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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@xs4all.nl>
7   Jan Nieuwenhuizen <janneke@gnu.org>
8 */
9
10
11 #include "slur-scoring.hh"
12 #include "libc-extension.hh"
13 #include "slur-configuration.hh"
14 #include "beam.hh"
15 #include "directional-element-interface.hh"
16 #include "pointer-group-interface.hh"
17 #include "slur.hh"
18 #include "note-column.hh"
19 #include "output-def.hh"
20 #include "pitch.hh"
21 #include "spanner.hh"
22 #include "staff-symbol-referencer.hh"
23 #include "staff-symbol.hh"
24 #include "stem.hh"
25 #include "warn.hh"
26 #include "paper-column.hh"
27 #include "accidental-interface.hh"
28
29 /*
30   TODO:
31
32   - curve around flag for y coordinate
33
34   - short-cut: try a smaller region first.
35
36   - handle non-visible stems better.
37
38   - try to prune number of scoring criteria
39
40   - take encompass-objects more into account when determining
41   slur shape
42
43   - calculate encompass scoring directly after determining slur shape.
44
45   - optimize.
46 */
47 struct Slur_score_state;
48
49 Slur_score_state::Slur_score_state ()
50 {
51   musical_dy_ = 0.0;
52   valid_ = false;
53   edge_has_beams_ = false;
54   has_same_beam_ = false;
55   is_broken_ = false;
56   dir_ = CENTER;
57   slur_ = 0;
58   common_[X_AXIS] = 0;
59   common_[Y_AXIS] = 0;
60 }
61
62 Slur_score_state::~Slur_score_state ()
63 {
64   junk_pointers (configurations_);
65 }
66
67 Real
68 get_detail (SCM alist, SCM sym)
69 {
70   SCM entry = scm_assq (sym, alist);
71   return robust_scm2double (scm_is_pair (entry)
72                             ? scm_cdr (entry)
73                             : SCM_EOL,
74                             0.0);
75 }
76
77 void
78 Slur_score_parameters::fill (Grob *me)
79 {
80   SCM details = me->get_property ("details");
81
82   region_size_
83     = (int) get_detail (details, ly_symbol2scm ("region-size"));
84   head_encompass_penalty_
85     = get_detail (details, ly_symbol2scm ("head-encompass-penalty"));
86   stem_encompass_penalty_
87     = get_detail (details, ly_symbol2scm ("stem-encompass-penalty"));
88   closeness_factor_
89     = get_detail (details, ly_symbol2scm ("closeness-factor"));
90   edge_attraction_factor_
91     = get_detail (details, ly_symbol2scm ("edge-attraction-factor"));
92   same_slope_penalty_
93     = get_detail (details, ly_symbol2scm ("same-slope-penalty"));
94   steeper_slope_factor_
95     = get_detail (details, ly_symbol2scm ("steeper-slope-factor"));
96   non_horizontal_penalty_
97     = get_detail (details, ly_symbol2scm ("non-horizontal-penalty"));
98   max_slope_
99     = get_detail (details, ly_symbol2scm ("max-slope"));
100   max_slope_factor_
101     = get_detail (details, ly_symbol2scm ("max-slope-factor"));
102   free_head_distance_
103     = get_detail (details, ly_symbol2scm ("free-head-distance"));
104   absolute_closeness_measure_
105     = get_detail (details, ly_symbol2scm ("absolute-closeness-measure"));
106   extra_object_collision_penalty_
107     = get_detail (details, ly_symbol2scm ("extra-object-collision-penalty"));
108   accidental_collision_
109     = get_detail (details, ly_symbol2scm ("accidental-collision"));
110   extra_encompass_free_distance_
111     = get_detail (details, ly_symbol2scm ("extra-encompass-free-distance"));
112   head_slur_distance_factor_
113     = get_detail (details, ly_symbol2scm ("head-slur-distance-factor"));
114   head_slur_distance_max_ratio_
115     = get_detail (details, ly_symbol2scm ("head-slur-distance-max-ratio"));
116   free_slur_distance_
117     = get_detail (details, ly_symbol2scm ("free-slur-distance"));
118   edge_slope_exponent_
119     = get_detail (details, ly_symbol2scm ("edge-slope-exponent"));
120 }
121
122 Real
123 broken_trend_y (Slur_score_state const &state, Direction hdir)
124 {
125   /* A broken slur should maintain the same vertical trend
126      the unbroken slur would have had.  */
127   Real by = 0.0;
128   if (Spanner *mother = dynamic_cast<Spanner *> (state.slur_->original ()))
