lily/grob.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   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.
  10
  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.
  15
  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/>.
  18 */
  19
  20 #include "grob.hh"
  21
  22 #include <cstring>
  23
  24 #include "align-interface.hh"
  25 #include "axis-group-interface.hh"
  26 #include "input.hh"
  27 #include "international.hh"
  28 #include "item.hh"
  29 #include "main.hh"
  30 #include "misc.hh"
  31 #include "music.hh"
  32 #include "output-def.hh"
  33 #include "pointer-group-interface.hh"
  34 #include "program-option.hh"
  35 #include "stencil.hh"
  36 #include "stream-event.hh"
  37 #include "system.hh"
  38 #include "warn.hh"
  39
  40 #include "ly-smobs.icc"
  41
  42 Grob *
  43 Grob::clone () const
  44 {
  45   return new Grob (*this);
  46 }
  47
  48 Grob::Grob (SCM basicprops)
  49 {
  50
  51   /* FIXME: default should be no callback.  */
  52   self_scm_ = SCM_EOL;
  53   layout_ = 0;
  54   original_ = 0;
  55   interfaces_ = SCM_EOL;
  56   immutable_property_alist_ = basicprops;
  57   mutable_property_alist_ = SCM_EOL;
  58   object_alist_ = SCM_EOL;
  59
  60   /* We do smobify_self () as the first step.  Since the object lives
  61      on the heap, none of its SCM variables are protected from
  62      GC. After smobify_self (), they are.  */
  63   smobify_self ();
  64
  65   SCM meta = get_property ("meta");
  66   if (scm_is_pair (meta))
  67     {
  68       interfaces_ = scm_cdr (scm_assq (ly_symbol2scm ("interfaces"), meta));
  69
  70       SCM object_cbs = scm_assq (ly_symbol2scm ("object-callbacks"), meta);
  71       if (scm_is_pair (object_cbs))
  72         {
  73           for (SCM s = scm_cdr (object_cbs); scm_is_pair (s); s = scm_cdr (s))
  74             set_object (scm_caar (s), scm_cdar (s));
  75         }
  76     }
  77
  78   if (get_property_data ("X-extent") == SCM_EOL)
  79     set_property ("X-extent", Grob::stencil_width_proc);
  80   if (get_property_data ("Y-extent") == SCM_EOL)
  81     set_property ("Y-extent", Grob::stencil_height_proc);
  82 }
  83
  84 Grob::Grob (Grob const &s)
  85   : dim_cache_ (s.dim_cache_)
  86 {
  87   original_ = (Grob *) & s;
  88   self_scm_ = SCM_EOL;
  89
  90   immutable_property_alist_ = s.immutable_property_alist_;
  91   mutable_property_alist_ = ly_deep_copy (s.mutable_property_alist_);
  92   interfaces_ = s.interfaces_;
  93   object_alist_ = SCM_EOL;
  94
  95   layout_ = 0;
  96
  97   smobify_self ();
  98 }
  99
 100 Grob::~Grob ()
 101 {
 102 }
 103 /****************************************************************
 104   STENCILS
 105 ****************************************************************/
 106
 107 Stencil *
 108 Grob::get_stencil () const
 109 {
 110   if (!is_live ())
 111     return 0;
 112
 113   SCM stil = get_property ("stencil");
 114   return unsmob_stencil (stil);
 115 }
 116
 117 Stencil
 118 Grob::get_print_stencil () const
 119 {
 120   SCM stil = get_property ("stencil");
 121
 122   Stencil retval;
 123   if (Stencil *m = unsmob_stencil (stil))
 124     {
 125       retval = *m;
 126       bool transparent = to_boolean (get_property ("transparent"));
 127
 128       if (transparent)
 129         retval = Stencil (m->extent_box (), SCM_EOL);
 130       else
 131         {
 132           SCM expr = m->expr ();
