Run `make grand-replace'.

[lilypond.git] / lily / axis-group-interface.cc

diff --git a/lily/axis-group-interface.cc b/lily/axis-group-interface.cc
index e87a108e7a200e9a7bb8247432290bab164b6f21..cc6ff24fc7d6a30fda4f7764b83cb9695bcface8 100644 (file)
--- a/lily/axis-group-interface.cc
+++ b/lily/axis-group-interface.cc
@@ -3,7 +3,7 @@
 
   source file of the GNU LilyPond music typesetter
 
 
   source file of the GNU LilyPond music typesetter
 

-  (c) 2000--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  (c) 2000--2008 Han-Wen Nienhuys <hanwen@xs4all.nl>

 */
 
 #include "axis-group-interface.hh"
 */
 
 #include "axis-group-interface.hh"


@@ -14,9 +14,12 @@
 #include "grob-array.hh"
 #include "hara-kiri-group-spanner.hh"
 #include "international.hh"
 #include "grob-array.hh"
 #include "hara-kiri-group-spanner.hh"
 #include "international.hh"

+#include "lookup.hh"

 #include "paper-column.hh"
 #include "paper-score.hh"
 #include "separation-item.hh"
 #include "paper-column.hh"
 #include "paper-score.hh"
 #include "separation-item.hh"

+#include "skyline-pair.hh"
+#include "stencil.hh"

 #include "system.hh"
 #include "warn.hh"
 
 #include "system.hh"
 #include "warn.hh"
 


@@ -61,9 +64,12 @@ Axis_group_interface::relative_group_extent (vector<Grob*> const &elts,
   for (vsize i = 0; i < elts.size (); i++)
     {
       Grob *se = elts[i];
   for (vsize i = 0; i < elts.size (); i++)
     {
       Grob *se = elts[i];

-      Interval dims = se->extent (common, a);
-      if (!dims.is_empty ())
-       r.unite (dims);
+      if (!to_boolean (se->get_property ("cross-staff")))
+       {
+         Interval dims = se->extent (common, a);
+         if (!dims.is_empty ())
+           r.unite (dims);
+       }

     }
   return r;
 }
     }
   return r;
 }


@@ -77,63 +83,94 @@ Axis_group_interface::relative_group_extent (vector<Grob*> const &elts,
 */
 
 Interval
 */
 
 Interval

-Axis_group_interface::cached_pure_height (Grob *me,
-                                         vector<Grob*> const &elts,
-                                         Grob *common,
-                                         int start, int end)
+Axis_group_interface::cached_pure_height (Grob *me, int start, int end)

 {
   Paper_score *ps = get_root_system (me)->paper_score ();
   vector<vsize> breaks = ps->get_break_indices ();
   vector<Grob*> cols = ps->get_columns ();
 {
   Paper_score *ps = get_root_system (me)->paper_score ();
   vector<vsize> breaks = ps->get_break_indices ();
   vector<Grob*> cols = ps->get_columns ();

-  vsize start_index = VPOS;
-  vsize end_index = VPOS;

 
 

-  for (vsize i = 0; i < breaks.size (); i++)
+  SCM extents = me->get_property ("adjacent-pure-heights");
+
+  if (!scm_is_vector (extents))
+    return Interval (0, 0);
+
+  Interval ext;
+  for (vsize i = 0; i + 1 < breaks.size (); i++)

     {
       int r = Paper_column::get_rank (cols[breaks[i]]);
     {
       int r = Paper_column::get_rank (cols[breaks[i]]);

-      if (start == r)
-       start_index = i;
-      if (end == r)
-       end_index = i;
-    }
-  if (end == INT_MAX)
-    end_index = breaks.size () - 1;
+      if (r >= end)
+       break;

 
 

-  if (start_index == VPOS || end_index == VPOS)
-    {
-      programming_error (_ ("tried to calculate pure-height at a non-breakpoint"));
-      return Interval (0, 0);
+      if (r >= start)
+       ext.unite (ly_scm2interval (scm_c_vector_ref (extents, i)));

