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 docme: why do we take duration-log from request, not from note
59 int duration_log = gi.music_cause ()->duration_log ();
60 stem_->set_property ("duration-log", scm_int2num (duration_log));
64 /* Stem tremolo is never applied to a note by default,
65 is must me requested. But there is a default for the
70 the first and last (quarter) note bothe get one tremolo flag. */
72 = scm_to_int (tremolo_ev_->get_property ("tremolo-type"));
73 SCM f = get_property ("tremoloFlags");
76 if (scm_is_number (f))
77 requested_type = scm_to_int (f);
82 context ()->set_property ("tremoloFlags", scm_int2num (requested_type));
84 int tremolo_flags = intlog2 (requested_type) - 2
85 - (duration_log > 2 ? duration_log - 2 : 0);
86 if (tremolo_flags <= 0)
88 tremolo_ev_->origin ()->warning (_ ("tremolo duration is too long"));
94 tremolo_ = make_item ("StemTremolo", tremolo_ev_->self_scm ());
96 /* The number of tremolo flags is the number of flags of the
97 tremolo-type minus the number of flags of the note itself. */
98 tremolo_->set_property ("flag-count", scm_int2num (tremolo_flags));
99 tremolo_->set_parent (stem_, X_AXIS);
100 stem_->set_property ("tremolo-flag", tremolo_->self_scm ());
101 tremolo_->set_property ("stem", stem_->self_scm ());
107 Stem_engraver::acknowledge_grob (Grob_info gi)
109 if (Rhythmic_head::has_interface (gi.grob_))
111 if (Rhythmic_head::get_stem (gi.grob_))
114 Music *cause = gi.music_cause ();
121 int duration_log = cause->duration_log ();
122 if (Stem::duration_log (stem_) != duration_log)
125 gi.music_cause ()->origin ()->warning (_f ("adding note head to incompatible stem (type = %d)", 1 << Stem::duration_log (stem_)));
126 gi.music_cause ()->origin ()->warning (_f ("maybe input should specify polyphonic voices"));
129 Stem::add_head (stem_, gi.grob_);
134 Stem_engraver::stop_translation_timestep ()
139 /* FIXME: junk these properties. */
140 SCM prop = get_property ("stemLeftBeamCount");
141 if (scm_is_number (prop))
143 Stem::set_beaming (stem_, scm_to_int (prop), LEFT);
144 context ()->unset_property (ly_symbol2scm ("stemLeftBeamCount"));
146 prop = get_property ("stemRightBeamCount");
147 if (scm_is_number (prop))
149 Stem::set_beaming (stem_, scm_to_int (prop), RIGHT);
150 context ()->unset_property (ly_symbol2scm ("stemRightBeamCount"));
158 Stem_engraver::try_music (Music *m)
160 if (m->is_mus_type ("tremolo-event"))
168 ADD_TRANSLATOR (Stem_engraver,
169 /* descr */ "Create stems and single-stem tremolos. It also works together with "
170 "the beam engraver for overriding beaming.",
171 /* creats*/ "Stem StemTremolo",
172 /* accepts */ "tremolo-event",
173 /* acks */ "rhythmic-head-interface",
174 /* reads */ "tremoloFlags stemLeftBeamCount stemRightBeamCount",