bool
Hara_kiri_group_spanner::request_suicide (Grob *me, int start, int end)
+{
+ if (!request_suicide_alone (me, start, end))
+ return false;
+
+ extract_grob_set (me, "keep-alive-with", friends);
+ for (vsize i = 0; i < friends.size (); ++i)
+ if (friends[i]->is_live () && !request_suicide_alone (friends[i], start, end))
+ return false;
+
+ return true;
+}
+
+bool
+Hara_kiri_group_spanner::request_suicide_alone (Grob *me, int start, int end)
{
if (!to_boolean (me->get_property ("remove-empty")))
return false;
/* properties */
"items-worth-living "
"important-column-ranks "
+ "keep-alive-with "
"remove-empty "
"remove-first "
);
--- /dev/null
+/*
+ This file is part of LilyPond, the GNU music typesetter.
+
+ Copyright (C) 2010 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
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ LilyPond is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "context.hh"
+#include "dispatcher.hh"
+#include "engraver.hh"
+#include "grob.hh"
+#include "grob-array.hh"
+
+#include "translator.icc"
+
+class Keep_alive_together_engraver: public Engraver
+{
+ vector<Grob*> group_spanners_;
+
+public:
+ TRANSLATOR_DECLARATIONS (Keep_alive_together_engraver);
+ DECLARE_ACKNOWLEDGER (hara_kiri_group_spanner);
+
+ virtual void finalize ();
+};
+
+Keep_alive_together_engraver::Keep_alive_together_engraver ()
+{
+}
+
+void
+Keep_alive_together_engraver::acknowledge_hara_kiri_group_spanner (Grob_info i)
+{
+ group_spanners_.push_back (i.grob ());
+}
+
+void
+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);
+ }
+}
+
+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 */
+ ""
+ );