X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fstaff-symbol.cc;h=6fefc48010750e7daa9b2f9ed0078305047eff4b;hb=97e2736adbb9fde2121d9fcea436ac98a4453e7e;hp=3604be85a33bc1a5118a0aef52a7fb66da46dfde;hpb=6fb6249345ce846c8c55f843b21c6e85024a720b;p=lilypond.git

diff --git a/lily/staff-symbol.cc b/lily/staff-symbol.cc
index 3604be85a3..6fefc48010 100644
--- a/lily/staff-symbol.cc
+++ b/lily/staff-symbol.cc
@@ -167,16 +167,43 @@ 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);
+}
 
 ADD_INTERFACE (Staff_symbol,
-	       "This spanner draws the lines of a staff.  A staff symbol "
-	       "defines a vertical unit, the @empf{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.",
+	       "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 "