2 This file is part of LilyPond, the GNU music typesetter.
4 Copyright (C) 2009--2010 Joe Neeman <joeneeman@gmail.com>
6 LilyPond is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 LilyPond is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
20 #include "page-layout-problem.hh"
22 #include "align-interface.hh"
23 #include "axis-group-interface.hh"
24 #include "hara-kiri-group-spanner.hh"
25 #include "international.hh"
27 #include "output-def.hh"
28 #include "paper-book.hh"
29 #include "paper-column.hh"
30 #include "paper-score.hh"
31 #include "pointer-group-interface.hh"
33 #include "skyline-pair.hh"
36 Page_layout_problem::Page_layout_problem (Paper_book *pb, SCM page_scm, SCM systems)
37 : bottom_skyline_ (DOWN)
39 Prob *page = unsmob_prob (page_scm);
48 Stencil *head = unsmob_stencil (page->get_property ("head-stencil"));
49 Stencil *foot = unsmob_stencil (page->get_property ("foot-stencil"));
51 header_height_ = head ? head->extent (Y_AXIS).length () : 0;
52 footer_height_ = foot ? foot->extent (Y_AXIS).length () : 0;
53 page_height_ = robust_scm2double (page->get_property ("paper-height"), 100);
56 // Initially, bottom_skyline_ represents the top of the page. Make
57 // it solid, so that the top of the first system will be forced
58 // below the top of the printable area.
59 bottom_skyline_.set_minimum_height (-header_height_);
61 SCM system_system_spacing = SCM_EOL;
62 SCM score_system_spacing = SCM_EOL;
63 SCM markup_system_spacing = SCM_EOL;
64 SCM score_markup_spacing = SCM_EOL;
65 SCM markup_markup_spacing = SCM_EOL;
67 // top_system_spacing controls the spring from the top of the printable
68 // area to the first staff. It allows the user to control the offset of
69 // the first staff (as opposed to the top of the first system) from the
70 // top of the page. Similarly for last_bottom_spacing.
71 SCM top_system_spacing = SCM_EOL;
72 SCM last_bottom_spacing = SCM_EOL;
75 Output_def *paper = pb->paper_;
76 system_system_spacing = paper->c_variable ("system-system-spacing");
77 score_system_spacing = paper->c_variable ("score-system-spacing");
78 markup_system_spacing = paper->c_variable ("markup-system-spacing");
79 score_markup_spacing = paper->c_variable ("score-markup-spacing");
80 markup_markup_spacing = paper->c_variable ("markup-markup-spacing");
81 last_bottom_spacing = paper->c_variable ("last-bottom-spacing");
82 top_system_spacing = paper->c_variable ("top-system-spacing");
83 if (scm_is_pair (systems) && unsmob_prob (scm_car (systems)))
84 top_system_spacing = paper->c_variable ("top-markup-spacing");
86 // Note: the page height here does _not_ reserve space for headers and
87 // footers. This is because we want to anchor the top-system-spacing
88 // spring at the _top_ of the header.
89 page_height_ -= robust_scm2double (paper->c_variable ("top-margin"), 0)
90 + robust_scm2double (paper->c_variable ("bottom-margin"), 0);
92 read_spacing_spec (top_system_spacing, &header_padding_, ly_symbol2scm ("padding"));
93 read_spacing_spec (last_bottom_spacing, &footer_padding_, ly_symbol2scm ("padding"));
95 bool last_system_was_title = false;
98 for (SCM s = systems; scm_is_pair (s); s = scm_cdr (s))
100 bool first = (s == systems);
102 if (Grob *g = unsmob_grob (scm_car (s)))
104 System *sys = dynamic_cast<System*> (g);
107 programming_error ("got a grob for vertical spacing that wasn't a System");
111 SCM spec = system_system_spacing;
113 spec = top_system_spacing;
114 else if (last_system_was_title)
115 spec = markup_system_spacing;
116 else if (0 == Paper_column::get_rank (sys->get_bound (LEFT)))
117 spec = score_system_spacing;
119 Spring spring (0, 0);
121 Real indent = line_dimensions_int (sys->paper_score ()->layout (), sys->get_rank ())[LEFT];
122 alter_spring_from_spacing_spec (spec, &spring);
123 read_spacing_spec (spec, &padding, ly_symbol2scm ("padding"));
125 append_system (sys, spring, indent, padding);
126 last_system_was_title = false;
128 else if (Prob *p = unsmob_prob (scm_car (s)))
130 SCM spec = first ? top_system_spacing
131 : (last_system_was_title ? markup_markup_spacing : score_markup_spacing);
132 Spring spring (0, 0);
134 alter_spring_from_spacing_spec (spec, &spring);
135 read_spacing_spec (spec, &padding, ly_symbol2scm ("padding"));
137 append_prob (p, spring, padding);
138 last_system_was_title = true;
141 programming_error ("got a system that was neither a Grob nor a Prob");
144 Spring last_spring (0, 0);
145 Real last_padding = 0;
146 alter_spring_from_spacing_spec (last_bottom_spacing, &last_spring);
147 read_spacing_spec (last_bottom_spacing, &last_padding, ly_symbol2scm ("padding"));
148 last_spring.ensure_min_distance (last_padding - bottom_skyline_.max_height () + footer_height_);
149 springs_.push_back (last_spring);
151 if (elements_.size ())
153 Real bottom_padding = 0;
155 // TODO: junk bottom-space now that we have last-bottom-spacing?
