lily/beam-engraver.cc

   1 /*
   2   beam-engraver.cc -- implement Beam_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1998--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "engraver.hh"
  10 #include "beam.hh"
  11 #include "stem.hh"
  12 #include "warn.hh"
  13 #include "beaming.hh"
  14 #include "score-engraver.hh"
  15 #include "rest.hh"
  16 #include "drul-array.hh"
  17 #include "item.hh"
  18 #include "spanner.hh"
  19 #include "context.hh"
  20
  21 class Beam_engraver : public Engraver
  22 {
  23 protected:
  24   Music *start_ev_;
  25
  26   Spanner *finished_beam_;
  27   Spanner *beam_;
  28   Music *prev_start_ev_;
  29
  30   Music *now_stop_ev_;
  31
  32   Beaming_info_list *beam_info_;
  33   Beaming_info_list *finished_beam_info_;
  34
  35   /// location  within measure where beam started.
  36   Moment beam_start_location_;
  37
  38   /// moment (global time) where beam started.
  39   Moment beam_start_mom_;
  40
  41   bool subdivide_beams_;
  42   Moment beat_length_;
  43
  44   void typeset_beam ();
  45   void set_melisma (bool);
  46
  47   Moment last_stem_added_at_;
  48   virtual void stop_translation_timestep ();
  49   virtual void start_translation_timestep ();
  50   virtual void finalize ();
  51
  52   virtual void acknowledge_grob (Grob_info);
  53   virtual bool try_music (Music *);
  54   virtual void process_music ();
  55
  56   virtual bool valid_start_point ();
  57   virtual bool valid_end_point ();
  58
  59 public:
  60   TRANSLATOR_DECLARATIONS (Beam_engraver);
  61 };
  62
  63 /*
  64   Hmm. this isn't necessary, since grace beams and normal beams are
  65   always nested.
  66 */
  67 bool
  68 Beam_engraver::valid_start_point ()
  69 {
  70   Moment n = now_mom ();
  71
  72   return n.grace_part_ == Rational (0);
  73 }
  74
  75 bool
  76 Beam_engraver::valid_end_point ()
  77 {
  78   return valid_start_point ();
  79 }
  80
  81 Beam_engraver::Beam_engraver ()
  82 {
  83   beam_ = 0;
  84   finished_beam_ = 0;
  85   finished_beam_info_ = 0;
  86   beam_info_ = 0;
  87   now_stop_ev_ = 0;
  88   start_ev_ = 0;
  89   prev_start_ev_ = 0;
  90 }
  91
  92 bool
  93 Beam_engraver::try_music (Music *m)
  94 {
  95   if (m->is_mus_type ("beam-event"))
  96     {
  97       Direction d = to_dir (m->get_property ("span-direction"));
  98       if (d == START && !valid_start_point ())
  99         return false;
 100       if (d == STOP && !valid_end_point ())
 101         return false;
 102
 103       if (d == START)
 104         {
 105           start_ev_ = m;
 106         }
 107       else if (d == STOP)
 108         {
 109           now_stop_ev_ = m;
 110         }
 111       return true;
 112     }
 113   return false;
 114 }
 115
 116 void
 117 Beam_engraver::set_melisma (bool ml)
 118 {
 119   SCM b = get_property ("autoBeaming");
 120   if (!to_boolean (b))
 121     context ()->set_property ("beamMelismaBusy", ml ? SCM_BOOL_T : SCM_BOOL_F);
 122 }
 123
 124 void
 125 Beam_engraver::process_music ()
 126 {
 127   if (beam_ && !to_boolean (get_property ("allowBeamBreak")))
 128     {
 129       get_score_engraver ()->forbid_breaks ();
 130     }
 131
 132   if (start_ev_)
 133     {
 134       if (beam_)
 135         {
 136           start_ev_->origin ()->warning (_ ("already have a beam"));
 137           return;
 138         }
 139
 140       set_melisma (true);
 141       prev_start_ev_ = start_ev_;
 142       beam_ = make_spanner ("Beam", start_ev_->self_scm ());
 143       Moment mp (robust_scm2moment (get_property ("measurePosition"), Moment (0)));
 144
 145       beam_start_location_ = mp;
 146       beam_start_mom_ = now_mom ();
 147
 148       beam_info_ = new Beaming_info_list;
 149
 150       /* urg, must copy to Auto_beam_engraver too */
 151     }
 152 }
 153
 154 void
 155 Beam_engraver::typeset_beam ()
 156 {
 157   if (finished_beam_)
 158     {
 159       finished_beam_info_->beamify (beat_length_, subdivide_beams_);
 160       Beam::set_beaming (finished_beam_, finished_beam_info_);
 161
 162       delete finished_beam_info_;
 163       finished_beam_info_ = 0;
 164       finished_beam_ = 0;
 165     }
 166 }
 167
 168 void
 169 Beam_engraver::start_translation_timestep ()
 170 {
 171   start_ev_ = 0;
 172
 173   if (beam_)
 174     {
 175       set_melisma (true);
 176
 177       subdivide_beams_ = to_boolean (get_property ("subdivideBeams"));