129     {
130       int k = broken_spanner_index (state.slur_);
131       int j = k + hdir;
132       if (j < 0 || j >= mother->broken_intos_.size ())
133         return by;
134
135       Grob *neighbor = mother->broken_intos_[j];
136       Spanner *common_mother
137         = dynamic_cast<Spanner *> (state.common_[Y_AXIS]->original ());
138       int common_k
139         = broken_spanner_index (dynamic_cast<Spanner *> (state.common_[Y_AXIS]));
140       int common_j = common_k + hdir;
141
142       if (common_j < 0 || common_j >= common_mother->broken_intos_.size ())
143         return by;
144
145       Grob *common_next_system = common_mother->broken_intos_[common_j];
146
147       SCM last_point = scm_car (scm_last_pair (neighbor->get_property ("control-points")));
148
149       return scm_to_double (scm_cdr (last_point))
150         + neighbor->relative_coordinate (common_next_system, Y_AXIS);
151     }
152   return by;
153 }
154
155 /*
156   copy slur dir forwards across line break.
157 */
158 void
159 Slur_score_state::set_next_direction ()
160 {
161   if (extremes_[RIGHT].note_column_)
162     return;
163
164   if (Spanner *mother = dynamic_cast<Spanner *> (slur_->original ()))
165     {
166       int k = broken_spanner_index (slur_);
167       int j = k + 1;
168       if (j < 0 || j >= mother->broken_intos_.size ())
169         return;
170
171       Grob *neighbor = mother->broken_intos_[j];
172       set_grob_direction (neighbor, dir_);
173     }
174 }
175
176 Encompass_info
177 Slur_score_state::get_encompass_info (Grob *col) const
178 {
179   Grob *stem = unsmob_grob (col->get_object ("stem"));
180   Encompass_info ei;
181
182   if (!stem)
183     {
184       programming_error ("no stem for note column");
185       ei.x_ = col->relative_coordinate (common_[X_AXIS], X_AXIS);
186       ei.head_ = ei.stem_ = col->extent (common_[Y_AXIS],
187                                          Y_AXIS)[dir_];
188       return ei;
189     }
190   Direction stem_dir = get_grob_direction (stem);
191
192   if (Grob *head = Note_column::first_head (col))
193     ei.x_ = head->extent (common_[X_AXIS], X_AXIS).center ();
194   else
195     ei.x_ = col->extent (common_[X_AXIS], X_AXIS).center ();
196
197   Grob *h = Stem::extremal_heads (stem)[Direction (dir_)];
198   if (!h)
199     {
200       ei.head_ = ei.stem_ = col->extent (common_[Y_AXIS], Y_AXIS)[dir_];
201       return ei;
202     }
203
204   ei.head_ = h->extent (common_[Y_AXIS], Y_AXIS)[dir_];
205
206   if ((stem_dir == dir_)
207       && !stem->extent (stem, Y_AXIS).is_empty ())
208     {
209       ei.stem_ = stem->extent (common_[Y_AXIS], Y_AXIS)[dir_];
210       if (Grob *b = Stem::get_beam (stem))
211         ei.stem_ += stem_dir * 0.5 * Beam::get_thickness (b);
212
213       Interval x = stem->extent (common_[X_AXIS], X_AXIS);
214       ei.x_ = x.is_empty ()
215         ? stem->relative_coordinate (common_[X_AXIS], X_AXIS)
216         : x.center ();
217     }
218   else
219     ei.stem_ = ei.head_;
220
221   return ei;
222 }
223
224 Drul_array<Bound_info>
225 Slur_score_state::get_bound_info () const
226 {
227   Drul_array<Bound_info> extremes;
228
229   Direction d = LEFT;
230   Direction dir = dir_;
231
232   do
233     {
234       extremes[d].bound_ = slur_->get_bound (d);
235       if (Note_column::has_interface (extremes[d].bound_))
236         {
237           extremes[d].note_column_ = extremes[d].bound_;
238           extremes[d].stem_ = Note_column::get_stem (extremes[d].note_column_);
239           if (extremes[d].stem_)
240             {
241               extremes[d].stem_dir_ = get_grob_direction (extremes[d].stem_);
242
243               for (int a = X_AXIS; a < NO_AXES; a++)
244                 {
245                   Axis ax = Axis (a);
246                   Interval s = extremes[d].stem_->extent (common_[ax], ax);
247                   if (s.is_empty ())
248                     {
249                       /*
250                         do not issue warning. This happens for rests and
251                         whole notes.