     }
 
     }
 

-  SCM extents = me->get_property ("cached-pure-extents");
-  if (!scm_is_vector (extents))
+  return ext;
+}
+
+MAKE_SCHEME_CALLBACK (Axis_group_interface, adjacent_pure_heights, 1)
+SCM
+Axis_group_interface::adjacent_pure_heights (SCM smob)
+{
+  Grob *me = unsmob_grob (smob);
+
+  Grob *common = calc_pure_elts_and_common (me);
+  extract_grob_set (me, "pure-relevant-items", items);
+  extract_grob_set (me, "pure-relevant-spanners", spanners);
+
+  Paper_score *ps = get_root_system (me)->paper_score ();
+  vector<vsize> breaks = ps->get_break_indices ();
+  vector<Grob*> cols = ps->get_columns ();
+
+  SCM ret = scm_c_make_vector (breaks.size () - 1, SCM_EOL);
+  vsize it_index = 0;
+  for (vsize i = 0; i + 1 < breaks.size (); i++)

     {
     {

-      extents = scm_c_make_vector (breaks.size () - 1, SCM_EOL);
-      for (vsize i = 0; i + 1 < breaks.size (); i++)
+      int start = Paper_column::get_rank (cols[breaks[i]]);
+      int end = Paper_column::get_rank (cols[breaks[i+1]]);
+      Interval iv;
+
+      for (vsize j = it_index; j < items.size (); j++)

        {
        {

-         int st = Paper_column::get_rank (cols[breaks[i]]);
-         int ed = Paper_column::get_rank (cols[breaks[i+1]]);
-         Interval iv = relative_pure_height (me, elts, common, st, ed, false);
-         scm_vector_set_x (extents, scm_from_int (i), ly_interval2scm (iv));
+         Item *it = dynamic_cast<Item*> (items[j]);
+         int rank = it->get_column ()->get_rank ();
+
+         if (rank <= end && it->pure_is_visible (start, end)
+             && !to_boolean (it->get_property ("cross-staff")))
+           {
+             Interval dims = items[j]->pure_height (common, start, end);
+             if (!dims.is_empty ())
+               iv.unite (dims);
+           }
+
+         if (rank < end)
+           it_index++;
+         else if (rank > end)
+           break;

        }
        }

-      me->set_property ("cached-pure-extents", extents);
-    }

 
 

-  Interval ext (0, 0);
-  for (vsize i = start_index; i < end_index; i++)
-    ext.unite (ly_scm2interval (scm_c_vector_ref (extents, i)));
-  return ext;
+      for (vsize j = 0; j < spanners.size (); j++)
+       {
+         Interval_t<int> rank_span = spanners[j]->spanned_rank_interval ();
+         if (rank_span[LEFT] <= end && rank_span[RIGHT] >= start
+             && !to_boolean (spanners[j]->get_property ("cross-staff")))
+           {
+             Interval dims = spanners[j]->pure_height (common, start, end);
+             if (!dims.is_empty ())
+               iv.unite (dims);
+           }
+       }
+
+      scm_vector_set_x (ret, scm_from_int (i), ly_interval2scm (iv));
+    }
+  return ret;

 }
 
 Interval
 }
 
 Interval

-Axis_group_interface::relative_pure_height (Grob *me,
-                                           vector<Grob*> const &elts,
-                                           Grob *common,
-                                           int start, int end,
-                                           bool use_cache)
+Axis_group_interface::relative_pure_height (Grob *me, int start, int end)

 {
   /* It saves a _lot_ of time if we assume a VerticalAxisGroup is additive
 {
   /* It saves a _lot_ of time if we assume a VerticalAxisGroup is additive

-     (ie. height (i, k) = height (i, j) + height (j, k) for all i <= j <= k).
+     (ie. height (i, k) = max (height (i, j) height (j, k)) for all i <= j <= k).

