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 "pointer-group-interface.hh"
32 #include "skyline-pair.hh"
35 Page_layout_problem::Page_layout_problem (Paper_book
*pb
, SCM page_scm
, SCM systems
)
36 : bottom_skyline_ (DOWN
)
38 Prob
*page
= unsmob_prob (page_scm
);
47 Stencil
*head
= unsmob_stencil (page
->get_property ("head-stencil"));
48 Stencil
*foot
= unsmob_stencil (page
->get_property ("foot-stencil"));
50 header_height_
= head
? head
->extent (Y_AXIS
).length () : 0;
51 footer_height_
= foot
? foot
->extent (Y_AXIS
).length () : 0;
52 page_height_
= robust_scm2double (page
->get_property ("paper-height"), 100);
55 // Initially, bottom_skyline_ represents the top of the page. Make
56 // it solid, so that the top of the first system will be forced
57 // below the top of the printable area.
58 bottom_skyline_
.set_minimum_height (-header_height_
);
60 SCM between_system_spacing
= SCM_EOL
;
61 SCM between_scores_system_spacing
= SCM_EOL
;
62 SCM after_title_spacing
= SCM_EOL
;
63 SCM before_title_spacing
= SCM_EOL
;
64 SCM between_title_spacing
= SCM_EOL
;
66 // top_system_spacing controls the spring from the top of the printable
67 // area to the first staff. It allows the user to control the offset of
68 // the first staff (as opposed to the top of the first system) from the
69 // top of the page. Similarly for bottom_system_spacing.
70 SCM top_system_spacing
= SCM_EOL
;
71 SCM bottom_system_spacing
= SCM_EOL
;
74 Output_def
*paper
= pb
->paper_
;
75 between_system_spacing
= paper
->c_variable ("between-system-spacing");
76 between_scores_system_spacing
= paper
->c_variable ("between-scores-system-spacing");
77 after_title_spacing
= paper
->c_variable ("after-title-spacing");
78 before_title_spacing
= paper
->c_variable ("before-title-spacing");
79 between_title_spacing
= paper
->c_variable ("between-title-spacing");
80 bottom_system_spacing
= paper
->c_variable ("bottom-system-spacing");
81 top_system_spacing
= paper
->c_variable ("top-system-spacing");
82 if (scm_is_pair (systems
) && unsmob_prob (scm_car (systems
)))
83 top_system_spacing
= paper
->c_variable ("top-title-spacing");
85 // Note: the page height here does _not_ reserve space for headers and
86 // footers. This is because we want to anchor the top-system-spacing
87 // spring at the _top_ of the header.
88 page_height_
-= robust_scm2double (paper
->c_variable ("top-margin"), 0)
89 + robust_scm2double (paper
->c_variable ("bottom-margin"), 0);
91 read_spacing_spec (top_system_spacing
, &header_padding_
, ly_symbol2scm ("padding"));
92 read_spacing_spec (bottom_system_spacing
, &footer_padding_
, ly_symbol2scm ("padding"));
94 bool last_system_was_title
= false;
97 for (SCM s
= systems
; scm_is_pair (s
); s
= scm_cdr (s
))
99 bool first
= (s
== systems
);
101 if (Grob
*g
= unsmob_grob (scm_car (s
)))
103 System
*sys
= dynamic_cast<System
*> (g
);
106 programming_error ("got a grob for vertical spacing that wasn't a System");
110 SCM spec
= between_system_spacing
;
112 spec
= top_system_spacing
;
113 else if (last_system_was_title
)
114 spec
= after_title_spacing
;
115 else if (0 == Paper_column::get_rank (sys
->get_bound (LEFT
)))
116 spec
= between_scores_system_spacing
;
118 Spring
spring (0, 0);
120 alter_spring_from_spacing_spec (spec
, &spring
);
121 read_spacing_spec (spec
, &padding
, ly_symbol2scm ("padding"));
123 append_system (sys
, spring
, padding
);
124 last_system_was_title
= false;
126 else if (Prob
*p
= unsmob_prob (scm_car (s
)))
128 SCM spec
= first
? top_system_spacing
129 : (last_system_was_title
? between_title_spacing
: before_title_spacing
);
130 Spring
spring (0, 0);
132 alter_spring_from_spacing_spec (spec
, &spring
);
133 read_spacing_spec (spec
, &padding
, ly_symbol2scm ("padding"));
135 append_prob (p
, spring
, padding
);
136 last_system_was_title
= true;
139 programming_error ("got a system that was neither a Grob nor a Prob");
142 Spring
last_spring (0, 0);
143 Real last_padding
= 0;
144 alter_spring_from_spacing_spec (bottom_system_spacing
, &last_spring
);
145 read_spacing_spec (bottom_system_spacing
, &last_padding
, ly_symbol2scm ("padding"));
146 last_spring
.ensure_min_distance (last_padding
- bottom_skyline_
.max_height () + footer_height_
);
147 springs_
.push_back (last_spring
);
149 if (elements_
.size ())
151 Real bottom_padding
= 0;
153 // TODO: junk bottom-space now that we have bottom-system-spacing?
