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]
24 #include "molecule.hh"
25 #include "leastsquares.hh"
27 #include "paper-def.hh"
29 #include "grouping.hh"
41 Stem_info(Stem const *);
44 Stem_info::Stem_info(Stem const *s)
48 beams_i_ = intlog2( s->flag_i_ ) - 2;
56 miny_f_ = interline + #beams * interbeam
57 ideal8 = 2 * interline + interbeam
58 ideal16,32,64,128 = 1.5 * interline + #beams * interbeam
61 miny_f_ = interline + #beams * interbeam
62 ideal8,16 = 2 interline + #beams * interbeam
63 ideal32,64,128 = 1.5 interline + #beams * interbeam
67 Real notehead_y = s->paper()->interline_f();
68 // huh? why do i need the / 2
69 // Real interbeam_f = s->paper()->interbeam_f();
70 Real interbeam_f = s->paper()->interbeam_f() / 2;
73 idealy_f_ = dir_i_ * s->stem_start_f() + beams_i_ * interbeam_f;
75 idealy_f_ += 2 * interline_f;
77 idealy_f_ += 1.5 * interline_f;
80 idealy_f_ = dir_i_ * s->stem_end_f();
82 miny_f_ = dir_i_ * s->stem_start_f() + notehead_y + beams_i_ * interbeam_f;
84 idealy_f_ = miny_f_ >? idealy_f_;
85 // assert(miny_f_ <= idealy_f_);
95 Real w=(paper()->note_width() + width().length())/2.0;
96 return Offset(w, (left_pos + w* slope)*paper()->internote_f());
110 s->add_dependency(this);
111 s->print_flag_b_ = false;
115 Beam::set_default_dir()
117 int up = 0, down = 0;
118 int up_count = 0, down_count = 0;
120 for (int i=0; i <stems.size(); i++) {
122 int cur_down = sl->get_center_distance_from_top();
123 int cur_up = sl->get_center_distance_from_bottom();
138 // the following relation is equal to
139 // up / up_count > down / down_count
140 dir_i_ = (up * down_count > down * up_count) ? 1 : -1;
142 for (int i=0; i <stems.size(); i++) {
149 should use minimum energy formulation (cf linespacing)
152 the y of the (start) of the beam should be quantisized,
153 so that no stafflines appear just in between two beam-flags
159 Array<Stem_info> sinfo;
160 for (int j=0; j <stems.size(); j++) {
163 i->set_default_extents();
164 if (i->invisible_b())
171 slope = left_pos = 0;
172 else if (sinfo.size() == 1) {
174 left_pos = sinfo[0].idealy_f_;
177 Real leftx = sinfo[0].x;
179 for (int i=0; i < sinfo.size(); i++) {
181 l.input.push(Offset(sinfo[i].x, sinfo[i].idealy_f_));
184 l.minimise(slope, left_pos);
188 for (int i=0; i < sinfo.size(); i++) {
189 Real y = sinfo[i].x * slope + left_pos;
190 Real my = sinfo[i].miny_f_;
201 This neat trick is by Werner Lemberg, damped = tanh(slope) corresponds
202 with some tables in [Wanske]
204 slope = 0.6 * tanh(slope);
207 Real sl = slope*paper()->internote_f();
208 paper()->lookup_l()->beam(sl, 20 PT);
209 slope = sl /paper()->internote_f();
215 Real x0 = stems[0]->hpos_f();
216 for (int j=0; j <stems.size(); j++) {
219 Real x = s->hpos_f()-x0;
220 s->set_stemend(left_pos + slope * x);
226 Beam::do_post_processing()
228 if ( stems.size() < 2) {
229 warning("Beam with less than 2 stems");
230 transparent_b_ = true;
238 Beam::set_grouping(Rhythmic_grouping def, Rhythmic_grouping cur)
242 assert(cur.children.size() == stems.size());
249 for (int j=0; j <stems.size(); j++) {
252 int f = intlog2(abs(s->flag_i_))-2;
257 b= cur.generate_beams(flags, fi);
260 assert(stems.size() == b.size()/2);
263 for (int j=0, i=0; i < b.size() && j <stems.size(); i+= 2, j++) {
265 s->beams_left_i_ = b[i];
266 s->beams_right_i_ = b[i+1];
271 Beam::do_pre_processing()
280 Beam::do_width() const
282 return Interval( stems[0]->hpos_f(),
283 stems.top()->hpos_f() );
287 beams to go with one stem.
290 Beam::stem_beams(Stem *here, Stem *next, Stem *prev)const
292 assert( !next || next->hpos_f() > here->hpos_f() );
293 assert( !prev || prev->hpos_f() < here->hpos_f() );
294 // Real dy=paper()->internote_f()*2;
295 Real dy = paper()->interbeam_f();
296 Real stemdx = paper()->rule_thickness();
297 Real sl = slope*paper()->internote_f();
298 paper()->lookup_l()->beam(sl, 20 PT);
303 /* half beams extending to the left. */
305 int lhalfs= lhalfs = here->beams_left_i_ - prev->beams_right_i_ ;
306 int lwholebeams= here->beams_left_i_ <? prev->beams_right_i_ ;
307 Real w = (here->hpos_f() - prev->hpos_f())/4;
310 if (lhalfs) // generates warnings if not
311 a = paper()->lookup_l()->beam(sl, w);
312 a.translate(Offset (-w, -w * sl));
313 for (int j = 0; j < lhalfs; j++) {
315 b.translate_y( -dir_i_ * dy * (lwholebeams+j));
321 int rhalfs = here->beams_right_i_ - next->beams_left_i_;
322 int rwholebeams = here->beams_right_i_ <? next->beams_left_i_;
324 Real w = next->hpos_f() - here->hpos_f();
325 Atom a = paper()->lookup_l()->beam(sl, w + stemdx);
328 for (; j < rwholebeams; j++) {
330 b.translate_y( -dir_i_ * dy * j);
336 a = paper()->lookup_l()->beam(sl, w);
338 for (; j < rwholebeams + rhalfs; j++) {
340 b.translate_y( -dir_i_ * dy * j);
345 leftbeams.add(rightbeams);
351 Beam::brew_molecule_p() const
354 Molecule *mol_p = new Molecule;
356 // Real inter_f = paper()->interbeam_f();
357 Real inter_f = paper()->internote_f();
358 Real x0 = stems[0]->hpos_f();
359 for (int j=0; j <stems.size(); j++) {
361 Stem * prev = (j > 0)? stems[j-1] : 0;
362 Stem * next = (j < stems.size()-1) ? stems[j+1] :0;
364 Molecule sb = stem_beams(i, next, prev);
365 Real x = i->hpos_f()-x0;
366 sb.translate(Offset(x, (x * slope + left_pos)* inter_f));
369 mol_p->translate_x(x0 - left_col_l_->hpos_f_);
373 IMPLEMENT_STATIC_NAME(Beam);
374 IMPLEMENT_IS_TYPE_B1(Beam, Spanner);
377 Beam::do_print()const
380 mtor << "slope " <<slope << "left ypos " << left_pos;
386 Beam::do_substitute_dependent(Score_elem*o,Score_elem*n)
388 if (o->is_type_b( Stem::static_name() )) {
389 stems.substitute( (Stem*)o->item(), n?(Stem*) n->item():0);