Pango: Skip glyph lookups for zero-width characters.

[lilypond.git] / lily / page-turn-page-breaking.cc

diff --git a/lily/page-turn-page-breaking.cc b/lily/page-turn-page-breaking.cc
index e239cc2f2854f3a5b416e554541f50e9813658d5..c9029cf7b53e649fde6ff4455b468976b9c9117c 100644 (file)
--- a/lily/page-turn-page-breaking.cc
+++ b/lily/page-turn-page-breaking.cc
@@ -1,9 +1,20 @@
 /*
-  page-turn-page-breaking.cc -- implement Page_turn_page_breaking
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the GNU LilyPond music typesetter
+  Copyright (C) 2006--2009 Joe Neeman <joeneeman@gmail.com>
 
-  (c) 2006--2008 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 "page-turn-page-breaking.hh"
@@ -21,7 +32,17 @@
 static bool
 is_break (Grob *g)
 {
-  return scm_is_symbol (g->get_property ("page-turn-permission"));
+  bool turnable = scm_is_symbol (g->get_property ("page-turn-permission"));
+
+  if (turnable &&
+      (!scm_is_symbol (g->get_property ("page-break-permission"))
+       || !scm_is_symbol (g->get_property ("line-break-permission"))))
+    {
+      programming_error ("found a page-turnable place which was not breakable");
+      turnable = false;
+    }
+
+  return turnable;
 }
 
 Page_turn_page_breaking::Page_turn_page_breaking (Paper_book *pb)