 133           expr = scm_list_3 (ly_symbol2scm ("grob-cause"),
 134                              self_scm (), expr);
 135
 136           retval = Stencil (m->extent_box (), expr);
 137         }
 138
 139       SCM rot = get_property ("rotation");
 140       if (scm_is_pair (rot))
 141         {
 142           Real angle = scm_to_double (scm_car (rot));
 143           Real x = scm_to_double (scm_cadr (rot));
 144           Real y = scm_to_double (scm_caddr (rot));
 145
 146           retval.rotate_degrees (angle, Offset (x, y));
 147         }
 148
 149       /* color support... see interpret_stencil_expression () for more... */
 150       SCM color = get_property ("color");
 151       if (scm_is_pair (color))
 152         {
 153           SCM expr = scm_list_3 (ly_symbol2scm ("color"),
 154                                  color,
 155                                  retval.expr ());
 156
 157           retval = Stencil (retval.extent_box (), expr);
 158         }
 159
 160       /* process whiteout */
 161       /* a grob has to be visible, otherwise the whiteout property has no effect */
 162       if (!transparent && to_boolean (get_property ("whiteout")))
 163         {
 164           /* Call the scheme procedure stencil-whiteout in scm/stencils.scm */
 165           /* to add a round-filled-box stencil to the stencil list */
 166           retval
 167             = *unsmob_stencil (scm_call_1 (ly_lily_module_constant ("stencil-whiteout"),
 168                                            retval.smobbed_copy()));
 169         }
 170     }
 171
 172   return retval;
 173 }
 174
 175 /****************************************************************
 176   VIRTUAL STUBS
 177 ****************************************************************/
 178 void
 179 Grob::do_break_processing ()
 180 {
 181 }
 182
 183 void
 184 Grob::discretionary_processing ()
 185 {
 186 }
 187
 188 System *
 189 Grob::get_system () const
 190 {
 191   return 0;
 192 }
 193
 194 /* This version of get_system is more reliable than this->get_system ()
 195    before line-breaking has been done, at which point there is only
 196    one system in the whole score and we can find it just by following
 197    parent pointers. */
 198 System *
 199 Grob::get_system(Grob *me)
 200 {
 201   Grob *p = me->get_parent (X_AXIS);
 202   return p ? get_system (p) : dynamic_cast<System *>(me);
 203 }
 204
 205 void
 206 Grob::handle_broken_dependencies ()
 207 {
 208   Spanner *sp = dynamic_cast<Spanner *> (this);
 209   if (original () && sp)
 210     return;
 211
 212   if (sp)
 213     /* THIS, SP is the original spanner.  We use a special function
 214        because some Spanners have enormously long lists in their
 215        properties, and a special function fixes FOO  */
 216     {
 217       for (SCM s = object_alist_; scm_is_pair (s); s = scm_cdr (s))
 218         sp->substitute_one_mutable_property (scm_caar (s), scm_cdar (s));
 219     }
 220   System *system = get_system ();
 221
 222   if (is_live ()
 223       && system
 224       && common_refpoint (system, X_AXIS)
 225       && common_refpoint (system, Y_AXIS))
 226     substitute_object_links (system->self_scm (), object_alist_);
 227   else if (dynamic_cast<System *> (this))
 228     substitute_object_links (SCM_UNDEFINED, object_alist_);
 229   else
 230     /* THIS element is `invalid'; it has been removed from all
 231        dependencies, so let's junk the element itself.
