lily/slur-scoring.cc

   1 /*
   2   slur-scoring.cc -- Score based slur formatting
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1996--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7   Jan Nieuwenhuizen <janneke@gnu.org>
   8 */
   9
  10 #include <math.h>
  11
  12 #include "slur-scoring.hh"
  13 #include "libc-extension.hh"
  14 #include "slur-configuration.hh"
  15 #include "beam.hh"
  16 #include "directional-element-interface.hh"
  17 #include "group-interface.hh"
  18 #include "slur.hh"
  19 #include "note-column.hh"
  20 #include "output-def.hh"
  21 #include "pitch.hh"
  22 #include "spanner.hh"
  23 #include "staff-symbol-referencer.hh"
  24 #include "staff-symbol.hh"
  25 #include "stem.hh"
  26 #include "warn.hh"
  27 #include "paper-column.hh"
  28 #include "accidental-interface.hh"
  29
  30 /*
  31   TODO:
  32
  33   - curve around flag for y coordinate
  34
  35   - this file is a mess, clean it up
  36
  37   - short-cut: try a smaller region first.
  38
  39   - handle non-visible stems better.
  40
  41   - try to prune number of scoring criteria
  42
  43   - take encompass-objects more into account when determining
  44   slur shape
  45
  46   - calculate encompass scoring directly after determining slur shape.
  47
  48   - optimize.
  49 */
  50 struct Slur_score_state;
  51
  52 Slur_score_state::Slur_score_state ()
  53 {
  54   musical_dy_ = 0.0;
  55   valid_ = false;
  56   edge_has_beams_ = false;
  57   has_same_beam_ = false;
  58   is_broken_ = false;
  59   dir_ = CENTER;
  60   slur_ = 0;
  61   common_[X_AXIS] = 0;
  62   common_[Y_AXIS] = 0;
  63 }
  64
  65 Slur_score_state::~Slur_score_state ()
  66 {
  67   junk_pointers (configurations_);
  68 }
  69
  70 Real
  71 get_detail (SCM alist, SCM sym)
  72 {
  73   SCM entry = scm_assq (sym, alist);
  74   return robust_scm2double (scm_is_pair (entry)
  75                             ? scm_cdr (entry)
  76                             : SCM_EOL,
  77                             0.0);
  78 }
  79
  80 void
  81 Slur_score_parameters::fill (Grob *me)
  82 {
  83   SCM details = me->get_property ("slur-details");
  84
  85   region_size_
  86     = (int) get_detail (details, ly_symbol2scm ("region-size"));
  87   head_encompass_penalty_
  88     = get_detail (details, ly_symbol2scm ("head-encompass-penalty"));
  89   stem_encompass_penalty_
  90     = get_detail (details, ly_symbol2scm ("stem-encompass-penalty"));
  91   closeness_factor_
  92     = get_detail (details, ly_symbol2scm ("closeness-factor"));
  93   edge_attraction_factor_
  94     = get_detail (details, ly_symbol2scm ("edge-attraction-factor"));
  95   same_slope_penalty_
  96     = get_detail (details, ly_symbol2scm ("same-slope-penalty"));
  97   steeper_slope_factor_
  98     = get_detail (details, ly_symbol2scm ("steeper-slope-factor"));
  99   non_horizontal_penalty_
 100     = get_detail (details, ly_symbol2scm ("non-horizontal-penalty"));
 101   max_slope_
 102     = get_detail (details, ly_symbol2scm ("max-slope"));
 103   max_slope_factor_
 104     = get_detail (details, ly_symbol2scm ("max-slope-factor"));
 105   free_head_distance_
 106     = get_detail (details, ly_symbol2scm ("free-head-distance"));
 107   absolute_closeness_measure_
 108     = get_detail (details, ly_symbol2scm ("absolute-closeness-measure"));
 109   extra_object_collision_
 110     = get_detail (details, ly_symbol2scm ("extra-object-collision"));
 111   accidental_collision_
 112     = get_detail (details, ly_symbol2scm ("accidental-collision"));
 113   extra_encompass_free_distance_
 114     = get_detail (details, ly_symbol2scm ("extra-encompass-free-distance"));
 115   head_slur_distance_factor_
 116     = get_detail (details, ly_symbol2scm ("head-slur-distance-factor"));
 117   head_slur_distance_max_ratio_