154 // bottom-space has the flexibility that one can do it per-system.
155 // NOTE: bottom-space is misnamed since it is not stretchable space.
156 if (Prob
*p
= elements_
.back ().prob
)
157 bottom_padding
= robust_scm2double (p
->get_property ("bottom-space"), 0);
158 else if (elements_
.back ().staves
.size ())
160 SCM details
= get_details (elements_
.back ());
161 bottom_padding
= robust_scm2double (ly_assoc_get (ly_symbol2scm ("bottom-space"),
166 page_height_
-= bottom_padding
;
171 Page_layout_problem::set_header_height (Real height
)
173 header_height_
= height
;
177 Page_layout_problem::set_footer_height (Real height
)
179 footer_height_
= height
;
183 Page_layout_problem::append_system (System
*sys
, Spring
const& spring
, Real padding
)
185 Grob
*align
= sys
->get_vertical_alignment ();
189 align
->set_property ("positioning-done", SCM_BOOL_T
);
191 extract_grob_set (align
, "elements", all_elts
);
192 vector
<Grob
*> elts
= filter_dead_elements (all_elts
);
193 vector
<Real
> minimum_offsets
= Align_interface::get_minimum_translations (align
, elts
, Y_AXIS
,
196 Skyline
up_skyline (UP
);
197 Skyline
down_skyline (DOWN
);
198 build_system_skyline (elts
, minimum_offsets
, &up_skyline
, &down_skyline
);
200 Real minimum_distance
= up_skyline
.distance (bottom_skyline_
) + padding
;
202 Spring spring_copy
= spring
;
203 spring_copy
.ensure_min_distance (minimum_distance
);
204 springs_
.push_back (spring_copy
);
206 bottom_skyline_
= down_skyline
;
207 elements_
.push_back (Element (elts
, minimum_offsets
));
209 // Add the springs for the VerticalAxisGroups in this system.
211 // If the user has specified the offsets of the individual staves, fix the
212 // springs at the given distances. Otherwise, use stretchable springs.
213 SCM details
= get_details (elements_
.back ());
214 SCM manual_dists
= ly_assoc_get (ly_symbol2scm ("alignment-distances"), details
, SCM_EOL
);
215 vsize last_spaceable_staff
= 0;
216 bool found_spaceable_staff
= false;
217 for (vsize i
= 0; i
< elts
.size (); ++i
)
219 if (is_spaceable (elts
[i
]))
221 // We don't add a spring for the first staff, since
222 // we are only adding springs _between_ staves here.
223 if (!found_spaceable_staff
)
225 found_spaceable_staff
= true;
226 last_spaceable_staff
= i
;
230 Spring
spring (0.5, 0.0);
231 SCM spec
= elts
[last_spaceable_staff
]->get_property ("next-staff-spacing");
232 alter_spring_from_spacing_spec (spec
, &spring
);
234 springs_
.push_back (spring
);
235 Real min_distance
= (found_spaceable_staff
? minimum_offsets
[last_spaceable_staff
] : 0) - minimum_offsets
[i
];
236 springs_
.back ().ensure_min_distance (min_distance
);
238 if (scm_is_pair (manual_dists
))
240 if (scm_is_number (scm_car (manual_dists
)))
242 Real dy
= scm_to_double (scm_car (manual_dists
));
244 springs_
.back ().set_distance (dy
);
245 springs_
.back ().set_min_distance (dy
);
246 springs_
.back ().set_inverse_stretch_strength (0);
248 manual_dists
= scm_cdr (manual_dists
);
250 last_spaceable_staff
= i
;
254 // Corner case: there was only one staff, and it wasn't spaceable.
