2 beam.cc -- implement Beam
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
7 Jan Nieuwenhuizen <janneke@gnu.org>
13 * shorter! (now +- 1000 lines)
15 * move paper vars to scm
17 remove *-hs variables, and do all y-position stuff in staff-space.
21 #include <math.h> // tanh.
23 #include "molecule.hh"
24 #include "directional-element-interface.hh"
28 #include "least-squares.hh"
30 #include "paper-def.hh"
32 #include "group-interface.hh"
33 #include "staff-symbol-referencer.hh"
39 Beam::add_stem (Grob*me, Grob*s)
41 Pointer_group_interface:: add_element(me, "stems", s);
43 s->add_dependency (me);
45 assert (!Stem::beam_l (s));
46 s->set_grob_property ("beam", me->self_scm ());
48 add_bound_item (dynamic_cast<Spanner*> (me), dynamic_cast<Item*> (s));
52 Beam::get_multiplicity (Grob*me)
55 for (SCM s = me->get_grob_property ("stems"); gh_pair_p (s); s = gh_cdr (s))
57 Grob * sc = unsmob_grob (gh_car (s));
59 if (Stem::has_interface (sc))
60 m = m >? Stem::beam_count (sc,LEFT) >? Stem::beam_count (sc,RIGHT);
66 After pre-processing all directions should be set.
67 Several post-processing routines (stem, slur, script) need stem/beam
69 Currenly, this means that beam has set all stem's directions.
70 [Alternatively, stems could set its own directions, according to
71 their beam, during 'final-pre-processing'.]
73 MAKE_SCHEME_CALLBACK(Beam,before_line_breaking,1);
75 Beam::before_line_breaking (SCM smob)
77 Grob * me = unsmob_grob (smob);
81 Why what? Why the warning (beams with less than 2 stems are
82 degenerate beams, should never happen), or why would this ever
83 happen (don't know). */
84 if (visible_stem_count (me) < 2)
86 warning (_ ("beam has less than two stems"));
88 if (visible_stem_count (me) >= 1)
90 if (!Directional_element_interface::get (me))
91 Directional_element_interface::set (me, get_default_dir (me));
93 consider_auto_knees (me);
94 set_stem_directions (me);
95 set_stem_shorten (me);
101 Beam::get_default_dir (Grob*me)
103 Drul_array<int> total;
104 total[UP] = total[DOWN] = 0;
105 Drul_array<int> count;
106 count[UP] = count[DOWN] = 0;
109 Link_array<Item> stems=
110 Pointer_group_interface__extract_elements (me, (Item*)0, "stems");
112 for (int i=0; i <stems.size (); i++)
115 Direction sd = Directional_element_interface::get (s);
116 int current = sd ? (1 + d * sd)/2
117 : Stem::get_center_distance (s, (Direction)-d);
125 } while (flip(&d) != DOWN);
127 SCM func = me->get_grob_property ("dir-function");
128 SCM s = gh_call2 (func,
129 gh_cons (gh_int2scm (count[UP]),
130 gh_int2scm (count[DOWN])),
131 gh_cons (gh_int2scm (total[UP]),
132 gh_int2scm (total[DOWN])));
134 if (gh_number_p (s) && gh_scm2int (s))
138 If dir is not determined: get default
140 return to_dir (me->get_grob_property ("default-neutral-direction"));
145 Set all stems with non-forced direction to beam direction.
146 Urg: non-forced should become `without/with unforced' direction,
147 once stem gets cleaned-up.
150 Beam::set_stem_directions (Grob*me)
152 Link_array<Item> stems
153 =Pointer_group_interface__extract_elements (me, (Item*) 0, "stems");
154 Direction d = Directional_element_interface::get (me);
156 for (int i=0; i <stems.size (); i++)
159 SCM force = s->remove_grob_property ("dir-forced");
160 if (!gh_boolean_p (force) || !gh_scm2bool (force))
161 Directional_element_interface ::set (s,d);
166 Simplistic auto-knees; only consider vertical gap between two
169 `Forced' stem directions are ignored. If you don't want auto-knees,
170 don't set, or unset auto-knee-gap.
