1 /*
2 This file is part of LilyPond, the GNU music typesetter.
3
4 Copyright (C) 2000--2021 Han-Wen Nienhuys <hanwen@xs4all.nl>
5 Erik Sandberg <mandolaerik@gmail.com>
6
7 LilyPond is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
11
12 LilyPond is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
19 */
20
21 #include "beam.hh"
22 #include "engraver-group.hh"
23 #include "international.hh"
24 #include "item.hh"
25 #include "misc.hh"
26 #include "rhythmic-head.hh"
27 #include "spanner.hh"
28 #include "stem-tremolo.hh"
29 #include "stem.hh"
30 #include "stream-event.hh"
31 #include "warn.hh"
32
33 #include "translator.icc"
34
35 using std::string;
36
37 /**
38
39 This acknowledges repeated music with "tremolo" style. It typesets
40 a beam.
41
42 TODO:
43
44 - perhaps use engraver this to steer other engravers? That would
45 create dependencies between engravers, which is bad.
46
47 - create dots if appropriate.
48
49 - create TremoloBeam iso Beam?
50 */
51 class Chord_tremolo_engraver : public Engraver
52 {
53 TRANSLATOR_DECLARATIONS (Chord_tremolo_engraver);
54 protected:
55 Stream_event *repeat_;
56
57 Spanner *beam_;
58 // Store the pointer to the previous stem, so we can create a beam if
59 // necessary and end the spanner
60 Grob *previous_stem_;
61
62 protected:
63 void finalize () override;
64 void process_music ();
65 void listen_tremolo_span (Stream_event *);
66 void acknowledge_stem (Grob_info);
67 };
68
Chord_tremolo_engraver(Context * c)69 Chord_tremolo_engraver::Chord_tremolo_engraver (Context *c)
70 : Engraver (c)
71 {
72 beam_ = 0;
73 repeat_ = 0;
74 previous_stem_ = 0;
75 }
76
77 void
listen_tremolo_span(Stream_event * ev)78 Chord_tremolo_engraver::listen_tremolo_span (Stream_event *ev)
79 {
80 Direction span_dir = from_scm<Direction> (get_property (ev, "span-direction"));
81 if (span_dir == START)
82 {
83 ASSIGN_EVENT_ONCE (repeat_, ev);
84 }
85 else if (span_dir == STOP)
86 {
87 if (!repeat_)
88 ev->warning (_ ("No tremolo to end"));
89 repeat_ = 0;
90 beam_ = 0;
91 previous_stem_ = 0;
92 }
93 }
94
95 void
process_music()96 Chord_tremolo_engraver::process_music ()
97 {
98 if (repeat_ && !beam_)
99 {
100 beam_ = make_spanner ("Beam", repeat_->self_scm ());
101 }
102 }
103
104 void
finalize()105 Chord_tremolo_engraver::finalize ()
106 {
107 if (beam_)
108 {
109 repeat_->warning (_ ("unterminated chord tremolo"));
110 announce_end_grob (beam_, SCM_EOL);
111 beam_->suicide ();
112 }
113 }
114
115 void
acknowledge_stem(Grob_info info)116 Chord_tremolo_engraver::acknowledge_stem (Grob_info info)
117 {
118 if (beam_)
119 {
120 int tremolo_type = from_scm (get_property (repeat_, "tremolo-type"), 1);
121 int flags = std::max (0, intlog2 (tremolo_type) - 2);
122 int repeat_count = from_scm (get_property (repeat_, "repeat-count"), 1);
123 int gap_count = std::min (flags, intlog2 (repeat_count) + 1);
124
125 Grob *s = info.grob ();
126 if (previous_stem_)
127 {
128 // FIXME: We know that the beam has ended only in listen_tremolo_span
129 // but then it is too late for Spanner_break_forbid_engraver
130 // to allow a line break... So, as a nasty hack, announce the
131 // spanner's end after each note except the first. The only
132 // "drawback" is that for multi-note tremolos a break would
133 // theoretically be allowed after the second note (but since
134 // that note is typically not at a barline, I don't think
135 // anyone will ever notice!)
136 announce_end_grob (beam_, previous_stem_->self_scm ());
137 // Create the whole beam between previous and current note
138 Stem::set_beaming (previous_stem_, flags, RIGHT);
139 Stem::set_beaming (s, flags, LEFT);
140 }
141
142 if (Stem::duration_log (s) != 1)
143 set_property (beam_, "gap-count", to_scm (gap_count));
144
145 if (info.ultimate_event_cause ()->in_event_class ("rhythmic-event"))
146 Beam::add_stem (beam_, s);
147 else
148 s->warning (_ ("stem must have Rhythmic structure"));
149
150 // Store current grob, so we can possibly end the spanner here (and
151 // reset the beam direction to RIGHT)
152 previous_stem_ = s;
153 }
154 }
155
156 void
boot()157 Chord_tremolo_engraver::boot ()
158 {
159 ADD_LISTENER (Chord_tremolo_engraver, tremolo_span);
160 ADD_ACKNOWLEDGER (Chord_tremolo_engraver, stem);
161 }
162
163 ADD_TRANSLATOR (Chord_tremolo_engraver,
164 /* doc */
165 "Generate beams for tremolo repeats.",
166
167 /* create */
168 "Beam ",
169
170 /* read */
171 "",
172
173 /* write */
174 ""
175 );
176