255 // Mark it spaceable, because we do not allow non-spaceable staves
256 // to be at the top or bottom of a system.
257 if (!found_spaceable_staff
&& elts
.size ())
258 mark_as_spaceable (elts
[0]);
262 Page_layout_problem::append_prob (Prob
*prob
, Spring
const& spring
, Real padding
)
264 Skyline_pair
*sky
= Skyline_pair::unsmob (prob
->get_property ("vertical-skylines"));
265 Real minimum_distance
= 0;
266 bool tight_spacing
= to_boolean (prob
->get_property ("tight-spacing"));
270 minimum_distance
= (*sky
)[UP
].distance (bottom_skyline_
);
271 bottom_skyline_
= (*sky
)[DOWN
];
273 else if (Stencil
*sten
= unsmob_stencil (prob
->get_property ("stencil")))
275 Interval iv
= sten
->extent (Y_AXIS
);
276 minimum_distance
= iv
[UP
] - bottom_skyline_
.max_height ();
278 bottom_skyline_
.clear ();
279 bottom_skyline_
.set_minimum_height (iv
[DOWN
]);
282 Spring spring_copy
= spring
;
285 spring_copy
.set_min_distance (minimum_distance
);
286 spring_copy
.set_inverse_stretch_strength (0.0);
287 spring_copy
.set_distance (0.0);
290 spring_copy
.ensure_min_distance (minimum_distance
+ padding
);
292 springs_
.push_back (spring_copy
);
293 elements_
.push_back (Element (prob
));
297 Page_layout_problem::solve_rod_spring_problem (bool ragged
)
299 Simple_spacer spacer
;
301 for (vsize i
= 0; i
< springs_
.size (); ++i
)
302 spacer
.add_spring (springs_
[i
]);
304 spacer
.solve (page_height_
, ragged
);
305 solution_
= spacer
.spring_positions ();
308 warning (_ ("couldn't fit music on page"));
311 // The solution_ vector stores the position of every live VerticalAxisGroup
312 // and every title. From that information,
313 // 1) within each system, stretch the staves so they land at the right position
314 // 2) find the offset of each system (relative to the printable area of the page).
315 // TODO: this function is getting too long, maybe split it up?
317 Page_layout_problem::find_system_offsets ()
319 SCM system_offsets
= SCM_EOL
;
320 SCM
*tail
= &system_offsets
;
322 // spring_idx 0 is the top of the page. Interesting values start from 1.
323 vsize spring_idx
= 1;
324 vector
<Grob
*> loose_lines
;
325 vector
<Real
> loose_line_min_distances
;
326 Grob
*last_spaceable_line
= 0;
327 Real last_spaceable_line_translation
= 0;
328 Interval last_title_extent
;
329 for (vsize i
= 0; i
< elements_
.size (); ++i
)
331 if (elements_
[i
].prob
)
333 *tail
= scm_cons (scm_from_double (solution_
[spring_idx
]), SCM_EOL
);
334 tail
= SCM_CDRLOC (*tail
);
335 Interval prob_extent
= unsmob_stencil (elements_
[i
].prob
->get_property ("stencil"))->extent (Y_AXIS
);
337 // Lay out any non-spaceable lines between this line and
339 if (loose_lines
.size ())
341 Interval loose_extent
= loose_lines
.back ()->extent (loose_lines
.back (), Y_AXIS
);
342 Real min_distance
= -loose_extent
[DOWN
] + prob_extent
[UP
]; // TODO: include padding/minimum-distance
344 loose_line_min_distances
.push_back (min_distance
);
345 loose_lines
.push_back (0);
347 distribute_loose_lines (loose_lines
, loose_line_min_distances
,
348 last_spaceable_line_translation
, -solution_
[spring_idx
]);
349 loose_lines
.clear ();
350 loose_line_min_distances
.clear ();
353 last_spaceable_line
= 0;
354 last_spaceable_line_translation
= -solution_
[spring_idx
];
355 last_title_extent
= prob_extent
;
360 // Getting this signs right here is a little tricky. The configuration
361 // we return has zero at the top of the page and positive numbers further
362 // down, as does the solution_ vector. Within a staff, however, positive
364 // TODO: perhaps change the way the page 'configuration variable works so
365 // that it is consistent with the usual up/down sign conventions in
366 // Lilypond. Then this would be less confusing.
