2 coherent-ligature-engraver.cc -- implement Coherent_ligature_engraver
4 source file of the GNU LilyPond music typesetter
6 (c) 2003--2005 Juergen Reuter <reuter@ipd.uka.de>
9 #include "coherent-ligature-engraver.hh"
12 #include "staff-symbol-referencer.hh"
14 #include "paper-column.hh"
16 #include "pointer-group-interface.hh"
19 * This abstract class serves as common superclass for all ligature
20 * engravers thet produce a single connected graphical object of fixed
21 * width, consisting of noteheads and other primitives (see class
22 * Ligature_engraver for more information on the interaction between
23 * this class and its superclass). In particular, it cares for the
26 * - provide a function for putting all grobs of the ligature into a
27 * single paper column,
29 * - delegate actual creation of ligature to concrete subclass,
31 * - collect all accidentals that occur within the ligature and put
32 * them at the left side of the ligature (TODO; see function
33 * collect_accidentals ()),
35 * - collapse superflous space after each ligature (TODO).
37 * Concrete subclasses must implement function build_ligature (Spanner
38 * *, Array<Grob_info>). This function is responsible for actually
39 * building the ligature by transforming the array of noteheads.
41 * Currently, there are two subclasses: Gregorian_ligature_engraver
42 * for Gregorian chant notation (also known as plain song or cantus
43 * planus) and Mensural_ligature_engraver for white mensural notation.
44 * Subclasses for other music notation styles such as modal notation
45 * or ars nova notation may eventually be added.
49 * TODO: local accidentals: collect accidentals that occur within a
50 * ligature and put them before the ligature. If an accidental
51 * changes within a ligature, print a warning (user error) and ignore
52 * any further accidental for that pitch within that ligature
53 * (actually, in such a case, the user should split the ligature into
54 * two separate ligatures). Similarly, any object that, in ordinary
55 * notation, may be put to the left or to the right of a note-head,
56 * should be collected and put before or after the ligature.
58 * TODO: make spacing more robust: do not screw up spacing if user
59 * erroneously puts rest in ligature.
61 * TODO: for each ligature, add Rod that represents the total length
62 * of the ligature (to preemptively avoid collision with adjacent
63 * notes); or maybe just additionally create a
64 * mensural/vaticana/whatever-ligature grob (e.g. via
65 * Mensural_ligature::print (SCM)) that just consists of a
66 * bounding box around all primitives of the ligature.
68 * TODO: Maybe move functions fold_up_primitives () and
69 * join_primitives () from subclasses to here? N.B. it is not
70 * appropriate to put these into Ligature_engraver, since, for
71 * example, Ligature_bracket_engraver does not share any of this code.
75 * TODO: Let superflous space after each ligature collapse. The
76 * following code should help in doing so (though it does not yet
77 * fully work). Just put the following code into
78 * Spacing_spanner::do_measure (). I put it temporarily here as memo
79 * until it really works and I also get Han-Wen's/Jan's permission to
80 * add it to the spacing spanner code.
82 #if 0 // experimental code to collapse spacing after ligature
83 SCM incr_scm = lc->get_property ("forced-spacing");
84 if (incr_scm != SCM_EOL) /* (Paper_column::is_musical (l)) */
86 me->warning (_f ("gotcha: ptr=%ul", lc));//debug
87 ly_display_scm (lc->self_scm ());
89 if (incr_scm != SCM_EOL)
91 distance = scm_to_double (incr_scm);
95 me->warning (_ ("distance undefined, assuming 0.1"));
98 me->warning (_f ("distance=%f", distance));//debug
99 Real inverse_strength = 1.0;
100 Spaceable_grob::add_spring (lc, rc, distance, inverse_strength);
101 if (Item *rb = r->find_prebroken_piece (LEFT))
102 Spaceable_grob::add_spring (lc, rb, distance, inverse_strength);
108 Coherent_ligature_engraver::Coherent_ligature_engraver ()
113 * TODO: move this function to class Item?
116 Coherent_ligature_engraver::get_set_column (Item *item, Paper_column *column)
118 Item *parent = dynamic_cast<Item *> (item->get_parent (X_AXIS));
121 programming_error ("failed tweaking paper column in ligature");
125 String name = parent->name ();
126 if (!String::compare (name, "PaperColumn"))
128 // Change column not only for targeted item (NoteColumn), but
129 // also for all associated grobs (NoteSpacing, SeparationItem).
130 Grob *sl = Staff_symbol_referencer::get_staff_symbol (item);
132 extract_item_set (parent, "elements", elements);
134 for (int i = elements.size (); i--;)
136 Item *sibling = elements[i];
138 && (Staff_symbol_referencer::get_staff_symbol (sibling) == sl))
140 #if 0 // experimental code to collapse spacing after ligature
141 Grob *sibling_parent = sibling->get_parent (X_AXIS);
142 sibling_parent->warning (_f ("Coherent_ligature_engraver: "
143 "setting `spacing-increment="
144 "0.01': ptr=%ul", parent));
145 sibling_parent->set_property ("forced-spacing",
146 scm_make_real (0.01));
148 sibling->set_parent (column, X_AXIS);
154 get_set_column (parent, column);
159 * TODO: This function should collect all accidentals that occur
160 * within the ligature (by scanning through the primitives array) and
161 * place all of them at the left of the ligature. If there is an
162 * alteration within the ligature (e.g. an "f" followed by a "fis"
163 * somewhere later in the ligature), issue a warning (and maybe create
164 * an additional natural symbol to explicitly make clear that there is
165 * an "f" first?). The warning should suggest the user to break the
166 * ligature into two or more smaller ligatures such that no alteration
167 * occurs within the broken ligatures any more.
170 Coherent_ligature_engraver::collect_accidentals (Spanner *, Array<Grob_info>)
176 compute_delta_pitches (Array<Grob_info> primitives)
180 Item *prev_primitive = 0, *primitive = 0;
181 for (int i = 0; i < primitives.size (); i++)
183 primitive = dynamic_cast<Item *> (primitives[i].grob ());
184 Music *music_cause = primitives[i].music_cause ();
186 = unsmob_pitch (music_cause->get_property ("pitch"))->steps ();
189 delta_pitch = pitch - prev_pitch;
190 prev_primitive->set_property ("delta-pitch",
191 scm_int2num (delta_pitch));
194 prev_primitive = primitive;
196 primitive->set_property ("delta-pitch", scm_int2num (0));
200 Coherent_ligature_engraver::build_ligature (Spanner *, Array<Grob_info>)
202 programming_error ("Coherent_ligature_engraver::build_ligature (): "
203 "this is an abstract method that should not be called, "
204 "but overridden by a subclass");
208 Coherent_ligature_engraver::typeset_ligature (Spanner *ligature,
209 Array<Grob_info> primitives)
211 // compute some commonly needed context info stored as grob
213 compute_delta_pitches (primitives);
215 // prepare ligature for typesetting
216 build_ligature (ligature, primitives);
217 collect_accidentals (ligature, primitives);
220 #include "translator.icc"
222 ADD_TRANSLATOR (Coherent_ligature_engraver,
223 /* descr */ "This is an abstract class. Subclasses such as Gregorian_ligature_engraver handle ligatures by glueing special ligature heads together.",
225 /* accepts */ "ligature-event",
226 /* acks */ "note-head-interface rest-interface",