 232
 233        Do not do this for System, since that would remove references
 234        to the originals of score-grobs, which get then GC'd (a bad
 235        thing).  */
 236     suicide ();
 237 }
 238
 239 /* Note that we still want references to this element to be
 240    rearranged, and not silently thrown away, so we keep pointers like
 241    {broken_into_{drul, array}, original}
 242 */
 243 void
 244 Grob::suicide ()
 245 {
 246   if (!is_live ())
 247     return;
 248
 249   for (int a = X_AXIS; a < NO_AXES; a++)
 250     dim_cache_[a].clear ();
 251
 252   mutable_property_alist_ = SCM_EOL;
 253   object_alist_ = SCM_EOL;
 254   immutable_property_alist_ = SCM_EOL;
 255   interfaces_ = SCM_EOL;
 256 }
 257
 258 void
 259 Grob::handle_prebroken_dependencies ()
 260 {
 261   /* Don't do this in the derived method, since we want to keep access to
 262      object_alist_ centralized.  */
 263   if (original ())
 264     {
 265       Item *it = dynamic_cast<Item *> (this);
 266       substitute_object_links (scm_from_int (it->break_status_dir ()),
 267                                original ()->object_alist_);
 268     }
 269 }
 270
 271 Grob *
 272 Grob::find_broken_piece (System *) const
 273 {
 274   return 0;
 275 }
 276
 277 /****************************************************************
 278    OFFSETS
 279 ****************************************************************/
 280
 281 void
 282 Grob::translate_axis (Real y, Axis a)
 283 {
 284   if (isinf (y) || isnan (y))
 285     {
 286       programming_error (_ ("Infinity or NaN encountered"));
 287       return ;
 288     }
 289
 290   if (!dim_cache_[a].offset_)
 291     dim_cache_[a].offset_ = new Real (y);
 292   else
 293     *dim_cache_[a].offset_ += y;
 294 }
 295
 296 /* Find the offset relative to D.  If D equals THIS, then it is 0.
 297    Otherwise, it recursively defd as
 298
 299    OFFSET_ + PARENT_L_->relative_coordinate (D) */
 300 Real
 301 Grob::relative_coordinate (Grob const *refp, Axis a) const
 302 {
 303   /* eaa - hmmm, should we do a programming_error() here? */
 304   if ((this == NULL) || (refp == this))
 305     return 0.0;
 306
 307   /* We catch PARENT_L_ == nil case with this, but we crash if we did
 308      not ask for the absolute coordinate (ie. REFP == nil.)  */
 309   Real off = get_offset (a);
 310   if (refp == dim_cache_[a].parent_)
 311     return off;
 312
 313   off += dim_cache_[a].parent_->relative_coordinate (refp, a);
 314
 315   return off;
 316 }
 317
 318 Real
 319 Grob::pure_relative_y_coordinate (Grob const *refp, int start, int end)
 320 {
 321   if (refp == this)
 322     return 0.0;
 323
 324   Real off = 0;
 325
 326   if (dim_cache_[Y_AXIS].offset_)
 327     {
 328       if (to_boolean (get_property ("pure-Y-offset-in-progress")))
 329         programming_error ("cyclic chain in pure-Y-offset callbacks");
 330
 331       off = *dim_cache_[Y_AXIS].offset_;
 332     }
 333   else
 334     {
 335       SCM proc = get_property_data ("Y-offset");
 336
 337       dim_cache_[Y_AXIS].offset_ = new Real (0.0);
 338       set_property ("pure-Y-offset-in-progress", SCM_BOOL_T);
 339       off = robust_scm2double (call_pure_function (proc,
 340                                                    scm_list_1 (self_scm ()),
 341                                                    start, end),
 342                                0.0);
 343       del_property ("pure-Y-offset-in-progress");
 344       delete dim_cache_[Y_AXIS].offset_;
 345       dim_cache_[Y_AXIS].offset_ = 0;
 346     }
 347
 348   /* we simulate positioning-done if we are the child of a VerticalAlignment,
 349      but only if we don't have a cached offset. If we do have a cached offset,
 350      it probably means that the Alignment was fixed and it has already been
 351      calculated.