173 Beam::consider_auto_knees (Grob *me)
175 SCM scm = me->get_grob_property ("auto-knee-gap");
177 if (gh_number_p (scm))
181 Real staff_space = Staff_symbol_referencer::staff_space (me);
182 Real gap = gh_scm2double (scm) / staff_space;
184 Direction d = Directional_element_interface::get (me);
185 Link_array<Item> stems=
186 Pointer_group_interface__extract_elements (me, (Item*)0, "stems");
188 Grob *common = me->common_refpoint (stems[0], Y_AXIS);
189 for (int i=1; i < stems.size (); i++)
190 if (!Stem::invisible_b (stems[i]))
191 common = common->common_refpoint (stems[i], Y_AXIS);
194 for (int i=1; i < stems.size (); i++)
196 if (!Stem::invisible_b (stems[i-1]))
198 if (Stem::invisible_b (stems[l]))
200 if (Stem::invisible_b (stems[i]))
203 Real left = Stem::extremal_heads (stems[l])[d]
204 ->relative_coordinate (common, Y_AXIS);
205 Real right = Stem::extremal_heads (stems[i])[d]
206 ->relative_coordinate (common, Y_AXIS);
208 Real dy = right - left;
212 knee_y = (right + left) / 2;
220 for (int i=0; i < stems.size (); i++)
222 if (Stem::invisible_b (stems[i]))
225 Real y = Stem::extremal_heads (stems[i])[d]
226 ->relative_coordinate (common, Y_AXIS);
228 Directional_element_interface::set (s, y < knee_y ? UP : DOWN);
229 s->set_grob_property ("dir-forced", SCM_BOOL_T);
236 Set stem's shorten property if unset.
238 take some y-position (chord/beam/nearest?) into account
239 scmify forced-fraction
242 Beam::set_stem_shorten (Grob*m)
244 Spanner*me = dynamic_cast<Spanner*> (m);
246 Real forced_fraction = forced_stem_count (me) / visible_stem_count (me);
247 if (forced_fraction < 0.5)
250 int multiplicity = get_multiplicity (me);
252 SCM shorten = me->get_grob_property ("beamed-stem-shorten");
253 if (shorten == SCM_EOL)
256 int sz = scm_ilength (shorten);
258 Real staff_space = Staff_symbol_referencer::staff_space (me);
259 SCM shorten_elt = scm_list_ref (shorten, gh_int2scm (multiplicity <? (sz - 1)));
260 Real shorten_f = gh_scm2double (shorten_elt) * staff_space;
262 /* cute, but who invented me -- how to customise ? */
263 if (forced_fraction < 1)
266 Link_array<Item> stems=
267 Pointer_group_interface__extract_elements (me, (Item*)0, "stems");
269 for (int i=0; i < stems.size (); i++)
272 if (Stem::invisible_b (s))
274 if (gh_number_p (s->get_grob_property ("shorten")))
275 s->set_grob_property ("shorten", gh_double2scm (shorten_f));
280 Set elt properties height and y-position if not set.
281 Adjust stem lengths to reach beam.
283 MAKE_SCHEME_CALLBACK(Beam,after_line_breaking,1);
285 Beam::after_line_breaking (SCM smob)
287 Grob * me = unsmob_grob (smob);
289 /* first, calculate y, dy */
291 calc_default_position_and_height (me, &y, &dy);
292 if (visible_stem_count (me))
294 if (suspect_slope_b (me, y, dy))
297 Real damped_dy = calc_slope_damping_f (me, dy);
298 Real quantised_dy = quantise_dy_f (me, damped_dy);
300 y += (dy - quantised_dy) / 2;
304 until here, we used only stem_info, which acts as if dir=up
306 y *= Directional_element_interface::get (me);
307 dy *= Directional_element_interface::get (me);