156 // bottom-space has the flexibility that one can do it per-system.
157 // NOTE: bottom-space is misnamed since it is not stretchable space.
158 if (Prob *p = elements_.back ().prob)
159 bottom_padding = robust_scm2double (p->get_property ("bottom-space"), 0);
160 else if (elements_.back ().staves.size ())
162 SCM details = get_details (elements_.back ());
163 bottom_padding = robust_scm2double (ly_assoc_get (ly_symbol2scm ("bottom-space"),
168 page_height_ -= bottom_padding;
173 Page_layout_problem::set_header_height (Real height)
175 header_height_ = height;
179 Page_layout_problem::set_footer_height (Real height)
181 footer_height_ = height;
185 Page_layout_problem::append_system (System *sys, Spring const& spring, Real indent, Real padding)
187 Grob *align = sys->get_vertical_alignment ();
191 align->set_property ("positioning-done", SCM_BOOL_T);
193 extract_grob_set (align, "elements", all_elts);
194 vector<Grob*> elts = filter_dead_elements (all_elts);
195 vector<Real> minimum_offsets = Align_interface::get_minimum_translations_without_min_dist (align, elts, Y_AXIS);
197 Skyline up_skyline (UP);
198 Skyline down_skyline (DOWN);
199 build_system_skyline (elts, minimum_offsets, &up_skyline, &down_skyline);
200 up_skyline.shift (indent);
201 down_skyline.shift (indent);
203 Real minimum_distance = up_skyline.distance (bottom_skyline_) + padding;
205 Spring spring_copy = spring;
206 spring_copy.ensure_min_distance (minimum_distance);
207 springs_.push_back (spring_copy);
209 bottom_skyline_ = down_skyline;
210 elements_.push_back (Element (elts, minimum_offsets));
212 // Add the springs for the VerticalAxisGroups in this system.
214 // If the user has specified the offsets of the individual staves, fix the
215 // springs at the given distances. Otherwise, use stretchable springs.
216 SCM details = get_details (elements_.back ());
217 SCM manual_dists = ly_assoc_get (ly_symbol2scm ("alignment-distances"), details, SCM_EOL);
218 vsize last_spaceable_staff = 0;
219 bool found_spaceable_staff = false;
220 for (vsize i = 0; i < elts.size (); ++i)
222 if (is_spaceable (elts[i]))
224 // We don't add a spring for the first staff, since
225 // we are only adding springs _between_ staves here.
226 if (!found_spaceable_staff)
228 found_spaceable_staff = true;
229 last_spaceable_staff = i;
233 Spring spring (0.5, 0.0);
234 SCM spec = elts[last_spaceable_staff]->get_property ("staff-staff-spacing");
235 alter_spring_from_spacing_spec (spec, &spring);
237 springs_.push_back (spring);
238 Real min_distance = (found_spaceable_staff ? minimum_offsets[last_spaceable_staff] : 0) - minimum_offsets[i];
239 springs_.back ().ensure_min_distance (min_distance);
241 if (scm_is_pair (manual_dists))
243 if (scm_is_number (scm_car (manual_dists)))
245 Real dy = scm_to_double (scm_car (manual_dists));
247 springs_.back ().set_distance (dy);
248 springs_.back ().set_min_distance (dy);
249 springs_.back ().set_inverse_stretch_strength (0);
251 manual_dists = scm_cdr (manual_dists);
253 last_spaceable_staff = i;
257 // Corner case: there was only one staff, and it wasn't spaceable.
