2 beam.cc -- implement Beam
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
7 Jan Nieuwenhuizen <janneke@gnu.org>
13 - Determine auto knees based on positions if it's set by the user.
15 - the code is littered with * and / staff_space calls for
16 #'positions. Consider moving to real-world coordinates?
18 Problematic issue is user tweaks (user tweaks are in staff-coordinates.)
22 - Stems run to the Y-center of the beam.
24 - beam_translation is the offset between Y centers of the beam.
28 #include "interval-set.hh"
29 #include "directional-element-interface.hh"
32 #include "least-squares.hh"
34 #include "output-def.hh"
36 #include "pointer-group-interface.hh"
37 #include "staff-symbol-referencer.hh"
43 #include "text-interface.hh" // debug output.
44 #include "font-interface.hh" // debug output.
48 Beam::add_stem (Grob *me, Grob *s)
50 if (Stem::get_beam (s))
52 programming_error ("Stem already has beam");
56 Pointer_group_interface::add_grob (me, ly_symbol2scm ("stems"), s);
57 s->set_object ("beam", me->self_scm ());
58 add_bound_item (dynamic_cast<Spanner *> (me), dynamic_cast<Item *> (s));
62 Beam::get_thickness (Grob *me)
64 return robust_scm2double (me->get_property ("thickness"), 0)
65 * Staff_symbol_referencer::staff_space (me);
68 /* Return the translation between 2 adjoining beams. */
70 Beam::get_beam_translation (Grob *me)
72 int beam_count = get_beam_count (me);
73 Real staff_space = Staff_symbol_referencer::staff_space (me);
74 Real line = Staff_symbol_referencer::line_thickness (me);
75 Real thickness = get_thickness (me);
76 Real fract = robust_scm2double (me->get_property ("length-fraction"), 1.0);
78 Real beam_translation = beam_count < 4
79 ? (2 * staff_space + line - thickness) / 2.0
80 : (3 * staff_space + line - thickness) / 3.0;
82 return fract * beam_translation;
85 /* Maximum beam_count. */
87 Beam::get_beam_count (Grob *me)
91 extract_grob_set (me, "stems", stems);
92 for (int i = 0; i < stems.size (); i++)
94 Grob *stem = stems[i];
95 m = max (m, (Stem::beam_multiplicity (stem).length () + 1));
101 /* After pre-processing all directions should be set.
102 Several post-processing routines (stem, slur, script) need stem/beam
104 Currenly, this means that beam has set all stem's directions.
105 [Alternatively, stems could set its own directions, according to
106 their beam, during 'final-pre-processing'.] */
107 MAKE_SCHEME_CALLBACK (Beam, calc_direction, 1);
109 Beam::calc_direction (SCM smob)
111 Grob *me = unsmob_grob (smob);
113 /* Beams with less than 2 two stems don't make much sense, but could happen
118 For a beam that only has one stem, we try to do some disappearance magic:
119 we revert the flag, and move on to The Eternal Engraving Fields. */
121 Direction d = CENTER;
123 int count = visible_stem_count (me);
126 extract_grob_set (me, "stems", stems);
127 if (stems.size () == 1)
129 me->warning (_ ("removing beam with less than two stems"));
131 stems[0]->set_object ("beam", SCM_EOL);
134 return SCM_UNSPECIFIED;
136 else if (stems.size () == 0)
139 return SCM_UNSPECIFIED;
146 can happen in stem-tremolo case.
