lily/mensural-ligature-engraver.cc

   1 /*
   2   mensural-ligature-engraver.cc -- implement Mensural_ligature_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2002--2003 Juergen Reuter <reuter@ipd.uka.de>
   7  */
   8
   9 #include "mensural-ligature.hh"
  10 #include "coherent-ligature-engraver.hh"
  11 #include "event.hh"
  12 #include "warn.hh"
  13 #include "item.hh"
  14 #include "spanner.hh"
  15 #include "rod.hh"
  16 #include "paper-column.hh"
  17 #include "note-column.hh"
  18 #include "rhythmic-head.hh"
  19 #include "note-head.hh"
  20 #include "staff-symbol-referencer.hh"
  21 #include "paper-def.hh"
  22 #include "font-interface.hh"
  23
  24 /*
  25  * TODO: My resources on Franco of Cologne's rules claim that his
  26  * rules map ligature<->mensural timing in a non-ambigous way, but in
  27  * fact, as presented in these resources, the rules become ambigous as
  28  * soon as there appear durations other than breves within a ligature
  29  * with more than two heads (ligatura ternaria etc.).  Hence, the
  30  * below implementation is an approximation of what I think the rules
  31  * could look like if forced to be non-ambigous.  This should be
  32  * further investigated.
  33  *
  34  * TODO: The automat is quite complicated, and its design is error
  35  * prone (and most probably, it behaves wrong for some very special
  36  * cases).  Maybe we can find a better paradigm for modelling Franco
  37  * of Cologne's rules?
  38  *
  39  * TODO: dotted heads: when applying Franco of Cologne's mapping, put
  40  * dots *above* (rather than after) affected ligature heads.
  41  *
  42  * TODO: prohibit multiple voices within a ligature.
  43  *
  44  * TODO: enhance robustness: in case of an illegal ligature (e.g. the
  45  * user events for a ligature that contains a minima or STATE_ERROR
  46  * is reached), automatically break the ligature into smaller, valid
  47  * pieces.
  48  */
  49 class Mensural_ligature_engraver : public Coherent_ligature_engraver
  50 {
  51
  52 protected:
  53   virtual Spanner *create_ligature_spanner ();
  54   virtual void build_ligature (Spanner *ligature, Array<Grob_info> primitives);
  55
  56 public:
  57   TRANSLATOR_DECLARATIONS(Mensural_ligature_engraver);
  58
  59 private:
  60   int apply_transition (Array<Grob_info> primitives,
  61                         int state, int input, int i);
  62   void transform_heads (Array<Grob_info> primitives);
  63   void propagate_properties (Spanner *ligature, Array<Grob_info> primitives);
  64   void fold_up_primitives (Array<Grob_info> primitives);
  65   void join_primitives (Array<Grob_info> primitives);
  66 };
  67
  68
  69 Mensural_ligature_engraver::Mensural_ligature_engraver ()
  70 {
  71 }
  72
  73 Spanner *
  74 Mensural_ligature_engraver::create_ligature_spanner ()
  75 {
  76   return new Spanner (get_property ("MensuralLigature"));
  77 }
  78
  79 /*
  80  * The following lines implement a finite state automat.  Given a
  81  * sequence of durations (Longa, Brevis, Semibrevis) or
  82  * end-of-ligature-event as input, the automat outputs a sequence of
  83  * events for grobs that form a proper ligature.
  84  */
  85
  86 /*
  87  * This enumeration represents the set of possible input values to the
  88  * automat.  There may (potentially) be any sequence of Longa, Brevis,
  89  * and Semibrevis duration symbols fed into the automat, with a final
  90  * EndOfLigature symbol to terminate the ligature.  Other durations
  91  * are explicitly prohibited.  Depending on the note's pitch of the
  92  * preceding and the current input, the melodic line may be ascending
  93  * or descending.  Per definition, the melodic line must either ascend
  94  * or descend, because if the pitches were twice the same, the two
  95  * notes would be merged into a single one (as long as not resulting
  96  * in a prohibited duration).  In the case of the EndOfLigature
  97  * symbol, the melodic line is undefined (but we still have ascending
  98  * and descending case for the sake of consistency, making the automat
  99  * simpler).
