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. Better slope calculations.
11 knee: ([\stem 1; c8 \stem -1; c8]
25 #include "molecule.hh"
26 #include "leastsquares.hh"
28 #include "paper-def.hh"
30 #include "grouping.hh"
42 Stem_info(Stem const *);
45 Stem_info::Stem_info(Stem const *s)
49 beams_i_ = intlog2( s->flag_i_ ) - 2;
57 miny_f_ = interline + #beams * interbeam
58 ideal8 = 2 * interline + interbeam
59 ideal16,32,64,128 = 1.5 * interline + #beams * interbeam
62 miny_f_ = interline + #beams * interbeam
63 ideal8,16 = 2 interline + #beams * interbeam
64 ideal32,64,128 = 1.5 interline + #beams * interbeam
68 Real notehead_y = s->paper()->interline_f();
69 // huh? why do i need the / 2
70 // Real interbeam_f = s->paper()->interbeam_f();
71 Real interbeam_f = s->paper()->interbeam_f() / 2;
74 idealy_f_ = dir_i_ * s->stem_start_f() + beams_i_ * interbeam_f;
76 idealy_f_ += 2 * interline_f;
78 idealy_f_ += 1.5 * interline_f;
81 idealy_f_ = dir_i_ * s->stem_end_f();
83 miny_f_ = dir_i_ * s->stem_start_f() + notehead_y + beams_i_ * interbeam_f;
85 idealy_f_ = miny_f_ >? idealy_f_;
86 // assert(miny_f_ <= idealy_f_);
96 Real w=(paper()->note_width() + width().length())/2.0;
97 return Offset(w, (left_pos + w* slope)*paper()->internote_f());
111 s->add_dependency(this);
112 s->print_flag_b_ = false;
116 Beam::set_default_dir()
118 int up = 0, down = 0;
119 int up_count = 0, down_count = 0;
121 for (int i=0; i <stems.size(); i++) {
123 int cur_down = sl->get_center_distance_from_top();
124 int cur_up = sl->get_center_distance_from_bottom();
139 // the following relation is equal to
140 // up / up_count > down / down_count
141 dir_i_ = (up * down_count > down * up_count) ? 1 : -1;
143 for (int i=0; i <stems.size(); i++) {
150 should use minimum energy formulation (cf linespacing)
153 the y of the (start) of the beam should be quantisized,
154 so that no stafflines appear just in between two beam-flags
160 Array<Stem_info> sinfo;
161 for (int j=0; j <stems.size(); j++) {
164 i->set_default_extents();
165 if (i->invisible_b())
172 slope = left_pos = 0;
173 else if (sinfo.size() == 1) {
175 left_pos = sinfo[0].idealy_f_;
178 Real leftx = sinfo[0].x;
180 for (int i=0; i < sinfo.size(); i++) {
182 l.input.push(Offset(sinfo[i].x, sinfo[i].idealy_f_));
185 l.minimise(slope, left_pos);
189 for (int i=0; i < sinfo.size(); i++) {
190 Real y = sinfo[i].x * slope + left_pos;
191 Real my = sinfo[i].miny_f_;
202 This neat trick is by Werner Lemberg, damped = tanh(slope) corresponds
203 with some tables in [Wanske]
205 slope = 0.6 * tanh(slope);
208 Real sl = slope*paper()->internote_f();
209 paper()->lookup_l()->beam(sl, 20 PT);
210 slope = sl /paper()->internote_f();
216 Real x0 = stems[0]->hpos_f();
217 for (int j=0; j <stems.size(); j++) {
220 Real x = s->hpos_f()-x0;
221 s->set_stemend(left_pos + slope * x);
227 Beam::do_post_processing()
229 if ( stems.size() < 2) {
230 warning("Beam with less than 2 stems");
231 transparent_b_ = true;
239 Beam::set_grouping(Rhythmic_grouping def, Rhythmic_grouping cur)
243 assert(cur.children.size() == stems.size());
250 for (int j=0; j <stems.size(); j++) {
253 int f = intlog2(abs(s->flag_i_))-2;
258 b= cur.generate_beams(flags, fi);
261 assert(stems.size() == b.size()/2);
264 for (int j=0, i=0; i < b.size() && j <stems.size(); i+= 2, j++) {
266 s->beams_left_i_ = b[i];
267 s->beams_right_i_ = b[i+1];
272 Beam::do_pre_processing()
281 Beam::do_width() const
283 return Interval( stems[0]->hpos_f(),
284 stems.top()->hpos_f() );
288 beams to go with one stem.
291 Beam::stem_beams(Stem *here, Stem *next, Stem *prev)const
293 assert( !next || next->hpos_f() > here->hpos_f() );
294 assert( !prev || prev->hpos_f() < here->hpos_f() );
295 // Real dy=paper()->internote_f()*2;
296 Real dy = paper()->interbeam_f();
297 Real stemdx = paper()->rule_thickness();
298 Real sl = slope*paper()->internote_f();
299 paper()->lookup_l()->beam(sl, 20 PT);
304 /* half beams extending to the left. */
306 int lhalfs= lhalfs = here->beams_left_i_ - prev->beams_right_i_ ;
307 int lwholebeams= here->beams_left_i_ <? prev->beams_right_i_ ;
308 Real w = (here->hpos_f() - prev->hpos_f())/4;
311 if (lhalfs) // generates warnings if not
312 a = paper()->lookup_l()->beam(sl, w);
313 a.translate(Offset (-w, -w * sl));
314 for (int j = 0; j < lhalfs; j++) {
316 b.translate_y( -dir_i_ * dy * (lwholebeams+j));
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);
329 for (; j < rwholebeams; j++) {
331 b.translate_y( -dir_i_ * dy * j);
337 a = paper()->lookup_l()->beam(sl, w);
339 for (; j < rwholebeams + rhalfs; j++) {
341 b.translate_y( -dir_i_ * dy * j);
346 leftbeams.add(rightbeams);
352 Beam::brew_molecule_p() const
355 Molecule *mol_p = new Molecule;
357 // Real inter_f = paper()->interbeam_f();
358 Real inter_f = paper()->internote_f();
359 Real x0 = stems[0]->hpos_f();
360 for (int j=0; j <stems.size(); j++) {
362 Stem * prev = (j > 0)? stems[j-1] : 0;
363 Stem * next = (j < stems.size()-1) ? stems[j+1] :0;
365 Molecule sb = stem_beams(i, next, prev);
366 Real x = i->hpos_f()-x0;
367 sb.translate(Offset(x, (x * slope + left_pos)* inter_f));
370 mol_p->translate_x(x0 - left_col_l_->hpos);
374 IMPLEMENT_STATIC_NAME(Beam);
375 IMPLEMENT_IS_TYPE_B1(Beam, Spanner);
378 Beam::do_print()const
381 mtor << "slope " <<slope << "left ypos " << left_pos;
386 duh. The stem is not a dependency but a dependent
389 Beam::do_substitute_dependency(Score_elem*o,Score_elem*n)
391 if (o->is_type_b( Stem::static_name() )) {
392 stems.substitute( (Stem*)o->item(), n?(Stem*) n->item():0);