2 coherent-ligature-engraver.cc -- implement Coherent_ligature_engraver
4 source file of the GNU LilyPond music typesetter
6 (c) 2003 Juergen Reuter <reuter@ipd.uka.de>
9 #include "coherent-ligature-engraver.hh"
12 #include "staff-symbol-referencer.hh"
14 #include "paper-column.hh"
17 * This abstract class serves as common superclass for all ligature
18 * engravers thet produce a single connected graphical object of fixed
19 * width, consisting of noteheads and other primitives (see class
20 * Ligature_engraver for more information on the interaction between
21 * this class and its superclass). In particular, it cares for the
24 * - provide a function for putting all grobs of the ligature into a
25 * single paper column,
27 * - delegate actual creation of ligature to concrete subclass,
29 * - collect all accidentals that occur within the ligature and put
30 * them at the left side of the ligature (TODO; see function
31 * collect_accidentals ()),
33 * - collapse superflous space after each ligature (TODO).
35 * Concrete subclasses must implement function build_ligature (Spanner
36 * *, Array<Grob_info>). This function is responsible for actually
37 * building the ligature by transforming the array of noteheads.
39 * Currently, there are two subclasses: Gregorian_ligature_engraver
40 * for Gregorian chant notation (also known as plain song or cantus
41 * planus) and Mensural_ligature_engraver for white mensural notation.
42 * Subclasses for other music notation styles such as modal notation
43 * or ars nova notation may eventually be added.
47 * TODO: local accidentals: collect accidentals that occur within a
48 * ligature and put them before the ligature. If an accidental
49 * changes within a ligature, print a warning (user error) and ignore
50 * any further accidental for that pitch within that ligature
51 * (actually, in such a case, the user should split the ligature into
52 * two separate ligatures). Similarly, any object that, in ordinary
53 * notation, may be put to the left or to the right of a note-head,
54 * should be collected and put before or after the ligature.
56 * TODO: make spacing more robust: do not screw up spacing if user
57 * erroneously puts rest in ligature.
59 * TODO: for each ligature, add Rod that represents the total length
60 * of the ligature (to preemptively avoid collision with adjacent
61 * notes); or maybe just additionally create a
62 * mensural/vaticana/whatever-ligature grob (e.g. via
63 * Mensural_ligature::print (SCM)) that just consists of a
64 * bounding box around all primitives of the ligature.
66 * TODO: Maybe move functions fold_up_primitives () and
67 * join_primitives () from subclasses to here? N.B. it is not
68 * appropriate to put these into Ligature_engraver, since, for
69 * example, Ligature_bracket_engraver does not share any of this code.
73 * TODO: Let superflous space after each ligature collapse. The
74 * following code should help in doing so (though it does not yet
75 * fully work). Just put the following code into
76 * Spacing_spanner::do_measure (). I put it temporarily here as memo
77 * until it really works and I also get Han-Wen's/Jan's permission to
78 * add it to the spacing spanner code.
80 #if 0 // experimental code to collapse spacing after ligature
81 SCM incr_scm
= lc
->get_property ("forced-spacing");
82 if (incr_scm
!= SCM_EOL
) /* (Paper_column::is_musical (l)) */
84 me
->warning (_f ("gotcha: ptr=%ul", lc
));//debug
85 ly_display_scm (lc
->self_scm ());
87 if (incr_scm
!= SCM_EOL
)
89 distance
= ly_scm2double (incr_scm
);
93 me
->warning ("distance undefined, assuming 0.1");
96 me
->warning (_f ("distance=%f", distance
));//debug
98 Spaceable_grob::add_spring (lc
, rc
, distance
, strength
, false);
99 if (Item
*rb
= r
->find_prebroken_piece (LEFT
))
100 Spaceable_grob::add_spring (lc
, rb
, distance
, strength
, false);
106 Coherent_ligature_engraver::Coherent_ligature_engraver ()
111 * TODO: move this function to class Item?
114 Coherent_ligature_engraver::get_set_column (Item
*item
, Paper_column
*column
)
116 Item
*parent
= dynamic_cast<Item
*> (item
->get_parent (X_AXIS
));
119 programming_error ("failed tweaking paper column in ligature");
123 String name
= parent
->name ();
124 if (!String::compare (name
, "PaperColumn"))
126 // Change column not only for targeted item (NoteColumn), but
127 // also for all associated grobs (NoteSpacing, SeparationItem).
128 Grob
*sl
= Staff_symbol_referencer::get_staff_symbol (item
);
129 for (SCM tail
= parent
->get_property ("elements");
131 tail
= ly_cdr (tail
))
133 Item
*sibling
= unsmob_item (ly_car (tail
));
135 (Staff_symbol_referencer::get_staff_symbol (sibling
) == sl
))
137 #if 0 // experimental code to collapse spacing after ligature
138 Grob
*sibling_parent
= sibling
->get_parent (X_AXIS
);
139 sibling_parent
->warning (_f ("Coherent_ligature_engraver: "
140 "setting `spacing-increment = "
141 "0.01': ptr=%ul", parent
));
142 sibling_parent
->set_property ("forced-spacing",
143 scm_make_real (0.01));
145 sibling
->set_parent (column
, X_AXIS
);
151 get_set_column (parent
, column
);
156 * TODO: This function should collect all accidentals that occur
157 * within the ligature (by scanning through the primitives array) and
158 * place all of them at the left of the ligature. If there is an
159 * alteration within the ligature (e.g. an "f" followed by a "fis"
160 * somewhere later in the ligature), issue a warning (and maybe create
161 * an additional natural symbol to explicitly make clear that there is
162 * an "f" first?). The warning should suggest the user to break the
163 * ligature into two or more smaller ligatures such that no alteration
164 * occurs within the broken ligatures any more.
167 Coherent_ligature_engraver::collect_accidentals (Spanner
*, Array
<Grob_info
>)
173 compute_delta_pitches (Array
<Grob_info
> primitives
)
177 Item
*prev_primitive
= 0, *primitive
= 0;
178 for (int i
= 0; i
< primitives
.size (); i
++) {
179 primitive
= dynamic_cast<Item
*> (primitives
[i
].grob_
);
180 Music
*music_cause
= primitives
[i
].music_cause ();
182 unsmob_pitch (music_cause
->get_property ("pitch"))->steps ();
185 delta_pitch
= pitch
- prev_pitch
;
186 prev_primitive
->set_property ("delta-pitch",
187 scm_int2num (delta_pitch
));
190 prev_primitive
= primitive
;
192 primitive
->set_property ("delta-pitch", scm_int2num (0));
196 Coherent_ligature_engraver::build_ligature (Spanner
*, Array
<Grob_info
>)
198 programming_error ("Coherent_ligature_engraver::build_ligature (): "
199 "this is an abstract method that should not be called, "
200 "but overridden by a subclass");
204 Coherent_ligature_engraver::typeset_ligature (Spanner
*ligature
,
205 Array
<Grob_info
> primitives
)
207 // compute some commonly needed context info stored as grob
209 compute_delta_pitches (primitives
);
211 // prepare ligature for typesetting
212 build_ligature (ligature
, primitives
);
213 collect_accidentals (ligature
, primitives
);
216 ENTER_DESCRIPTION (Coherent_ligature_engraver
,
217 /* descr */ "This is an abstract class. Subclasses such as Gregorian_ligature_engraver handle ligatures by glueing special ligature heads together.",
219 /* accepts */ "ligature-event",
220 /* acks */ "note-head-interface rest-interface",