149 d = Stem::get_default_dir (stems[0]);
156 d = get_default_dir (me);
157 consider_auto_knees (me);
162 set_stem_directions (me, d);
164 set_stem_shorten (me);
167 return scm_from_int (d);
170 /* We want a maximal number of shared beams, but if there is choice, we
171 * take the one that is closest to the end of the stem. This is for
183 position_with_maximal_common_beams (SCM left_beaming, SCM right_beaming,
187 Slice lslice = int_list_to_slice (scm_cdr (left_beaming));
191 for (int i = lslice[-left_dir];
192 (i - lslice[left_dir]) * left_dir <= 0; i += left_dir)
195 for (SCM s = scm_car (right_beaming); scm_is_pair (s); s = scm_cdr (s))
197 int k = -right_dir * scm_to_int (scm_car (s)) + i;
198 if (scm_c_memq (scm_from_int (k), left_beaming) != SCM_BOOL_F)
202 if (count >= best_count)
213 Beam::connect_beams (Grob *me)
215 extract_grob_set (me, "stems", stems);
218 last_int.set_empty ();
220 // SCM last_beaming = SCM_EOL;
221 SCM last_beaming = scm_cons (SCM_EOL, scm_list_1 (scm_from_int (0)));
222 Direction last_dir = CENTER;
223 for (int i = 0; i < stems.size (); i++)
225 Grob *this_stem = stems[i];
226 SCM this_beaming = this_stem->get_property ("beaming");
228 Direction this_dir = get_grob_direction (this_stem);
229 if (scm_is_pair (last_beaming) && scm_is_pair (this_beaming))
231 int start_point = position_with_maximal_common_beams
232 (last_beaming, this_beaming,
233 last_dir ? last_dir : this_dir,
240 new_slice.set_empty ();
241 SCM s = index_get_cell (this_beaming, d);
242 for (; scm_is_pair (s); s = scm_cdr (s))
245 = start_point - this_dir * scm_to_int (scm_car (s));
247 new_slice.add_point (new_beam_pos);
248 scm_set_car_x (s, scm_from_int (new_beam_pos));
251 while (flip (&d) != LEFT);
253 if (!new_slice.is_empty ())
254 last_int = new_slice;
258 SCM s = scm_cdr (this_beaming);
259 for (; scm_is_pair (s); s = scm_cdr (s))
261 int np = -this_dir * scm_to_int (scm_car (s));
262 scm_set_car_x (s, scm_from_int (np));
263 last_int.add_point (np);
267 if (scm_ilength (scm_cdr (this_beaming)) > 0)
269 last_beaming = this_beaming;
276 I really enjoy spaghetti, but spaghetti should be kept on a plate
277 with a little garlic and olive oil. This is too much.
281 MAKE_SCHEME_CALLBACK (Beam, print, 1);
283 Beam::print (SCM grob)
285 Spanner *me = unsmob_spanner (grob);
287 extract_grob_set (me, "stems", stems);
288 Grob *xcommon = common_refpoint_of_array (stems, me, X_AXIS);
290 xcommon = me->get_bound (LEFT)->common_refpoint (xcommon, X_AXIS);
291 xcommon = me->get_bound (RIGHT)->common_refpoint (xcommon, X_AXIS);
294 if (visible_stem_count (me))
296 // ugh -> use commonx
297 x0 = first_visible_stem (me)->relative_coordinate (xcommon, X_AXIS);
298 dx = last_visible_stem (me)->relative_coordinate (xcommon, X_AXIS) - x0;
302 x0 = stems[0]->relative_coordinate (xcommon, X_AXIS);
303 dx = stems.top ()->relative_coordinate (xcommon, X_AXIS) - x0;
306 SCM posns = me->get_property ("positions");
307 Drul_array<Real> pos;
308 if (!is_number_pair (posns))
310 programming_error ("no beam positions?");
311 pos = Interval (0, 0);
314 pos = ly_scm2realdrul (posns);
316 scale_drul (&pos, Staff_symbol_referencer::staff_space (me));
318 Real dy = pos[RIGHT] - pos[LEFT];
319 Real slope = (dy && dx) ? dy / dx : 0;
321 Real thick = get_thickness (me);
322 Real bdy = get_beam_translation (me);
324 SCM last_beaming = SCM_EOL;
325 Real last_xposn = -1;
326 Real last_stem_width = -1;
328 Real gap_length = robust_scm2double (me->get_property ("gap"), 0.0);
331 Real lt = me->get_layout ()->get_dimension (ly_symbol2scm ("linethickness"));
333 for (int i = 0; i <= stems.size (); i++)
335 Grob *stem = (i < stems.size ()) ? stems[i] : 0;
337 SCM this_beaming = stem ? stem->get_property ("beaming") : SCM_EOL;
338 Real xposn = stem ? stem->relative_coordinate (xcommon, X_AXIS) : 0.0;
339 Real stem_width = stem ? robust_scm2double (stem->get_property ("thickness"), 1.0) * lt : 0;
340 Direction stem_dir = stem ? to_dir (stem->get_property ("direction")) : CENTER;
342 We do the space left of ST, with lfliebertjes pointing to the
343 right from the left stem, and rfliebertjes pointing left from
346 SCM left = (i > 0) ? scm_cdr (last_beaming) : SCM_EOL;
347 SCM right = stem ? scm_car (this_beaming) : SCM_EOL;
349 Array<int> full_beams;
350 Array<int> lfliebertjes;
351 Array<int> rfliebertjes;