 178       beat_length_ = robust_scm2moment (get_property ("beatLength"), Moment (1, 4));
 179     }
 180 }
 181
 182 void
 183 Beam_engraver::stop_translation_timestep ()
 184 {
 185   typeset_beam ();
 186   if (now_stop_ev_)
 187     {
 188       finished_beam_ = beam_;
 189       finished_beam_info_ = beam_info_;
 190
 191       now_stop_ev_ = 0;
 192       beam_ = 0;
 193       beam_info_ = 0;
 194       typeset_beam ();
 195       set_melisma (false);
 196     }
 197 }
 198
 199 void
 200 Beam_engraver::finalize ()
 201 {
 202   typeset_beam ();
 203   if (beam_)
 204     {
 205       prev_start_ev_->origin ()->warning (_ ("unterminated beam"));
 206
 207       /*
 208         we don't typeset it, (we used to, but it was commented
 209         out. Reason unknown) */
 210       beam_->suicide ();
 211       delete beam_info_;
 212     }
 213 }
 214
 215 void
 216 Beam_engraver::acknowledge_grob (Grob_info info)
 217 {
 218   if (beam_)
 219     {
 220       if (Rest::has_interface (info.grob ()))
 221         {
 222           info.grob ()->add_offset_callback (Beam::rest_collision_callback_proc, Y_AXIS);
 223         }
 224       else if (Stem::has_interface (info.grob ()))
 225         {
 226           Moment now = now_mom ();
 227
 228           if (!valid_start_point ())
 229             return;
 230
 231           Item *stem = dynamic_cast<Item *> (info.grob ());
 232           if (Stem::get_beam (stem))
 233             return;
 234
 235           Music *m = info.music_cause ();
 236           if (!m->is_mus_type ("rhythmic-event"))
 237             {
 238               String s = _ ("stem must have Rhythmic structure");
 239               if (info.music_cause ())
 240                 info.music_cause ()->origin ()->warning (s);
 241               else
 242                 ::warning (s);
 243
 244               return;
 245             }
 246
 247           last_stem_added_at_ = now;
 248           int durlog = unsmob_duration (m->get_property ("duration"))->duration_log ();
 249           if (durlog <= 2)
 250             {
 251               m->origin ()->warning (_ ("stem doesn't fit in beam"));
 252               prev_start_ev_->origin ()->warning (_ ("beam was started here"));
 253               /*
 254                 don't return, since
 255
 256                 [r4 c8] can just as well be modern notation.
 257               */
 258             }
 259
 260           stem->set_property ("duration-log",
 261                               scm_int2num (durlog));
 262           Moment stem_location = now - beam_start_mom_ + beam_start_location_;
 263           beam_info_->add_stem (stem_location,
 264                                 max (durlog- 2, 0));
 265           Beam::add_stem (beam_, stem);
 266         }
 267     }
 268 }
 269
 270 ADD_TRANSLATOR (Beam_engraver,
 271                 /* descr */ "Handles Beam events by engraving Beams.    If omitted, then notes will be "
 272                 "printed with flags instead of beams.",
 273                 /* creats*/ "Beam",
 274                 /* accepts */ "beam-event",
 275                 /* acks  */ "stem-interface rest-interface",
 276                 /* reads */ "beamMelismaBusy beatLength subdivideBeams",
 277                 /* write */ "");
 278
 279 class Grace_beam_engraver : public Beam_engraver
 280 {
 281 public:
 282   TRANSLATOR_DECLARATIONS (Grace_beam_engraver);
 283
 284 protected:
 285   virtual bool valid_start_point ();
 286   virtual bool valid_end_point ();
 287 };
 288
 289 Grace_beam_engraver::Grace_beam_engraver ()
 290 {
 291 }
 292
 293 bool
 294 Grace_beam_engraver::valid_start_point ()
 295 {
 296   Moment n = now_mom ();
 297
 298   return n.grace_part_ != Rational (0);
 299 }
 300
 301 bool
 302 Grace_beam_engraver::valid_end_point ()
 303 {
 304   return beam_ && valid_start_point ();
 305 }
 306
 307 ADD_TRANSLATOR (Grace_beam_engraver,
 308                 /* descr */ "Handles Beam events by engraving Beams.  If omitted, then notes will "
 309                 "be printed with flags instead of beams. Only engraves beams when we "
 310                 " are at grace points in time. ",
 311                 /* creats*/ "Beam",
 312                 /* accepts */ "beam-event",
 313                 /* acks  */ "stem-interface rest-interface",
 314                 /* reads */ "beamMelismaBusy beatLength allowBeamBreak subdivideBeams",
 315                 /* write */ "");
 316