 118     = get_detail (details, ly_symbol2scm ("head-slur-distance-max-ratio"));
 119   free_slur_distance_
 120     = get_detail (details, ly_symbol2scm ("free-slur-distance"));
 121   edge_slope_exponent_
 122     = get_detail (details, ly_symbol2scm ("edge-slope-exponent"));
 123 }
 124
 125 Real
 126 broken_trend_y (Slur_score_state const &state, Direction hdir)
 127 {
 128   /* A broken slur should maintain the same vertical trend
 129      the unbroken slur would have had.  */
 130   Real by = 0.0;
 131   if (Spanner *mother = dynamic_cast<Spanner *> (state.slur_->original_))
 132     {
 133       int k = broken_spanner_index (state.slur_);
 134       int j = k + hdir;
 135       if (j < 0 || j >= mother->broken_intos_.size ())
 136         return by;
 137
 138       Grob *neighbor = mother->broken_intos_[j];
 139       Spanner *common_mother
 140         = dynamic_cast<Spanner *> (state.common_[Y_AXIS]->original_);
 141       int common_k
 142         = broken_spanner_index (dynamic_cast<Spanner *> (state.common_[Y_AXIS]));
 143       int common_j = common_k + hdir;
 144
 145       if (common_j < 0 || common_j >= common_mother->broken_intos_.size ())
 146         return by;
 147
 148       Grob *common_next_system = common_mother->broken_intos_[common_j];
 149
 150       SCM last_point = scm_car (scm_last_pair (neighbor->get_property ("control-points")));
 151
 152       return scm_to_double (scm_cdr (last_point))
 153         + neighbor->relative_coordinate (common_next_system, Y_AXIS);
 154     }
 155   return by;
 156 }
 157
 158 /*
 159   copy slur dir forwards across line break.
 160 */
 161 void
 162 Slur_score_state::set_next_direction ()
 163 {
 164   if (extremes_[RIGHT].note_column_)
 165     return;
 166
 167   if (Spanner *mother = dynamic_cast<Spanner *> (slur_->original_))
 168     {
 169       int k = broken_spanner_index (slur_);
 170       int j = k + 1;
 171       if (j < 0 || j >= mother->broken_intos_.size ())
 172         return;
 173
 174       Grob *neighbor = mother->broken_intos_[j];
 175       set_grob_direction (neighbor, dir_);
 176     }
 177 }
 178
 179 Encompass_info
 180 Slur_score_state::get_encompass_info (Grob *col) const
 181 {
 182   Grob *stem = unsmob_grob (col->get_property ("stem"));
 183   Encompass_info ei;
 184
 185   if (!stem)
 186     {
 187       programming_error ("no stem for note column");
 188       ei.x_ = col->relative_coordinate (common_[X_AXIS], X_AXIS);
 189       ei.head_ = ei.stem_ = col->extent (common_[Y_AXIS],
 190                                          Y_AXIS)[dir_];
 191       return ei;
 192     }
 193   Direction stem_dir = get_grob_direction (stem);
 194
 195   if (Grob *head = Note_column::first_head (col))
 196     ei.x_ = head->extent (common_[X_AXIS], X_AXIS).center ();
 197   else
 198     ei.x_ = col->extent (common_[X_AXIS], X_AXIS).center ();
 199
 200   Grob *h = Stem::extremal_heads (stem)[Direction (dir_)];
 201   if (!h)
 202     {
 203       ei.head_ = ei.stem_ = col->extent (common_[Y_AXIS], Y_AXIS)[dir_];
 204       return ei;
 205     }
 206
 207   ei.head_ = h->extent (common_[Y_AXIS], Y_AXIS)[dir_];
 208
 209   if ((stem_dir == dir_)
 210       && !stem->extent (stem, Y_AXIS).is_empty ())
 211     {
 212       ei.stem_ = stem->extent (common_[Y_AXIS], Y_AXIS)[dir_];
 213       if (Grob *b = Stem::get_beam (stem))
 214         ei.stem_ += stem_dir * 0.5 * Beam::get_thickness (b);
 215
 216       Interval x = stem->extent (common_[X_AXIS], X_AXIS);
 217       ei.x_ = x.is_empty ()
 218         ? stem->relative_coordinate (common_[X_AXIS], X_AXIS)
 219         : x.center ();
 220     }
 221   else
 222     ei.stem_ = ei.head_;
 223
 224   return ei;
 225 }
 226
 227 Drul_array<Bound_info>
 228 Slur_score_state::get_bound_info () const
 229 {