 100  */
 101 enum Ligature_input
 102 {
 103   // Ascending/Descending Longa/Brevis/Semibrevis/EndOfLigature
 104   INPUT_AL = 0,
 105   INPUT_DL,
 106   INPUT_AB,
 107   INPUT_DB,
 108   INPUT_AS,
 109   INPUT_DS,
 110   INPUT_AE,
 111   INPUT_DE,
 112 };
 113
 114 /*
 115  * This enumeration represents all possible internal states of the
 116  * automat.  Besides the generic states START, ERROR, and END, the
 117  * remaining states L, B, S, and SS describe pending values from the
 118  * sequence of input values that have not yet been transformed to
 119  * proper output values, including the melodic direction
 120  * (ascending/descending) for state L.
 121  */
 122 enum Ligature_state
 123 {
 124   // aL = ascending Longa, dL descending Longa, B = Brevis, S =
 125   // Semibrevis, SS = 2 Semibreves
 126   STATE_START = 0,
 127   STATE_aL,
 128   STATE_dL,
 129   STATE_B,
 130   STATE_S,
 131   STATE_SS,
 132   STATE_ERROR,
 133   STATE_END,
 134 };
 135
 136 /*
 137  * The following array represents the transitions of the automat:
 138  * given some state and input, it maps to a new state, according (with
 139  * the limitations as described above) to the rules of Franco of
 140  * Cologne.
 141  */
 142 const int/*new state*/ transition_state[/*old state*/][8/*input*/] =
 143 {
 144   {STATE_aL,    STATE_dL,    STATE_B,     STATE_B,
 145    STATE_S,     STATE_S,     STATE_ERROR, STATE_ERROR}, // was: STATE_START
 146   {STATE_aL,    STATE_dL,    STATE_B,     STATE_START,
 147    STATE_ERROR, STATE_ERROR, STATE_END,   STATE_END},   // was: STATE_aL
 148   {STATE_aL,    STATE_dL,    STATE_B,     STATE_START,
 149    STATE_ERROR, STATE_ERROR, STATE_END,   STATE_END},   // was: STATE_dL
 150   {STATE_aL,    STATE_dL,    STATE_B,     STATE_START,
 151    STATE_ERROR, STATE_ERROR, STATE_END,   STATE_END},   // was: STATE_B
 152   {STATE_ERROR, STATE_ERROR, STATE_ERROR, STATE_ERROR,
 153    STATE_SS,    STATE_SS,    STATE_ERROR, STATE_ERROR}, // was: STATE_S
 154   {STATE_aL,    STATE_dL,    STATE_B,     STATE_B,
 155    STATE_S,     STATE_S,     STATE_END,   STATE_END},   // was: STATE_SS
 156   {STATE_ERROR, STATE_ERROR, STATE_ERROR, STATE_ERROR,
 157    STATE_ERROR, STATE_ERROR, STATE_ERROR, STATE_ERROR}, // was: STATE_ERROR
 158   {STATE_ERROR, STATE_ERROR, STATE_ERROR, STATE_ERROR,
 159    STATE_ERROR, STATE_ERROR, STATE_ERROR, STATE_ERROR}, // was: STATE_END
 160 };
 161
 162 /*
 163  * The following array represents the output of the automat while
 164  * switching from one state to another: given some state and input, it
 165  * maps to the output produced when switching to the next state,
 166  * according (with the limitations as described above) to the rules of
 167  * Franco of Cologne.