252                       */
253                       s = Interval (0, 0)
254                         + extremes[d].stem_->relative_coordinate (common_[ax], ax);
255                     }
256                   extremes[d].stem_extent_[ax] = s;
257                 }
258
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                 extremes[d].slur_head_ = Note_column::get_rest (extremes[d].bound_);
264               extremes[d].staff_ = Staff_symbol_referencer
265                 ::get_staff_symbol (extremes[d].stem_);
266               extremes[d].staff_space_ = Staff_symbol_referencer
267                 ::staff_space (extremes[d].stem_);
268             }
269
270           if (extremes[d].slur_head_)
271             extremes[d].slur_head_x_extent_
272               = extremes[d].slur_head_->extent (common_[X_AXIS], X_AXIS);
273
274         }
275     }
276   while (flip (&d) != LEFT);
277
278   return extremes;
279 }
280
281 void
282 Slur_score_state::fill (Grob *me)
283 {
284   slur_ = dynamic_cast<Spanner *> (me);
285   columns_
286     = internal_extract_grob_array (me, ly_symbol2scm ("note-columns"));
287
288   if (columns_.is_empty ())
289     {
290       me->suicide ();
291       return;
292     }
293
294   staff_space_ = Staff_symbol_referencer::staff_space (me);
295   Real lt = me->layout ()->get_dimension (ly_symbol2scm ("linethickness"));
296   thickness_ = robust_scm2double (me->get_property ("thickness"), 1.0) * lt;
297
298   dir_ = get_grob_direction (me);
299   parameters_.fill (me);
300
301   extract_grob_set (me, "note-columns", columns);
302   extract_grob_set (me, "encompass-objects", extra_objects);
303
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_array (columns, me, a);
310       common_[a] = common_refpoint_of_array (extra_objects, 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           && extremes_[d].slur_head_)
351         musical_dy_ += d
352           * extremes_[d].slur_head_->relative_coordinate (common_[Y_AXIS], Y_AXIS);
353     }
354   while (flip (&d) != LEFT);
355
356   edge_has_beams_
357     = (extremes_[LEFT].stem_ && Stem::get_beam (extremes_[LEFT].stem_))
358     || (extremes_[RIGHT].stem_ && Stem::get_beam (extremes_[RIGHT].stem_));
359
360   set_next_direction ();
361
362   if (is_broken_)
363     musical_dy_ = 0.0;
364 }
365
366
367 MAKE_SCHEME_CALLBACK(Slur, calc_control_points, 1)
368 SCM
369 Slur::calc_control_points (SCM smob)
370 {
371   Spanner *me = unsmob_spanner (smob);
372
373   Slur_score_state state;
374   state.fill (me);
375
376   if (!state.valid_)
377     return SCM_EOL;
378
379   state.generate_curves ();
380
381   SCM end_ys = me->get_property ("positions");
382   Bezier best;
383
384   if (is_number_pair (end_ys))
385     best = state.configurations_[state.get_closest_index (end_ys)]->curve_;
386   else
387     best = state.get_best_curve ();
388
389   SCM controls = SCM_EOL;
390   for (int i = 4; i--;)
391     {
392       Offset o = best.control_[i]
393         - Offset (me->relative_coordinate (state.common_[X_AXIS], X_AXIS),
394                   me->relative_coordinate (state.common_[Y_AXIS], Y_AXIS));
395       controls = scm_cons (ly_offset2scm (o), controls);
396     }
397
398   return controls;
399 }
400
401 Bezier
402 Slur_score_state::get_best_curve ()
403 {
404   int opt_idx = -1;
405   Real opt = 1e6;
406
407 #if DEBUG_SLUR_SCORING
408   SCM inspect_quants = slur_->get_property ("inspect-quants");
409   if (to_boolean (slur_->layout ()
