release: 1.2.8

[lilypond.git] / lily / include / simple-spacer.hh

diff --git a/lily/include/simple-spacer.hh b/lily/include/simple-spacer.hh
index 1f6fc479c09714833435adfe94c2441a16f2ec8b..80f7a32904e504633d5e8e80a4b18e742949fc48 100644 (file)
--- a/lily/include/simple-spacer.hh
+++ b/lily/include/simple-spacer.hh
@@ -1,47 +1,87 @@
 /*   
-  simple-spacer.hh -- declare 
+  simple-spacer.hh -- declare Simple_spacer
   
   source file of the GNU LilyPond music typesetter
   
-  (c) 1998 Han-Wen Nienhuys <hanwen@cs.uu.nl>
+  (c) 1999 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   
  */
 
 #ifndef SIMPLE_SPACER_HH
 #define SIMPLE_SPACER_HH
 
-#include "real.hh"
-#include "array.hh"
-#include "lily-proto.hh"
-#include "list.hh"
-#include "drul-array.hh"
+#include "parray.hh"
+#include "line-spacer.hh"
 
-struct Rod_info {
-  Real distance_f_;
-  Drul_array<int> cols_;
-};
-
-struct Spring_info {
-  /// the ideal distance
-  Real space_f_;
 
-  /// Hooke's constant: how strong are the "springs" attached to columns
+struct Spring_description
+{
+  Real ideal_f_;
   Real hooke_f_;
+  bool active_b_;
 
-  Real blocking_stretch_f_;
-  Rod_info * blocking_rod_l_;
-  void set (Idealspacing *);
-  Spring_info();
+  Real block_force_f_;
+
+  Real length (Real force) const;
+  Spring_description ();
+  Real energy_f (Real) const;
 };
 
+/**
+   A simple spacing constraint solver. The approach:
+
+   Stretch the line uniformly until none of the constraints (rods)
+   block.  It then is very wide.
+
+
+      Compress until the next constraint blocks,
+
+      Mark the springs over the constrained part to be non-active.
+      
+   Repeat with the smaller set of non-active constraints, until all
+   constraints blocked, or until the line is as short as desired.
+
+   This is much simpler, and much much faster than full scale
+   Constrained QP. On the other hand, a situation like this will not
+   be typeset as dense as possible, because
 
-class Simple_spring_spacer {
-  Array<Spring_info> springs_;
-  Pointer_list<Rod_info*> rods_;
+   c4                   c4           c4                  c4
+   veryveryverylongsyllable2         veryveryverylongsyllable2
+   " "4                 veryveryverylongsyllable2        syllable4
 
-  void init ();
-  Array<Real> solve ();
+
+   can be further compressed to
+
+
+   c4    c4                        c4   c4
+   veryveryverylongsyllable2       veryveryverylongsyllable2
+   " "4  veryveryverylongsyllable2      syllable4
+
+
+   Perhaps this is not a bad thing, because the 1st looks better anyway.  */
+struct Simple_spacer: public Line_spacer
+{
+  Array<Spring_description> springs_;
+  Real force_f_;
+
+  Simple_spacer ();
   
+  virtual void solve (Column_x_positions *) const;
+  virtual void lower_bound_solution (Column_x_positions *) const;
+  virtual void add_columns (Link_array<Paper_column>);
+    
+  void my_solve_linelen ();
+  void my_solve_natural_len ();
+  Real active_springs_stiffness () const;
+  Real range_stiffness (int, int) const;
+  void add_rod (int l, int r, Real dist);
+  Real range_ideal_len (int l, int r)const;
+  Real active_blocking_force ()const;
+  Real configuration_length ()const;
+  void set_active_states ();
+  Real energy_f () const;
+
+  bool active_b () const;
 };
 
 #endif /* SIMPLE_SPACER_HH */