354 scm_is_pair (s); s = scm_cdr (s))
356 int b = scm_to_int (scm_car (s));
357 if (scm_c_memq (scm_car (s), right) != SCM_BOOL_F)
360 lfliebertjes.push (b);
363 scm_is_pair (s); s = scm_cdr (s))
365 int b = scm_to_int (scm_car (s));
366 if (scm_c_memq (scm_car (s), left) == SCM_BOOL_F)
367 rfliebertjes.push (b);
370 Drul_array<Real> break_overshoot
371 = robust_scm2drul (me->get_property ("break-overshoot"),
372 Drul_array<Real> (-0.5, 0.0));
374 Real w = (i > 0 && stem)
375 ? (xposn - last_xposn)
376 : break_overshoot[ (i == 0) ? LEFT : RIGHT];
378 Real stem_offset = 0.0;
381 w += last_stem_width / 2;
382 stem_offset = -last_stem_width / 2;
388 Real blot = me->get_layout ()->get_dimension (ly_symbol2scm ("blotdiameter"));
389 Stencil whole = Lookup::beam (slope, w, thick, blot);
393 if (scm_is_number (me->get_property ("gap-count")))
395 gap_count = scm_to_int (me->get_property ("gap-count"));
396 gapped = Lookup::beam (slope, w - 2 * gap_length, thick, blot);
398 full_beams.sort (default_compare);
400 full_beams.reverse ();
404 for (int j = full_beams.size (); j--;)
411 b.translate_axis (gap_length, X_AXIS);
413 b.translate_axis (last_xposn - x0 + stem_offset, X_AXIS);
414 b.translate_axis (slope * (last_xposn - x0) + bdy * full_beams[j], Y_AXIS);
416 the_beam.add_stencil (b);
419 if (lfliebertjes.size () || rfliebertjes.size ())
425 int t = Stem::duration_log (stem);
433 nw_f = break_overshoot[RIGHT] / 2;
435 /* Half beam should be one note-width,
436 but let's make sure two half-beams never touch */
440 rw = min (nw_f, ((xposn - last_xposn) / 2));
443 if (me->get_bound (LEFT)->break_status_dir ())
444 rw = xposn - me->get_bound (LEFT)->extent (xcommon, X_AXIS)[RIGHT]
445 + break_overshoot[LEFT];
451 lw = min (nw_f, ((xposn - last_xposn) / 2));
454 lw = me->get_bound (RIGHT)->relative_coordinate (xcommon, X_AXIS)
456 + break_overshoot[RIGHT];
458 rw += stem_width / 2;
459 lw += last_stem_width / 2;
461 Stencil rhalf = Lookup::beam (slope, rw, thick, blot);
462 Stencil lhalf = Lookup::beam (slope, lw, thick, blot);
463 for (int j = lfliebertjes.size (); j--;)
466 b.translate_axis (last_xposn - x0 - last_stem_width /2,
468 b.translate_axis (slope * (last_xposn - x0)
469 + bdy * lfliebertjes[j],
471 the_beam.add_stencil (b);
473 for (int j = rfliebertjes.size (); j--;)
476 b.translate_axis (xposn - x0 - rw + stem_width / 2, X_AXIS);
477 b.translate_axis (slope * (xposn - x0 - rw)
478 + bdy * rfliebertjes[j], Y_AXIS);
479 the_beam.add_stencil (b);
484 last_stem_width = stem_width;
485 last_beaming = this_beaming;
488 the_beam.translate_axis (x0 - me->relative_coordinate (xcommon, X_AXIS),
490 the_beam.translate_axis (pos[LEFT], Y_AXIS);
493 SCM quant_score = me->get_property ("quant-score");
494 SCM debug = me->get_layout ()->lookup_variable (ly_symbol2scm ("debug-beam-quanting"));
495 if (to_boolean (debug) && scm_is_string (quant_score))
499 This code prints the demerits for each beam. Perhaps this
500 should be switchable for those who want to twiddle with the
504 SCM properties = Font_interface::text_font_alist_chain (me);
506 Direction stem_dir = stems.size () ? to_dir (stems[0]->get_property ("direction")) : UP;
508 Stencil score = *unsmob_stencil (Text_interface::interpret_markup
509 (me->get_layout ()->self_scm (), properties, quant_score));
511 if (!score.is_empty ())
512 the_beam.add_at_edge (Y_AXIS, stem_dir, score, 1.0, 0);
516 return the_beam.smobbed_copy ();
520 Beam::get_default_dir (Grob *me)
522 Drul_array<int> total;
523 total[UP] = total[DOWN] = 0;
524 Drul_array<int> count;
525 count[UP] = count[DOWN] = 0;
527 extract_grob_set (me, "stems", stems);
529 for (int i = 0; i < stems.size (); i++)
532 Direction stem_dir = CENTER;
533 SCM stem_dir_scm = s->get_property_data (ly_symbol2scm ("direction"));
534 if (is_direction (stem_dir_scm))
535 stem_dir = to_dir (stem_dir_scm);
537 stem_dir = Stem::get_default_dir (s);
542 total[stem_dir] += max (int (- stem_dir * Stem::head_positions (s) [-stem_dir]), 0);
546 Direction dir = CENTER;
548 if (Direction d = (Direction) sign (count[UP] - count[DOWN]))
550 else if (Direction d = (Direction) sign (total[UP] / count[UP] - total[DOWN]/count[DOWN]))
552 else if (Direction d = (Direction) sign (total[UP] - total[DOWN]))
555 dir = to_dir (me->get_property ("neutral-direction"));
560 /* Set all stems with non-forced direction to beam direction.