410                   ->lookup_variable (ly_symbol2scm ("debug-slur-scoring")))
411       && scm_is_pair (inspect_quants))
412     {
413       opt_idx = get_closest_index (inspect_quants);
414       configurations_[opt_idx]->score (*this);
415       opt = configurations_[opt_idx]->score_;
416     }
417   else
418 #endif
419     {
420       for (int i = 0; i < configurations_.size (); i++)
421         configurations_[i]->score (*this);
422       for (int i = 0; i < configurations_.size (); i++)
423         {
424           if (configurations_[i]->score_ < opt)
425             {
426               opt = configurations_[i]->score_;
427               opt_idx = i;
428             }
429         }
430     }
431
432 #if DEBUG_SLUR_SCORING
433   configurations_[opt_idx]->score_card_ += to_string ("=%.2f", opt);
434   configurations_[opt_idx]->score_card_ += to_string ("i%d", opt_idx);
435
436   // debug quanting
437   slur_->set_property ("quant-score",
438                        scm_makfrom0str (configurations_[opt_idx]->score_card_.to_str0 ()));
439
440 #endif
441
442   return configurations_[opt_idx]->curve_;
443 }
444
445 int
446 Slur_score_state::get_closest_index (SCM inspect_quants) const
447 {
448   Drul_array<Real> ins = ly_scm2interval (inspect_quants);
449
450   int opt_idx = -1;
451   Real mindist = 1e6;
452   for (int i = 0; i < configurations_.size (); i++)
453     {
454       Real d = fabs (configurations_[i]->attachment_[LEFT][Y_AXIS] - ins[LEFT])
455         + fabs (configurations_[i]->attachment_[RIGHT][Y_AXIS] - ins[RIGHT]);
456       if (d < mindist)
457         {
458           opt_idx = i;
459           mindist = d;
460         }
461     }
462   if (mindist > 1e5)
463     programming_error ("can't not find quant");
464   return opt_idx;
465 }
466
467 /*
468   TODO: should analyse encompasses to determine sensible region, and
469   should limit slopes available.
470 */
471
472 Drul_array<Real>
473 Slur_score_state::get_y_attachment_range () const
474 {
475   Drul_array<Real> end_ys;
476   Direction d = LEFT;
477   do
478     {
479       if (extremes_[d].note_column_)
480         {
481           end_ys[d] = dir_
482             * max (max (dir_ * (base_attachments_[d][Y_AXIS]
483                                           + parameters_.region_size_ * dir_),
484                         dir_ * (dir_ + extremes_[d].note_column_->extent (common_[Y_AXIS], Y_AXIS)[dir_])),
485                    dir_ * base_attachments_[-d][Y_AXIS]);
486         }
487       else
488         end_ys[d] = base_attachments_[d][Y_AXIS] + parameters_.region_size_ * dir_;
489     }
490   while (flip (&d) != LEFT);
491
492   return end_ys;
493 }
494
495 bool
496 spanner_less (Spanner *s1, Spanner *s2)
497 {
498   Slice b1, b2;
499   Direction d = LEFT;
500   do
501     {
502       b1[d] = s1->get_bound (d)->get_column ()->get_rank ();
503       b2[d] = s2->get_bound (d)->get_column ()->get_rank ();
504     }
505   while (flip (&d) != LEFT);
506
507   return b2[LEFT] <= b1[LEFT] && b2[RIGHT] >= b1[RIGHT]
508     && (b2[LEFT] != b1[LEFT] || b2[RIGHT] != b1[RIGHT]);
509 }
510
511 Drul_array<Offset>
512 Slur_score_state::get_base_attachments () const
513 {
514   Drul_array<Offset> base_attachment;
515   Direction d = LEFT;
516   do
517     {
518       Grob *stem = extremes_[d].stem_;
519       Grob *head = extremes_[d].slur_head_;
520
521       Real x = 0.0;
522       Real y = 0.0;
523       if (extremes_[d].note_column_)
524         {
525
526           /*
527             fixme: X coord should also be set in this case.