      Unfortunately, it isn't always true, particularly if there is a
      VerticalAlignment somewhere in the descendants.
 
      Unfortunately, it isn't always true, particularly if there is a
      VerticalAlignment somewhere in the descendants.
 


@@ -142,18 +179,38 @@ Axis_group_interface::relative_pure_height (Grob *me,
      reasonably safe to assume that if our parent is a VerticalAlignment,
      we can assume additivity and cache things nicely. */
   Grob *p = me->get_parent (Y_AXIS);
      reasonably safe to assume that if our parent is a VerticalAlignment,
      we can assume additivity and cache things nicely. */
   Grob *p = me->get_parent (Y_AXIS);

-  if (use_cache && p && Align_interface::has_interface (p))
-    return Axis_group_interface::cached_pure_height (me, elts, common, start, end);
+  if (p && Align_interface::has_interface (p))
+    return Axis_group_interface::cached_pure_height (me, start, end);
+
+  Grob *common = calc_pure_elts_and_common (me);
+  extract_grob_set (me, "pure-relevant-items", items);
+  extract_grob_set (me, "pure-relevant-spanners", spanners);

 
   Interval r;
 
 
   Interval r;
 

-  for (vsize i = 0; i < elts.size (); i++)
+  for (vsize i = 0; i < items.size (); i++)

     {
     {

-      Interval_t<int> rank_span = elts[i]->spanned_rank_iv ();
-      Item *it = dynamic_cast<Item*> (elts[i]);
-      if (rank_span[LEFT] <= end && rank_span[RIGHT] >= start && (!it || it->pure_is_visible (start, end)))
+      Item *it = dynamic_cast<Item*> (items[i]);
+      int rank = it->get_column ()->get_rank ();
+
+      if (rank > end)
+       break;
+      else if (rank >= start && it->pure_is_visible (start, end)
+              && !to_boolean (it->get_property ("cross-staff")))
+       {
+         Interval dims = it->pure_height (common, start, end);
+         if (!dims.is_empty ())
+           r.unite (dims);
+       }
+    }
+
+  for (vsize i = 0; i < spanners.size (); i++)
+    {
+      Interval_t<int> rank_span = spanners[i]->spanned_rank_interval ();
+      if (rank_span[LEFT] <= end && rank_span[RIGHT] >= start
+         && !to_boolean (spanners[i]->get_property ("cross-staff")))

        {
        {

-         Interval dims = elts[i]->pure_height (common, start, end);
+         Interval dims = spanners[i]->pure_height (common, start, end);

          if (!dims.is_empty ())
            r.unite (dims);
        }
          if (!dims.is_empty ())
            r.unite (dims);
        }


@@ -196,7 +253,7 @@ Axis_group_interface::pure_height (SCM smob, SCM start_scm, SCM end_scm)
        return scm_cdr (system_y_extent);
     }
 
        return scm_cdr (system_y_extent);
     }
 

-  return pure_group_height (me, start, end);
+  return ly_interval2scm (pure_group_height (me, start, end));

 }
 
 MAKE_SCHEME_CALLBACK (Axis_group_interface, calc_skylines, 1);
 }
 
 MAKE_SCHEME_CALLBACK (Axis_group_interface, calc_skylines, 1);


@@ -205,7 +262,9 @@ Axis_group_interface::calc_skylines (SCM smob)
 {
   Grob *me = unsmob_grob (smob);
   extract_grob_set (me, "elements", elts);
 {
   Grob *me = unsmob_grob (smob);
   extract_grob_set (me, "elements", elts);

-  return skyline_spacing (me, elts).smobbed_copy ();
+  Skyline_pair skylines = skyline_spacing (me, elts);
+
+  return skylines.smobbed_copy ();

