2 ledger-line-spanner.cc -- implement Ledger_line_spanner
4 source file of the GNU LilyPond music typesetter
6 (c) 2004--2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
12 #include "note-head.hh"
13 #include "staff-symbol-referencer.hh"
14 #include "staff-symbol.hh"
17 #include "group-interface.hh"
18 #include "paper-column.hh"
20 struct Ledger_line_spanner
22 DECLARE_SCHEME_CALLBACK (print, (SCM));
23 DECLARE_SCHEME_CALLBACK (set_spacing_rods, (SCM));
24 static Stencil brew_ledger_lines (Grob *me,
31 static bool has_interface (Grob *);
35 Ledger_line_spanner::brew_ledger_lines (Grob *staff,
39 Real ledgerlinethickness,
43 int line_count = ((abs (pos) < interspaces)
45 : (abs (pos) - interspaces) / 2);
49 Real blotdiameter = ledgerlinethickness;
51 = Interval (-0.5 * (ledgerlinethickness),
52 +0.5 * (ledgerlinethickness));
53 Stencil proto_ledger_line
54 = Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
56 x_extent[LEFT] += left_shorten;
57 Stencil proto_first_line
58 = Lookup::round_filled_box (Box (x_extent, y_extent), blotdiameter);
60 Direction dir = (Direction)sign (pos);
61 Real offs = (Staff_symbol_referencer::on_staffline (staff, pos))
65 offs += pos * halfspace;
66 for (int i = 0; i < line_count; i++)
68 Stencil ledger_line ((i == 0)
71 ledger_line.translate_axis (-dir * halfspace * i * 2 + offs, Y_AXIS);
72 stencil.add_stencil (ledger_line);
80 set_rods (Drul_array<Interval> const ¤t_extents,
81 Drul_array<Interval> const &previous_extents,
83 Item *previous_column,
84 Real min_length_fraction)
89 if (!current_extents[d].is_empty ()
90 && !previous_extents[d].is_empty ())
92 Real total_head_length = previous_extents[d].length ()
93 + current_extents[d].length ();
96 rod.distance_ = total_head_length
97 * (3 / 2 * min_length_fraction)
99 we go from right to left.
101 - previous_extents[d][LEFT]
102 + current_extents[d][RIGHT];
104 rod.item_drul_[LEFT] = current_column;
105 rod.item_drul_[RIGHT] = previous_column;
109 while (flip (&d) != DOWN);
112 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, set_spacing_rods, 1);
114 Ledger_line_spanner::set_spacing_rods (SCM smob)
116 Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
118 // find size of note heads.
119 Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
123 SCM heads = me->get_property ("note-heads");
125 Real min_length_fraction
126 = robust_scm2double (me->get_property ("minimum-length-fraction"), 0.15);
128 Drul_array<Interval> current_extents;
129 Drul_array<Interval> previous_extents;
130 Item *previous_column = 0;
131 Item *current_column = 0;
134 Run through heads using a loop. Since Legder_line_spanner can
135 contain a lot of noteheads, superlinear performance is too slow.
137 int interspaces = Staff_symbol::line_count (staff) - 1;
138 for (SCM hp = heads; scm_is_pair (hp); hp = scm_cdr (hp))
140 Item *h = dynamic_cast<Item *> (unsmob_grob (scm_car (hp)));
142 int pos = Staff_symbol_referencer::get_rounded_position (h);
143 if (abs (pos) <= interspaces)
146 Item *column = h->get_column ();
147 if (current_column != column)
149 set_rods (current_extents, previous_extents,
150 current_column, previous_column,
151 min_length_fraction);
153 previous_column = current_column;
154 current_column = column;
155 previous_extents = current_extents;
157 current_extents[DOWN].set_empty ();
158 current_extents[UP].set_empty ();
161 Interval head_extent = h->extent (column, X_AXIS);
162 Direction vdir = Direction (sign (pos));
166 current_extents[vdir].unite (head_extent);
169 if (previous_column && current_column)
170 set_rods (current_extents, previous_extents,
171 current_column, previous_column,
172 min_length_fraction);
174 return SCM_UNSPECIFIED;
177 struct Ledger_request
179 Interval ledger_extent_;
180 Interval head_extent_;
185 ledger_extent_.set_empty ();
186 head_extent_.set_empty ();
191 typedef std::map < int, Drul_array<Ledger_request> > Ledger_requests;
194 TODO: ledger share a lot of info. Lots of room to optimize away
195 common use of objects/variables.
197 MAKE_SCHEME_CALLBACK (Ledger_line_spanner, print, 1);
199 Ledger_line_spanner::print (SCM smob)
201 Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
202 Link_array<Grob> heads (extract_grob_array (me, ly_symbol2scm ("note-heads")));
204 if (heads.is_empty ())
207 // find size of note heads.
