X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fkeep-alive-together-engraver.cc;h=c65ff455313f382a74a1f3c28504da924fbdc5f4;hb=324ff94afc62c7011b7377f24392f95391ed3b84;hp=8cda5a0d5fecec3d4b342a2a4670095079633220;hpb=1c846b2c2348b4e0ca4a3c2e8fb267047ba2d203;p=lilypond.git

diff --git a/lily/keep-alive-together-engraver.cc b/lily/keep-alive-together-engraver.cc
index 8cda5a0d5f..c65ff45531 100644
--- a/lily/keep-alive-together-engraver.cc
+++ b/lily/keep-alive-together-engraver.cc
@@ -1,7 +1,7 @@
 /*
   This file is part of LilyPond, the GNU music typesetter.
 
-  Copyright (C) 2010--2011 Joe Neeman <joeneeman@gmail.com>
+  Copyright (C) 2010--2014 Joe Neeman <joeneeman@gmail.com>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -27,7 +27,7 @@
 
 class Keep_alive_together_engraver: public Engraver
 {
-  vector<Grob*> group_spanners_;
+  vector<Grob *> group_spanners_;
 
 public:
   TRANSLATOR_DECLARATIONS (Keep_alive_together_engraver);
@@ -51,35 +51,61 @@ Keep_alive_together_engraver::finalize ()
 {
   for (vsize i = 0; i < group_spanners_.size (); ++i)
     {
-      SCM grob_array_scm = Grob_array::make_array ();
-      Grob_array *ga = unsmob_grob_array (grob_array_scm);
-
-      // It would make Hara_kiri_group_spanner::request_suicide a _little_
-      // faster if we removed each grob from its own array. It seems
-      // unnecessary for now, though.
-      ga->set_array (group_spanners_);
-      group_spanners_[i]->set_object ("keep-alive-with", grob_array_scm);
+      SCM this_layer = group_spanners_[i]->get_property ("remove-layer");
+      if (scm_is_false (this_layer))
+        continue;
+
+      SCM live_scm = Grob_array::make_array ();
+      Grob_array *live = Grob_array::unsmob (live_scm);
+      SCM dead_scm = Grob_array::make_array ();
+      Grob_array *dead = Grob_array::unsmob (dead_scm);
+
+      for (vsize j = 0; j < group_spanners_.size (); ++j)
+        {
+          if (i == j)
+            continue;
+          SCM that_layer = group_spanners_[j]->get_property ("remove-layer");
+          if (scm_is_false (that_layer))
+            continue;
+          if (!scm_is_integer (this_layer))
+            {
+              // Unspecified layers are kept alive by anything else
+              live->add (group_spanners_[j]);
+              continue;
+            }
+          // an explicit layer is only affected by explicit layers
+          if (!scm_is_integer (that_layer))
+            continue;
+          if (scm_is_true (scm_num_eq_p (that_layer, this_layer)))
+            live->add (group_spanners_[j]);
+          else if (scm_is_true (scm_less_p (that_layer, this_layer)))
+            dead->add (group_spanners_[j]);
+        }
+      if (!live->empty ())
+        group_spanners_[i]->set_object ("keep-alive-with", live_scm);
+      if (!dead->empty ())
+        group_spanners_[i]->set_object ("make-dead-when", dead_scm);
     }
 }
 
 ADD_ACKNOWLEDGER (Keep_alive_together_engraver, hara_kiri_group_spanner);
 
 ADD_TRANSLATOR (Keep_alive_together_engraver,
-		/* doc */
-		"This engraver collects all @code{Hara_kiri_group_spanner}s "
-		"that are created in contexts at or below its own.  "
-		"These spanners are then tied together so that one will "
-		"be removed only if all are removed.  For example, "
-		"if a @code{StaffGroup} uses this engraver, then the staves "
-		"in the group will all be visible as long as there is a note "
-		"in at least one of them.",
-
-		/* create */
-		"",
-
-		/* read */
-		"",
-
-		/* write */
-		""
-		);
+                /* doc */
+                "This engraver collects all @code{Hara_kiri_group_spanner}s "
+                "that are created in contexts at or below its own.  "
+                "These spanners are then tied together so that one will "
+                "be removed only if all are removed.  For example, "
+                "if a @code{StaffGroup} uses this engraver, then the staves "
+                "in the group will all be visible as long as there is a note "
+                "in at least one of them.",
+
+                /* create */
+                "",
+
+                /* read */
+                "",
+
+                /* write */
+                ""
+               );