310 Real half_space = Staff_symbol_referencer::staff_space (me) / 2;
312 /* weird: why do we do calc_position_and_height () ? regardless of
315 If the user sets height, we still need to calculate the y-position.
316 If the user sets height-hs, we still need to calculate and
319 We use least squares to calculate y-position and height, so we
320 inherently always calculate both. */
322 /* check for user-override of dy */
323 SCM s = me->remove_grob_property ("height-hs");
326 dy = gh_scm2double (s) * half_space;
328 me->set_grob_property ("height", gh_double2scm (dy));
330 /* check for user-override of y */
331 s = me->remove_grob_property ("y-position-hs");
334 y = gh_scm2double (s) * half_space;
338 /* we can modify y, so we should quantise y */
339 Real y_shift = check_stem_length_f (me, y, dy);
341 y = quantise_y_f (me,y, dy, 0);
342 set_stem_length (me, y, dy);
343 y_shift = check_stem_length_f (me, y, dy);
345 if (y_shift > half_space / 4)
350 for significantly lengthened or shortened stems,
351 request quanting the other way.
354 if (abs (y_shift) > half_space / 2)
355 quant_dir = sign (y_shift) * Directional_element_interface::get (me);
356 y = quantise_y_f (me, y, dy, quant_dir);
359 // UGH. Y is not in staff position unit?
360 // Ik dacht datwe daar juist van weg wilden?
361 set_stem_length (me, y, dy);
362 me->set_grob_property ("y-position", gh_double2scm (y));
364 return SCM_UNSPECIFIED;
368 See Documentation/tex/fonts.doc
371 Beam::calc_default_position_and_height (Grob*me,Real* y, Real* dy)
375 if (visible_stem_count (me) <= 1)
378 Real first_ideal = Stem::calc_stem_info (first_visible_stem (me)).idealy_f_;
379 if (first_ideal == Stem::calc_stem_info (last_visible_stem (me)).idealy_f_)
386 Array<Offset> ideals;
388 // ugh -> use commonx
389 Real x0 = first_visible_stem (me)->relative_coordinate (0, X_AXIS);
390 Link_array<Item> stems=
391 Pointer_group_interface__extract_elements (me, (Item*)0, "stems");
393 for (int i=0; i < stems.size (); i++)
396 if (Stem::invisible_b (s))
398 ideals.push (Offset (s->relative_coordinate (0, X_AXIS) - x0,
399 Stem::calc_stem_info (s).idealy_f_));
402 minimise_least_squares (&dydx, y, ideals); // duh, takes references
404 Real dx = last_visible_stem (me)->relative_coordinate (0, X_AXIS) - x0;
409 Beam::suspect_slope_b (Grob*me, Real y, Real dy)
411 /* first, calculate y, dy */
413 steep slope running against lengthened stem is suspect
415 Real first_ideal = Stem::calc_stem_info (first_visible_stem (me)).idealy_f_;
416 Real last_ideal = Stem::calc_stem_info (last_visible_stem (me)).idealy_f_;
417 Real lengthened = gh_scm2double (me->get_grob_property ("outer-stem-length-limit"));
418 Real steep = gh_scm2double (me->get_grob_property ("slope-limit"));
420 // ugh -> use commonx
421 Real dx = last_visible_stem (me)->relative_coordinate (0, X_AXIS) - first_visible_stem (me)->relative_coordinate (0, X_AXIS);
422 Real dydx = dy && dx ? dy/dx : 0;
424 if (((y - first_ideal > lengthened) && (dydx > steep))
425 || ((y + dy - last_ideal > lengthened) && (dydx < -steep)))
433 This neat trick is by Werner Lemberg,
434 damped = tanh (slope)
435 corresponds with some tables in [Wanske]
438 Beam::calc_slope_damping_f (Grob*me,Real dy)
440 SCM damp = me->get_grob_property ("damping");
441 int damping = gh_scm2int (damp);
445 // ugh -> use commonx
446 Real dx = last_visible_stem (me)->relative_coordinate (0, X_AXIS)
447 - first_visible_stem (me)->relative_coordinate (0, X_AXIS);
448 Real dydx = dy && dx ? dy/dx : 0;
449 dydx = 0.6 * tanh (dydx) / damping;
456 Beam::calc_stem_y_f (Grob*me,Item* s, Real y, Real dy)
458 int beam_multiplicity = get_multiplicity (me);
459 int stem_multiplicity = (Stem::flag_i (s) - 2) >? 0;
461 SCM space_proc = me->get_grob_property ("space-function");
462 SCM space = gh_call1 (space_proc, gh_int2scm (beam_multiplicity));
464 Real thick = gh_scm2double (me->get_grob_property ("thickness")) ;
465 Real interbeam_f = gh_scm2double (space) ;
467 // ugh -> use commonx
468 Real x0 = first_visible_stem (me)->relative_coordinate (0, X_AXIS);
469 Real dx = last_visible_stem (me)->relative_coordinate (0, X_AXIS) - x0;
470 Real stem_y = (dy && dx ? (s->relative_coordinate (0, X_AXIS) - x0) / dx * dy : 0) + y;
473 Direction dir = Directional_element_interface::get (me);
474 Direction sdir = Directional_element_interface::get (s);
480 * (thick / 2 + (beam_multiplicity - 1) * interbeam_f);
484 // huh, why not for first visible?