368 // These two positions are relative to the page (with positive numbers being
370 Real first_staff_position
= solution_
[spring_idx
];
371 Real first_staff_min_translation
= elements_
[i
].min_offsets
.size () ? elements_
[i
].min_offsets
[0] : 0;
372 Real system_position
= first_staff_position
+ first_staff_min_translation
;
374 // Position the staves within this system.
375 Real translation
= 0;
376 vector
<Real
> const& min_offsets
= elements_
[i
].min_offsets
;
377 bool found_spaceable_staff
= false;
378 for (vsize staff_idx
= 0; staff_idx
< elements_
[i
].staves
.size (); ++staff_idx
)
380 Grob
*staff
= elements_
[i
].staves
[staff_idx
];
381 staff
->set_property ("system-Y-offset", scm_from_double (-system_position
));
383 if (is_spaceable (staff
))
385 // this is relative to the system: negative numbers are down.
386 translation
= system_position
- solution_
[spring_idx
];
389 // Lay out any non-spaceable lines between this line and
391 if (loose_lines
.size ())
393 loose_line_min_distances
.push_back (min_offsets
[staff_idx
-1] - min_offsets
[staff_idx
]);
394 loose_lines
.push_back (staff
);
396 distribute_loose_lines (loose_lines
, loose_line_min_distances
,
397 last_spaceable_line_translation
, translation
- system_position
);
398 loose_lines
.clear ();
399 loose_line_min_distances
.clear ();
401 last_spaceable_line
= staff
;
402 // Negative is down but the translation is relative to the whole page.
403 last_spaceable_line_translation
= -system_position
+ translation
;
405 staff
->translate_axis (translation
, Y_AXIS
);
406 found_spaceable_staff
= true;
410 if (loose_lines
.empty ())
411 loose_lines
.push_back (last_spaceable_line
);
414 loose_line_min_distances
.push_back (min_offsets
[staff_idx
-1] - min_offsets
[staff_idx
]);
418 if (loose_lines
.back ())
419 min_dist
= Axis_group_interface::minimum_distance (loose_lines
.back (),
422 else if (!last_title_extent
.is_empty ())
423 { // distance to the preceding title
424 // TODO: add options for controlling the space between a loose line
425 // and a title/markup preceding it.
426 min_dist
= staff
->extent (staff
, Y_AXIS
)[UP
] - last_title_extent
[DOWN
];
428 else // distance to the top margin
429 min_dist
= header_padding_
+ header_height_
+ staff
->extent (staff
, Y_AXIS
)[UP
];
431 loose_line_min_distances
.push_back (min_dist
);
433 loose_lines
.push_back (staff
);
437 // Corner case: even if a system has no live staves, it still takes up
438 // one spring (a system with one live staff also takes up one spring),
439 // which we need to increment past.
440 if (!found_spaceable_staff
)
443 *tail
= scm_cons (scm_from_double (system_position
), SCM_EOL
);
444 tail
= SCM_CDRLOC (*tail
);
448 if (loose_lines
.size ())
450 Grob
*last
= loose_lines
.back ();
451 Interval last_ext
= last
->extent (last
, Y_AXIS
);
452 loose_line_min_distances
.push_back (-last_ext
[DOWN
] + footer_height_
+ footer_padding_
);
453 loose_lines
.push_back (0);
455 distribute_loose_lines (loose_lines
, loose_line_min_distances
,
456 last_spaceable_line_translation
, -page_height_
);
460 assert (spring_idx
== solution_
.size () - 1);
461 return system_offsets
;
464 // Given two lines that are already spaced (the first and last
465 // elements of loose_lines), distribute some unspaced lines between
467 // first_translation and last_translation are relative to the page.