 168  */
 169 const int/*output*/ transition_output[/*old state*/][8/*input*/] =
 170 {
 171   {MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE,
 172    MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE}, // was: STATE_START
 173   {MLP_sc,    MLP_ss,    MLP_sc,    MLP_LB,
 174    MLP_NONE,  MLP_NONE,  MLP_sc,    MLP_sc},   // was: STATE_aL
 175   {MLP_sc,    MLP_ss,    MLP_sc,    MLP_LB,
 176    MLP_NONE,  MLP_NONE,  MLP_ss,    MLP_ss},   // was: STATE_dL
 177   {MLP_ss,    MLP_cs,    MLP_ss,    MLP_BB,
 178    MLP_NONE,  MLP_NONE,  MLP_ss,    MLP_ss} ,  // was: STATE_B
 179   {MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE,
 180    MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE}, // was: STATE_S
 181   {MLP_SS,    MLP_SS,    MLP_SS,    MLP_SS,
 182    MLP_SS,    MLP_SS,    MLP_SS,    MLP_SS} ,  // was: STATE_SS
 183   {MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE,
 184    MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE}, // was: STATE_ERROR
 185   {MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE,
 186    MLP_NONE,  MLP_NONE,  MLP_NONE,  MLP_NONE}, // was: STATE_END
 187 };
 188
 189 int
 190 Mensural_ligature_engraver::apply_transition (Array<Grob_info> primitives,
 191                                               int state, int input, int i)
 192 {
 193   int output = transition_output[state][input];
 194   Item *last_last_primitive = (i > 1) ?
 195     dynamic_cast<Item*> (primitives[i-2].grob_) : 0;
 196   Item *last_primitive = (i > 0) ?
 197     dynamic_cast<Item*> (primitives[i-1].grob_) : 0;
 198   Item *primitive = (i < primitives.size ()) ?
 199     dynamic_cast<Item*> (primitives[i].grob_) : 0;
 200   switch (output)
 201     {
 202       case MLP_NONE:
 203         // skip note head, expecting a primitive with two note heads
 204         break;
 205       case MLP_sc:
 206       case MLP_ss:
 207       case MLP_cs:
 208         // primitive with single note head
 209         if (!last_primitive)
 210           {
 211             programming_error ("last_primitive undefined");
 212             break;
 213           }
 214         last_primitive->set_grob_property ("primitive", gh_int2scm (output));
 215         break;
 216       case MLP_BB:
 217       case MLP_LB:
 218         // primitive with two note heads
 219         if (!last_primitive)
 220           {
 221             programming_error ("last_primitive undefined");
 222             break;
 223           }
 224         if (!primitive)
 225           {
 226             programming_error ("primitive undefined");
 227             break;
 228           }
 229         last_primitive->set_grob_property ("primitive", gh_int2scm (output));
 230         primitive->set_grob_property ("primitive", gh_int2scm (MLP_NONE));
 231         break;
 232       case MLP_SS:
 233         // delayed primitive with two note heads
 234         if (!last_last_primitive)
 235           {
 236             programming_error ("last_last_primitive undefined");
 237             break;
 238           }
 239         if (!last_primitive)
 240           {
 241             programming_error ("last_primitive undefined");
 242             break;
 243           }
 244         last_last_primitive->set_grob_property ("primitive", gh_int2scm (output));
 245         last_primitive->set_grob_property ("primitive", gh_int2scm (MLP_NONE));
 246         break;
 247       default:
 248         programming_error (_f ("unexpected case fall-through"));
 249         break;
 250     }
 251   return transition_state[state][input];
 252 }
 253
 254 void
 255 Mensural_ligature_engraver::transform_heads (Array<Grob_info> primitives)
 256 {
 257   if (primitives.size () < 2)
 258     {
 259       warning (_f ("ligature with less than 2 heads -> skipping"));
 260       return;
 261     }
 262   int state = STATE_START;
 263   Pitch last_pitch, pitch;
 264   bool have_last_pitch = 0, have_pitch = 0;
 265   for (int i = 0; i < primitives.size (); i++) {
 266     last_pitch = pitch;
 267     have_last_pitch = have_pitch;
 268     Grob_info info = primitives[i];
 269     int duration_log =
 270       Note_head::get_balltype (dynamic_cast<Item*> (info.grob_));
 271
 272     Music *nr = info.music_cause ();
 273
 274     /*
 275     ugh. why not simply check for pitch?