 352   */
 353   if (Grob *p = get_parent (Y_AXIS))
 354     {
 355       Real trans = 0;
 356       if (Align_interface::has_interface (p) && !dim_cache_[Y_AXIS].offset_)
 357         trans = Align_interface::get_pure_child_y_translation (p, this, start, end);
 358
 359       return off + trans + p->pure_relative_y_coordinate (refp, start, end);
 360     }
 361   return off;
 362 }
 363
 364 /* Invoke callbacks to get offset relative to parent.  */
 365 Real
 366 Grob::get_offset (Axis a) const
 367 {
 368   if (dim_cache_[a].offset_)
 369     return *dim_cache_[a].offset_;
 370
 371   Grob *me = (Grob *) this;
 372
 373   SCM sym = axis_offset_symbol (a);
 374   me->dim_cache_[a].offset_ = new Real (0.0);
 375
 376   /*
 377     UGH: can't fold next 2 statements together. Apparently GCC thinks
 378     dim_cache_[a].offset_ is unaliased.
 379   */
 380   Real off = robust_scm2double (internal_get_property (sym), 0.0);
 381   if (me->dim_cache_[a].offset_)
 382     {
 383       *me->dim_cache_[a].offset_ += off;
 384       me->del_property (sym);
 385       return *me->dim_cache_[a].offset_;
 386     }
 387   else
 388     return 0.0;
 389 }
 390
 391 Real
 392 Grob::maybe_pure_coordinate (Grob const *refp, Axis a, bool pure, int start, int end)
 393 {
 394   if (pure && a != Y_AXIS)
 395     programming_error ("tried to get pure X-offset");
 396   return (pure && a == Y_AXIS) ? pure_relative_y_coordinate (refp, start, end)
 397     : relative_coordinate (refp, a);
 398 }
 399
 400 /****************************************************************
 401   extents
 402 ****************************************************************/
 403
 404 void
 405 Grob::flush_extent_cache (Axis axis)
 406 {
 407   if (dim_cache_[axis].extent_)
 408     {
 409       /*
 410         Ugh, this is not accurate; will flush property, causing
 411         callback to be called if.
 412        */
 413       del_property ((axis == X_AXIS) ? ly_symbol2scm ("X-extent") : ly_symbol2scm ("Y-extent"));
 414       delete dim_cache_[axis].extent_;
 415       dim_cache_[axis].extent_ = 0;
 416       if (get_parent (axis))
 417         get_parent (axis)->flush_extent_cache (axis);
 418     }
 419 }
 420
 421
 422 Interval
 423 Grob::extent (Grob *refp, Axis a) const
 424 {
 425   Real offset = relative_coordinate (refp, a);
 426   Interval real_ext;
 427   if (dim_cache_[a].extent_)
 428     {
 429       real_ext = *dim_cache_[a].extent_;
 430     }
 431   else
 432     {
 433       /*
 434         Order is significant: ?-extent may trigger suicide.
 435        */
 436       SCM ext_sym =
 437         (a == X_AXIS)
 438         ? ly_symbol2scm ("X-extent")
 439         : ly_symbol2scm ("Y-extent");
 440
 441       SCM ext = internal_get_property (ext_sym);
 442       if (is_number_pair (ext))
 443         real_ext.unite (ly_scm2interval (ext));
 444
 445       SCM min_ext_sym =
 446         (a == X_AXIS)
 447         ? ly_symbol2scm ("minimum-X-extent")
 448         : ly_symbol2scm ("minimum-Y-extent");
 449       SCM min_ext = internal_get_property (min_ext_sym);
 450       if (is_number_pair (min_ext))
 451         real_ext.unite (ly_scm2interval (min_ext));
 452
 453       ((Grob*)this)->dim_cache_[a].extent_ = new Interval (real_ext);
 454     }
 455
 456   real_ext.translate (offset);
 457
 458   return real_ext;
 459 }
 460
 461 Interval
 462 Grob::pure_height (Grob *refp, int start, int end)
 463 {