258 // Mark it spaceable, because we do not allow non-spaceable staves
259 // to be at the top or bottom of a system.
260 if (!found_spaceable_staff && elts.size ())
261 mark_as_spaceable (elts[0]);
265 Page_layout_problem::append_prob (Prob *prob, Spring const& spring, Real padding)
267 Skyline_pair *sky = Skyline_pair::unsmob (prob->get_property ("vertical-skylines"));
268 Real minimum_distance = 0;
269 bool tight_spacing = to_boolean (prob->get_property ("tight-spacing"));
273 minimum_distance = (*sky)[UP].distance (bottom_skyline_);
274 bottom_skyline_ = (*sky)[DOWN];
276 else if (Stencil *sten = unsmob_stencil (prob->get_property ("stencil")))
278 Interval iv = sten->extent (Y_AXIS);
279 minimum_distance = iv[UP] - bottom_skyline_.max_height ();
281 bottom_skyline_.clear ();
282 bottom_skyline_.set_minimum_height (iv[DOWN]);
285 Spring spring_copy = spring;
288 spring_copy.set_min_distance (minimum_distance);
289 spring_copy.set_inverse_stretch_strength (0.0);
290 spring_copy.set_distance (0.0);
293 spring_copy.ensure_min_distance (minimum_distance + padding);
295 springs_.push_back (spring_copy);
296 elements_.push_back (Element (prob));
300 Page_layout_problem::solve_rod_spring_problem (bool ragged)
302 Simple_spacer spacer;
304 for (vsize i = 0; i < springs_.size (); ++i)
305 spacer.add_spring (springs_[i]);
307 spacer.solve (page_height_, ragged);
308 solution_ = spacer.spring_positions ();
311 warning (_f ("couldn't fit music on page: overflow is %f",
312 spacer.configuration_length(spacer.force()) - page_height_));
315 // The solution_ vector stores the position of every live VerticalAxisGroup
316 // and every title. From that information,
317 // 1) within each system, stretch the staves so they land at the right position
318 // 2) find the offset of each system (relative to the printable area of the page).
319 // TODO: this function is getting too long, maybe split it up?
321 Page_layout_problem::find_system_offsets ()
323 SCM system_offsets = SCM_EOL;
324 SCM *tail = &system_offsets;
326 // spring_idx 0 is the top of the page. Interesting values start from 1.
327 vsize spring_idx = 1;
328 vector<Grob*> loose_lines;
329 vector<Real> loose_line_min_distances;
330 Grob *last_spaceable_line = 0;
331 Real last_spaceable_line_translation = 0;
332 Interval last_title_extent;
333 for (vsize i = 0; i < elements_.size (); ++i)
335 if (elements_[i].prob)
337 *tail = scm_cons (scm_from_double (solution_[spring_idx]), SCM_EOL);
338 tail = SCM_CDRLOC (*tail);
339 Interval prob_extent = unsmob_stencil (elements_[i].prob->get_property ("stencil"))->extent (Y_AXIS);
341 // Lay out any non-spaceable lines between this line and
343 if (loose_lines.size ())
345 Interval loose_extent = loose_lines.back ()->extent (loose_lines.back (), Y_AXIS);
346 Real min_distance = -loose_extent[DOWN] + prob_extent[UP]; // TODO: include padding/minimum-distance
348 loose_line_min_distances.push_back (min_distance);
349 loose_lines.push_back (0);
351 distribute_loose_lines (loose_lines, loose_line_min_distances,
352 last_spaceable_line_translation, -solution_[spring_idx]);
353 loose_lines.clear ();
354 loose_line_min_distances.clear ();
357 last_spaceable_line = 0;
358 last_spaceable_line_translation = -solution_[spring_idx];
359 last_title_extent = prob_extent;
364 // Getting this signs right here is a little tricky. The configuration
365 // we return has zero at the top of the page and positive numbers further
366 // down, as does the solution_ vector. Within a staff, however, positive
368 // TODO: perhaps change the way the page 'configuration variable works so
369 // that it is consistent with the usual up/down sign conventions in
370 // Lilypond. Then this would be less confusing.