 276      */
 277     if (!nr->is_mus_type ("note-event"))
 278       {
 279         info.music_cause ()->origin ()->warning (_f ("can not determine pitch of ligature primitive -> skipping"));
 280         i++;
 281         state = STATE_START;
 282         have_pitch = 0;
 283         continue;
 284       }
 285     else
 286       {
 287         pitch = *unsmob_pitch (nr->get_mus_property ("pitch"));
 288         have_pitch = 1;
 289       }
 290
 291     int delta_pitch;
 292
 293     if (!have_last_pitch)
 294       {
 295         delta_pitch = 0; // first pitch; delta undefined
 296       }
 297     else
 298       {
 299         delta_pitch = (pitch.steps () - last_pitch.steps ());
 300         if (Pitch::compare (last_pitch, pitch) == 0)
 301           {
 302             info.music_cause ()->origin ()->warning (_f ("prime interval within ligature -> skipping"));
 303             i++;
 304             state = STATE_START;
 305             have_pitch = 0;
 306             continue;
 307           }
 308       }
 309
 310     if ((duration_log < -2) || (duration_log > 0))
 311       {
 312         info.music_cause ()->origin ()->warning (_f ("mensural ligature: duration none of L, B, S -> skipping"));
 313         i++;
 314         state = STATE_START;
 315         have_pitch = 0;
 316         continue;
 317       }
 318
 319     int input = (duration_log + 2) * 2 + ((delta_pitch < 0) ? 1 : 0);
 320     state = apply_transition (primitives, state, input, i);
 321     // TODO: if (state == STATE_ERROR) { ... }
 322   }
 323
 324   state = apply_transition (primitives, state, INPUT_AE, primitives.size ());
 325   // TODO: if (state == STATE_ERROR) { ... }
 326 }
 327
 328 /*
 329  * A MensuralLigature grob consists of a bunch of NoteHead grobs that
 330  * are glued together.  It (a) does not make sense to change
 331  * properties like thickness or flexa-width from one head to the next
 332  * within a ligature (this would totally screw up alignment), and (b)
 333  * some of these properties (like flexa-width) are specific to
 334  * e.g. the MensuralLigature (as in contrast to e.g. LigatureBracket),
 335  * and therefore should not be handled in the NoteHead code (which is
 336  * also used by LigatureBracket).  Therefore, we let the user control
 337  * these properties via the concrete Ligature grob (like
 338  * MensuralLigature) and then copy these properties as necessary to
 339  * each of the NoteHead grobs.  This is what
 340  * propagate_properties() does.
 341  */
 342 void
 343 Mensural_ligature_engraver::propagate_properties (Spanner *ligature,
 344                                                   Array<Grob_info> primitives)
 345 {
 346   SCM thickness_scm = ligature->get_grob_property ("thickness");
 347   Real thickness = (thickness_scm != SCM_EOL) ?
 348     gh_scm2double (thickness_scm) : 1.4;
 349   thickness *= ligature->get_paper ()->get_realvar (ly_symbol2scm ("linethickness"));
 350
 351   Real head_width =
 352     Font_interface::get_default_font (ligature)->
 353     find_by_name ("noteheads--1mensural").extent (X_AXIS).length ();
