lily/gourlay-breaking.cc

   1 /*
   2   gourlay-breaking.cc -- implement Gourlay_breaking
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--1999 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "gourlay-breaking.hh"
  10 #include "column-x-positions.hh"
  11 #include "debug.hh"
  12 #include "paper-column.hh"
  13 #include "paper-score.hh"
  14 #include "paper-def.hh"
  15 #include "simple-spacer.hh"
  16
  17 #include "killing-cons.tcc"
  18
  19 /// How often to print operator pacification marks?
  20 const int HAPPY_DOTS_I = 3;
  21
  22 /**
  23   Helper to trace back an optimal path
  24  */
  25 struct Break_node {
  26   /** this was the previous. If negative, this break should not be
  27     considered: this path has infinite energy
  28
  29     */
  30   int prev_break_i_;
  31   /**
  32      Which system number so far?
  33    */
  34   int line_i_;
  35
  36   Real demerits_f_;
  37   Column_x_positions line_config_;
  38
  39   Break_node ()
  40   {
  41     prev_break_i_ = -1;
  42     line_i_ = 0;
  43   }
  44 };
  45
  46 /**
  47   This algorithms is adapted from the OSU Tech report on breaking lines.
  48  */
  49 Array<Column_x_positions>
  50 Gourlay_breaking::do_solve () const
  51 {
  52   Array<Break_node> optimal_paths;
  53   Line_of_cols all = pscore_l_->col_l_arr_ ;
  54   Array<int> breaks = find_break_indices ();
  55
  56   optimal_paths.set_size (breaks.size ());
  57
  58   Break_node first_node ;
  59   first_node.prev_break_i_ = -1;
  60   first_node.line_config_.force_f_ = 0;
  61   first_node.line_config_.energy_f_ = 0;
  62   first_node.line_i_ = 0;
  63
  64   optimal_paths[0] = first_node;
  65   int break_idx=1;
  66
  67   for (; break_idx< breaks.size (); break_idx++)
  68     {
  69       /*
  70         start with a short line, add measures. At some point
  71         the line becomes infeasible. Then we don't try to add more
  72         */
  73       int minimal_start_idx = -1;
  74       Column_x_positions minimal_sol;
  75       Real minimal_demerits = infinity_f;
  76
  77       for (int start_idx = break_idx; start_idx--;)
  78         {
  79 #if 0
  80           if  (break_idx - start_idx > max_measures_i_)
  81             break;
  82 #endif
  83
  84           if (optimal_paths[start_idx].prev_break_i_ < 0
  85               && optimal_paths[start_idx].line_config_.energy_f_)
  86             continue;
  87
  88
  89
  90           Line_of_cols line = all.slice (breaks[start_idx], breaks[break_idx]+1);
  91
  92           line[0] = dynamic_cast<Paper_column*>(line[0]->find_broken_piece (RIGHT));
  93           line.top () =  dynamic_cast<Paper_column*>(line.top ()->find_broken_piece (LEFT));
  94
  95           if (!feasible (line))
  96             break;
  97
  98           Column_x_positions cp;
  99           cp.cols_ = line;
 100
 101           Interval line_dims
 102             = pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_);
 103           Simple_spacer * sp = generate_spacing_problem (line, line_dims);
 104           sp->solve (&cp);
 105           delete sp;
 106
 107           if (!cp.satisfies_constraints_b_)
 108             break;
 109
 110           Real this_demerits
 111             = combine_demerits (optimal_paths[start_idx].line_config_, cp)
 112             + optimal_paths[start_idx].demerits_f_;
 113
 114           if (this_demerits < minimal_demerits)
 115             {
 116               minimal_start_idx = start_idx;
 117               minimal_sol = cp;
 118               minimal_demerits = this_demerits;
 119             }
 120         }
 121
 122       if (minimal_start_idx < 0)
 123         {
 124           optimal_paths[break_idx].prev_break_i_ = -1;
 125           optimal_paths[break_idx].line_config_.energy_f_ = infinity_f;
 126         }
 127       else
 128         {
 129           optimal_paths[break_idx].prev_break_i_ = minimal_start_idx;
 130           optimal_paths[break_idx].line_config_ = minimal_sol;
 131           optimal_paths[break_idx].demerits_f_ = minimal_demerits;
 132           optimal_paths[break_idx].line_i_ =
 133             optimal_paths[minimal_start_idx].line_i_ + 1;
 134         }
 135
 136       if (! (break_idx % HAPPY_DOTS_I))
 137         *mlog << "[" << break_idx << "]" << flush;
 138     }
 139
 140   /* do the last one */
 141   if  (break_idx % HAPPY_DOTS_I)
 142     *mlog << "[" << break_idx << "]";
 143
 144   *mlog << endl;
 145
 146   Array<int> final_breaks;
 147   Array<Column_x_positions> lines;
 148
 149   /* skip 0-th element, since it is a "dummy" elt*/
 150   for (int i = optimal_paths.size ()-1; i> 0;)
 151     {
 152       final_breaks.push (i);
 153       assert (i > optimal_paths[i].prev_break_i_);
 154
 155       // there was no "feasible path"
 156       if (!optimal_paths[i].line_config_.config_.size ()) {
 157         final_breaks.set_size (0);
 158         break;
 159       }
 160       i = optimal_paths[i].prev_break_i_;
 161     }
 162
 163
 164   for (int i= final_breaks.size (); i--;)
 165     lines.push (optimal_paths[final_breaks[i]].line_config_);
 166
 167   return lines;
 168 }
 169
 170
 171 Gourlay_breaking::Gourlay_breaking ()
 172 {
 173   energy_bound_f_ = infinity_f;
 174   max_measures_i_ = INT_MAX;
 175 }
 176
 177 void
 178 Gourlay_breaking::do_set_pscore ()
 179 {
 180   max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));
 181 }
 182
 183
 184 /*
 185   TODO: uniformity parameter to control rel. importance of spacing differences.
 186  */
 187 Real
 188 Gourlay_breaking::combine_demerits (Column_x_positions const &prev,
 189                                     Column_x_positions const &this_one) const
 190 {
 191   return abs (this_one.force_f_) + abs (prev.force_f_ - this_one.force_f_);
 192 }