 230   Drul_array<Bound_info> extremes;
 231
 232   Direction d = LEFT;
 233   Direction dir = dir_;
 234
 235   do
 236     {
 237       extremes[d].bound_ = slur_->get_bound (d);
 238       if (Note_column::has_interface (extremes[d].bound_))
 239         {
 240           extremes[d].note_column_ = extremes[d].bound_;
 241           extremes[d].stem_ = Note_column::get_stem (extremes[d].note_column_);
 242           extremes[d].stem_dir_ = get_grob_direction (extremes[d].stem_);
 243
 244           for (int a = X_AXIS; a < NO_AXES; a++)
 245             {
 246               Axis ax = Axis (a);
 247               Interval s = extremes[d].stem_->extent (common_[ax], ax);
 248               if (s.is_empty ())
 249                 {
 250                   programming_error ("Stem has no extent in Slur_score_state");
 251                   s = Interval (0,0)
 252                     + extremes[d].stem_->relative_coordinate (common_[ax], ax);
 253                 }
 254               extremes[d].stem_extent_[ax] = s;
 255             }
 256
 257           extremes[d].stem_extent_[Y_AXIS]
 258             = extremes[d].stem_->extent (common_[Y_AXIS], Y_AXIS);
 259           extremes[d].slur_head_
 260             = Stem::extremal_heads (extremes[d].stem_)[dir];
 261           if (!extremes[d].slur_head_
 262               && Note_column::has_rests (extremes[d].bound_))
 263             {
 264               extremes[d].slur_head_ = Note_column::get_rest (extremes[d].bound_);
 265             }
 266
 267           if (extremes[d].slur_head_)
 268             extremes[d].slur_head_extent_
 269               = extremes[d].slur_head_->extent (common_[X_AXIS], X_AXIS);
 270
 271           extremes[d].staff_ = Staff_symbol_referencer
 272             ::get_staff_symbol (extremes[d].stem_);
 273           extremes[d].staff_space_ = Staff_symbol_referencer
 274             ::staff_space (extremes[d].stem_);
 275         }
 276     }
 277   while (flip (&d) != LEFT);
 278
 279   return extremes;
 280 }
 281
 282 void
 283 Slur_score_state::fill (Grob *me)
 284 {
 285   slur_ = dynamic_cast<Spanner *> (me);
 286   columns_
 287     = extract_grob_array (me, ly_symbol2scm ("note-columns"));
 288
 289   if (columns_.is_empty ())
 290     {
 291       me->suicide ();
 292       return;
 293     }
 294
 295   staff_space_ = Staff_symbol_referencer::staff_space (me);
 296   Real lt = me->get_layout ()->get_dimension (ly_symbol2scm ("linethickness"));
 297   thickness_ = robust_scm2double (me->get_property ("thickness"), 1.0) * lt;
 298
 299   dir_ = get_grob_direction (me);
 300   parameters_.fill (me);
 301
 302   SCM eltlist = me->get_property ("note-columns");
 303   SCM extra_list = me->get_property ("encompass-objects");
 304   Spanner *sp = dynamic_cast<Spanner *> (me);
 305
 306   for (int i = X_AXIS; i < NO_AXES; i++)
 307     {
 308       Axis a = (Axis)i;
 309       common_[a] = common_refpoint_of_list (eltlist, me, a);
 310       common_[a] = common_refpoint_of_list (extra_list, common_[a], a);
 311
 312       Direction d = LEFT;
 313       do
 314         {
 315           /*
 316             If bound is not in note-columns, we don't want to know about
 317             its Y-position
 318           */
 319           if (a != Y_AXIS)
 320             common_[a] = common_[a]->common_refpoint (sp->get_bound (d), a);
 321         }
 322       while (flip (&d) != LEFT);
 323     }
 324
 325   extremes_ = get_bound_info ();
 326   is_broken_ = (!extremes_[LEFT].note_column_
 327                 || !extremes_[RIGHT].note_column_);
 328
 329   has_same_beam_
 330     = (extremes_[LEFT].stem_ && extremes_[RIGHT].stem_
 331        && Stem::get_beam (extremes_[LEFT].stem_) == Stem::get_beam (extremes_[RIGHT].stem_));
 332
 333   base_attachments_ = get_base_attachments ();
 334
