2 stem-engraver.cc -- implement Stem_engraver
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
10 #include "directional-element-interface.hh"
11 #include "engraver.hh"
14 #include "rhythmic-head.hh"
15 #include "script-interface.hh"
16 #include "staff-symbol-referencer.hh"
17 #include "stem-tremolo.hh"
21 Make stems upon receiving noteheads.
23 class Stem_engraver : public Engraver
30 TRANSLATOR_DECLARATIONS (Stem_engraver);
33 void make_stem (Grob_info);
35 virtual void acknowledge_grob (Grob_info);
36 virtual void stop_translation_timestep ();
37 virtual bool try_music (Music *);
40 Stem_engraver::Stem_engraver ()
49 Stem_engraver::make_stem (Grob_info gi)
51 /* Announce the cause of the head as cause of the stem. The
52 stem needs a rhythmic structure to fit it into a beam. */
53 stem_ = make_item ("Stem", gi.music_cause ()->self_scm ());
56 we take the duration log from the Event, since the duration-log
57 for a note head is always <= 2.
59 Music *music = gi.music_cause ();
60 Duration *dur = unsmob_duration (music->get_property ("duration"));
62 stem_->set_property ("duration-log", dur ? scm_int2num (dur->duration_log ()) : 0);
66 /* Stem tremolo is never applied to a note by default,
67 is must me requested. But there is a default for the
72 the first and last (quarter) note bothe get one tremolo flag. */
74 = scm_to_int (tremolo_ev_->get_property ("tremolo-type"));
75 SCM f = get_property ("tremoloFlags");
78 if (scm_is_number (f))
79 requested_type = scm_to_int (f);
84 context ()->set_property ("tremoloFlags", scm_int2num (requested_type));
86 int tremolo_flags = intlog2 (requested_type) - 2
87 - (dur->duration_log () > 2 ? dur->duration_log () - 2 : 0);
88 if (tremolo_flags <= 0)
90 tremolo_ev_->origin ()->warning (_ ("tremolo duration is too long"));
96 tremolo_ = make_item ("StemTremolo", tremolo_ev_->self_scm ());
98 /* The number of tremolo flags is the number of flags of the
99 tremolo-type minus the number of flags of the note itself. */
100 tremolo_->set_property ("flag-count", scm_int2num (tremolo_flags));
101 tremolo_->set_parent (stem_, X_AXIS);
102 stem_->set_property ("tremolo-flag", tremolo_->self_scm ());
103 tremolo_->set_property ("stem", stem_->self_scm ());
109 Stem_engraver::acknowledge_grob (Grob_info gi)
111 if (Rhythmic_head::has_interface (gi.grob ()))
113 if (Rhythmic_head::get_stem (gi.grob ()))
116 Music *cause = gi.music_cause ();
119 Duration *d = unsmob_duration (cause->get_property ("duration"));
126 if (Stem::duration_log (stem_) != d->duration_log ())
129 gi.music_cause ()->origin ()->warning (_f ("adding note head to incompatible stem (type = %d)",
130 1 << Stem::duration_log (stem_)));
131 gi.music_cause ()->origin ()->warning (_f ("maybe input should specify polyphonic voices"));
134 Stem::add_head (stem_, gi.grob ());
139 Stem_engraver::stop_translation_timestep ()
144 /* FIXME: junk these properties. */
145 SCM prop = get_property ("stemLeftBeamCount");
146 if (scm_is_number (prop))
148 Stem::set_beaming (stem_, scm_to_int (prop), LEFT);
149 context ()->unset_property (ly_symbol2scm ("stemLeftBeamCount"));
151 prop = get_property ("stemRightBeamCount");
152 if (scm_is_number (prop))
154 Stem::set_beaming (stem_, scm_to_int (prop), RIGHT);
155 context ()->unset_property (ly_symbol2scm ("stemRightBeamCount"));
163 Stem_engraver::try_music (Music *m)
165 if (m->is_mus_type ("tremolo-event"))
173 ADD_TRANSLATOR (Stem_engraver,
174 /* descr */ "Create stems and single-stem tremolos. It also works together with "
175 "the beam engraver for overriding beaming.",
176 /* creats*/ "Stem StemTremolo",
177 /* accepts */ "tremolo-event",
178 /* acks */ "rhythmic-head-interface",
179 /* reads */ "tremoloFlags stemLeftBeamCount stemRightBeamCount",