208 Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
213 = robust_scm2double (me->get_property ("length-fraction"), 0.25);
216 Stencil default_ledger;
218 Grob *common[NO_AXES];
220 for (int i = X_AXIS; i < NO_AXES; i++)
223 common[a] = common_refpoint_of_array (heads, me, a);
224 for (int i = heads.size (); i--;)
225 if (Grob *g = unsmob_grob (me->get_property ("accidental-grob")))
226 common[a] = common[a]->common_refpoint (g, a);
229 int interspaces = Staff_symbol::line_count (staff) - 1;
230 Ledger_requests reqs;
231 for (int i = heads.size (); i--;)
233 Item *h = dynamic_cast<Item *> (heads[i]);
235 int pos = Staff_symbol_referencer::get_rounded_position (h);
237 && abs (pos) > interspaces)
239 Interval head_extent = h->extent (common[X_AXIS], X_AXIS);
240 Interval ledger_extent = head_extent;
241 ledger_extent.widen (length_fraction * head_extent.length ());
243 Direction vdir = Direction (sign (pos));
244 int rank = Paper_column::get_rank (h->get_column ());
246 reqs[rank][vdir].ledger_extent_.unite (ledger_extent);
247 reqs[rank][vdir].head_extent_.unite (head_extent);
248 reqs[rank][vdir].position_
249 = vdir * ((vdir * reqs[rank][vdir].position_) >? (vdir * pos));
253 // determine maximum size for non-colliding ledger.
254 Real gap = robust_scm2double (me->get_property ("gap"), 0.1);
255 Ledger_requests::iterator last (reqs.end ());
256 for (Ledger_requests::iterator i (reqs.begin ());
257 i != reqs.end (); last = i++)
259 if (last == reqs.end ())
267 if (abs (last->second[d].position_) > interspaces
268 && abs (i->second[d].position_) > interspaces)
271 = (last->second[d].head_extent_[RIGHT]
272 + i->second[d].head_extent_[LEFT]) / 2;
274 Direction which = LEFT;
277 Ledger_request &lr = ((which == LEFT) ? * last : *i).second[d];
279 // due tilt of quarter note-heads
281 = (abs (last->second[d].position_) > interspaces + 1
282 && abs (i->second[d].position_) > interspaces + 1);
284 Real limit = (center + (both ? which * gap / 2 : 0));
285 lr.ledger_extent_.elem_ref (-which)
286 = which * (which * lr.ledger_extent_[-which] >? which * limit);
288 while (flip (&which) != LEFT);
291 while (flip (&d) != DOWN);
294 // create ledgers for note heads
295 Real ledgerlinethickness
296 = Staff_symbol::get_ledger_line_thickness (staff);
297 Real halfspace = Staff_symbol::staff_space (staff) / 2;
298 for (int i = heads.size (); i--;)
300 Item *h = dynamic_cast<Item *> (heads[i]);
302 int pos = Staff_symbol_referencer::get_rounded_position (h);
303 if (abs (pos) > interspaces + 1)
305 Interval head_size = h->extent (common[X_AXIS], X_AXIS);
306 Interval ledger_size = head_size;
307 ledger_size.widen (ledger_size.length () * length_fraction);
309 Interval max_size = reqs[Paper_column::get_rank (h->get_column ())][Direction (sign (pos))].ledger_extent_;
311 ledger_size.intersect (max_size);
312 Real left_shorten = 0.0;
313 if (Grob *g = unsmob_grob (h->get_property ("accidental-grob")))
315 Interval accidental_size = g->extent (common[X_AXIS], X_AXIS);
317 = linear_combination (Drul_array<Real> (accidental_size[RIGHT],
321 left_shorten = (-ledger_size[LEFT] + d) >? 0;
324 TODO: shorten 2 ledger lines for the case natural +
329 ledgers.add_stencil (brew_ledger_lines (staff, pos, interspaces,
337 ledgers.translate_axis (-me->relative_coordinate (common[X_AXIS], X_AXIS),
340 return ledgers.smobbed_copy ();
343 ADD_INTERFACE (Ledger_line_spanner,
344 "ledger-line-interface",
346 "This spanner draws the ledger lines of a staff.\n"
347 "This is a separate grob because it has to process\n"
348 "all potential collisions between all note heads.",
350 "note-heads thickness minimum-length-fraction length-fraction gap");
352 struct Ledgered_interface
354 static bool has_interface (Grob *);
357 ADD_INTERFACE (Ledgered_interface,
358 "ledgered-interface",
360 "Objects that need ledger lines, typically "
361 "note heads. See also @ref{ledger-line-interface}.",