 335   Drul_array<Real> end_ys
 336     = get_y_attachment_range ();
 337
 338   configurations_ = enumerate_attachments (end_ys);
 339   for (int i = 0; i < columns_.size (); i++)
 340     encompass_infos_.push (get_encompass_info (columns_[i]));
 341
 342   extra_encompass_infos_ = get_extra_encompass_infos ();
 343   valid_ = true;
 344
 345   musical_dy_ = 0.0;
 346   Direction d = LEFT;
 347   do
 348     {
 349       if (!is_broken_)
 350         musical_dy_ += d
 351           * extremes_[d].slur_head_->relative_coordinate (common_[Y_AXIS], Y_AXIS);
 352     }
 353   while (flip (&d) != LEFT);
 354
 355   edge_has_beams_
 356     = (extremes_[LEFT].stem_ && Stem::get_beam (extremes_[LEFT].stem_))
 357     || (extremes_[RIGHT].stem_ && Stem::get_beam (extremes_[RIGHT].stem_));
 358
 359   set_next_direction ();
 360
 361   if (is_broken_)
 362     musical_dy_ = 0.0;
 363 }
 364
 365 void
 366 set_slur_control_points (Grob *me)
 367 {
 368   Slur_score_state state;
 369   state.fill (me);
 370
 371   if (!state.valid_)
 372     return;
 373
 374   state.generate_curves ();
 375
 376   SCM end_ys = me->get_property ("positions");
 377   Bezier best;
 378
 379   if (is_number_pair (end_ys))
 380     {
 381       best = state.configurations_[state.get_closest_index (end_ys)]->curve_;
 382     }
 383   else
 384     {
 385       best = state.get_best_curve ();
 386     }
 387
 388   SCM controls = SCM_EOL;
 389   for (int i = 4; i--;)
 390     {
 391       Offset o = best.control_[i]
 392         - Offset (me->relative_coordinate (state.common_[X_AXIS], X_AXIS),
 393                   me->relative_coordinate (state.common_[Y_AXIS], Y_AXIS));
 394       controls = scm_cons (ly_offset2scm (o), controls);
 395     }
 396   me->set_property ("control-points", controls);
 397 }
 398
 399 Bezier
 400 Slur_score_state::get_best_curve ()
 401 {
 402   for (int i = 0; i < configurations_.size (); i++)
 403     {
 404       configurations_[i]->score (*this);
 405     }
 406
 407   Real opt = 1e6;
 408   int opt_idx = -1;
 409   for (int i = 0; i < configurations_.size (); i++)
 410     {
 411       if (configurations_[i]->score_ < opt)
 412         {
 413           opt = configurations_[i]->score_;
 414           opt_idx = i;
 415         }
 416     }
 417
 418 #if DEBUG_SLUR_SCORING
 419   SCM inspect_quants = slur_->get_property ("inspect-quants");
 420   if (to_boolean (slur_->get_layout ()
 421                   ->lookup_variable (ly_symbol2scm ("debug-slur-scoring")))
 422       && scm_is_pair (inspect_quants))
 423     opt_idx = get_closest_index (inspect_quants);
 424
 425   configurations_[opt_idx]->score_card_ += to_string ("=%.2f", opt);
 426   configurations_[opt_idx]->score_card_ += to_string ("i%d", opt_idx);
 427
 428   // debug quanting
 429   slur_->set_property ("quant-score",
 430                        scm_makfrom0str (configurations_[opt_idx]->score_card_.to_str0 ()));
 431
 432 #endif
 433
 434   return configurations_[opt_idx]->curve_;
 435 }
 436
 437 int
 438 Slur_score_state::get_closest_index (SCM inspect_quants) const
 439 {
 440   Drul_array<Real> ins = ly_scm2interval (inspect_quants);
 441
 442   int opt_idx = -1;
 443   Real mindist = 1e6;
 444   for (int i = 0; i < configurations_.size (); i++)
 445     {
 446       Real d = fabs (configurations_[i]->attachment_[LEFT][Y_AXIS] - ins[LEFT])
 447         + fabs (configurations_[i]->attachment_[RIGHT][Y_AXIS] - ins[RIGHT]);
 448       if (d < mindist)
 449         {
 450           opt_idx = i;
 451           mindist = d;
 452         }
 453     }
 454   if (mindist > 1e5)
 455     programming_error ("can't not find quant");
 456   return opt_idx;
 457 }
 458
 459 /*
 460   TODO: should analyse encompasses to determine sensible region, and
 461   should limit slopes available.