469 Page_layout_problem::distribute_loose_lines (vector
<Grob
*> const &loose_lines
,
470 vector
<Real
> const &min_distances
,
471 Real first_translation
, Real last_translation
)
473 Simple_spacer spacer
;
474 for (vsize i
= 0; i
+ 1 < loose_lines
.size (); ++i
)
476 SCM spec
= get_spacing_spec (loose_lines
[i
], loose_lines
[i
+1]);
477 Spring
spring (1.0, 0.0);
478 alter_spring_from_spacing_spec (spec
, &spring
);
479 spring
.ensure_min_distance (min_distances
[i
]);
480 spacer
.add_spring (spring
);
483 // Remember: offsets are decreasing, since we're going from UP to DOWN!
484 spacer
.solve (first_translation
- last_translation
, false);
486 vector
<Real
> solution
= spacer
.spring_positions ();
487 for (vsize i
= 1; i
+ 1 < solution
.size (); ++i
)
489 Real system_offset
= scm_to_double (loose_lines
[i
]->get_property ("system-Y-offset"));
490 loose_lines
[i
]->translate_axis (first_translation
- solution
[i
] - system_offset
, Y_AXIS
);
495 Page_layout_problem::solution (bool ragged
)
497 solve_rod_spring_problem (ragged
);
498 return find_system_offsets ();
501 // Build upper and lower skylines for a system. We don't yet know the positions
502 // of the staves within the system, so we make the skyline as conservative as
503 // possible. That is, for the upper skyline, we pretend that all of the staves
504 // in the system are packed together close to the top system; for the lower
505 // skyline, we pretend that all of the staves are packed together close to
506 // the bottom system.
508 // The upper skyline is relative to the top staff; the lower skyline is relative to
511 Page_layout_problem::build_system_skyline (vector
<Grob
*> const& staves
,
512 vector
<Real
> const& minimum_translations
,
516 if (minimum_translations
.empty ())
519 assert (staves
.size () == minimum_translations
.size ());
520 Real first_translation
= minimum_translations
[0];
521 Real last_spaceable_dy
= 0;
522 Real first_spaceable_dy
= 0;
523 bool found_spaceable_staff
= false;
525 for (vsize i
= 0; i
< staves
.size (); ++i
)
527 Real dy
= minimum_translations
[i
] - first_translation
;
529 Skyline_pair
*sky
= Skyline_pair::unsmob (g
->get_property ("vertical-skylines"));
533 up
->merge ((*sky
)[UP
]);
537 down
->merge ((*sky
)[DOWN
]);
540 if (is_spaceable (staves
[i
]))
542 if (!found_spaceable_staff
)
544 found_spaceable_staff
= true;
545 first_spaceable_dy
= dy
;
547 last_spaceable_dy
= dy
;
551 // Leave the up skyline at a position relative
552 // to the top spaceable staff.
553 up
->raise (-first_spaceable_dy
);
555 // Leave the down skyline at a position
556 // relative to the bottom spaceable staff.
557 down
->raise (-last_spaceable_dy
);
561 Page_layout_problem::prob_extent (Prob
*p
)
563 Stencil
*sten
= unsmob_stencil (p
->get_property ("stencil"));
564 return sten
? sten
->extent (Y_AXIS
) : Interval (0, 0);
568 Page_layout_problem::first_staff_extent (Element
const& e
)
571 return prob_extent (e
.prob
);
572 else if (e
.staves
.size ())
573 return e
.staves
[0]->extent (e
.staves
[0], Y_AXIS
);
575 return Interval (0, 0);
579 Page_layout_problem::last_staff_extent (Element
const& e
)
582 return prob_extent (e
.prob
);
583 else if (e
.staves
.size ())
584 return e
.staves
.back ()->extent (e
.staves
.back (), Y_AXIS
);
586 return Interval (0, 0);
590 Page_layout_problem::get_details (Element
const& elt
)
592 if (elt
.staves
.empty ())
595 return get_details (elt
.staves
.back ()->get_system ());
599 Page_layout_problem::get_details (Grob
*g
)
601 Grob
*left_bound
= dynamic_cast<Spanner
*> (g
)->get_bound (LEFT
);
602 return left_bound
->get_property ("line-break-system-details");
606 Page_layout_problem::is_spaceable (Grob
*g
)
608 return !scm_is_number (g
->get_property ("staff-affinity"));
612 Page_layout_problem::mark_as_spaceable (Grob
*g
)
614 g
->set_property ("staff-affinity", SCM_BOOL_F
);
618 Page_layout_problem::read_spacing_spec (SCM spec
, Real
* dest
, SCM sym
)
620 SCM pair
= scm_sloppy_assq (sym
, spec
);
621 if (scm_is_pair (pair
) && scm_is_number (scm_cdr (pair
)))
623 *dest
= scm_to_double (scm_cdr (pair
));
630 add_stretchability (SCM alist
, Real stretch
)
632 if (!scm_is_pair (scm_sloppy_assq (ly_symbol2scm ("stretchability"), alist
)))
633 return scm_acons (ly_symbol2scm ("stretchability"), scm_from_double (stretch
), alist
);
638 // We want to put a large stretch between a non-spaceable line and its
639 // non-affinity staff. We want to put an even larger stretch between
640 // a non-spaceable line and the top/bottom of the page. That way,
641 // a spacing-affinity UP line at the bottom of the page will still be
642 // placed close to its staff.