528           */
529           if (stem
530               && !Stem::is_invisible (stem)
531               && extremes_[d].stem_dir_ == dir_
532               && Stem::get_beaming (stem, -d)
533               && (!spanner_less (slur_, Stem::get_beam (stem))
534                   || has_same_beam_))
535             y = extremes_[d].stem_extent_[Y_AXIS][dir_];
536           else if (head)
537             y = head->extent (common_[Y_AXIS], Y_AXIS)[dir_];
538           y += dir_ * 0.5 * staff_space_;
539
540           y = move_away_from_staffline (y, head);
541
542           Grob *fh = Note_column::first_head (extremes_[d].note_column_);
543           x
544             = (fh ? fh->extent (common_[X_AXIS], X_AXIS)
545                : extremes_[d].bound_->extent (common_[X_AXIS], X_AXIS))
546             .linear_combination (CENTER);
547         }
548       base_attachment[d] = Offset (x, y);
549     }
550   while (flip (&d) != LEFT);
551
552   do
553     {
554       if (!extremes_[d].note_column_)
555         {
556           Real x, y;
557           if (d == RIGHT)
558             x = extremes_[d].bound_->extent (common_[X_AXIS], X_AXIS)[d];
559           else
560             x = slur_->get_broken_left_end_align ();
561           Grob *col = (d == LEFT) ? columns_[0] : columns_.top ();
562
563           if (extremes_[-d].bound_ != col)
564             {
565               y = robust_relative_extent (col, common_[Y_AXIS], Y_AXIS)[dir_];
566               y += dir_ * 0.5 * staff_space_;
567
568               if (get_grob_direction (col) == dir_
569                   && Note_column::get_stem (col)
570                   && !Stem::is_invisible (Note_column::get_stem (col)))
571                 y -= dir_ * 1.5 * staff_space_;
572             }
573           else
574             y = base_attachment[-d][Y_AXIS];
575
576           y = move_away_from_staffline (y, col);
577
578           base_attachment[d] = Offset (x, y);
579         }
580     }
581   while (flip (&d) != LEFT);
582
583   do
584     {
585       for (int a = X_AXIS; a < NO_AXES; a++)
586         {
587           Real &b = base_attachment[d][Axis (a)];
588
589           if (isinf (b) || isnan (b))
590             {
591               programming_error ("slur attachment is inf/nan");
592               b = 0.0;
593             }
594         }
595     }
596   while (flip (&d) != LEFT);
597
598   return base_attachment;
599 }
600
601 Real
602 Slur_score_state::move_away_from_staffline (Real y,
603                                             Grob *on_staff) const
604 {
605   if (!on_staff)
606     return y;
607   
608   Grob *staff_symbol = Staff_symbol_referencer::get_staff_symbol (on_staff);
609   if (!staff_symbol)
610     return y;
611
612   Real pos
613     = (y - staff_symbol->relative_coordinate (common_[Y_AXIS],
614                                               Y_AXIS))
615     * 2.0 / staff_space_;
616
617   if (fabs (pos - my_round (pos)) < 0.2
618       && Staff_symbol_referencer::on_staffline (on_staff, (int) rint (pos))
619       && Staff_symbol_referencer::line_count (on_staff) - 1 >= rint (pos))
620     y += 1.5 * staff_space_ * dir_ / 10;
621
622   return y;
623 }
624
625 Array<Offset>
626 Slur_score_state::generate_avoid_offsets () const
627 {
628   Array<Offset> avoid;
629   Link_array<Grob> encompasses = columns_;
630
631   for (int i = 0; i < encompasses.size (); i++)
632     {
633       if (extremes_[LEFT].note_column_ == encompasses[i]
634           || extremes_[RIGHT].note_column_ == encompasses[i])
635         continue;
636
637       Encompass_info inf (get_encompass_info (encompasses[i]));
638       Real y = dir_ * (max (dir_ * inf.head_, dir_ * inf.stem_));
639
640       avoid.push (Offset (inf.x_, y + dir_ * parameters_.free_head_distance_));
641     }
642
643   extract_grob_set (slur_, "encompass-objects", extra_encompasses);
644   for (int i = 0; i < extra_encompasses.size (); i++)
645     {
646       if (Slur::has_interface (extra_encompasses[i]))
647         {
648           Grob *small_slur = extra_encompasses[i];