 354   SCM flexa_width_scm = ligature->get_grob_property ("flexa-width");
 355   Real flexa_width = (flexa_width_scm != SCM_EOL) ?
 356     gh_scm2double (flexa_width_scm) : 2.0;
 357   flexa_width *= Staff_symbol_referencer::staff_space (ligature);
 358
 359   Real half_flexa_width = 0.5 * (flexa_width + thickness);
 360
 361   for (int i = 0; i < primitives.size (); i++)
 362     {
 363       Item *primitive = dynamic_cast<Item*> (primitives[i].grob_);
 364       int output = gh_scm2int (primitive->get_grob_property ("primitive"));
 365       primitive->set_grob_property ("thickness",
 366                                     gh_double2scm (thickness));
 367       switch (output) {
 368         case MLP_NONE:
 369           primitive->set_grob_property ("head-width",
 370                                         gh_double2scm (half_flexa_width));
 371           break;
 372         case MLP_sc:
 373         case MLP_ss:
 374         case MLP_cs:
 375           primitive->set_grob_property ("head-width",
 376                                         gh_double2scm (head_width));
 377           break;
 378         case MLP_BB:
 379         case MLP_LB:
 380         case MLP_SS:
 381           primitive->set_grob_property ("head-width",
 382                                         gh_double2scm (half_flexa_width));
 383           primitive->set_grob_property ("flexa-width",
 384                                         gh_double2scm (flexa_width));
 385           break;
 386         default:
 387           programming_error (_f ("unexpected case fall-through"));
 388           break;
 389       }
 390     }
 391 }
 392
 393 void
 394 Mensural_ligature_engraver::fold_up_primitives (Array<Grob_info> primitives)
 395 {
 396   Item *first = 0;
 397   Real distance = 0;
 398   for (int i = 0; i < primitives.size (); i++)
 399     {
 400       Item *current = dynamic_cast<Item*> (primitives[i].grob_);
 401       if (i == 0)
 402         {
 403           first = current;
 404         }
 405
 406       get_set_column (current, first->get_column ());
 407
 408       if (i > 0)
 409         {
 410 #if 0
 411           Rod r;
 412           r.distance_ = distance;
 413           r.item_l_drul_[LEFT] = first;
 414           r.item_l_drul_[RIGHT] = current;
 415           r.add_to_cols ();
 416 #endif
 417           current->translate_axis (distance, X_AXIS);
 418         }
 419
 420       distance +=
 421         gh_scm2double (current->get_grob_property ("head-width")) -
 422         gh_scm2double (current->get_grob_property ("thickness"));
 423     }
 424 }
 425
 426 void
 427 Mensural_ligature_engraver::join_primitives (Array<Grob_info> primitives)
 428 {
 429   Pitch last_pitch;
 430   for (int i = 0; i < primitives.size (); i++)
 431     {
 432       Grob_info info = primitives[i];
 433       Pitch pitch = *unsmob_pitch (info.music_cause ()->get_mus_property ("pitch"));
 434       if (i > 0)
 435         {
 436           Item *primitive = dynamic_cast<Item*> (info.grob_);
 437           int output = gh_scm2int (primitive->get_grob_property ("primitive"));
 438           if (output & MLP_ANY)
 439             {
 440               int delta_pitch = (pitch.steps () - last_pitch.steps ());
 441               primitive->set_grob_property ("join-left-amount",
 442                                             gh_int2scm (delta_pitch));
 443             }
 444         }
 445       last_pitch = pitch;
 446     }
 447 }
 448
 449 void
 450 Mensural_ligature_engraver::build_ligature (Spanner *ligature,
 451                                             Array<Grob_info> primitives)
 452 {
 453   transform_heads (primitives);
 454   propagate_properties (ligature, primitives);
 455   fold_up_primitives (primitives);
 456   join_primitives (primitives);
 457 }
 458
 459 ENTER_DESCRIPTION (Mensural_ligature_engraver,
 460 /* descr */       "Handles Mensural_ligature_events by glueing special ligature heads together.",
 461 /* creats*/       "MensuralLigature",
 462 /* accepts */     "ligature-event abort-event",
 463 /* acks  */      "note-head-interface rest-interface",
 464 /* reads */       "",
 465 /* write */       "");