Merge branch 'master' of git://git.savannah.gnu.org/lilypond.git

[lilypond.git] / lily / simple-spacer.cc

diff --git a/lily/simple-spacer.cc b/lily/simple-spacer.cc
index fcad2f18c126897929ce27c4690d994334810ede..4376b0133c2d47942884acb8cce9686311ff8db3 100644 (file)
--- a/lily/simple-spacer.cc
+++ b/lily/simple-spacer.cc
@@ -1,12 +1,23 @@
 /*
-  simple-spacer.cc -- implement Simple_spacer
+  This file is part of LilyPond, the GNU music typesetter.
 
-  source file of the GNU LilyPond music typesetter
-
-  (c) 1999--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
+  Copyright (C) 1999--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   TODO:
   - add support for different stretch/shrink constants?
+
+  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 <cstdio>
@@ -84,7 +95,7 @@ Simple_spacer::rod_force (int l, int r, Real dist)
   Real c = range_stiffness (l, r, dist > d);
   Real block_stretch = dist - d;
 
-  if (isinf (c)) /* take care of the 0*infinity_f case */
+  if (isinf (c) && block_stretch == 0) /* take care of the 0*infinity_f case */
     return 0;
   return c * block_stretch;
 }
@@ -105,7 +116,12 @@ 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;
     }
@@ -180,7 +196,6 @@ Simple_spacer::expand_line ()
 Real
 Simple_spacer::compress_line ()
 {
-  double inv_hooke = 0;
   double cur_len = configuration_length (force_);
   double cur_force = force_;
   bool compressed = false;
@@ -197,21 +212,24 @@ Simple_spacer::compress_line ()
     }
 
   fits_ = true;
-  for (vsize i=0; i < springs_.size (); i++)
-    inv_hooke += compressed
-      ? springs_[i].inverse_compress_strength ()
-      : springs_[i].inverse_stretch_strength ();
 
   assert (line_len_ <= cur_len);
 
   vector<Spring> sorted_springs = springs_;
   sort (sorted_springs.begin (), sorted_springs.end (), greater<Spring> ());
 
-  for (vsize i = 0; i < sorted_springs.size (); i++)
+  /* inv_hooke is the total flexibility of currently-active springs */
+  double inv_hooke = 0;
+  vsize i = sorted_springs.size ();
+  for ( ; i && sorted_springs[i - 1].blocking_force () < cur_force; i--)
+    inv_hooke += compressed
+      ? sorted_springs[i - 1].inverse_compress_strength ()
+      : sorted_springs[i - 1].inverse_stretch_strength ();
+  /* i now indexes the first active spring, so */
+  for ( ; i < sorted_springs.size (); i++)
     {
       Spring sp = sorted_springs[i];
 
-      assert (sp.blocking_force () <= cur_force);
       if (isinf (sp.blocking_force ()))
        break;
 
@@ -229,7 +247,7 @@ Simple_spacer::compress_line ()
        }
       
       cur_len -= block_dist;
-      inv_hooke -= sp.inverse_compress_strength ();
+      inv_hooke -= compressed ? sp.inverse_compress_strength () : sp.inverse_stretch_strength ();
       cur_force = sp.blocking_force ();
     }
 
@@ -266,7 +284,7 @@ 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);
 }
 
 /****************************************************************/