561 Urg: non-forced should become `without/with unforced' direction,
562 once stem gets cleaned-up. */
564 Beam::set_stem_directions (Grob *me, Direction d)
566 extract_grob_set (me, "stems", stems);
568 for (int i = 0; i < stems.size (); i++)
572 SCM forcedir = s->get_property_data (ly_symbol2scm ("direction"));
573 if (!to_dir (forcedir))
574 set_grob_direction (s, d);
579 Only try horizontal beams for knees. No reliable detection of
580 anything else is possible here, since we don't know funky-beaming
581 settings, or X-distances (slopes!) People that want sloped
582 knee-beams, should set the directions manually.
587 this routine should take into account the stemlength scoring
588 of a possible knee/nonknee beam.
591 Beam::consider_auto_knees (Grob *me)
593 SCM scm = me->get_property ("auto-knee-gap");
594 if (!scm_is_number (scm))
601 extract_grob_set (me, "stems", stems);
603 Grob *common = common_refpoint_of_array (stems, me, Y_AXIS);
604 Real staff_space = Staff_symbol_referencer::staff_space (me);
606 Array<Interval> head_extents_array;
607 for (int i = 0; i < stems.size (); i++)
609 Grob *stem = stems[i];
610 if (Stem::is_invisible (stem))
613 Interval head_extents = Stem::head_positions (stem);
614 if (!head_extents.is_empty ())
616 head_extents[LEFT] += -1;
617 head_extents[RIGHT] += 1;
618 head_extents *= staff_space * 0.5;
621 We could subtract beam Y position, but this routine only
622 sets stem directions, a constant shift does not have an
625 head_extents += stem->relative_coordinate (common, Y_AXIS);
627 if (to_dir (stem->get_property_data (ly_symbol2scm ("direction"))))
629 Direction stemdir = to_dir (stem->get_property ("direction"));
630 head_extents[-stemdir] = -stemdir * infinity_f;
633 head_extents_array.push (head_extents);
635 gaps.remove_interval (head_extents);
639 Real max_gap_len = 0.0;
641 for (int i = gaps.allowed_regions_.size () -1; i >= 0; i--)
643 Interval gap = gaps.allowed_regions_[i];
646 the outer gaps are not knees.
648 if (isinf (gap[LEFT]) || isinf (gap[RIGHT]))
651 if (gap.length () >= max_gap_len)
653 max_gap_len = gap.length ();
658 Real beam_translation = get_beam_translation (me);
659 Real beam_thickness = Beam::get_thickness (me);
660 int beam_count = Beam::get_beam_count (me);
661 Real height_of_beams = beam_thickness / 2
662 + (beam_count - 1) * beam_translation;
663 Real threshold = scm_to_double (scm) + height_of_beams;
665 if (max_gap_len > threshold)
668 for (int i = 0; i < stems.size (); i++)
670 Grob *stem = stems[i];
671 if (Stem::is_invisible (stem))
674 Interval head_extents = head_extents_array[j++];
676 Direction d = (head_extents.center () < max_gap.center ())
679 stem->set_property ("direction", scm_from_int (d));
681 head_extents.intersect (max_gap);
682 assert (head_extents.is_empty () || head_extents.length () < 1e-6);
687 /* Set stem's shorten property if unset.