 }
 
 /* whereas calc_skylines calculates skylines for axis-groups with a lot of
 }
 
 /* whereas calc_skylines calculates skylines for axis-groups with a lot of


@@ -221,18 +280,21 @@ Axis_group_interface::combine_skylines (SCM smob)
   Grob *me = unsmob_grob (smob);
   extract_grob_set (me, "elements", elements);
   Grob *y_common = common_refpoint_of_array (elements, me, Y_AXIS);
   Grob *me = unsmob_grob (smob);
   extract_grob_set (me, "elements", elements);
   Grob *y_common = common_refpoint_of_array (elements, me, Y_AXIS);

+  Grob *x_common = common_refpoint_of_array (elements, me, X_AXIS);

 
 

-  assert (y_common == me);
+  if (y_common != me)
+    programming_error ("combining skylines that don't belong to me");

 
   Skyline_pair ret;
   for (vsize i = 0; i < elements.size (); i++)
     {
 
   Skyline_pair ret;
   for (vsize i = 0; i < elements.size (); i++)
     {

-      SCM skyline_scm = elements[i]->get_property ("skylines");
+      SCM skyline_scm = elements[i]->get_property ("vertical-skylines");

       if (Skyline_pair::unsmob (skyline_scm))
        {
          Real offset = elements[i]->relative_coordinate (y_common, Y_AXIS);
          Skyline_pair other = *Skyline_pair::unsmob (skyline_scm);
          other.raise (offset);
       if (Skyline_pair::unsmob (skyline_scm))
        {
          Real offset = elements[i]->relative_coordinate (y_common, Y_AXIS);
          Skyline_pair other = *Skyline_pair::unsmob (skyline_scm);
          other.raise (offset);

+         other.shift (elements[i]->relative_coordinate (x_common, X_AXIS));

          ret.merge (other);
        }
     }
          ret.merge (other);
        }
     }


@@ -243,7 +305,8 @@ SCM
 Axis_group_interface::generic_group_extent (Grob *me, Axis a)
 {
   /* trigger the callback to do skyline-spacing on the children */
 Axis_group_interface::generic_group_extent (Grob *me, Axis a)
 {
   /* trigger the callback to do skyline-spacing on the children */

-  (void) me->get_property ("skylines");
+  if (a == Y_AXIS)
+    (void) me->get_property ("vertical-skylines");

 
   extract_grob_set (me, "elements", elts);
   Grob *common = common_refpoint_of_array (elts, me, a);
 
   extract_grob_set (me, "elements", elts);
   Grob *common = common_refpoint_of_array (elts, me, a);


@@ -254,6 +317,22 @@ Axis_group_interface::generic_group_extent (Grob *me, Axis a)
   return ly_interval2scm (r - my_coord);
 }
 
   return ly_interval2scm (r - my_coord);
 }
 

+/* This is like generic_group_extent, but it only counts the grobs that
+   are children of some other axis-group. This is uncached; if it becomes
+   commonly used, it may be necessary to cache it somehow. */
+Interval
+Axis_group_interface::staff_extent (Grob *me, Grob *refp, Axis ext_a, Grob *staff, Axis parent_a)
+{
+  extract_grob_set (me, "elements", elts);
+  vector<Grob*> new_elts;
+
+  for (vsize i = 0; i < elts.size (); i++)
+    if (elts[i]->common_refpoint (staff, parent_a) == staff)
+      new_elts.push_back (elts[i]);
+
+  return relative_group_extent (new_elts, refp, ext_a);
+}
+

 
 Grob *
 Axis_group_interface::calc_pure_elts_and_common (Grob *me)
 
 Grob *
 Axis_group_interface::calc_pure_elts_and_common (Grob *me)


@@ -263,13 +342,20 @@ Axis_group_interface::calc_pure_elts_and_common (Grob *me)
   
   extract_grob_set (me, "elements", elts);
 
   
   extract_grob_set (me, "elements", elts);
 

