X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;ds=inline;f=lily%2Fsimple-spacer.cc;h=1d38d9a70fda59eab91069b691339bd6a7d6b98d;hb=81abebcfecdb22d2e7b6b8e2a6d9f758aa45a13a;hp=4b30033601b29b74c4d14c205b40d5115a14a1f4;hpb=6b876e65197de4fcc073ebc19a5ef744db92c1c9;p=lilypond.git

diff --git a/lily/simple-spacer.cc b/lily/simple-spacer.cc
index 4b30033601..1d38d9a70f 100644
--- a/lily/simple-spacer.cc
+++ b/lily/simple-spacer.cc
@@ -3,7 +3,7 @@
 
   source file of the GNU LilyPond music typesetter
 
-  (c) 1999--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  (c) 1999--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   TODO:
   - add support for different stretch/shrink constants?
@@ -81,8 +81,11 @@ Real
 Simple_spacer::rod_force (int l, int r, Real dist)
 {
   Real d = range_ideal_len (l, r);
-  Real c = range_stiffness (l, r, d > dist);
+  Real c = range_stiffness (l, r, dist > d);
   Real block_stretch = dist - d;
+
+  if (isinf (c) && block_stretch == 0) /* take care of the 0*infinity_f case */
+    return 0;
   return c * block_stretch;
 }
 
@@ -102,7 +105,12 @@ Simple_spacer::add_rod (int l, int r, Real dist)
       Real spring_dist = range_ideal_len (l, r);
       if (spring_dist < dist)
 	for (int i = l; i < r; i++)
-	  springs_[i].set_distance (springs_[i].distance () * dist / spring_dist);
+	  {
+	    if (spring_dist)
+	      springs_[i].set_distance (springs_[i].distance () * dist / spring_dist);
+	    else
+	      springs_[i].set_distance (dist / (r - l));
+	  }
 
       return;
     }
@@ -167,6 +175,9 @@ Simple_spacer::expand_line ()
   for (vsize i=0; i < springs_.size (); i++)
     inv_hooke += springs_[i].inverse_stretch_strength ();
 
+  if (inv_hooke == 0.0) /* avoid division by zero. If springs are infinitely stiff */
+    return 0.0;         /* anyway, then it makes no difference what the force is */
+
   assert (cur_len <= line_len_);
   return (line_len_ - cur_len) / inv_hooke + force_;
 }
@@ -260,7 +271,7 @@ Simple_spacer::force_penalty (bool ragged) const
 
   /* Use a convex compression penalty. */
   Real f = force_;
-  return f - (f < 0 ? f*f*f*f*4 : 0);
+  return f - (f < 0 ? f*f*f*f*2 : 0);
 }
 
 /****************************************************************/