485 if (Staff_symbol_referencer::staff_symbol_l (s)
486 != Staff_symbol_referencer::staff_symbol_l (last_visible_stem (me)))
487 stem_y += Directional_element_interface::get (me)
488 * (beam_multiplicity - stem_multiplicity) * interbeam_f;
495 Beam::check_stem_length_f (Grob*me,Real y, Real dy)
499 Direction dir = Directional_element_interface::get (me);
501 Link_array<Item> stems=
502 Pointer_group_interface__extract_elements (me, (Item*)0, "stems");
504 for (int i=0; i < stems.size(); i++)
507 if (Stem::invisible_b (s))
510 Real stem_y = calc_stem_y_f (me, s, y, dy);
513 Stem_info info = Stem::calc_stem_info (s);
515 // if (0 > info.maxy_f_ - stem_y)
516 shorten = shorten <? info.maxy_f_ - stem_y;
517 // if (0 < info.miny_f_ - stem_y)
518 lengthen = lengthen >? info.miny_f_ - stem_y;
521 if (lengthen && shorten)
522 warning (_ ("weird beam vertical offset"));
524 /* when all stems are too short, normal stems win */
525 return dir * ((shorten) ? shorten : lengthen);
529 Hmm. At this time, beam position and slope are determined. Maybe,
530 stem directions and length should set to relative to the chord's
531 position of the beam. */
533 Beam::set_stem_length (Grob*me,Real y, Real dy)
535 Real half_space = Staff_symbol_referencer::staff_space (me)/2;
536 Link_array<Item> stems=
537 Pointer_group_interface__extract_elements (me, (Item*)0, "stems");
539 if (stems.size () < 1)
542 Grob *common = me->common_refpoint (stems[0], Y_AXIS);
543 for (int i=1; i < stems.size (); i++)
544 if (!Stem::invisible_b (stems[i]))
545 common = common->common_refpoint (stems[i], Y_AXIS);
547 for (int i=0; i < stems.size (); i++)
550 if (Stem::invisible_b (s))
553 Real stem_y = calc_stem_y_f (me, s, y, dy);
555 /* caution: stem measures in staff-positions */
556 Real id = me->relative_coordinate (common, Y_AXIS)
557 - stems[i]->relative_coordinate (common, Y_AXIS);
558 Stem::set_stemend (s, (stem_y + id) / half_space);
563 [Ross] (simplification of)
564 Set dy complying with:
566 - thick / 2 + staffline_f / 2
567 - thick + staffline_f
571 Beam::quantise_dy_f (Grob*me,Real dy)
575 SCM proc = me->get_grob_property ("height-quants");
576 SCM quants = gh_call2 (proc, me->self_scm (),
577 gh_double2scm (me->paper_l ()->get_var ("stafflinethickness")
581 for (SCM s = quants; gh_pair_p (s); s = gh_cdr (s))
582 a.push (gh_scm2double (gh_car (s)));
587 Real staff_space = Staff_symbol_referencer::staff_space (me);
589 Interval iv = quantise_iv (a, abs (dy)/staff_space) * staff_space;
590 Real q = (abs (dy) - iv[SMALLER] <= iv[BIGGER] - abs (dy))
594 return q * sign (dy);
598 Prevent interference from stafflines and beams.
599 See Documentation/tex/fonts.doc
601 We only need to quantise the (left) y-position of the beam,
602 since dy is quantised too.