-  vector<Grob*> relevant_elts;
+  vector<Grob*> relevant_items;
+  vector<Grob*> relevant_spanners;

   SCM pure_relevant_p = ly_lily_module_constant ("pure-relevant?");
 
   for (vsize i = 0; i < elts.size (); i++)
     {
       if (to_boolean (scm_apply_1 (pure_relevant_p, elts[i]->self_scm (), SCM_EOL)))
   SCM pure_relevant_p = ly_lily_module_constant ("pure-relevant?");
 
   for (vsize i = 0; i < elts.size (); i++)
     {
       if (to_boolean (scm_apply_1 (pure_relevant_p, elts[i]->self_scm (), SCM_EOL)))

-       relevant_elts.push_back (elts[i]);
+       {
+         if (dynamic_cast<Item*> (elts[i]))
+           relevant_items.push_back (elts[i]);
+         else if (dynamic_cast<Spanner*> (elts[i]))
+           relevant_spanners.push_back (elts[i]);
+       }
+           

 
       Item *it = dynamic_cast<Item*> (elts[i]);
       Direction d = LEFT;
 
       Item *it = dynamic_cast<Item*> (elts[i]);
       Direction d = LEFT;


@@ -278,54 +364,66 @@ Axis_group_interface::calc_pure_elts_and_common (Grob *me)
          {
            Item *piece = it->find_prebroken_piece (d);
            if (piece && to_boolean (scm_apply_1 (pure_relevant_p, piece->self_scm (), SCM_EOL)))
          {
            Item *piece = it->find_prebroken_piece (d);
            if (piece && to_boolean (scm_apply_1 (pure_relevant_p, piece->self_scm (), SCM_EOL)))

-             relevant_elts.push_back (piece);
+             relevant_items.push_back (piece);

          }
        while (flip (&d) != LEFT);
     }
          }
        while (flip (&d) != LEFT);
     }

+  vector_sort (relevant_items, Item::less);
+
+  Grob *common = common_refpoint_of_array (relevant_items, me, Y_AXIS);
+  common = common_refpoint_of_array (relevant_spanners, common, Y_AXIS);

 
 

-  Grob *common = common_refpoint_of_array (relevant_elts, me, Y_AXIS);

   me->set_object ("pure-Y-common", common->self_scm ());
   
   me->set_object ("pure-Y-common", common->self_scm ());
   

-  SCM ga_scm = Grob_array::make_array ();
-  Grob_array *ga = unsmob_grob_array (ga_scm);
-  ga->set_array (relevant_elts);
-  me->set_object ("pure-relevant-elements", ga_scm);
+  SCM items_scm = Grob_array::make_array ();
+  SCM spanners_scm = Grob_array::make_array ();
+
+  unsmob_grob_array (items_scm)->set_array (relevant_items);
+  unsmob_grob_array (spanners_scm)->set_array (relevant_spanners);
+  me->set_object ("pure-relevant-items", items_scm);
+  me->set_object ("pure-relevant-spanners", spanners_scm);

 
   return common;
 }
 
 
   return common;
 }
 

-MAKE_SCHEME_CALLBACK(Axis_group_interface,calc_x_common, 1);

 SCM
 SCM

-Axis_group_interface::calc_x_common (SCM grob)
+Axis_group_interface::calc_common (Grob *me, Axis axis)

 {
 {

-  Grob *me = unsmob_grob (grob);
-

   extract_grob_set (me, "elements", elts);
   extract_grob_set (me, "elements", elts);

-  Grob *common = common_refpoint_of_array (elts, me, X_AXIS);
+  Grob *common = common_refpoint_of_array (elts, me, axis);
+  if (!common)
+    {
+      me->programming_error ("No common parent found in calc_common axis.");
+      return SCM_EOL;
+    }
+  

   return common->self_scm ();
 }
 
   return common->self_scm ();
 }
 

-MAKE_SCHEME_CALLBACK(Axis_group_interface,calc_y_common, 1);
+
+MAKE_SCHEME_CALLBACK (Axis_group_interface, calc_x_common, 1);

