1 /*
2 This file is part of LilyPond, the GNU music typesetter.
3
4 Copyright (C) 2003--2021 Juergen Reuter <reuter@ipd.uka.de>
5
6 LilyPond is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
10
11 LilyPond is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include "coherent-ligature-engraver.hh"
21
22 #include "warn.hh"
23 #include "paper-column.hh"
24 #include "pitch.hh"
25 #include "pointer-group-interface.hh"
26 #include "spanner.hh"
27 #include "staff-symbol-referencer.hh"
28 #include "stream-event.hh"
29
30 using std::vector;
31
32 /*
33 * This abstract class serves as common superclass for all ligature
34 * engravers thet produce a single connected graphical object of fixed
35 * width, consisting of noteheads and other primitives (see class
36 * Ligature_engraver for more information on the interaction between
37 * this class and its superclass). In particular, it cares for the
38 * following tasks:
39 *
40 * - provide a function for putting all grobs of the ligature into a
41 * single paper column,
42 *
43 * - delegate actual creation of ligature to concrete subclass,
44 *
45 * - except in Kievan notation, collect all accidentals that occur
46 * within the ligature and put them at the left side of the ligature
47 * (TODO; see function collect_accidentals ()),
48 *
49 * - collapse superflous space after each ligature (TODO).
50 *
51 * Concrete subclasses must implement function build_ligature (Spanner *,
52 * vector<Grob_info_t<Item>>). This function is responsible for actually
53 * building the ligature by transforming the array of noteheads.
54 *
55 * Currently, there are two subclasses: Gregorian_ligature_engraver
56 * for Gregorian chant notation (also known as plain song or cantus
57 * planus) and Mensural_ligature_engraver for white mensural notation.
58 * Subclasses for other music notation styles such as modal notation
59 * or ars nova notation may eventually be added.
60 */
61
62 /*
63 * TODO: local accidentals: collect accidentals that occur within a
64 * ligature and put them before the ligature. If an accidental
65 * changes within a ligature, print a warning (user error) and ignore
66 * any further accidental for that pitch within that ligature
67 * (actually, in such a case, the user should split the ligature into
68 * two separate ligatures). Similarly, any object that, in ordinary
69 * notation, may be put to the left or to the right of a note-head,
70 * should be collected and put before or after the ligature.
71 *
72 * TODO: make spacing more robust: do not screw up spacing if user
73 * erroneously puts rest in ligature.
74 *
75 * TODO: for each ligature, add Rod that represents the total length
76 * of the ligature (to preemptively avoid collision with adjacent
77 * notes); or maybe just additionally create a
78 * mensural/vaticana/whatever-ligature grob (e.g. via
79 * Mensural_ligature::print (SCM)) that just consists of a
80 * bounding box around all primitives of the ligature.
81 *
82 * TODO: Maybe move functions fold_up_primitives () and
83 * join_primitives () from subclasses to here? N.B. it is not
84 * appropriate to put these into Ligature_engraver, since, for
85 * example, Ligature_bracket_engraver does not share any of this code.
86 */
87
88 /*
89 * TODO: move this function to class Item?
90 */
91 void
move_related_items_to_column(Item * item,Paper_column * target_column,Real offset)92 Coherent_ligature_engraver::move_related_items_to_column
93 (Item *item, Paper_column *target_column, Real offset)
94 {
95 Paper_column *source_column = item->get_column ();
96 Grob *staff_symbol = Staff_symbol_referencer::get_staff_symbol (item);
97 extract_item_set (source_column, "elements", elements);
98 for (vsize i = elements.size (); i--;)
99 {
100 Item *sibling = elements[i];
101 if (!sibling)
102 // should not occur, but who knows... -jr
103 continue;
104
105 if (Staff_symbol_referencer::get_staff_symbol (sibling) != staff_symbol)
106 // sibling is from a staff different than that of the item of
107 // interest
108 continue;
109
110 #if 0 /* experimental code to collapse spacing after ligature */
111 Grob *sibling_parent = sibling->get_x_parent ();
112 sibling_parent->warning (_f ("Coherent_ligature_engraver: "
113 "setting `spacing-increment="
114 "0.01': ptr=%ul", parent));
115 set_property (sibling_parent, "forced-spacing",
116 to_scm (0.01));
117 #endif
118
119 sibling->set_x_parent (target_column);
120 sibling->translate_axis (offset, X_AXIS);
121 }
122 }
123
124 /*
125 * TODO: This function should collect all accidentals that occur
126 * within the ligature (by scanning through the primitives array) and
127 * place all of them at the left of the ligature. If there is an
128 * alteration within the ligature (e.g. an "f" followed by a "fis"
129 * somewhere later in the ligature), issue a warning (and maybe create
130 * an additional natural symbol to explicitly make clear that there is
131 * an "f" first?). The warning should suggest the user to break the
132 * ligature into two or more smaller ligatures such that no alteration
133 * occurs within the broken ligatures any more.
134 */
135 void
collect_accidentals(Spanner *,vector<Item * > const &)136 Coherent_ligature_engraver::collect_accidentals (Spanner *,
137 vector<Item *> const &)
138 {
139 /* TODO */
140 /* NOTE: if implementing such a function, note that in Kievan notation,
141 * the B-flat accidental should not be "collected", but rather prints
142 * immediately before the note head as usual. */
143 }
144
145 void
calc_delta_pitches(vector<Item * > const & primitives)146 calc_delta_pitches (vector<Item *> const &primitives)
147 {
148 if (primitives.empty ())
149 return;
150
151 auto prev_pitch = unsmob<Pitch> (get_property (primitives[0]->event_cause (),
152 "pitch"))->steps ();
153 for (vsize i = 1; i < primitives.size (); ++i)
154 {
155 auto *const cause = primitives[i]->event_cause ();
156 auto pitch = unsmob<Pitch> (get_property (cause, "pitch"))->steps ();
157
158 auto *const prev_item = primitives[i - 1];
159 set_property (prev_item, "delta-position", to_scm (pitch - prev_pitch));
160
161 prev_pitch = pitch;
162 }
163
164 set_property (primitives.back (), "delta-position", to_scm (0));
165 }
166
167 void
typeset_ligature(Spanner * ligature,vector<Item * > const & primitives)168 Coherent_ligature_engraver::typeset_ligature (Spanner *ligature,
169 vector<Item *> const &primitives)
170 {
171 // compute some commonly needed context info stored as grob
172 // properties
173 calc_delta_pitches (primitives);
174
175 // prepare ligature for typesetting
176 build_ligature (ligature, primitives);
177 collect_accidentals (ligature, primitives);
178 }
179
180 // no ADD_ACKNOWLEDGER / ADD_ACKNOWLEDGER / ADD_TRANSLATOR macro calls
181 // since this class is abstract
182