lily/beam.cc

   1 /*
   2   beam.cc -- implement Beam
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997 Han-Wen Nienhuys <hanwen@stack.nl>
   7
   8   TODO
   9
  10   Less hairy code.  knee: ([\stem 1; c8 \stem -1; c8]
  11
  12 */
  13
  14 #include <math.h>
  15
  16 #include "p-col.hh"
  17 #include "varray.hh"
  18 #include "proto.hh"
  19 #include "dimen.hh"
  20 #include "beam.hh"
  21 #include "abbreviation-beam.hh"
  22 #include "misc.hh"
  23 #include "debug.hh"
  24 #include "atom.hh"
  25 #include "molecule.hh"
  26 #include "leastsquares.hh"
  27 #include "stem.hh"
  28 #include "paper-def.hh"
  29 #include "lookup.hh"
  30 #include "grouping.hh"
  31 #include "stem-info.hh"
  32
  33
  34 IMPLEMENT_IS_TYPE_B1(Beam, Spanner);
  35
  36 Beam::Beam()
  37 {
  38   slope = 0;
  39   left_pos = 0.0;
  40 }
  41
  42 void
  43 Beam::add (Stem*s)
  44 {
  45   stems.push (s);
  46   s->add_dependency (this);
  47   s->beam_l_ = this;
  48
  49   if (!spanned_drul_[LEFT])
  50     set_bounds (LEFT,s);
  51   else
  52     set_bounds (RIGHT,s);
  53 }
  54
  55 Molecule*
  56 Beam::brew_molecule_p() const
  57 {
  58   Molecule *mol_p = new Molecule;
  59   // huh? inter-what
  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++)
  64     {
  65       Stem *i = stems[j];
  66       Stem * prev = (j > 0)? stems[j-1] : 0;
  67       Stem * next = (j < stems.size()-1) ? stems[j+1] :0;
  68
  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));
  72       mol_p->add (sb);
  73     }
  74   mol_p->translate (x0 - spanned_drul_[LEFT]->absolute_coordinate(X_AXIS), X_AXIS);
  75   return mol_p;
  76 }
  77
  78 Offset
  79 Beam::center() const
  80 {
  81   Real w=(paper()->note_width () + width ().length ())/2.0;
  82   return Offset (w, (left_pos + w* slope)*paper()->internote_f ());
  83 }
  84
  85 void
  86 Beam::do_pre_processing()
  87 {
  88   if (!dir_)
  89     set_default_dir();
  90 }
  91
  92 void
  93 Beam::do_print() const
  94 {
  95 #ifndef NPRINT
  96   DOUT << "slope " <<slope << "left ypos " << left_pos;
  97   Spanner::do_print();
  98 #endif
  99 }
 100
 101 void
 102 Beam::do_post_processing()
 103 {
 104   if (stems.size() < 2)
 105     {
 106       warning ("Beam with less than 2 stems");
 107       transparent_b_ = true;
 108       return ;
 109     }
 110   solve_slope();
 111   set_stemlens();
 112 }
 113
 114 void
 115 Beam::do_substitute_dependent (Score_elem*o,Score_elem*n)
 116 {
 117   if (o->is_type_b (Stem::static_name()))
 118       stems.substitute ((Stem*)o->item(),  n?(Stem*) n->item ():0);
 119 }
 120
 121 Interval
 122 Beam::do_width() const
 123 {
 124   return Interval (stems[0]->hpos_f(),
 125                    stems.top()->hpos_f ());
 126 }
 127
 128 void
 129 Beam::set_default_dir()
 130 {
 131   int up = 0, down = 0;
 132   int up_count = 0, down_count = 0;
 133
 134   for (int i=0; i <stems.size(); i++)
 135     {
 136       Stem *sl = stems[i];
 137       int cur_down = sl->get_center_distance_from_top();
 138       int cur_up = sl->get_center_distance_from_bottom();
 139       if (cur_down)
 140         {
 141           down += cur_down;
 142           down_count++;
 143         }
 144       if (cur_up)
 145         {
 146           up += cur_up;
 147           up_count++;
 148         }
 149     }
 150   if (!down)
 151     down_count = 1;
 152   if (!up)
 153     up_count = 1;
 154
 155   // the following relation is equal to
 156   //        up / up_count > down / down_count
 157   dir_ = (up * down_count > down * up_count) ? UP : DOWN;
 158
 159   for (int i=0; i <stems.size(); i++)
 160     {
 161       Stem *sl = stems[i];
 162       sl->dir_ = dir_;
 163     }
 164 }
 165
 166 /*
 167   should use minimum energy formulation (cf linespacing)
 168
 169   [todo]
 170   the y of the (start) of the beam should be quantisized,
 171   so that no stafflines appear just in between two beam-flags
 172
 173 */
 174 void
 175 Beam::solve_slope()
 176 {
 177   Array<Stem_info> sinfo;
 178   for (int j=0; j <stems.size(); j++)
 179     {
 180       Stem *i = stems[j];
 181
 182       i->set_default_extents();
 183       if (i->invisible_b())
 184         continue;
 185
 186       Stem_info info (i);
 187       sinfo.push (info);
 188     }
 189   if (! sinfo.size())
 190     slope = left_pos = 0;
 191   else if (sinfo.size() == 1)
 192     {
 193       slope = 0;
 194       left_pos = sinfo[0].idealy_f_;