690 take some y-position (chord/beam/nearest?) into account
691 scmify forced-fraction
693 This is done in beam because the shorten has to be uniform over the
697 Beam::set_stem_shorten (Grob *me)
700 shortening looks silly for x staff beams
705 Real forced_fraction = 1.0 * forced_stem_count (me)
706 / visible_stem_count (me);
708 int beam_count = get_beam_count (me);
710 SCM shorten_list = me->get_property ("beamed-stem-shorten");
711 if (shorten_list == SCM_EOL)
714 Real staff_space = Staff_symbol_referencer::staff_space (me);
717 = robust_list_ref (beam_count -1, shorten_list);
718 Real shorten = scm_to_double (shorten_elt) * staff_space;
720 shorten *= forced_fraction;
723 me->set_property ("shorten", scm_from_double (shorten));
726 MAKE_SCHEME_CALLBACK (Beam, calc_positions, 1);
728 Beam::calc_positions (SCM smob)
730 Grob *me = unsmob_grob (smob);
734 (void) me->get_property ("direction");
736 SCM posns = scm_cons (SCM_BOOL_F, SCM_BOOL_F);
737 me->set_property ("positions", posns);
739 SCM callbacks = me->get_property ("position-callbacks");
740 for (SCM i = callbacks; scm_is_pair (i); i = scm_cdr (i))
741 scm_call_1 (scm_car (i), me->self_scm ());
743 return SCM_UNSPECIFIED;
749 set_minimum_dy (Grob *me, Real *dy)
754 If dy is smaller than the smallest quant, we
755 get absurd direction-sign penalties.
758 Real ss = Staff_symbol_referencer::staff_space (me);
759 Real thickness = Beam::get_thickness (me) / ss;
760 Real slt = Staff_symbol_referencer::line_thickness (me) / ss;
761 Real sit = (thickness - slt) / 2;
763 Real hang = 1.0 - (thickness - slt) / 2;
765 *dy = sign (*dy) * max (fabs (*dy),
766 min (min (sit, inter), hang));
771 Compute a first approximation to the beam slope.
773 MAKE_SCHEME_CALLBACK (Beam, calc_least_squares_positions, 2);
775 Beam::calc_least_squares_positions (SCM smob, SCM posns)
779 Grob *me = unsmob_grob (smob);
781 int count = visible_stem_count (me);
785 extract_grob_set (me, "stems", stems);
786 Grob *commonx = common_refpoint_of_array (stems, me, X_AXIS);
787 Grob *commony = common_refpoint_of_array (stems, me, Y_AXIS);
789 Real my_y = me->relative_coordinate (commony, Y_AXIS);
791 Grob *fvs = first_visible_stem (me);
792 Grob *lvs = last_visible_stem (me);
794 Interval ideal (Stem::get_stem_info (fvs).ideal_y_
795 + fvs->relative_coordinate (commony, Y_AXIS) -my_y,
796 Stem::get_stem_info (lvs).ideal_y_
797 + lvs->relative_coordinate (commony, Y_AXIS) - my_y);
799 Real x0 = first_visible_stem (me)->relative_coordinate (commonx, X_AXIS);
800 for (int i = 0; i < stems.size (); i++)
804 Real x = s->relative_coordinate (commonx, X_AXIS) - x0;
807 Real dx = last_visible_stem (me)->relative_coordinate (commonx, X_AXIS) - x0;
815 Interval chord (Stem::chord_start_y (first_visible_stem (me)),
816 Stem::chord_start_y (last_visible_stem (me)));
818 /* Simple beams (2 stems) on middle line should be allowed to be
821 However, if both stems reach middle line,
822 ideal[LEFT] == ideal[RIGHT] and ideal.delta () == 0.
824 For that case, we apply artificial slope */
825 if (!ideal[LEFT] && chord.delta () && count == 2)
828 Direction d = (Direction) (sign (chord.delta ()) * UP);
829 pos[d] = get_thickness (me) / 2;
836 For broken beams this doesn't work well. In this case, the
837 slope esp. of the first part of a broken beam should predict
838 where the second part goes.
840 ldy = pos[RIGHT] - pos[LEFT];
844 Array<Offset> ideals;
845 for (int i = 0; i < stems.size (); i++)
848 if (Stem::is_invisible (s))
850 ideals.push (Offset (x_posns[i],
851 Stem::get_stem_info (s).ideal_y_
852 + s->relative_coordinate (commony, Y_AXIS)
856 minimise_least_squares (&slope, &y, ideals);
860 set_minimum_dy (me, &dy);
863 pos = Interval (y, (y + dy));
867 "position" is relative to the staff.
869 scale_drul (&pos, 1 / Staff_symbol_referencer::staff_space (me));
871 me->set_property ("least-squares-dy", scm_from_double (ldy));
872 return ly_interval2scm (pos);
876 We can't combine with previous function, since check concave and
877 slope damping comes first.
