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"
18 * This abstract class serves as common superclass for all ligature
19 * engravers thet produce a single connected graphical object of fixed
20 * width, consisting of noteheads and other primitives (see class
21 * Ligature_engraver for more information on the interaction between
22 * this class and its superclass). In particular, it cares for the
25 * - provide a function for putting all grobs of the ligature into a
26 * single paper column,
28 * - delegate actual creation of ligature to concrete subclass,
30 * - collect all accidentals that occur within the ligature and put
31 * them at the left side of the ligature (TODO; see function
32 * collect_accidentals ()),
34 * - collapse superflous space after each ligature (TODO).
36 * Concrete subclasses must implement function build_ligature (Spanner
37 * *, Array<Grob_info>). This function is responsible for actually
38 * building the ligature by transforming the array of noteheads.
40 * Currently, there are two subclasses: Gregorian_ligature_engraver
41 * for Gregorian chant notation (also known as plain song or cantus
42 * planus) and Mensural_ligature_engraver for white mensural notation.
43 * Subclasses for other music notation styles such as modal notation
44 * or ars nova notation may eventually be added.
48 * TODO: local accidentals: collect accidentals that occur within a
49 * ligature and put them before the ligature. If an accidental
50 * changes within a ligature, print a warning (user error) and ignore
51 * any further accidental for that pitch within that ligature
52 * (actually, in such a case, the user should split the ligature into
53 * two separate ligatures). Similarly, any object that, in ordinary
54 * notation, may be put to the left or to the right of a note-head,
55 * should be collected and put before or after the ligature.
57 * TODO: make spacing more robust: do not screw up spacing if user
58 * erroneously puts rest in ligature.
60 * TODO: for each ligature, add Rod that represents the total length
61 * of the ligature (to preemptively avoid collision with adjacent
62 * notes); or maybe just additionally create a
63 * mensural/vaticana/whatever-ligature grob (e.g. via
64 * Mensural_ligature::print (SCM)) that just consists of a
65 * bounding box around all primitives of the ligature.
67 * TODO: Maybe move functions fold_up_primitives () and
68 * join_primitives () from subclasses to here? N.B. it is not
69 * appropriate to put these into Ligature_engraver, since, for
70 * example, Ligature_bracket_engraver does not share any of this code.
74 * TODO: Let superflous space after each ligature collapse. The
75 * following code should help in doing so (though it does not yet
76 * fully work). Just put the following code into
77 * Spacing_spanner::do_measure (). I put it temporarily here as memo
78 * until it really works and I also get Han-Wen's/Jan's permission to
79 * add it to the spacing spanner code.
81 #if 0 // experimental code to collapse spacing after ligature
82 SCM incr_scm = lc->get_property ("forced-spacing");
83 if (incr_scm != SCM_EOL) /* (Paper_column::is_musical (l)) */
85 me->warning (_f ("gotcha: ptr=%ul", lc));//debug
86 ly_display_scm (lc->self_scm ());
88 if (incr_scm != SCM_EOL)
90 distance = scm_to_double (incr_scm);
94 me->warning (_ ("distance undefined, assuming 0.1"));
97 me->warning (_f ("distance=%f", distance));//debug
98 Real inverse_strength = 1.0;
99 Spaceable_grob::add_spring (lc, rc, distance, inverse_strength);
100 if (Item *rb = r->find_prebroken_piece (LEFT))
101 Spaceable_grob::add_spring (lc, rb, distance, inverse_strength);
107 Coherent_ligature_engraver::Coherent_ligature_engraver ()
112 * TODO: move this function to class Item?
115 Coherent_ligature_engraver::get_set_column (Item *item, Paper_column *column)
117 Item *parent = dynamic_cast<Item *> (item->get_parent (X_AXIS));
120 programming_error ("failed tweaking paper column in ligature");
124 String name = parent->name ();
125 if (!String::compare (name, "PaperColumn"))
127 // Change column not only for targeted item (NoteColumn), but
128 // also for all associated grobs (NoteSpacing, SeparationItem).
129 Grob *sl = Staff_symbol_referencer::get_staff_symbol (item);
130 for (SCM tail = parent->get_property ("elements");
132 tail = scm_cdr (tail))
134 Item *sibling = unsmob_item (scm_car (tail));
136 && (Staff_symbol_referencer::get_staff_symbol (sibling) == sl))
138 #if 0 // experimental code to collapse spacing after ligature
139 Grob *sibling_parent = sibling->get_parent (X_AXIS);
140 sibling_parent->warning (_f ("Coherent_ligature_engraver: "
141 "setting `spacing-increment="
142 "0.01': ptr=%ul", parent));
143 sibling_parent->set_property ("forced-spacing",
144 scm_make_real (0.01));
146 sibling->set_parent (column, X_AXIS);
152 get_set_column (parent, column);
157 * TODO: This function should collect all accidentals that occur
158 * within the ligature (by scanning through the primitives array) and
159 * place all of them at the left of the ligature. If there is an
160 * alteration within the ligature (e.g. an "f" followed by a "fis"
161 * somewhere later in the ligature), issue a warning (and maybe create
162 * an additional natural symbol to explicitly make clear that there is
163 * an "f" first?). The warning should suggest the user to break the
164 * ligature into two or more smaller ligatures such that no alteration
165 * occurs within the broken ligatures any more.
168 Coherent_ligature_engraver::collect_accidentals (Spanner *, Array<Grob_info>)
174 compute_delta_pitches (Array<Grob_info> primitives)
178 Item *prev_primitive = 0, *primitive = 0;
179 for (int i = 0; i < primitives.size (); i++)
181 primitive = dynamic_cast<Item *> (primitives[i].grob ());
182 Music *music_cause = primitives[i].music_cause ();
184 = unsmob_pitch (music_cause->get_property ("pitch"))->steps ();
187 delta_pitch = pitch - prev_pitch;
188 prev_primitive->set_property ("delta-pitch",
189 scm_int2num (delta_pitch));
192 prev_primitive = primitive;
194 primitive->set_property ("delta-pitch", scm_int2num (0));
198 Coherent_ligature_engraver::build_ligature (Spanner *, Array<Grob_info>)
200 programming_error ("Coherent_ligature_engraver::build_ligature (): "
201 "this is an abstract method that should not be called, "
202 "but overridden by a subclass");
206 Coherent_ligature_engraver::typeset_ligature (Spanner *ligature,
207 Array<Grob_info> primitives)
209 // compute some commonly needed context info stored as grob
211 compute_delta_pitches (primitives);
213 // prepare ligature for typesetting
214 build_ligature (ligature, primitives);
215 collect_accidentals (ligature, primitives);
218 ADD_TRANSLATOR (Coherent_ligature_engraver,
219 /* descr */ "This is an abstract class. Subclasses such as Gregorian_ligature_engraver handle ligatures by glueing special ligature heads together.",
221 /* accepts */ "ligature-event",
222 /* acks */ "note-head-interface rest-interface",