2 stem-grav.cc -- implement Stem_engraver
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
10 #include "directional-element-interface.hh"
11 #include "engraver.hh"
15 #include "rhythmic-head.hh"
16 #include "script-interface.hh"
17 #include "staff-symbol-referencer.hh"
18 #include "stem-tremolo.hh"
23 Make stems upon receiving noteheads.
25 class Stem_engraver : public Engraver
31 TRANSLATOR_DECLARATIONS (Stem_engraver);
34 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 ());
55 int duration_log = gi.music_cause ()->duration_log ();
56 stem_->set_property ("duration-log", scm_int2num (duration_log));
60 /* Stem tremolo is never applied to a note by default,
61 is must me requested. But there is a default for the
66 the first and last (quarter) note bothe get one tremolo flag. */
68 = ly_scm2int (tremolo_ev_->get_property ("tremolo-type"));
69 SCM f = get_property ("tremoloFlags");
72 if (ly_c_number_p (f))
73 requested_type = ly_scm2int (f);
78 context ()->set_property ("tremoloFlags", scm_int2num (requested_type));
80 int tremolo_flags = intlog2 (requested_type) - 2
81 - (duration_log > 2 ? duration_log - 2 : 0);
82 if (tremolo_flags <= 0)
84 tremolo_ev_->origin ()->warning (_("tremolo duration is too long"));
90 tremolo_ = make_item ("StemTremolo", tremolo_ev_->self_scm ());
92 /* The number of tremolo flags is the number of flags of the
93 tremolo-type minus the number of flags of the note itself. */
94 tremolo_->set_property ("flag-count", scm_int2num (tremolo_flags));
95 tremolo_->set_parent (stem_, X_AXIS);
96 stem_->set_property ("tremolo-flag", tremolo_->self_scm ());
97 tremolo_->set_property ("stem", stem_->self_scm ());
103 Stem_engraver::acknowledge_grob (Grob_info gi)
105 if (Rhythmic_head::has_interface (gi.grob_))
107 if (Rhythmic_head::get_stem (gi.grob_))
110 Music * cause = gi.music_cause ();
117 int duration_log = cause->duration_log ();
118 if (Stem::duration_log (stem_) != duration_log)
121 gi.music_cause ()->origin ()->warning (_f ("Adding note head to incompatible stem (type = %d)", 1 << Stem::duration_log (stem_)));
123 gi.music_cause ()->origin ()->warning (_f ("Don't you want polyphonic voices instead?"));
126 Stem::add_head (stem_, gi.grob_);
131 Stem_engraver::stop_translation_timestep ()
136 /* FIXME: junk these properties. */
137 SCM prop = get_property ("stemLeftBeamCount");
138 if (ly_c_number_p (prop))
140 Stem::set_beaming (stem_,ly_scm2int (prop),LEFT);
141 context ()->unset_property (ly_symbol2scm ("stemLeftBeamCount"));
143 prop = get_property ("stemRightBeamCount");
144 if (ly_c_number_p (prop))
146 Stem::set_beaming (stem_,ly_scm2int (prop), RIGHT);
147 context ()->unset_property (ly_symbol2scm ("stemRightBeamCount"));
155 Stem_engraver::try_music (Music *m)
157 if (m->is_mus_type ("tremolo-event"))
165 ENTER_DESCRIPTION (Stem_engraver,
166 /* descr */ "Create stems and single-stem tremolos. It also works together with "
167 "the beam engraver for overriding beaming.",
168 /* creats*/ "Stem StemTremolo",
169 /* accepts */ "tremolo-event",
170 /* acks */ "rhythmic-head-interface",
171 /* reads */ "tremoloFlags stemLeftBeamCount stemRightBeamCount",