2 beam.cc -- implement Beam
4 source file of the GNU LilyPond music typesetter
6 (c) 1997 Han-Wen Nienhuys <hanwen@stack.nl>
10 Less hairy code. knee: ([\stem 1; c8 \stem -1; c8]
21 #include "abbreviation-beam.hh"
25 #include "molecule.hh"
26 #include "leastsquares.hh"
28 #include "paper-def.hh"
30 #include "grouping.hh"
31 #include "stem-info.hh"
34 IMPLEMENT_IS_TYPE_B1(Beam, Spanner);
46 s->add_dependency (this);
49 if (!spanned_drul_[LEFT])
56 Beam::brew_molecule_p() const
58 Molecule *mol_p = new Molecule;
60 // Real inter_f = paper()->interbeam_f ();
61 Real inter_f = paper()->internote_f ();
62 Real x0 = stems[0]->hpos_f();
63 for (int j=0; j <stems.size(); j++)
66 Stem * prev = (j > 0)? stems[j-1] : 0;
67 Stem * next = (j < stems.size()-1) ? stems[j+1] :0;
69 Molecule sb = stem_beams (i, next, prev);
70 Real x = i->hpos_f()-x0;
71 sb.translate (Offset (x, (x * slope + left_pos)* inter_f));
74 mol_p->translate (x0 - spanned_drul_[LEFT]->absolute_coordinate(X_AXIS), X_AXIS);
81 Real w=(paper()->note_width () + width ().length ())/2.0;
82 return Offset (w, (left_pos + w* slope)*paper()->internote_f ());
86 Beam::do_pre_processing()
93 Beam::do_print() const
96 DOUT << "slope " <<slope << "left ypos " << left_pos;
102 Beam::do_post_processing()
104 if (stems.size() < 2)
106 warning ("Beam with less than 2 stems");
107 transparent_b_ = true;
115 Beam::do_substitute_dependent (Score_elem*o,Score_elem*n)
117 if (o->is_type_b (Stem::static_name()))
118 stems.substitute ((Stem*)o->item(), n?(Stem*) n->item ():0);
122 Beam::do_width() const
124 return Interval (stems[0]->hpos_f(),
125 stems.top()->hpos_f ());
129 Beam::set_default_dir()
131 int up = 0, down = 0;
132 int up_count = 0, down_count = 0;
134 for (int i=0; i <stems.size(); i++)
137 int cur_down = sl->get_center_distance_from_top();
138 int cur_up = sl->get_center_distance_from_bottom();
155 // the following relation is equal to
156 // up / up_count > down / down_count
157 dir_ = (up * down_count > down * up_count) ? UP : DOWN;
159 for (int i=0; i <stems.size(); i++)
167 should use minimum energy formulation (cf linespacing)
170 the y of the (start) of the beam should be quantisized,
171 so that no stafflines appear just in between two beam-flags
177 Array<Stem_info> sinfo;
178 for (int j=0; j <stems.size(); j++)
182 i->set_default_extents();
183 if (i->invisible_b())
190 slope = left_pos = 0;
191 else if (sinfo.size() == 1)
194 left_pos = sinfo[0].idealy_f_;
199 Real leftx = sinfo[0].x;
201 for (int i=0; i < sinfo.size(); i++)
204 l.input.push (Offset (sinfo[i].x, sinfo[i].idealy_f_));
207 l.minimise (slope, left_pos);
211 for (int i=0; i < sinfo.size(); i++)
213 Real y = sinfo[i].x * slope + left_pos;
214 Real my = sinfo[i].miny_f_;
225 This neat trick is by Werner Lemberg, damped = tanh (slope) corresponds
226 with some tables in [Wanske]
228 slope = 0.6 * tanh (slope);
231 Real sl = slope*paper()->internote_f ();
232 paper()->lookup_l ()->beam (sl, 20 PT);
233 slope = sl /paper()->internote_f ();
239 Real x0 = stems[0]->hpos_f();
240 for (int j=0; j <stems.size(); j++)
244 Real x = s->hpos_f()-x0;
245 s->set_stemend (left_pos + slope * x);
250 Beam::set_grouping (Rhythmic_grouping def, Rhythmic_grouping cur)
254 assert (cur.children.size() == stems.size ());
261 for (int j=0; j <stems.size(); j++)
265 int f = s->flag_i_ - 2;
270 b= cur.generate_beams (flags, fi);
273 assert (stems.size() == b.size ()/2);
276 for (int j=0, i=0; i < b.size() && j <stems.size (); i+= 2, j++)
279 s->beams_left_i_ = b[i];
280 s->beams_right_i_ = b[i+1];
285 beams to go with one stem.
288 Beam::stem_beams (Stem *here, Stem *next, Stem *prev) const
290 assert (!next || next->hpos_f() > here->hpos_f ());
291 assert (!prev || prev->hpos_f() < here->hpos_f ());
292 // Real dy=paper()->internote_f ()*2;
293 Real dy = paper()->interbeam_f ();
294 Real stemdx = paper()->rule_thickness ();
295 Real sl = slope*paper()->internote_f ();
296 paper()->lookup_l ()->beam (sl, 20 PT);
301 /* half beams extending to the left. */
304 int lhalfs= lhalfs = here->beams_left_i_ - prev->beams_right_i_ ;
305 int lwholebeams= here->beams_left_i_ <? prev->beams_right_i_ ;
306 Real w = (here->hpos_f () - prev->hpos_f ())/4;
309 if (lhalfs) // generates warnings if not
310 a = paper()->lookup_l ()->beam (sl, w);
311 a.translate (Offset (-w, -w * sl));
312 for (int j = 0; j < lhalfs; j++)
315 b.translate (-dir_ * dy * (lwholebeams+j), Y_AXIS);
322 int rhalfs = here->beams_right_i_ - next->beams_left_i_;
323 int rwholebeams = here->beams_right_i_ <? next->beams_left_i_;
325 Real w = next->hpos_f() - here->hpos_f ();
326 Atom a = paper()->lookup_l ()->beam (sl, w + stemdx);
330 if (here->beam_gap_i_)
332 int nogap = rwholebeams - here->beam_gap_i_;
333 for (; j < nogap; j++)
336 b.translate (-dir_ * dy * j, Y_AXIS);
339 // TODO: notehead widths differ for different types
340 gap_f = paper()->note_width () / 2;
342 a = paper()->lookup_l ()->beam (sl, w + stemdx);
345 for (; j < rwholebeams; j++)
348 b.translate (Offset (gap_f, -dir_ * dy * j));
354 a = paper()->lookup_l ()->beam (sl, w);
356 for (; j < rwholebeams + rhalfs; j++)
359 b.translate (-dir_ * dy * j, Y_AXIS);
364 leftbeams.add (rightbeams);