 464   SCM iv_scm = get_pure_property ("Y-extent", start, end);
 465   Interval iv = robust_scm2interval (iv_scm, Interval (0, 0));
 466   Real offset = pure_relative_y_coordinate (refp, start, end);
 467
 468   SCM min_ext = get_property ("minimum-Y-extent");
 469
 470   /* we don't add minimum-Y-extent if the extent is empty. This solves
 471      a problem with Hara-kiri spanners. They would request_suicide and
 472      return empty extents, but we would force them here to be large. */
 473   if (!iv.is_empty () && is_number_pair (min_ext))
 474     iv.unite (ly_scm2interval (min_ext));
 475
 476   if (!iv.is_empty ())
 477     iv.translate (offset);
 478   return iv;
 479 }
 480
 481 Interval
 482 Grob::maybe_pure_extent (Grob *refp, Axis a, bool pure, int start, int end)
 483 {
 484   if (pure && a != Y_AXIS)
 485     programming_error ("tried to get pure width");
 486   return (pure && a == Y_AXIS) ? pure_height (refp, start, end) : extent (refp, a);
 487 }
 488
 489 Interval_t<int>
 490 Grob::spanned_rank_interval () const
 491 {
 492   return Interval_t<int> (-1, 0);
 493 }
 494
 495 bool
 496 Grob::pure_is_visible (int /* start */, int /* end */) const
 497 {
 498   return true;
 499 }
 500
 501 /* Sort grobs according to their starting column. */
 502 bool
 503 Grob::less (Grob *g1, Grob *g2)
 504 {
 505   return g1->spanned_rank_interval ()[LEFT] < g2->spanned_rank_interval ()[LEFT];
 506 }
 507
 508 /****************************************************************
 509   REFPOINTS
 510 ****************************************************************/
 511
 512 /* Find the group-element which has both #this# and #s#  */
 513 Grob *
 514 Grob::common_refpoint (Grob const *s, Axis a) const
 515 {
 516   /* I don't like the quadratic aspect of this code, but I see no
 517      other way.  The largest chain of parents might be 10 high or so,
 518      so it shouldn't be a real issue.  */
 519   for (Grob const *c = this; c; c = c->dim_cache_[a].parent_)
 520     for (Grob const *d = s; d; d = d->dim_cache_[a].parent_)
 521       if (d == c)
 522         return (Grob *) d;
 523
 524   return 0;
 525 }
 526
 527 void
 528 Grob::set_parent (Grob *g, Axis a)
 529 {
 530   dim_cache_[a].parent_ = g;
 531 }
 532
 533 Grob *
 534 Grob::get_parent (Axis a) const
 535 {
 536   return dim_cache_[a].parent_;
 537 }
 538
 539
 540 void
 541 Grob::fixup_refpoint ()
 542 {
 543   for (int a = X_AXIS; a < NO_AXES; a++)
 544     {
 545       Axis ax = (Axis)a;
 546       Grob *parent = get_parent (ax);
 547
 548       if (!parent)
 549         continue;
 550
 551       if (parent->get_system () != get_system () && get_system ())
 552         {
 553           Grob *newparent = parent->find_broken_piece (get_system ());
 554           set_parent (newparent, ax);
 555         }
 556
 557       if (Item *i = dynamic_cast<Item *> (this))
 558         {
 559           Item *parenti = dynamic_cast<Item *> (parent);
 560
 561           if (parenti && i)
 562             {
 563               Direction my_dir = i->break_status_dir ();
 564               if (my_dir != parenti->break_status_dir ())
 565                 {
 566                   Item *newparent = parenti->find_prebroken_piece (my_dir);
 567                   set_parent (newparent, ax);
 568                 }
 569             }
 570         }
 571     }
 572 }
 573
 574
 575 /****************************************************************