 SCM
 SCM

-Axis_group_interface::calc_y_common (SCM grob)
+Axis_group_interface::calc_x_common (SCM grob)

 {
 {

-  Grob *me = unsmob_grob (grob);
-
-  extract_grob_set (me, "elements", elts);
-  Grob *common = common_refpoint_of_array (elts, me, Y_AXIS);
-  return common->self_scm ();
+  return calc_common (unsmob_grob (grob), X_AXIS);

 }
 
 }
 

+MAKE_SCHEME_CALLBACK (Axis_group_interface, calc_y_common, 1);

 SCM
 SCM

+Axis_group_interface::calc_y_common (SCM grob)
+{
+  return calc_common (unsmob_grob (grob), Y_AXIS);
+}
+
+Interval

 Axis_group_interface::pure_group_height (Grob *me, int start, int end)
 {
   Grob *common = calc_pure_elts_and_common (me);
        
 Axis_group_interface::pure_group_height (Grob *me, int start, int end)
 {
   Grob *common = calc_pure_elts_and_common (me);
        

-  extract_grob_set (me, "pure-relevant-elements", elts);

   Real my_coord = me->relative_coordinate (common, Y_AXIS);
   Real my_coord = me->relative_coordinate (common, Y_AXIS);

-  Interval r (relative_pure_height (me, elts, common, start, end, true));
+  Interval r (relative_pure_height (me, start, end));

 
 

-  return ly_interval2scm (r - my_coord);
+  return r - my_coord;

 }
 
 void
 }
 
 void


@@ -355,6 +453,12 @@ staff_priority_less (Grob * const &g1, Grob * const &g2)
   else if (priority_1 > priority_2)
     return false;
 
   else if (priority_1 > priority_2)
     return false;
 

+  /* if neither grob has an outside-staff priority, the ordering will have no
+     effect -- we just need to choose a consistent ordering. We do this to
+     avoid the side-effect of calculating extents. */
+  if (isinf (priority_1))
+    return g1 < g2;
+

   /* if there is no preference in staff priority, choose the left-most one */
   Grob *common = g1->common_refpoint (g2, X_AXIS);
   Real start_1 = g1->extent (common, X_AXIS)[LEFT];
   /* if there is no preference in staff priority, choose the left-most one */
   Grob *common = g1->common_refpoint (g2, X_AXIS);
   Real start_1 = g1->extent (common, X_AXIS)[LEFT];


@@ -363,17 +467,27 @@ staff_priority_less (Grob * const &g1, Grob * const &g2)
 }
 
 static void
 }
 
 static void

-add_boxes (Grob *me, Grob *x_common, Grob *y_common, vector<Box> *const boxes)
+add_boxes (Grob *me, Grob *x_common, Grob *y_common, vector<Box> *const boxes, Skyline_pair *skylines)

 {
 {

-  /* if we are a parent, consider the children's boxes instead of mine */
-  if (Grob_array *elements = unsmob_grob_array (me->get_object ("elements")))
+  /* if a child has skylines, use them instead of the extent box */
+  if (Skyline_pair *pair = Skyline_pair::unsmob (me->get_property ("vertical-skylines")))
+    {
+      Skyline_pair s = *pair;
+      s.shift (me->relative_coordinate (x_common, X_AXIS));
+      s.raise (me->relative_coordinate (y_common, Y_AXIS));
+      skylines->merge (s);
+    }
+  else if (Grob_array *elements = unsmob_grob_array (me->get_object ("elements")))

     {
       for (vsize i = 0; i < elements->size (); i++)
     {
       for (vsize i = 0; i < elements->size (); i++)

