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 ());
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 (ly_c_number_p (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_)));
127 gi.music_cause ()->origin ()->warning (_f ("Don't you want polyphonic voices instead?"));
130 Stem::add_head (stem_, gi.grob_);
135 Stem_engraver::stop_translation_timestep ()
140 /* FIXME: junk these properties. */
141 SCM prop = get_property ("stemLeftBeamCount");
142 if (ly_c_number_p (prop))
144 Stem::set_beaming (stem_,scm_to_int (prop),LEFT);
145 context ()->unset_property (ly_symbol2scm ("stemLeftBeamCount"));
147 prop = get_property ("stemRightBeamCount");
148 if (ly_c_number_p (prop))
150 Stem::set_beaming (stem_,scm_to_int (prop), RIGHT);
151 context ()->unset_property (ly_symbol2scm ("stemRightBeamCount"));
159 Stem_engraver::try_music (Music *m)
161 if (m->is_mus_type ("tremolo-event"))
169 ENTER_DESCRIPTION (Stem_engraver,
170 /* descr */ "Create stems and single-stem tremolos. It also works together with "
171 "the beam engraver for overriding beaming.",
172 /* creats*/ "Stem StemTremolo",
173 /* accepts */ "tremolo-event",
174 /* acks */ "rhythmic-head-interface",
175 /* reads */ "tremoloFlags stemLeftBeamCount stemRightBeamCount",