879 TODO: we should use the concaveness to control the amount of damping
882 MAKE_SCHEME_CALLBACK (Beam, shift_region_to_valid, 2);
884 Beam::shift_region_to_valid (SCM grob, SCM posns)
886 Grob *me = unsmob_grob (grob);
891 extract_grob_set (me, "stems", stems);
892 Grob *commonx = common_refpoint_of_array (stems, me, X_AXIS);
893 Grob *commony = common_refpoint_of_array (stems, me, Y_AXIS);
895 Grob *fvs = first_visible_stem (me);
900 Real x0 = fvs->relative_coordinate (commonx, X_AXIS);
901 for (int i = 0; i < stems.size (); i++)
905 Real x = s->relative_coordinate (commonx, X_AXIS) - x0;
909 Grob *lvs = last_visible_stem (me);
913 Real dx = lvs->relative_coordinate (commonx, X_AXIS) - x0;
915 Drul_array<Real> pos = ly_scm2interval (posns);
918 scale_drul (&pos, Staff_symbol_referencer::staff_space (me));
920 Real dy = pos[RIGHT] - pos[LEFT];
922 Real slope = dx ? (dy / dx) : 0.0;
925 Shift the positions so that we have a chance of finding good
926 quants (i.e. no short stem failures.)
928 Interval feasible_left_point;
929 feasible_left_point.set_full ();
930 for (int i = 0; i < stems.size (); i++)
933 if (Stem::is_invisible (s))
936 Direction d = get_grob_direction (s);
939 = Stem::get_stem_info (s).shortest_y_
940 - slope * x_posns [i];
943 left_y is now relative to the stem S. We want relative to
944 ourselves, so translate:
947 += + s->relative_coordinate (commony, Y_AXIS)
948 - me->relative_coordinate (commony, Y_AXIS);
954 feasible_left_point.intersect (flp);
957 if (feasible_left_point.is_empty ())
958 warning (_ ("no viable initial configuration found: may not find good beam slope"));
959 else if (!feasible_left_point.contains (y))
961 const int REGION_SIZE = 2; // UGH UGH
962 if (isinf (feasible_left_point[DOWN]))
963 y = feasible_left_point[UP] - REGION_SIZE;
964 else if (isinf (feasible_left_point[UP]))
965 y = feasible_left_point[DOWN]+ REGION_SIZE;
967 y = feasible_left_point.center ();
970 pos = Drul_array<Real> (y, (y + dy));
971 scale_drul (&pos, 1 / Staff_symbol_referencer::staff_space (me));
973 return ly_interval2scm (pos);
976 /* This neat trick is by Werner Lemberg,
977 damped = tanh (slope)
978 corresponds with some tables in [Wanske] CHECKME */
979 MAKE_SCHEME_CALLBACK (Beam, slope_damping, 2);
981 Beam::slope_damping (SCM smob, SCM posns)
983 Grob *me = unsmob_grob (smob);
984 Drul_array<Real> pos = ly_scm2interval (posns);
986 if (visible_stem_count (me) <= 1)
987 return SCM_UNSPECIFIED;
990 SCM s = me->get_property ("damping");
991 Real damping = scm_to_double (s);
992 Real concaveness = robust_scm2double (me->get_property ("concaveness"), 0.0);
993 if (concaveness >= 10000)
995 pos[LEFT] = pos[RIGHT];
996 me->set_property ("least-squares-dy", scm_from_double (0));
1002 scale_drul (&pos, Staff_symbol_referencer::staff_space (me));
1004 Real dy = pos[RIGHT] - pos[LEFT];
1006 Grob *fvs = first_visible_stem (me);
1007 Grob *lvs = last_visible_stem (me);
1009 Grob *commonx = fvs->common_refpoint (lvs, X_AXIS);
1011 Real dx = last_visible_stem (me)->relative_coordinate (commonx, X_AXIS)
1012 - first_visible_stem (me)->relative_coordinate (commonx, X_AXIS);
1014 Real slope = dy && dx ? dy / dx : 0;
1016 slope = 0.6 * tanh (slope) / (damping + concaveness);
1018 Real damped_dy = slope * dx;
1020 set_minimum_dy (me, &damped_dy);
1022 pos[LEFT] += (dy - damped_dy) / 2;
1023 pos[RIGHT] -= (dy - damped_dy) / 2;
1025 scale_drul (&pos, 1 / Staff_symbol_referencer::staff_space (me));
1028 return ly_interval2scm (pos);
1032 Report slice containing the numbers that are both in (car BEAMING)
1036 where_are_the_whole_beams (SCM beaming)
1040 for (SCM s = scm_car (beaming); scm_is_pair (s); s = scm_cdr (s))
1042 if (scm_c_memq (scm_car (s), scm_cdr (beaming)) != SCM_BOOL_F)
1044 l.add_point (scm_to_int (scm_car (s)));
1050 /* Return the Y position of the stem-end, given the Y-left, Y-right
1051 in POS for stem S. This Y position is relative to S. */