603 if extend_b then stems must *not* get shorter
606 Beam::quantise_y_f (Grob*me,Real y, Real dy, int quant_dir)
608 int multiplicity = get_multiplicity (me);
610 Real staff_space = Staff_symbol_referencer::staff_space (me);
611 Real thick = me->paper_l ()->get_var ("stafflinethickness");
614 SCM proc = me->get_grob_property ("vertical-position-quant-function");
615 SCM quants = scm_apply (proc,
617 gh_list (gh_int2scm (multiplicity),
618 gh_double2scm (dy/staff_space),
619 gh_double2scm (thick/staff_space),
620 SCM_EOL, SCM_UNDEFINED));
624 for (; gh_pair_p (quants); quants = gh_cdr (quants))
625 a.push (gh_scm2double (gh_car (quants)));
630 Real up_y = Directional_element_interface::get (me) * y;
631 Interval iv = quantise_iv (a, up_y/staff_space) * staff_space;
633 Real q = up_y - iv[SMALLER] <= iv[BIGGER] - up_y
634 ? iv[SMALLER] : iv[BIGGER];
636 q = iv[(Direction)quant_dir];
638 return q * Directional_element_interface::get (me);
642 Beam::set_beaming (Grob*me,Beaming_info_list *beaming)
644 Link_array<Grob> stems=
645 Pointer_group_interface__extract_elements (me, (Grob*)0, "stems");
648 for (int i=0; i < stems.size(); i++)
652 /* Don't overwrite user override (?) */
653 if (Stem::beam_count (stems[i], d) == 0
654 /* Don't set beaming for outside of outer stems */
655 && ! (d == LEFT && i == 0)
656 && ! (d == RIGHT && i == stems.size () -1))
658 int b = beaming->infos_.elem (i).beams_i_drul_[d];
659 Stem::set_beaming (stems[i], b, d);
662 while (flip (&d) != LEFT);
669 beams to go with one stem.
674 Beam::stem_beams (Grob*me,Item *here, Item *next, Item *prev)
676 // ugh -> use commonx
677 if ((next && !(next->relative_coordinate (0, X_AXIS) > here->relative_coordinate (0, X_AXIS))) ||
678 (prev && !(prev->relative_coordinate (0, X_AXIS) < here->relative_coordinate (0, X_AXIS))))
679 programming_error ("Beams are not left-to-right");
681 Real staffline_f = me->paper_l ()->get_var ("stafflinethickness");
682 int multiplicity = get_multiplicity (me);