-       add_boxes (elements->grob (i), x_common, y_common, boxes);
+       add_boxes (elements->grob (i), x_common, y_common, boxes, skylines);
+    }
+  else if (!scm_is_number (me->get_property ("outside-staff-priority"))
+          && !to_boolean (me->get_property ("cross-staff")))
+    {
+      boxes->push_back (Box (me->extent (x_common, X_AXIS),
+                            me->extent (y_common, Y_AXIS)));

     }
     }

-  else if (!scm_is_number (me->get_property ("outside-staff-priority")))
-    boxes->push_back (Box (me->extent (x_common, X_AXIS),
-                          me->extent (y_common, Y_AXIS)));

 }
 
 /* We want to avoid situations like this:
 }
 
 /* We want to avoid situations like this:


@@ -391,7 +505,7 @@ add_boxes (Grob *me, Grob *x_common, Grob *y_common, vector<Box> *const boxes)
    positions, one for above the staff, one for below).
 
    In each pass, we loop through the unplaced grobs from left to right.
    positions, one for above the staff, one for below).
 
    In each pass, we loop through the unplaced grobs from left to right.

-   If the grob overlaps the right-most affected position, we place it
+   If the grob doesn't overlap the right-most affected position, we place it

    (and then update the right-most affected position to point to the right
    edge of the just-placed grob).  Otherwise, we skip it until the next pass.
 */
    (and then update the right-most affected position to point to the right
    edge of the just-placed grob).  Otherwise, we skip it until the next pass.
 */


@@ -427,9 +541,7 @@ add_grobs_of_one_priority (Skyline_pair *const skylines,
          if (b[X_AXIS][LEFT] - 2*horizon_padding < last_affected_position[dir])
            continue;
 
          if (b[X_AXIS][LEFT] - 2*horizon_padding < last_affected_position[dir])
            continue;
 

-         if (b[X_AXIS].is_empty () || b[Y_AXIS].is_empty ())
-           warning (_f ("outside-staff object %s has an empty extent", elements[i]->name ().c_str ()));
-         else
+         if (!b[X_AXIS].is_empty () && !b[Y_AXIS].is_empty ())

            {
              boxes.clear ();
              boxes.push_back (b);
            {
              boxes.clear ();
              boxes.push_back (b);


@@ -455,9 +567,27 @@ add_grobs_of_one_priority (Skyline_pair *const skylines,
     }
 }
 
     }
 }
 

+// TODO: it is tricky to correctly handle skyline placement of cross-staff grobs.
+// For example, cross-staff beams cannot be formatted until the distance between
+// staves is known and therefore any grobs that depend on the beam cannot be placed
+// until the skylines are known. On the other hand, the distance between staves should
+// really depend on position of the cross-staff grobs that lie between them.
+// Currently, we just leave cross-staff grobs out of the
+// skyline altogether, but this could mean that staves are placed so close together
+// that there is no room for the cross-staff grob. It also means, of course, that
+// we don't get the benefits of skyline placement for cross-staff grobs.

 Skyline_pair
 Axis_group_interface::skyline_spacing (Grob *me, vector<Grob*> elements)
 {
 Skyline_pair
 Axis_group_interface::skyline_spacing (Grob *me, vector<Grob*> elements)
 {

+  /* For grobs with an outside-staff-priority, the sorting function might
+     call extent and cause suicide. This breaks the contract that is required
+     for the STL sort function. To avoid this, we make sure that any suicides
+     are triggered beforehand.
+  */
+  for (vsize i = 0; i < elements.size (); i++)
+    if (scm_is_number (elements[i]->get_property ("outside-staff-priority")))
+      elements[i]->extent (elements[i], X_AXIS);
+

   vector_sort (elements, staff_priority_less);
   Grob *x_common = common_refpoint_of_array (elements, me, X_AXIS);
   Grob *y_common = common_refpoint_of_array (elements, me, Y_AXIS);
   vector_sort (elements, staff_priority_less);
   Grob *x_common = common_refpoint_of_array (elements, me, X_AXIS);
   Grob *y_common = common_refpoint_of_array (elements, me, Y_AXIS);