372 // These two positions are relative to the page (with positive numbers being
374 Real first_staff_position = solution_[spring_idx];
375 Real first_staff_min_translation = elements_[i].min_offsets.size () ? elements_[i].min_offsets[0] : 0;
376 Real system_position = first_staff_position + first_staff_min_translation;
378 // Position the staves within this system.
379 Real translation = 0;
380 vector<Real> const& min_offsets = elements_[i].min_offsets;
381 bool found_spaceable_staff = false;
382 for (vsize staff_idx = 0; staff_idx < elements_[i].staves.size (); ++staff_idx)
384 Grob *staff = elements_[i].staves[staff_idx];
385 staff->set_property ("system-Y-offset", scm_from_double (-system_position));
387 if (is_spaceable (staff))
389 // this is relative to the system: negative numbers are down.
390 translation = system_position - solution_[spring_idx];
393 // Lay out any non-spaceable lines between this line and
395 if (loose_lines.size ())
397 loose_line_min_distances.push_back (min_offsets[staff_idx-1] - min_offsets[staff_idx]);
398 loose_lines.push_back (staff);
400 distribute_loose_lines (loose_lines, loose_line_min_distances,
401 last_spaceable_line_translation, translation - system_position);
402 loose_lines.clear ();
403 loose_line_min_distances.clear ();
405 last_spaceable_line = staff;
406 // Negative is down but the translation is relative to the whole page.
407 last_spaceable_line_translation = -system_position + translation;
409 staff->translate_axis (translation, Y_AXIS);
410 found_spaceable_staff = true;
414 if (loose_lines.empty ())
415 loose_lines.push_back (last_spaceable_line);
418 loose_line_min_distances.push_back (min_offsets[staff_idx-1] - min_offsets[staff_idx]);
422 if (loose_lines.back ())
423 min_dist = Axis_group_interface::minimum_distance (loose_lines.back (),
426 else if (!last_title_extent.is_empty ())
427 { // distance to the preceding title
428 // TODO: add options for controlling the space between a loose line
429 // and a title/markup preceding it.
430 min_dist = staff->extent (staff, Y_AXIS)[UP] - last_title_extent[DOWN];
432 else // distance to the top margin
433 min_dist = header_padding_ + header_height_ + staff->extent (staff, Y_AXIS)[UP];
435 loose_line_min_distances.push_back (min_dist);
437 loose_lines.push_back (staff);
441 // Corner case: even if a system has no live staves, it still takes up
442 // one spring (a system with one live staff also takes up one spring),
443 // which we need to increment past.
444 if (!found_spaceable_staff)
447 *tail = scm_cons (scm_from_double (system_position), SCM_EOL);
448 tail = SCM_CDRLOC (*tail);
452 if (loose_lines.size ())
454 Grob *last = loose_lines.back ();
455 Interval last_ext = last->extent (last, Y_AXIS);
456 loose_line_min_distances.push_back (-last_ext[DOWN] + footer_height_ + footer_padding_);
457 loose_lines.push_back (0);
459 distribute_loose_lines (loose_lines, loose_line_min_distances,
460 last_spaceable_line_translation, -page_height_);
464 assert (spring_idx == solution_.size () - 1);
465 return system_offsets;
468 // Given two lines that are already spaced (the first and last
469 // elements of loose_lines), distribute some unspaced lines between
471 // first_translation and last_translation are relative to the page.
473 Page_layout_problem::distribute_loose_lines (vector<Grob*> const &loose_lines,
474 vector<Real> const &min_distances,
475 Real first_translation, Real last_translation)
477 Simple_spacer spacer;
478 for (vsize i = 0; i + 1 < loose_lines.size (); ++i)
480 SCM spec = get_spacing_spec (loose_lines[i], loose_lines[i+1], false, 0, INT_MAX);
481 Spring spring (1.0, 0.0);
482 alter_spring_from_spacing_spec (spec, &spring);
483 spring.ensure_min_distance (min_distances[i]);
484 spacer.add_spring (spring);
487 // Remember: offsets are decreasing, since we're going from UP to DOWN!
488 spacer.solve (first_translation - last_translation, false);
490 vector<Real> solution = spacer.spring_positions ();
491 for (vsize i = 1; i + 1 < solution.size (); ++i)
493 Real system_offset = scm_to_double (loose_lines[i]->get_property ("system-Y-offset"));
494 loose_lines[i]->translate_axis (first_translation - solution[i] - system_offset, Y_AXIS);
499 Page_layout_problem::solution (bool ragged)
501 solve_rod_spring_problem (ragged);
502 return find_system_offsets ();
505 // Build upper and lower skylines for a system. We don't yet know the positions
506 // of the staves within the system, so we make the skyline as conservative as
507 // possible. That is, for the upper skyline, we pretend that all of the staves
508 // in the system are packed together close to the top system; for the lower
509 // skyline, we pretend that all of the staves are packed together close to
510 // the bottom system.