 462 */
 463
 464 Drul_array<Real>
 465 Slur_score_state::get_y_attachment_range () const
 466 {
 467   Drul_array<Real> end_ys;
 468   Direction d = LEFT;
 469   do
 470     {
 471       if (extremes_[d].note_column_)
 472         {
 473           end_ys[d] = dir_
 474             * ((dir_ * (base_attachments_[d][Y_AXIS] + parameters_.region_size_ * dir_))
 475                >? (dir_ * (dir_ + extremes_[d].note_column_->extent (common_[Y_AXIS],
 476                                                                      Y_AXIS)[dir_]))
 477                >? (dir_ * base_attachments_[-d][Y_AXIS]));
 478         }
 479       else
 480         end_ys[d] = base_attachments_[d][Y_AXIS] + parameters_.region_size_ * dir_;
 481     }
 482   while (flip (&d) != LEFT);
 483
 484   return end_ys;
 485 }
 486
 487 bool
 488 spanner_less (Spanner *s1, Spanner *s2)
 489 {
 490   Slice b1, b2;
 491   Direction d = LEFT;
 492   do
 493     {
 494       b1[d] = s1->get_bound (d)->get_column ()->rank_;
 495       b2[d] = s2->get_bound (d)->get_column ()->rank_;
 496     }
 497   while (flip (&d) != LEFT);
 498
 499   return b2[LEFT] <= b1[LEFT] && b2[RIGHT] >= b1[RIGHT]
 500     && (b2[LEFT] != b1[LEFT] || b2[RIGHT] != b1[RIGHT]);
 501 }
 502
 503 Drul_array<Offset>
 504 Slur_score_state::get_base_attachments () const
 505 {
 506   Drul_array<Offset> base_attachment;
 507   Direction d = LEFT;
 508   do
 509     {
 510       Grob *stem = extremes_[d].stem_;
 511       Grob *head = extremes_[d].slur_head_;
 512
 513       Real x = 0.0;
 514       Real y = 0.0;
 515       if (extremes_[d].note_column_)
 516         {
 517
 518           /*
 519             fixme: X coord should also be set in this case.
 520           */
 521           if (stem
 522               && !Stem::is_invisible (stem)
 523               && extremes_[d].stem_dir_ == dir_
 524               && Stem::get_beaming (stem, -d)
 525               && (!spanner_less (slur_, Stem::get_beam (stem))
 526                   || has_same_beam_))
 527             y = extremes_[d].stem_extent_[Y_AXIS][dir_];
 528           else if (head)
 529             y = head->extent (common_[Y_AXIS], Y_AXIS)[dir_];
 530           y += dir_ * 0.5 * staff_space_;
 531
 532           y = move_away_from_staffline (y, head);
 533
 534           Grob *fh = Note_column::first_head (extremes_[d].note_column_);
 535           x
 536             = (fh ? fh->extent (common_[X_AXIS], X_AXIS)
 537                : extremes_[d].bound_->extent (common_[X_AXIS], X_AXIS))
 538             .linear_combination (CENTER);
 539         }
 540       base_attachment[d] = Offset (x, y);
 541     }
 542   while (flip (&d) != LEFT);
 543
 544   do
 545     {
 546       if (!extremes_[d].note_column_)
 547         {
 548           Real x, y;
 549           if (d == RIGHT)
 550             {
 551               x = extremes_[d].bound_->extent (common_[X_AXIS], X_AXIS)[d];
 552             }
 553           else
 554             {
 555               x = slur_->get_broken_left_end_align ();
 556             }
 557           Grob *col = (d == LEFT) ? columns_[0] : columns_.top ();
 558
 559           if (extremes_[-d].bound_ != col)
 560             {
 561               y = robust_relative_extent (col, common_[Y_AXIS], Y_AXIS)[dir_];
 562               y += dir_ * 0.5 * staff_space_;
 563
 564               if (get_grob_direction (col) == dir_
 565                   && Note_column::get_stem (col)
 566                   && !Stem::is_invisible (Note_column::get_stem (col)))
 567                 y -= dir_ * 1.5 * staff_space_;
 568             }
 569           else
 570             y = base_attachment[-d][Y_AXIS];
 571
 572           y = move_away_from_staffline (y, col);
 573
 574           base_attachment[d] = Offset (x, y);
 575         }
 576     }
 577   while (flip (&d) != LEFT);
 578
 579
 580   do
 581     {
 582       for (int a = X_AXIS; a < NO_AXES; a++)
 583         {
 584           Real &b = base_attachment[d][Axis (a)];
 585
 586           if (isinf (b) || isnan (b))
 587             {