1053 Beam::calc_stem_y (Grob *me, Grob *s, Grob ** common,
1055 Drul_array<Real> pos, bool french)
1057 Real beam_translation = get_beam_translation (me);
1059 Real r = s->relative_coordinate (common[X_AXIS], X_AXIS) - xl;
1060 Real dy = pos[RIGHT] - pos[LEFT];
1062 Real stem_y_beam0 = (dy && dx
1067 Direction my_dir = get_grob_direction (s);
1068 SCM beaming = s->get_property ("beaming");
1070 Real stem_y = stem_y_beam0;
1073 Slice bm = where_are_the_whole_beams (beaming);
1074 if (!bm.is_empty ())
1075 stem_y += beam_translation * bm[-my_dir];
1079 Slice bm = Stem::beam_multiplicity (s);
1080 if (!bm.is_empty ())
1081 stem_y += bm[my_dir] * beam_translation;
1084 Real id = me->relative_coordinate (common[Y_AXIS], Y_AXIS)
1085 - s->relative_coordinate (common[Y_AXIS], Y_AXIS);
1091 Hmm. At this time, beam position and slope are determined. Maybe,
1092 stem directions and length should set to relative to the chord's
1093 position of the beam. */
1094 MAKE_SCHEME_CALLBACK(Beam, set_stem_lengths, 2);
1096 Beam::set_stem_lengths (SCM smob, SCM posns)
1098 Grob *me = unsmob_grob (smob);
1100 extract_grob_set (me, "stems", stems);
1105 for (int a = 2; a--;)
1106 common[a] = common_refpoint_of_array (stems, me, Axis (a));
1108 Drul_array<Real> pos = ly_scm2realdrul (posns);
1109 Real staff_space = Staff_symbol_referencer::staff_space (me);
1110 scale_drul (&pos, staff_space);
1114 if (scm_is_number (me->get_property ("gap-count"))
1115 &&scm_to_int (me->get_property ("gap-count")))
1118 thick = get_thickness (me);
1121 // ugh -> use commonx
1122 Grob *fvs = first_visible_stem (me);
1123 Grob *lvs = last_visible_stem (me);
1125 Real xl = fvs ? fvs->relative_coordinate (common[X_AXIS], X_AXIS) : 0.0;
1126 Real xr = lvs ? lvs->relative_coordinate (common[X_AXIS], X_AXIS) : 0.0;
1128 for (int i = 0; i < stems.size (); i++)
1131 if (Stem::is_invisible (s))
1134 bool french = to_boolean (s->get_property ("french-beaming"));
1135 Real stem_y = calc_stem_y (me, s, common,
1137 pos, french && s != lvs && s!= fvs);
1140 Make the stems go up to the end of the beam. This doesn't matter
1141 for normal beams, but for tremolo beams it looks silly otherwise.
1144 stem_y += thick * 0.5 * get_grob_direction (s);
1146 Stem::set_stemend (s, 2 * stem_y / staff_space);
1153 Beam::set_beaming (Grob *me, Beaming_info_list const *beaming)
1155 extract_grob_set (me, "stems", stems);
1158 for (int i = 0; i < stems.size (); i++)
1161 Don't overwrite user settings.
1166 Grob *stem = stems[i];
1167 SCM beaming_prop = stem->get_property ("beaming");
1168 if (beaming_prop == SCM_EOL
1169 || index_get_cell (beaming_prop, d) == SCM_EOL)
1171 int b = beaming->infos_.elem (i).beams_i_drul_[d];
1173 && i < stems.size () -1
1174 && Stem::is_invisible (stem))
1175 b = min (b, beaming->infos_.elem (i).beams_i_drul_[-d]);
1177 Stem::set_beaming (stem, b, d);
1180 while (flip (&d) != LEFT);
1185 Beam::forced_stem_count (Grob *me)
1187 extract_grob_set (me, "stems", stems);
1190 for (int i = 0; i < stems.size (); i++)
1194 if (Stem::is_invisible (s))
1197 /* I can imagine counting those boundaries as a half forced stem,
1198 but let's count them full for now. */
1199 if (abs (Stem::chord_start_y (s)) > 0.1
1200 && (get_grob_direction (s) != Stem::get_default_dir (s)))
1207 Beam::visible_stem_count (Grob *me)
1209 extract_grob_set (me, "stems", stems);
1211 for (int i = stems.size (); i--;)
1213 if (!Stem::is_invisible (stems[i]))
1220 Beam::first_visible_stem (Grob *me)
1222 extract_grob_set (me, "stems", stems);
1224 for (int i = 0; i < stems.size (); i++)
1226 if (!Stem::is_invisible (stems[i]))
1233 Beam::last_visible_stem (Grob *me)
1235 extract_grob_set (me, "stems", stems);
1237 for (int i = stems.size (); i--;)
1239 if (!Stem::is_invisible (stems[i]))
1248 handle rest under beam (do_post: beams are calculated now)
1249 what about combination of collisions and rest under beam.