684 SCM space_proc = me->get_grob_property ("space-function");
685 SCM space = gh_call1 (space_proc, gh_int2scm (multiplicity));
687 Real thick = gh_scm2double (me->get_grob_property ("thickness")) ;
688 Real interbeam_f = gh_scm2double (space) ;
690 Real bdy = interbeam_f;
691 Real stemdx = staffline_f;
693 // ugh -> use commonx
694 Real dx = visible_stem_count (me) ?
695 last_visible_stem (me)->relative_coordinate (0, X_AXIS) - first_visible_stem (me)->relative_coordinate (0, X_AXIS)
697 Real dy = gh_scm2double (me->get_grob_property ("height"));
698 Real dydx = dy && dx ? dy/dx : 0;
704 if (!Stem::first_head (here))
707 int t = Stem::type_i (here);
709 SCM proc = me->get_grob_property ("flag-width-function");
710 SCM result = gh_call1 (proc, gh_int2scm (t));
711 nw_f = gh_scm2double (result);
715 Direction dir = Directional_element_interface::get (me);
717 /* half beams extending to the left. */
720 int lhalfs= lhalfs = Stem::beam_count (here,LEFT) - Stem::beam_count (prev,RIGHT);
721 int lwholebeams= Stem::beam_count (here,LEFT) <? Stem::beam_count (prev,RIGHT) ;
723 Half beam should be one note-width,
724 but let's make sure two half-beams never touch
726 Real w = here->relative_coordinate (0, X_AXIS) - prev->relative_coordinate (0, X_AXIS);
729 if (lhalfs) // generates warnings if not
730 a = Lookup::beam (dydx, w, thick);
731 a.translate (Offset (-w, -w * dydx));
732 for (int j = 0; j < lhalfs; j++)
735 b.translate_axis (-dir * bdy * (lwholebeams+j), Y_AXIS);
736 leftbeams.add_molecule (b);
742 int rhalfs = Stem::beam_count (here,RIGHT) - Stem::beam_count (next,LEFT);
743 int rwholebeams= Stem::beam_count (here,RIGHT) <? Stem::beam_count (next,LEFT) ;
745 Real w = next->relative_coordinate (0, X_AXIS) - here->relative_coordinate (0, X_AXIS);
746 Molecule a = Lookup::beam (dydx, w + stemdx, thick);
747 a.translate_axis( - stemdx/2, X_AXIS);
751 SCM gap = me->get_grob_property ("gap");
752 if (gh_number_p (gap))
754 int gap_i = gh_scm2int ( (gap));
755 int nogap = rwholebeams - gap_i;
757 for (; j < nogap; j++)
760 b.translate_axis (-dir * bdy * j, Y_AXIS);
761 rightbeams.add_molecule (b);
763 // TODO: notehead widths differ for different types
766 a = Lookup::beam (dydx, w + stemdx, thick);
769 for (; j < rwholebeams; j++)
772 b.translate (Offset (Stem::invisible_b (here) ? 0 : gap_f, -dir * bdy * j));
773 rightbeams.add_molecule (b);
778 a = Lookup::beam (dydx, w, thick);
780 for (; j < rwholebeams + rhalfs; j++)
783 b.translate_axis (- dir * bdy * j, Y_AXIS);
784 rightbeams.add_molecule (b);
788 leftbeams.add_molecule (rightbeams);
791 Does beam quanting think of the asymetry of beams?
792 Refpoint is on bottom of symbol. (FIXTHAT) --hwn.
798 TODO: it would be nice to introduce y-position via callbacks.
801 MAKE_SCHEME_CALLBACK(Beam,brew_molecule,1);
803 Beam::brew_molecule (SCM smob)
805 Grob * me =unsmob_grob (smob);
808 if (!gh_pair_p (me->get_grob_property ("stems")))
811 Link_array<Item>stems =
812 Pointer_group_interface__extract_elements (me, (Item*) 0, "stems");
813 if (visible_stem_count (me))
815 // ugh -> use commonx
816 x0 = first_visible_stem (me)->relative_coordinate (0, X_AXIS);
817 dx = last_visible_stem (me)->relative_coordinate (0, X_AXIS) - x0;
821 x0 = stems[0]->relative_coordinate (0, X_AXIS);
822 dx = stems.top()->relative_coordinate (0, X_AXIS) - x0;
826 Real dy = gh_scm2double (me->get_grob_property ("height"));
827 Real dydx = dy && dx ? dy/dx : 0;
828 Real y = gh_scm2double (me->get_grob_property ("y-position"));
831 for (int j=0; j <stems.size (); j++)
834 Item * prev = (j > 0)? stems[j-1] : 0;
835 Item * next = (j < stems.size()-1) ? stems[j+1] :0;
837 Molecule sb = stem_beams (me, i, next, prev);
838 Real x = i->relative_coordinate (0, X_AXIS)-x0;
839 sb.translate (Offset (x, x * dydx + y));
840 mol.add_molecule (sb);
842 mol.translate_axis (x0
843 - dynamic_cast<Spanner*> (me)->get_bound (LEFT)->relative_coordinate (0, X_AXIS), X_AXIS);
845 return mol.smobbed_copy ();
849 Beam::forced_stem_count (Grob*me)
851 Link_array<Item>stems =
852 Pointer_group_interface__extract_elements ( me, (Item*) 0, "stems");
854 for (int i=0; i < stems.size (); i++)
858 if (Stem::invisible_b (s))
861 if (((int)Stem::chord_start_f (s))
862 && (Stem::get_direction (s ) != Stem::get_default_dir (s )))
872 use filter and standard list functions.