 588               programming_error ("slur attachment is inf/nan");
 589               b = 0.0;
 590             }
 591
 592         }
 593     }
 594   while (flip (&d) != LEFT);
 595
 596
 597   return base_attachment;
 598 }
 599
 600 Real
 601 Slur_score_state::move_away_from_staffline (Real y,
 602                                             Grob *on_staff) const
 603 {
 604   Real pos
 605     = (y - Staff_symbol_referencer::get_staff_symbol (on_staff)->relative_coordinate (common_[Y_AXIS],
 606                                                                                       Y_AXIS))
 607     * 2.0 / staff_space_;
 608
 609   if (fabs (pos - my_round (pos)) < 0.2
 610       && Staff_symbol_referencer::on_staffline (on_staff, (int) rint (pos))
 611       && Staff_symbol_referencer::line_count (on_staff) - 1 >= rint (pos))
 612     y += 1.5 * staff_space_ * dir_ / 10;
 613
 614   return y;
 615 }
 616
 617 void
 618 Slur_score_state::generate_curves () const
 619 {
 620   Real r_0 = robust_scm2double (slur_->get_property ("ratio"), 0.33);
 621   Real h_inf = staff_space_ * scm_to_double (slur_->get_property ("height-limit"));
 622   for (int i = 0; i < configurations_.size (); i++)
 623     configurations_[i]->generate_curve (*this, r_0, h_inf);
 624 }
 625
 626 Link_array<Slur_configuration>
 627 Slur_score_state::enumerate_attachments (Drul_array<Real> end_ys) const
 628 {
 629   Link_array<Slur_configuration> scores;
 630
 631   Drul_array<Offset> os;
 632   os[LEFT] = base_attachments_[LEFT];
 633   Real minimum_length = staff_space_
 634     * robust_scm2double (slur_->get_property ("minimum-length"), 2.0);
 635
 636   for (int i = 0; dir_ * os[LEFT][Y_AXIS] <= dir_ * end_ys[LEFT]; i++)
 637     {
 638       os[RIGHT] = base_attachments_[RIGHT];
 639       for (int j = 0; dir_ * os[RIGHT][Y_AXIS] <= dir_ * end_ys[RIGHT]; j++)
 640         {
 641           Slur_configuration s;
 642           Direction d = LEFT;
 643           Drul_array<bool> attach_to_stem (false, false);
 644           do
 645             {
 646               os[d][X_AXIS] = base_attachments_[d][X_AXIS];
 647               if (extremes_[d].stem_
 648                   && !Stem::is_invisible (extremes_[d].stem_)
 649                   && extremes_[d].stem_dir_ == dir_)
 650                 {
 651                   Interval stem_y = extremes_[d].stem_extent_[Y_AXIS];
 652                   stem_y.widen (0.25 * staff_space_);
 653                   if (stem_y.contains (os[d][Y_AXIS]))
 654                     {
 655                       os[d][X_AXIS] = extremes_[d].stem_extent_[X_AXIS][-d]
 656                         - d * 0.3;
 657                       attach_to_stem[d] = true;
 658                     }
 659                   else if (dir_ * extremes_[d].stem_extent_[Y_AXIS][dir_]
 660                            < dir_ * os[d][Y_AXIS]
 661                            && !extremes_[d].stem_extent_[X_AXIS].is_empty ())
 662
 663                     os[d][X_AXIS] = extremes_[d].stem_extent_[X_AXIS].center ();
 664                 }
 665             }
 666           while (flip (&d) != LEFT);
 667
 668           Offset dz;
 669           dz = os[RIGHT] - os[LEFT];
 670           if (dz[X_AXIS] < minimum_length
 671               || fabs (dz[Y_AXIS] / dz[X_AXIS]) > parameters_.max_slope_)
 672             {
 673               do
 674                 {
 675                   if (extremes_[d].slur_head_)
 676                     {
 677                       os[d][X_AXIS] = extremes_[d].slur_head_extent_.center ();
 678                       attach_to_stem[d] = false;
 679                     }
 680                 }
 681               while (flip (&d) != LEFT);
 682             }
 683
 684           dz = os[RIGHT] - os[LEFT];
 685           do
 686             {
 687               if (extremes_[d].slur_head_
 688                   && !attach_to_stem[d])
 689                 {
 690                   /* Horizontally move tilted slurs a little.  Move
 691                      more for bigger tilts.