512 // The upper skyline is relative to the top staff; the lower skyline is relative to
515 Page_layout_problem::build_system_skyline (vector<Grob*> const& staves,
516 vector<Real> const& minimum_translations,
520 if (minimum_translations.empty ())
523 assert (staves.size () == minimum_translations.size ());
524 Real first_translation = minimum_translations[0];
525 Real last_spaceable_dy = 0;
526 Real first_spaceable_dy = 0;
527 bool found_spaceable_staff = false;
529 for (vsize i = 0; i < staves.size (); ++i)
531 Real dy = minimum_translations[i] - first_translation;
533 Skyline_pair *sky = Skyline_pair::unsmob (g->get_property ("vertical-skylines"));
537 up->merge ((*sky)[UP]);
541 down->merge ((*sky)[DOWN]);
544 if (is_spaceable (staves[i]))
546 if (!found_spaceable_staff)
548 found_spaceable_staff = true;
549 first_spaceable_dy = dy;
551 last_spaceable_dy = dy;
555 // Leave the up skyline at a position relative
556 // to the top spaceable staff.
557 up->raise (-first_spaceable_dy);
559 // Leave the down skyline at a position
560 // relative to the bottom spaceable staff.
561 down->raise (-last_spaceable_dy);
565 Page_layout_problem::prob_extent (Prob *p)
567 Stencil *sten = unsmob_stencil (p->get_property ("stencil"));
568 return sten ? sten->extent (Y_AXIS) : Interval (0, 0);
572 Page_layout_problem::first_staff_extent (Element const& e)
575 return prob_extent (e.prob);
576 else if (e.staves.size ())
577 return e.staves[0]->extent (e.staves[0], Y_AXIS);
579 return Interval (0, 0);
583 Page_layout_problem::last_staff_extent (Element const& e)
586 return prob_extent (e.prob);
587 else if (e.staves.size ())
588 return e.staves.back ()->extent (e.staves.back (), Y_AXIS);
590 return Interval (0, 0);
594 Page_layout_problem::get_details (Element const& elt)
596 if (elt.staves.empty ())
599 return get_details (elt.staves.back ()->get_system ());
603 Page_layout_problem::get_details (Grob *g)
605 Grob *left_bound = dynamic_cast<Spanner*> (g)->get_bound (LEFT);
606 return left_bound->get_property ("line-break-system-details");
610 Page_layout_problem::is_spaceable (Grob *g)
612 return !scm_is_number (g->get_property ("staff-affinity"));
616 Page_layout_problem::mark_as_spaceable (Grob *g)
618 g->set_property ("staff-affinity", SCM_BOOL_F);
622 Page_layout_problem::read_spacing_spec (SCM spec, Real* dest, SCM sym)
624 SCM pair = scm_sloppy_assq (sym, spec);
625 if (scm_is_pair (pair) && scm_is_number (scm_cdr (pair)))
627 *dest = scm_to_double (scm_cdr (pair));
633 // If there is a forced, fixed spacing between BEFORE and AFTER, return it.
634 // Otherwise, return -infinity_f.
635 // If after is spaceable, it is the (spaceable_index + 1)th spaceable grob in
638 Page_layout_problem::get_fixed_spacing (Grob *before, Grob *after, int spaceable_index, bool pure, int start, int end)
640 SCM spec = Page_layout_problem::get_spacing_spec (before, after, pure, start, end);
641 Real ret = -infinity_f;
642 Real stretchability = 0;
643 if (Page_layout_problem::read_spacing_spec (spec, &stretchability, ly_symbol2scm ("stretchability"))
644 && stretchability == 0)
645 Page_layout_problem::read_spacing_spec (spec, &ret, ly_symbol2scm ("space"));
647 // If we're pure, then paper-columns have not had their systems set,
648 // and so elts[i]->get_system () is unreliable.