643 const double LARGE_STRETCH
= 10e5
;
644 const double HUGE_STRETCH
= 10e7
;
646 // Returns the spacing spec connecting BEFORE to AFTER.
648 Page_layout_problem::get_spacing_spec (Grob
*before
, Grob
*after
)
650 // If there are no spacing wishes, return a very flexible spring.
651 // This will occur, for example, if there are lyrics at the bottom of
652 // the page, in which case we don't want the spring from the lyrics to
653 // the bottom of the page to have much effect.
654 if (!before
|| !after
)
655 return add_stretchability (SCM_EOL
, HUGE_STRETCH
);
657 if (is_spaceable (before
))
659 if (is_spaceable (after
))
660 return before
->get_property ("next-staff-spacing");
663 Direction affinity
= to_dir (after
->get_property ("staff-affinity"));
664 return (affinity
== DOWN
)
665 ? add_stretchability (after
->get_property ("non-affinity-spacing"), LARGE_STRETCH
)
666 : after
->get_property ("inter-staff-spacing");
671 if (is_spaceable (after
))
673 Direction affinity
= to_dir (before
->get_property ("staff-affinity"));
674 return (affinity
== UP
)
675 ? add_stretchability (before
->get_property ("non-affinity-spacing"), LARGE_STRETCH
)
676 : before
->get_property ("inter-staff-spacing");
680 Direction before_affinity
= to_dir (before
->get_property ("staff-affinity"));
681 Direction after_affinity
= to_dir (after
->get_property ("staff-affinity"));
682 if (after_affinity
> before_affinity
)
684 warning (_ ("staff-affinities should only decrease"));
685 after_affinity
= before_affinity
;
687 if (before_affinity
!= UP
)
688 return before
->get_property ("inter-loose-line-spacing");
689 else if (after_affinity
!= DOWN
)
690 return before
->get_property ("inter-loose-line-spacing");
691 return add_stretchability (before
->get_property ("non-affinity-spacing"), LARGE_STRETCH
);
700 Page_layout_problem::alter_spring_from_spacing_spec (SCM spec
, Spring
* spring
)
705 if (read_spacing_spec (spec
, &space
, ly_symbol2scm ("space")))
706 spring
->set_distance (space
);
707 if (read_spacing_spec (spec
, &min_dist
, ly_symbol2scm ("minimum-distance")))
708 spring
->set_min_distance (min_dist
);
709 spring
->set_default_strength ();
711 if (read_spacing_spec (spec
, &stretch
, ly_symbol2scm ("stretchability")))
713 spring
->set_inverse_stretch_strength (stretch
);
714 spring
->set_inverse_compress_strength (stretch
);
719 Page_layout_problem::filter_dead_elements (vector
<Grob
*> const& input
)
721 vector
<Grob
*> output
;
722 for (vsize i
= 0; i
< input
.size (); ++i
)
724 if (Hara_kiri_group_spanner::has_interface (input
[i
]))
725 Hara_kiri_group_spanner::consider_suicide (input
[i
]);
727 if (input
[i
]->is_live ())
728 output
.push_back (input
[i
]);