 692
 693                      TODO: parameter */
 694                   os[d][X_AXIS]
 695                     -= dir_ * extremes_[d].slur_head_extent_.length ()
 696                     * sin (dz.arg ()) / 3;
 697                 }
 698             }
 699           while (flip (&d) != LEFT);
 700
 701           s.attachment_ = os;
 702           s.index_ = scores.size ();
 703
 704           scores.push (new Slur_configuration (s));
 705
 706           os[RIGHT][Y_AXIS] += dir_ * staff_space_ / 2;
 707         }
 708
 709       os[LEFT][Y_AXIS] += dir_ * staff_space_ / 2;
 710     }
 711
 712   assert (scores.size () > 0);
 713   return scores;
 714 }
 715
 716 Array<Extra_collision_info>
 717 Slur_score_state::get_extra_encompass_infos () const
 718 {
 719   Link_array<Grob> encompasses
 720     = extract_grob_array (slur_, ly_symbol2scm ("encompass-objects"));
 721   Array<Extra_collision_info> collision_infos;
 722   for (int i = encompasses.size (); i--;)
 723     {
 724       if (Slur::has_interface (encompasses[i]))
 725         {
 726           Spanner *small_slur = dynamic_cast<Spanner *> (encompasses[i]);
 727           Bezier b = Slur::get_curve (small_slur);
 728
 729           Offset relative (small_slur->relative_coordinate (common_[X_AXIS], X_AXIS),
 730                            small_slur->relative_coordinate (common_[Y_AXIS], Y_AXIS));
 731
 732           for (int k = 0; k < 3; k++)
 733             {
 734               Direction hdir = Direction (k / 2 - 1);
 735
 736               /*
 737                 Only take bound into account if small slur starts
 738                 together with big slur.
 739               */
 740               if (hdir && small_slur->get_bound (hdir) != slur_->get_bound (hdir))
 741                 continue;
 742
 743               Offset z = b.curve_point (k / 2.0);
 744               z += relative;
 745
 746               Interval yext;
 747               yext.set_full ();
 748               yext[dir_] = z[Y_AXIS] + dir_ * thickness_ * 1.0;
 749
 750               Interval xext (-1, 1);
 751               xext = xext * (thickness_ * 2) + z[X_AXIS];
 752               Extra_collision_info info (small_slur,
 753                                          k - 1.0,
 754                                          xext,
 755                                          yext,
 756                                          parameters_.extra_object_collision_);
 757               collision_infos.push (info);
 758             }
 759         }
 760       else
 761         {
 762           Grob *g = encompasses [i];
 763           Interval xe = g->extent (common_[X_AXIS], X_AXIS);
 764           Interval ye = g->extent (common_[Y_AXIS], Y_AXIS);
 765
 766           Real xp = 0.0;
 767           Real penalty = parameters_.extra_object_collision_;
 768           if (Accidental_interface::has_interface (g))
 769             {
 770               penalty = parameters_.accidental_collision_;
 771               /* Begin copy accidental.cc */
 772               bool parens = false;
 773               if (to_boolean (g->get_property ("cautionary")))
 774                 {
 775                   SCM cstyle = g->get_property ("cautionary-style");
 776                   parens = ly_c_equal_p (cstyle, ly_symbol2scm ("parentheses"));
 777                 }
 778
 779               SCM accs = g->get_property ("accidentals");
 780               SCM scm_style = g->get_property ("style");
 781               if (!scm_is_symbol (scm_style)
 782                   && !parens
 783                   && scm_ilength (accs) == 1)
 784                 {
 785                   /* End copy accidental.cc */
 786                   switch (scm_to_int (scm_car (accs)))
 787                     {
 788                     case FLAT:
 789                     case DOUBLE_FLAT:
 790                       xp = LEFT;
 791                       break;
 792                     case SHARP:
 793                       xp = 0.5 * dir_;
 794                       break;
 795                     case NATURAL:
 796                       xp = -dir_;
 797                       break;
 798                     }
 799                 }
 800             }
 801
 802           ye.widen (thickness_ * 0.5);
 803           xe.widen (thickness_ * 1.0);
 804           Extra_collision_info info (g, xp, xe, ye, penalty);
 805           collision_infos.push (info);
 806         }
 807     }
 808
 809   return collision_infos;
 810 }
 811