lambda (direction)
298 (ly:grob-suicide! (ambitus-note-accidental (ambitus-note ambitus direction)))
299 (ly:grob-suicide! (ambitus-note-head (ambitus-note ambitus direction))))
301 (ly:grob-suicide! ambitus-line))))
304 %%% Ambitus engraver definition
306 #(define ambitus-engraver
309 ;; when music is processed: make the ambitus object, if not already built
311 ((process-music translator)
313 (set! ambitus (make-ambitus translator))))
314 ;; set the ambitus clef and key signature state
315 ((stop-translation-timestep translator)
317 (initialize-ambitus-state ambitus translator)))
318 ;; when a note-head grob is built, update the ambitus notes
320 ((note-head-interface engraver grob source-engraver)
322 (update-ambitus-notes ambitus grob))))
323 ;; finally, typeset the ambitus according to its upper and lower notes
325 ((finalize translator)
327 (typeset-ambitus ambitus translator)))))))
335 \new Staff { c'4 des' e' fis' gis' }
336 \new Staff { \clef "bass" c4 des ~ des ees b, }
338 \layout { \context { \Staff \consists #ambitus-engraver } }