2 ambitus-engraver.cc -- implement Ambitus_engraver
4 source file of the GNU LilyPond music typesetter
6 (c) 2002--2004 Juergen Reuter <reuter@ipd.uka.de>
11 #include "note-head.hh"
12 #include "staff-symbol-referencer.hh"
20 rewrite this complely. --hwn
24 * This class implements an engraver for ambitus grobs.
26 * TODO: There are quite some conceptional issues left open:
28 * - Many publishers put ambitus _before_ the first occurrence of a
29 * clef. Hence, formally the pitches are undefined in this case. Of
30 * course, one could always silently assume that ambitus pitches refer
31 * to the first occurrence of a clef. Or should we, by default, put
32 * the ambitus always after the first clef, if any?
34 * - Enharmonically equal pitches: Assume piece contains once a "gis",
35 * another time an "aes" as highest pitch. Which one should be
36 * selected for the ambitus grob? The "aes", because it is
37 * musically/notationally "higher" than "gis"? Or "gis", because (if
38 * using pure temperament) it has a slightly higher frequency? Or
39 * that pitch that come closer to the key signature? But there may be
40 * key signature changes in the piece...
42 * - Multiple voices in single staff: Assume a vocal piece of music,
43 * where the soprano voice and the alto voice are put into the same
44 * staff (this is generally a bad idea, but unfortunately common
45 * practice). Then, there probably should be two ambitus grobs, one
46 * for each voice. But how can you see which ambitus grob refers to
47 * which voice? Most probably you can guess it from the fact that the
48 * ambitus of the alto voice typically lies in a lower range than that
49 * of the soprano voice, but this is just a heuristic rather than a
50 * generally valid rule. In the case of only two voices, using stems
51 * in the ambitus grob might help, but probably looks quite ugly.
53 * - If a piece consists of several loosely coupled sections, should
54 * there be multiple ambitus grobs allowed, one for each section?
55 * Then there probably should be some "\ambitus" event added to
56 * mudela, stating where an ambitus grob should be placed. This
57 * ambitus grob should then represent the ambitus in the range of time
58 * between this "\ambitus" event and the next one (or the end of the
59 * piece, if there is no more such event). To be compliant with the
60 * current implementation, we might implicitly assume an "\ambitus"
61 * event at the beginning of the piece, but then the question where
62 * to put this first ambitus grob (before/after the clef?) becomes
65 * - Incipits of transcribed music may need special treatment for
66 * ambitus, since, for readability, the ambitus most probably should
67 * not refer to the ancient clefs of the incipit, but rather to the
68 * clefs used in the transcribed parts.
70 class Ambitus_engraver : public Engraver
73 TRANSLATOR_DECLARATIONS (Ambitus_engraver);
74 virtual void process_music ();
75 virtual void acknowledge_grob (Grob_info);
76 virtual void stop_translation_timestep ();
77 virtual void finalize ();
80 void create_ambitus ();
83 Pitch pitch_min, pitch_max;
86 Ambitus_engraver::Ambitus_engraver ()
92 * (pitch_min > pitch_max) means that pitches are not yet
95 pitch_min = Pitch (0, 0, SHARP);
96 pitch_max = Pitch (0, 0, FLAT);
100 Ambitus_engraver::process_music ()
103 * Ensure that ambitus is created in the very first timestep (on
104 * which lily does not call start_translation_timestep ()).
105 * Otherwise, if a voice begins with a rest, the ambitus grob will
106 * be placed after the rest.
114 Ambitus_engraver::stop_translation_timestep ()
116 if (ambitus_ && !is_typeset)
119 * Evaluate middleCPosition not until now, since otherwise we
120 * may then oversee a clef that is defined in a staff context if
121 * we are in a voice context; middleCPosition would then be
124 SCM c0 = get_property ("middleCPosition");
125 ambitus_->set_property ("c0-position", c0);
128 * Similar for keySignature.
130 SCM key_signature = get_property ("keySignature");
131 ambitus_->set_property ("accidentals", key_signature);
133 typeset_grob (ambitus_);
139 Ambitus_engraver::acknowledge_grob (Grob_info info)
141 Item *item = dynamic_cast <Item *>(info.grob_);
144 if (Note_head::has_interface (info.grob_))
146 Music *nr = info.music_cause ();
147 if (nr && nr->is_mus_type ("note-event"))
149 Pitch pitch = *unsmob_pitch (nr->get_property ("pitch"));
150 if (Pitch::compare (pitch_min, pitch_max) > 0) // already init'd?
152 // not yet init'd; use current pitch to init min/max
156 else if (Pitch::compare (pitch, pitch_max) > 0) // new max?
160 else if (Pitch::compare (pitch, pitch_min) < 0) // new min?
170 Ambitus_engraver::create_ambitus ()
172 ambitus_ = make_item ("Ambitus");
174 announce_grob (ambitus_, SCM_EOL);
178 Ambitus_engraver::finalize ()
182 if (Pitch::compare (pitch_min, pitch_max) <= 0)
184 ambitus_->set_property ("pitch-min",
185 pitch_min.smobbed_copy ());
186 ambitus_->set_property ("pitch-max",
187 pitch_max.smobbed_copy ());
189 else // have not seen any pitch, so forget about the ambitus
192 * Do not print a warning on empty ambitus range, since this
193 * most probably arises from an empty voice, such as shared
194 * global timesig/clef definitions.
196 ambitus_->suicide ();
201 ENTER_DESCRIPTION (Ambitus_engraver,
203 /* creats*/ "Ambitus",
205 /* acks */ "note-head-interface",