649           Bezier b = Slur::get_curve (small_slur);
650
651           Offset z = b.curve_point (0.5);
652           z += Offset (small_slur->relative_coordinate (common_[X_AXIS], X_AXIS),
653                        small_slur->relative_coordinate (common_[Y_AXIS], Y_AXIS));
654
655           z[Y_AXIS] += dir_ * parameters_.free_slur_distance_;
656           avoid.push (z);
657         }
658       else if (extra_encompasses[i]->get_property ("avoid-slur") == ly_symbol2scm ("inside"))
659         {
660           Grob *g = extra_encompasses [i];
661           Interval xe = g->extent (common_[X_AXIS], X_AXIS);
662           Interval ye = g->extent (common_[Y_AXIS], Y_AXIS);
663
664           if (!xe.is_empty ()
665               && !ye.is_empty ())
666             avoid.push (Offset (xe.center(), ye[dir_]));
667         }
668     }  
669   return avoid;
670 }
671
672 void
673 Slur_score_state::generate_curves () const
674 {
675   Real r_0 = robust_scm2double (slur_->get_property ("ratio"), 0.33);
676   Real h_inf = staff_space_ * scm_to_double (slur_->get_property ("height-limit"));
677
678   Array<Offset> avoid = generate_avoid_offsets ();
679   for (int i = 0; i < configurations_.size (); i++)
680     configurations_[i]->generate_curve (*this, r_0, h_inf, avoid);
681 }
682
683 Link_array<Slur_configuration>
684 Slur_score_state::enumerate_attachments (Drul_array<Real> end_ys) const
685 {
686   Link_array<Slur_configuration> scores;
687
688   Drul_array<Offset> os;
689   os[LEFT] = base_attachments_[LEFT];
690   Real minimum_length = staff_space_
691     * robust_scm2double (slur_->get_property ("minimum-length"), 2.0);
692
693   for (int i = 0; dir_ * os[LEFT][Y_AXIS] <= dir_ * end_ys[LEFT]; i++)
694     {
695       os[RIGHT] = base_attachments_[RIGHT];
696       for (int j = 0; dir_ * os[RIGHT][Y_AXIS] <= dir_ * end_ys[RIGHT]; j++)
697         {
698           Slur_configuration s;
699           Direction d = LEFT;
700           Drul_array<bool> attach_to_stem (false, false);
701           do
702             {
703               os[d][X_AXIS] = base_attachments_[d][X_AXIS];
704               if (extremes_[d].stem_
705                   && !Stem::is_invisible (extremes_[d].stem_)
706                   && extremes_[d].stem_dir_ == dir_)
707                 {
708                   Interval stem_y = extremes_[d].stem_extent_[Y_AXIS];
709                   stem_y.widen (0.25 * staff_space_);
710                   if (stem_y.contains (os[d][Y_AXIS]))
711                     {
712                       os[d][X_AXIS] = extremes_[d].stem_extent_[X_AXIS][-d]
713                         - d * 0.3;
714                       attach_to_stem[d] = true;
715                     }
716                   else if (dir_ * extremes_[d].stem_extent_[Y_AXIS][dir_]
717                            < dir_ * os[d][Y_AXIS]
718                            && !extremes_[d].stem_extent_[X_AXIS].is_empty ())
719
720                     os[d][X_AXIS] = extremes_[d].stem_extent_[X_AXIS].center ();
721                 }
722             }
723           while (flip (&d) != LEFT);
724
725           Offset dz;
726           dz = os[RIGHT] - os[LEFT];
727           if (dz[X_AXIS] < minimum_length
728               || fabs (dz[Y_AXIS] / dz[X_AXIS]) > parameters_.max_slope_)
729             {
730               do
731                 {
732                   if (extremes_[d].slur_head_
733                       && !extremes_[d].slur_head_x_extent_.is_empty ())
734                     {
735                       os[d][X_AXIS] = extremes_[d].slur_head_x_extent_.center ();
736                       attach_to_stem[d] = false;
737                     }
738                 }
739               while (flip (&d) != LEFT);
740             }
741
742           dz = os[RIGHT] - os[LEFT];
743           do
744             {
745               if (extremes_[d].slur_head_
746                   && !attach_to_stem[d])
747                 {
748                   /* Horizontally move tilted slurs a little.  Move
749                      more for bigger tilts.