649 System *sys = pure ? Grob::get_system (before) : before->get_system ();
650 Grob *left_bound = sys ? sys->get_maybe_pure_bound (LEFT, pure, start, end) : 0;
652 if (is_spaceable (before) && is_spaceable (after) && left_bound)
654 SCM details = left_bound->get_property ("line-break-system-details");
655 SCM manual_dists = ly_assoc_get (ly_symbol2scm ("alignment-distances"), details, SCM_EOL);
656 if (scm_is_pair (manual_dists))
658 SCM forced = robust_list_ref (spaceable_index - 1, manual_dists);
659 if (scm_is_number (forced))
660 ret = max (ret, scm_to_double (forced));
667 add_stretchability (SCM alist, Real stretch)
669 if (!scm_is_pair (scm_sloppy_assq (ly_symbol2scm ("stretchability"), alist)))
670 return scm_acons (ly_symbol2scm ("stretchability"), scm_from_double (stretch), alist);
675 // We want to put a large stretch between a non-spaceable line and its
676 // non-affinity staff. We want to put an even larger stretch between
677 // a non-spaceable line and the top/bottom of the page. That way,
678 // a spacing-affinity UP line at the bottom of the page will still be
679 // placed close to its staff.
680 const double LARGE_STRETCH = 10e5;
681 const double HUGE_STRETCH = 10e7;
683 // Returns the spacing spec connecting BEFORE to AFTER.
685 Page_layout_problem::get_spacing_spec (Grob *before, Grob *after, bool pure, int start, int end)
687 // If there are no spacing wishes, return a very flexible spring.
688 // This will occur, for example, if there are lyrics at the bottom of
689 // the page, in which case we don't want the spring from the lyrics to
690 // the bottom of the page to have much effect.
691 if (!before || !after)
692 return add_stretchability (SCM_EOL, HUGE_STRETCH);
694 if (is_spaceable (before))
696 if (is_spaceable (after))
697 return before->get_maybe_pure_property ("staff-staff-spacing", pure, start, end);
700 Direction affinity = to_dir (after->get_maybe_pure_property ("staff-affinity", pure, start, end));
701 return (affinity == DOWN)
702 ? add_stretchability (after->get_maybe_pure_property ("nonstaff-unrelatedstaff-spacing", pure, start, end),
704 : after->get_maybe_pure_property ("nonstaff-relatedstaff-spacing", pure, start, end);
709 if (is_spaceable (after))
711 Direction affinity = to_dir (before->get_maybe_pure_property ("staff-affinity", pure, start, end));
712 return (affinity == UP)
713 ? add_stretchability (before->get_maybe_pure_property ("nonstaff-unrelatedstaff-spacing", pure, start, end),
715 : before->get_maybe_pure_property ("nonstaff-relatedstaff-spacing", pure, start, end);
719 Direction before_affinity = to_dir (before->get_maybe_pure_property ("staff-affinity", pure, start, end));
720 Direction after_affinity = to_dir (after->get_maybe_pure_property ("staff-affinity", pure, start, end));
721 if (after_affinity > before_affinity)
723 warning (_ ("staff-affinities should only decrease"));
724 after_affinity = before_affinity;
726 if (before_affinity != UP)
727 return before->get_maybe_pure_property ("nonstaff-nonstaff-spacing", pure, start, end);
728 else if (after_affinity != DOWN)
729 return before->get_maybe_pure_property ("nonstaff-nonstaff-spacing", pure, start, end);
730 return add_stretchability (before->get_maybe_pure_property ("nonstaff-unrelatedstaff-spacing", pure, start, end),
740 Page_layout_problem::alter_spring_from_spacing_spec (SCM spec, Spring* spring)
745 if (read_spacing_spec (spec, &space, ly_symbol2scm ("space")))
746 spring->set_distance (space);
747 if (read_spacing_spec (spec, &min_dist, ly_symbol2scm ("minimum-distance")))
748 spring->set_min_distance (min_dist);
749 spring->set_default_strength ();
751 if (read_spacing_spec (spec, &stretch, ly_symbol2scm ("stretchability")))
753 spring->set_inverse_stretch_strength (stretch);
754 spring->set_inverse_compress_strength (stretch);
759 Page_layout_problem::filter_dead_elements (vector<Grob*> const& input)
761 vector<Grob*> output;
762 for (vsize i = 0; i < input.size (); ++i)
764 if (Hara_kiri_group_spanner::has_interface (input[i]))
765 Hara_kiri_group_spanner::consider_suicide (input[i]);
767 if (input[i]->is_live ())
768 output.push_back (input[i]);