 195     }
 196   else
 197     {
 198
 199       Real leftx = sinfo[0].x;
 200       Least_squares l;
 201       for (int i=0; i < sinfo.size(); i++)
 202         {
 203           sinfo[i].x -= leftx;
 204           l.input.push (Offset (sinfo[i].x, sinfo[i].idealy_f_));
 205         }
 206
 207       l.minimise (slope, left_pos);
 208     }
 209
 210   Real dy = 0.0;
 211   for (int i=0; i < sinfo.size(); i++)
 212     {
 213       Real y = sinfo[i].x * slope + left_pos;
 214       Real my = sinfo[i].miny_f_;
 215
 216       if (my - y > dy)
 217         dy = my -y;
 218     }
 219   left_pos += dy;
 220   left_pos *= dir_;
 221
 222   slope *= dir_;
 223
 224   /*
 225     This neat trick is by Werner Lemberg, damped = tanh (slope) corresponds
 226     with some tables in [Wanske]
 227     */
 228   slope = 0.6 * tanh (slope);
 229
 230   // ugh
 231   Real sl = slope*paper()->internote_f ();
 232   paper()->lookup_l ()->beam (sl, 20 PT);
 233   slope = sl /paper()->internote_f ();
 234 }
 235
 236 void
 237 Beam::set_stemlens()
 238 {
 239   Real x0 = stems[0]->hpos_f();
 240   for (int j=0; j <stems.size(); j++)
 241     {
 242       Stem *s = stems[j];
 243
 244       Real x =  s->hpos_f()-x0;
 245       s->set_stemend (left_pos + slope * x);
 246     }
 247 }
 248
 249 void
 250 Beam::set_grouping (Rhythmic_grouping def, Rhythmic_grouping cur)
 251 {
 252   def.OK();
 253   cur.OK();
 254   assert (cur.children.size() == stems.size ());
 255
 256   cur.split (def);
 257
 258   Array<int> b;
 259   {
 260     Array<int> flags;
 261     for (int j=0; j <stems.size(); j++)
 262       {
 263         Stem *s = stems[j];
 264
 265         int f = s->flag_i_ - 2;
 266         assert (f>0);
 267         flags.push (f);
 268       }
 269     int fi =0;
 270     b= cur.generate_beams (flags, fi);
 271     b.insert (0,0);
 272     b.push (0);
 273     assert (stems.size() == b.size ()/2);
 274   }
 275
 276   for (int j=0, i=0; i < b.size() && j <stems.size (); i+= 2, j++)
 277     {
 278       Stem *s = stems[j];
 279       s->beams_left_i_ = b[i];
 280       s->beams_right_i_ = b[i+1];
 281     }
 282 }
 283
 284 /*
 285   beams to go with one stem.
 286   */
 287 Molecule
 288 Beam::stem_beams (Stem *here, Stem *next, Stem *prev) const
 289 {
 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);
 297
 298   Molecule leftbeams;
 299   Molecule rightbeams;
 300
 301   /* half beams extending to the left. */
 302   if (prev)
 303     {
 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;
 307       Atom a;
 308       if (lhalfs)               // generates warnings if not
 309         a =  paper()->lookup_l ()->beam (sl, w);
 310       a.translate (Offset (-w, -w * sl));
 311       for (int j = 0; j  < lhalfs; j++)
 312         {
 313           Atom b (a);
 314           b.translate (-dir_ * dy * (lwholebeams+j), Y_AXIS);
 315           leftbeams.add (b);
 316         }
 317     }
 318
 319   if (next)
 320     {
 321       int rhalfs = here->beams_right_i_ - next->beams_left_i_;
 322       int rwholebeams = here->beams_right_i_ <? next->beams_left_i_;
 323
 324       Real w = next->hpos_f() - here->hpos_f ();
 325       Atom a = paper()->lookup_l ()->beam (sl, w + stemdx);
 326
 327       int j = 0;
 328       Real gap_f = 0;
 329       if (here->beam_gap_i_)
 330         {
 331           int nogap = rwholebeams - here->beam_gap_i_;
 332           for (; j  < nogap; j++)
 333             {
 334               Atom b (a);
 335               b.translate (-dir_ * dy * j, Y_AXIS);
 336               rightbeams.add (b);
 337             }
 338           // TODO: notehead widths differ for different types
 339           gap_f = paper()->note_width () / 2;
 340           w -= 2 * gap_f;
 341           a = paper()->lookup_l ()->beam (sl, w + stemdx);
 342         }
 343
 344       for (; j  < rwholebeams; j++)
 345         {
 346           Atom b (a);
 347           b.translate (Offset (gap_f, -dir_ * dy * j));
 348           rightbeams.add (b);
 349         }
 350
 351       w /= 4;
 352       if (rhalfs)
 353         a = paper()->lookup_l ()->beam (sl, w);
 354
 355       for (; j  < rwholebeams + rhalfs; j++)
 356         {
 357           Atom b (a);
 358           b.translate (-dir_ * dy * j, Y_AXIS);
 359           rightbeams.add (b);
 360         }
 361
 362     }
 363   leftbeams.add (rightbeams);
 364   return leftbeams;
 365 }