750
751                      TODO: parameter */
752                   os[d][X_AXIS]
753                     -= dir_ * extremes_[d].slur_head_x_extent_.length ()
754                     * sin (dz.arg ()) / 3;
755                 }
756             }
757           while (flip (&d) != LEFT);
758
759           s.attachment_ = os;
760           s.index_ = scores.size ();
761
762           scores.push (new Slur_configuration (s));
763
764           os[RIGHT][Y_AXIS] += dir_ * staff_space_ / 2;
765         }
766
767       os[LEFT][Y_AXIS] += dir_ * staff_space_ / 2;
768     }
769
770   assert (scores.size () > 0);
771   return scores;
772 }
773
774 Array<Extra_collision_info>
775 Slur_score_state::get_extra_encompass_infos () const
776 {
777   extract_grob_set (slur_, "encompass-objects", encompasses);
778   Array<Extra_collision_info> collision_infos;
779   for (int i = encompasses.size (); i--;)
780     {
781       if (Slur::has_interface (encompasses[i]))
782         {
783           Spanner *small_slur = dynamic_cast<Spanner *> (encompasses[i]);
784           Bezier b = Slur::get_curve (small_slur);
785
786           Offset relative (small_slur->relative_coordinate (common_[X_AXIS], X_AXIS),
787                            small_slur->relative_coordinate (common_[Y_AXIS], Y_AXIS));
788
789           for (int k = 0; k < 3; k++)
790             {
791               Direction hdir = Direction (k / 2 - 1);
792
793               /*
794                 Only take bound into account if small slur starts
795                 together with big slur.
796               */
797               if (hdir && small_slur->get_bound (hdir) != slur_->get_bound (hdir))
798                 continue;
799
800               Offset z = b.curve_point (k / 2.0);
801               z += relative;
802
803               Interval yext;
804               yext.set_full ();
805               yext[dir_] = z[Y_AXIS] + dir_ * thickness_ * 1.0;
806
807               Interval xext (-1, 1);
808               xext = xext * (thickness_ * 2) + z[X_AXIS];
809               Extra_collision_info info (small_slur,
810                                          k - 1.0,
811                                          xext,
812                                          yext,
813                                          parameters_.extra_object_collision_penalty_);
814               collision_infos.push (info);
815             }
816         }
817       else
818         {
819           Grob *g = encompasses [i];
820           Interval xe = g->extent (common_[X_AXIS], X_AXIS);
821           Interval ye = g->extent (common_[Y_AXIS], Y_AXIS);
822
823           Real xp = 0.0;
824           Real penalty = parameters_.extra_object_collision_penalty_;
825           if (Accidental_interface::has_interface (g))
826             {
827               penalty = parameters_.accidental_collision_;
828               /* Begin copy accidental.cc */
829               bool parens = false;
830               if (to_boolean (g->get_property ("cautionary")))
831                 {
832                   SCM cstyle = g->get_property ("cautionary-style");
833                   parens = ly_is_equal (cstyle, ly_symbol2scm ("parentheses"));
834                 }
835
836               SCM accs = g->get_property ("accidentals");
837               SCM scm_style = g->get_property ("style");
838               if (!scm_is_symbol (scm_style)
839                   && !parens
840                   && scm_ilength (accs) == 1)
841                 {
842                   /* End copy accidental.cc */
843                   switch (scm_to_int (scm_car (accs)))
844                     {
845                     case FLAT:
846                     case DOUBLE_FLAT:
847                       xp = LEFT;
848                       break;
849                     case SHARP:
850                       xp = 0.5 * dir_;
851                       break;
852                     case NATURAL:
853                       xp = -dir_;
854                       break;
855                     }
856                 }
857             }
858
859           ye.widen (thickness_ * 0.5);
860           xe.widen (thickness_ * 1.0);
861           Extra_collision_info info (g, xp, xe, ye, penalty);
862           collision_infos.push (info);
863         }
864     }
865
866   return collision_infos;
867 }
868  
869 Extra_collision_info::Extra_collision_info (Grob *g, Real idx, Interval x, Interval y, Real p)
870 {
871   idx_ = idx;
872   extents_[X_AXIS] = x;
873   extents_[Y_AXIS] = y;
874   penalty_ = p;
875   grob_ = g;
876   type_ = g->get_property ("avoid-slur");
877 }
878
879 Extra_collision_info::Extra_collision_info ()
880 {
881   idx_ = 0.0;
882   penalty_ = 0.;
883   grob_ = 0;
884   type_ = SCM_EOL; 
885 }