@@ -467,13 +597,20 @@ Axis_group_interface::skyline_spacing (Grob *me, vector<Grob*> elements)
   vsize i = 0;
   vector<Box> boxes;
 
   vsize i = 0;
   vector<Box> boxes;
 

+  Skyline_pair skylines;

   for (i = 0; i < elements.size ()
         && !scm_is_number (elements[i]->get_property ("outside-staff-priority")); i++)
   for (i = 0; i < elements.size ()
         && !scm_is_number (elements[i]->get_property ("outside-staff-priority")); i++)

-    add_boxes (elements[i], x_common, y_common, &boxes);
+    if (!to_boolean (elements[i]->get_property ("cross-staff")))
+      add_boxes (elements[i], x_common, y_common, &boxes, &skylines);

 
 

-  Skyline_pair skylines (boxes, 0, X_AXIS);
+  SCM padding_scm = me->get_property ("skyline-horizontal-padding");
+  Real padding = robust_scm2double (padding_scm, 0.1);
+  skylines.merge (Skyline_pair (boxes, padding, X_AXIS));

   for (; i < elements.size (); i++)
     {
   for (; i < elements.size (); i++)
     {

+      if (to_boolean (elements[i]->get_property ("cross-staff")))
+       continue;
+

       SCM priority = elements[i]->get_property ("outside-staff-priority");
       vector<Grob*> current_elts;
       current_elts.push_back (elements[i]);
       SCM priority = elements[i]->get_property ("outside-staff-priority");
       vector<Grob*> current_elts;
       current_elts.push_back (elements[i]);


@@ -483,6 +620,7 @@ Axis_group_interface::skyline_spacing (Grob *me, vector<Grob*> elements)
 
       add_grobs_of_one_priority (&skylines, current_elts, x_common, y_common);
     }
 
       add_grobs_of_one_priority (&skylines, current_elts, x_common, y_common);
     }

+  skylines.shift (-me->relative_coordinate (x_common, X_AXIS));

   return skylines;
 }
 
   return skylines;
 }
 


@@ -501,18 +639,39 @@ Axis_group_interface::calc_max_stretch (SCM smob)
   return scm_from_double (ret);
 }
 
   return scm_from_double (ret);
 }
 

-ADD_INTERFACE (Axis_group_interface,
+MAKE_SCHEME_CALLBACK (Axis_group_interface, print, 1)
+SCM
+Axis_group_interface::print (SCM smob)
+{
+  if (!debug_skylines)
+    return SCM_BOOL_F;
+
+  Grob *me = unsmob_grob (smob);
+  Stencil ret;
+  if (Skyline_pair *s = Skyline_pair::unsmob (me->get_property ("vertical-skylines")))
+    {
+      ret.add_stencil (Lookup::points_to_line_stencil (0.1, (*s)[UP].to_points (X_AXIS))
+                      .in_color (255, 0, 255));
+      ret.add_stencil (Lookup::points_to_line_stencil (0.1, (*s)[DOWN].to_points (X_AXIS))
+                      .in_color (0, 255, 255));
+    }
+  return ret.smobbed_copy ();
+}

 
 

+ADD_INTERFACE (Axis_group_interface,

               "An object that groups other layout objects.",
 
               /* properties */
               "X-common "
               "Y-common "
               "An object that groups other layout objects.",
 
               /* properties */
               "X-common "
               "Y-common "

+              "adjacent-pure-heights "

               "axes "
               "elements "
               "axes "
               "elements "

+              "keep-fixed-while-stretching "

               "max-stretch "
               "max-stretch "

+              "no-alignment "

               "pure-Y-common "
               "pure-Y-common "

-              "pure-relevant-elements "
-              "skylines "
-              "cached-pure-extents "
+              "pure-relevant-items "
+              "pure-relevant-spanners "
+              "vertical-skylines "

               );
               );