 576   MESSAGES
 577 ****************************************************************/
 578 void
 579 Grob::warning (string s) const
 580 {
 581   if (get_program_option ("warning-as-error"))
 582     error (s);
 583
 584   SCM cause = self_scm ();
 585   while (Grob *g = unsmob_grob (cause))
 586     cause = g->get_property ("cause");
 587
 588   /* ES TODO: cause can't be Music*/
 589   if (Music *m = unsmob_music (cause))
 590     m->origin ()->warning (s);
 591   else if (Stream_event *ev = unsmob_stream_event (cause))
 592     ev->origin ()->warning (s);
 593   else
 594     ::warning (s);
 595 }
 596
 597
 598 string
 599 Grob::name () const
 600 {
 601   SCM meta = get_property ("meta");
 602   SCM nm = scm_assq (ly_symbol2scm ("name"), meta);
 603   nm = (scm_is_pair (nm)) ? scm_cdr (nm) : SCM_EOL;
 604   return scm_is_symbol (nm) ? ly_symbol2string (nm) : this->class_name ();
 605 }
 606
 607 void
 608 Grob::programming_error (string s) const
 609 {
 610   if (get_program_option ("warning-as-error"))
 611     error (s);
 612
 613   SCM cause = self_scm ();
 614   while (Grob *g = unsmob_grob (cause))
 615     cause = g->get_property ("cause");
 616
 617   s = _f ("programming error: %s", s);
 618
 619   /* ES TODO: cause can't be Music*/
 620   if (Music *m = unsmob_music (cause))
 621     m->origin ()->message (s);
 622   else if (Stream_event *ev = unsmob_stream_event (cause))
 623     ev->origin ()->message (s);
 624   else
 625     ::message (s);
 626 }
 627
 628
 629 ADD_INTERFACE (Grob,
 630                "A grob represents a piece of music notation.\n"
 631                "\n"
 632                "All grobs have an X and Y@tie{}position on the page.  These"
 633                " X and Y@tie{}positions are stored in a relative format, thus"
 634                " they can easily be combined by stacking them, hanging one"
 635                " grob to the side of another, or coupling them into grouping"
 636                " objects.\n"
 637                "\n"
 638                "Each grob has a reference point (a.k.a.@: parent): The"
 639                " position of a grob is stored relative to that reference"
 640                " point.  For example, the X@tie{}reference point of a staccato"
 641                " dot usually is the note head that it applies to.  When the"
 642                " note head is moved, the staccato dot moves along"
 643                " automatically.\n"
 644                "\n"
 645                "A grob is often associated with a symbol, but some grobs do"
 646                " not print any symbols.  They take care of grouping objects."
 647                " For example, there is a separate grob that stacks staves"
 648                " vertically.  The @ref{NoteCollision} object is also an"
 649                " abstract grob: It only moves around chords, but doesn't print"
 650                " anything.\n"
 651                "\n"
 652                "Grobs have properties (Scheme variables) that can be read and"
 653                " set.  Two types of them exist: immutable and mutable."
 654                "  Immutable variables define the default style and behavior."
 655                "  They are shared between many objects.  They can be changed"
 656                " using @code{\\override} and @code{\\revert}.  Mutable"
 657                " properties are variables that are specific to one grob."