875 Beam::visible_stem_count (Grob*me)
877 Link_array<Item>stems =
878 Pointer_group_interface__extract_elements (me, (Item*) 0, "stems");
880 for (int i = stems.size (); i--;)
882 if (!Stem::invisible_b (stems[i]))
889 Beam::first_visible_stem(Grob*me)
891 Link_array<Item>stems =
892 Pointer_group_interface__extract_elements ( me, (Item*) 0, "stems");
894 for (int i = 0; i < stems.size (); i++)
896 if (!Stem::invisible_b (stems[i]))
903 Beam::last_visible_stem(Grob*me)
905 Link_array<Item>stems =
906 Pointer_group_interface__extract_elements ( me, (Item*) 0, "stems");
907 for (int i = stems.size (); i--;)
909 if (!Stem::invisible_b (stems[i]))
918 handle rest under beam (do_post: beams are calculated now)
919 what about combination of collisions and rest under beam.
923 rest -> stem -> beam -> interpolate_y_position ()
925 MAKE_SCHEME_CALLBACK(Beam,rest_collision_callback,2);
927 Beam::rest_collision_callback (SCM element_smob, SCM axis)
929 Grob *rest = unsmob_grob (element_smob);
930 Axis a = (Axis) gh_scm2int (axis);
932 assert (a == Y_AXIS);
934 Grob * st = unsmob_grob (rest->get_grob_property ("stem"));
937 return gh_double2scm (0.0);
938 Grob * beam = unsmob_grob (stem->get_grob_property ("beam"));
939 if (!beam || !Beam::has_interface (beam) || !Beam::visible_stem_count (beam))
940 return gh_double2scm (0.0);
942 // make callback for rest from this.
947 // todo: make sure this calced already.
948 SCM s = beam->get_grob_property ("height");
950 beam_dy = gh_scm2double (s);
952 s = beam->get_grob_property ("y-position");
954 beam_y = gh_scm2double (s);
956 // ugh -> use commonx
957 Real x0 = first_visible_stem(beam)->relative_coordinate (0, X_AXIS);
958 Real dx = last_visible_stem(beam)->relative_coordinate (0, X_AXIS) - x0;
959 Real dydx = beam_dy && dx ? beam_dy/dx : 0;
961 Direction d = Stem::get_direction (stem);
962 Real beamy = (stem->relative_coordinate (0, X_AXIS) - x0) * dydx + beam_y;
964 Real staff_space = Staff_symbol_referencer::staff_space (rest);
967 Real rest_dim = rest->extent (rest, Y_AXIS)[d]*2.0 / staff_space ; // refp??
970 = gh_scm2double (rest->get_grob_property ("minimum-beam-collision-distance"));
972 minimum_dist + -d * (beamy - rest_dim) >? 0;
974 int stafflines = Staff_symbol_referencer::line_count (rest);
976 // move discretely by half spaces.
977 int discrete_dist = int (ceil (dist));
979 // move by whole spaces inside the staff.
980 if (discrete_dist < stafflines+1)
981 discrete_dist = int (ceil (discrete_dist / 2.0)* 2.0);
983 return gh_double2scm (-d * discrete_dist);
988 Beam::has_interface (Grob*me)
990 return me->has_interface (ly_symbol2scm ("beam-interface"));
994 Beam::set_interface (Grob*me)
997 why the init? No way to tell difference between default and user
999 me->set_grob_property ("height", gh_int2scm (0)); // ugh.
1000 me->set_grob_property ("y-position" ,gh_int2scm (0));
1001 me->set_interface (ly_symbol2scm("beam-interface"));