1253 rest -> stem -> beam -> interpolate_y_position ()
1255 MAKE_SCHEME_CALLBACK (Beam, rest_collision_callback, 2);
1257 Beam::rest_collision_callback (SCM element_smob, SCM axis)
1259 Grob *rest = unsmob_grob (element_smob);
1262 if (scm_is_number (rest->get_property ("staff-position")))
1263 return scm_from_int (0);
1265 assert (scm_to_int (axis) == Y_AXIS);
1267 Grob *st = unsmob_grob (rest->get_object ("stem"));
1270 return scm_from_double (0.0);
1271 Grob *beam = unsmob_grob (stem->get_object ("beam"));
1273 || !Beam::has_interface (beam)
1274 || !Beam::visible_stem_count (beam))
1275 return scm_from_double (0.0);
1277 Drul_array<Real> pos (0, 0);
1278 SCM s = beam->get_property ("positions");
1279 if (scm_is_pair (s) && scm_is_number (scm_car (s)))
1280 pos = ly_scm2interval (s);
1282 programming_error ("positions property should always be pair of numbers.");
1284 Real staff_space = Staff_symbol_referencer::staff_space (rest);
1286 scale_drul (&pos, staff_space);
1288 Real dy = pos[RIGHT] - pos[LEFT];
1290 // ugh -> use commonx
1291 Real x0 = first_visible_stem (beam)->relative_coordinate (0, X_AXIS);
1292 Real dx = last_visible_stem (beam)->relative_coordinate (0, X_AXIS) - x0;
1293 Real slope = dy && dx ? dy / dx : 0;
1295 Direction d = get_grob_direction (stem);
1296 Real stem_y = pos[LEFT] + (stem->relative_coordinate (0, X_AXIS) - x0) * slope;
1298 Real beam_translation = get_beam_translation (beam);
1299 Real beam_thickness = Beam::get_thickness (beam);
1302 TODO: this is not strictly correct for 16th knee beams.
1305 = Stem::beam_multiplicity (stem).length () + 1;
1307 Real height_of_my_beams = beam_thickness / 2
1308 + (beam_count - 1) * beam_translation;
1309 Real beam_y = stem_y - d * height_of_my_beams;
1311 Grob *common_y = rest->common_refpoint (beam, Y_AXIS);
1313 Real rest_dim = rest->extent (common_y, Y_AXIS)[d];
1314 Real minimum_distance
1315 = + staff_space * (robust_scm2double (stem->get_property ("stemlet-length"), 0.0)
1316 + robust_scm2double (rest->get_property ("minimum-distance"), 0.0));
1318 Real shift = d * min (((beam_y - d * minimum_distance) - rest_dim) * d, 0.0);
1320 shift /= staff_space;
1321 Real rad = Staff_symbol_referencer::line_count (rest) * staff_space / 2;
1323 /* Always move discretely by half spaces */
1324 shift = ceil (fabs (shift * 2.0)) / 2.0 * sign (shift);
1326 /* Inside staff, move by whole spaces*/
1327 if ((rest->extent (common_y, Y_AXIS)[d] + staff_space * shift) * d
1329 || (rest->extent (common_y, Y_AXIS)[-d] + staff_space * shift) * -d
1331 shift = ceil (fabs (shift)) * sign (shift);
1333 return scm_from_double (staff_space * shift);
1337 Beam::is_knee (Grob *me)
1339 SCM k = me->get_property ("knee");
1340 if (scm_is_bool (k))
1341 return ly_scm2bool (k);
1345 extract_grob_set (me, "stems", stems);
1346 for (int i = stems.size (); i--;)
1348 Direction dir = get_grob_direction (stems[i]);
1357 me->set_property ("knee", ly_bool2scm (knee));
1363 Beam::get_direction_beam_count (Grob *me, Direction d)
1365 extract_grob_set (me, "stems", stems);
1368 for (int i = stems.size (); i--;)
1371 Should we take invisible stems into account?
1373 if (get_grob_direction (stems[i]) == d)
1374 bc = max (bc, (Stem::beam_multiplicity (stems[i]).length () + 1));
1380 ADD_INTERFACE (Beam,
1384 "The @code{thickness} property is the weight of beams, "
1385 "measured in staffspace. The @code{direction} property is not user-serviceable. Use "
1386 "the @code{direction} property of @code{Stem} instead. "
1392 "beamed-stem-shorten "
1405 "neutral-direction "
1406 "position-callbacks "