 658                "  Typically, lists of other objects, or results from"
 659                " computations are stored in mutable properties.  In"
 660                " particular, every call to @code{ly:grob-set-property!}"
 661                " (or its C++ equivalent) sets a mutable property.\n"
 662                "\n"
 663                "The properties @code{after-line-breaking} and"
 664                " @code{before-line-breaking} are dummies that are not"
 665                " user-serviceable.",
 666
 667                /* properties */
 668                "X-extent "
 669                "X-offset "
 670                "Y-extent "
 671                "Y-offset "
 672                "after-line-breaking "
 673                "avoid-slur "
 674                "axis-group-parent-X "
 675                "axis-group-parent-Y "
 676                "before-line-breaking "
 677                "cause "
 678                "color "
 679                "cross-staff "
 680                "extra-X-extent "
 681                "extra-Y-extent "
 682                "extra-offset "
 683                "interfaces "
 684                "layer "
 685                "meta "
 686                "minimum-X-extent "
 687                "minimum-Y-extent "
 688                "outside-staff-horizontal-padding "
 689                "outside-staff-padding "
 690                "outside-staff-priority "
 691                "pure-Y-offset-in-progress "
 692                "rotation "
 693                "springs-and-rods "
 694                "staff-symbol "
 695                "stencil "
 696                "transparent "
 697                "whiteout "
 698                );
 699
 700 /****************************************************************
 701   CALLBACKS
 702 ****************************************************************/
 703
 704 static SCM
 705 grob_stencil_extent (Grob *me, Axis a)
 706 {
 707   Stencil *m = me->get_stencil ();
 708   Interval e;
 709   if (m)
 710     e = m->extent (a);
 711   return ly_interval2scm (e);
 712 }
 713
 714
 715 MAKE_SCHEME_CALLBACK (Grob, stencil_height, 1);
 716 SCM
 717 Grob::stencil_height (SCM smob)
 718 {
 719   Grob *me = unsmob_grob (smob);
 720   return grob_stencil_extent (me, Y_AXIS);
 721 }
 722
 723 MAKE_SCHEME_CALLBACK (Grob, y_parent_positioning, 1);
 724 SCM
 725 Grob::y_parent_positioning (SCM smob)
 726 {
 727   Grob *me = unsmob_grob (smob);
 728   Grob *par = me->get_parent (Y_AXIS);
 729   if (par)
 730     (void) par->get_property ("positioning-done");
 731
 732   return scm_from_double (0.0);
 733 }
 734
 735
 736 MAKE_SCHEME_CALLBACK (Grob, x_parent_positioning, 1);
 737 SCM
 738 Grob::x_parent_positioning (SCM smob)
 739 {
 740   Grob *me = unsmob_grob (smob);
 741
 742   Grob *par = me->get_parent (X_AXIS);
 743   if (par)
 744     (void) par->get_property ("positioning-done");
 745
 746   return scm_from_double (0.0);
 747 }
 748
 749 MAKE_SCHEME_CALLBACK (Grob, stencil_width, 1);
 750 SCM
 751 Grob::stencil_width (SCM smob)
 752 {
 753   Grob *me = unsmob_grob (smob);
 754   return grob_stencil_extent (me, X_AXIS);
 755 }
 756
 757
 758 Grob *
 759 common_refpoint_of_list (SCM elist, Grob *common, Axis a)
 760 {
 761   for (; scm_is_pair (elist); elist = scm_cdr (elist))
 762     if (Grob *s = unsmob_grob (scm_car (elist)))
 763       {
 764         if (common)
 765           common = common->common_refpoint (s, a);
 766         else
 767           common = s;
 768       }
 769
 770   return common;
 771 }
 772
 773 Grob *
 774 common_refpoint_of_array (vector<Grob*> const &arr, Grob *common, Axis a)
 775 {
 776   for (vsize i = 0; i < arr.size (); i++)
 777     if (common)
 778       common = common->common_refpoint (arr[i], a);
 779     else
 780       common = arr[i];
 781
 782   return common;
 783 }
 784
 785 Interval
 786 robust_relative_extent (Grob *me, Grob *refpoint, Axis a)
 787 {
 788   Interval ext = me->extent (refpoint, a);
 789   if (ext.is_empty ())
 790     ext.add_point (me->relative_coordinate (refpoint, a));
 791
 792   return ext;
 793 }
 794
 795 // Checks whether there is a vertical alignment in the chain of
 796 // parents between this and commony.
 797 bool
 798 Grob::check_cross_staff (Grob *commony)
 799 {
 800   if (Align_interface::has_interface (commony))
 801     return true;
 802
 803   for (Grob *g = this; g && g != commony; g = g->get_parent (Y_AXIS))
 804     if (Align_interface::has_interface (g))
 805       return true;
 806
 807   return false;
 808 }
 809