Avoid collisions with ledger lines.

[lilypond.git] / lily / staff-symbol.cc

diff --git a/lily/staff-symbol.cc b/lily/staff-symbol.cc
index a6ab40d9093fcc1f58d4120be8a2f92da0a12783..30def52f2881ea93c9610461bbab3d7146a8eb49 100644 (file)
--- a/lily/staff-symbol.cc
+++ b/lily/staff-symbol.cc
@@ -1,9 +1,20 @@
 /*
-  staff-symbol.cc -- implement Staff_symbol
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the GNU LilyPond music typesetter
+  Copyright (C) 1997--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
-  (c) 1997--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  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 "staff-symbol.hh"
@@ -167,17 +178,61 @@ Staff_symbol::height  (SCM smob)
   return ly_interval2scm (y_ext);
 }
 
+bool
+Staff_symbol::on_line (Grob *me, int pos)
+{
+  SCM line_positions = me->get_property ("line-positions");
+  if (scm_is_pair (line_positions))
+    {
+      Real min_line = HUGE_VAL;
+      Real max_line = -HUGE_VAL;
+      for (SCM s = line_positions; scm_is_pair (s); s = scm_cdr (s))
+       {
+         Real current_line = scm_to_double (scm_car (s));
+         if (pos == current_line)
+           return true;
+         if (current_line > max_line)
+           max_line = current_line;
+         if (current_line < min_line)
+           min_line = current_line;
+       
+       }
+      if (pos < min_line)
+       return (( (int) (rint (pos - min_line)) % 2) == 0);
+      if (pos > max_line)
+       return (( (int) (rint (pos - max_line)) % 2) == 0);
 
+      return false;
+    }
+  else
+    return ((abs (pos + line_count (me)) % 2) == 1);
+}
 
+Interval
+Staff_symbol::line_span (Grob *me)
+{
+  SCM line_positions = me->get_property ("line-positions");
+  Interval iv;
 
-ADD_INTERFACE (Staff_symbol,
-              "This spanner draws the lines of a staff. "
-              "A staff symbol definines a vertical unit, the staff space. "
-              "Quantities that go by a half staff space are called positions "
-              "The center (i.e. middle line "
-              "or space) is position 0. The length of the symbol may be set by hand "
-              "through the @code{width} property. ",
+  if (scm_is_pair (line_positions))
+    for (SCM s = line_positions; scm_is_pair (s); s = scm_cdr (s))
+      iv.add_point (scm_to_double (scm_car (s)));
+  else
+    {
+      int count = line_count (me);
+      return Interval (-count + 1, count - 1);
+    }
 
+  return iv;
+}
+
+ADD_INTERFACE (Staff_symbol,
+              "This spanner draws the lines of a staff.  A staff symbol"
+              " defines a vertical unit, the @emph{staff space}.  Quantities"
+              " that go by a half staff space are called @emph{positions}."
+              "  The center (i.e., middle line or space) is position@tie{}0."
+              " The length of the symbol may be set by hand through the"
+              " @code{width} property.",
 
               /* properties */
               "ledger-line-thickness "