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     demerits_f_ = 0;
  44   }
  45 };
  46
  47 /**
  48   This algorithms is adapted from the OSU Tech report on breaking lines.
  49  */
  50 Array<Column_x_positions>
  51 Gourlay_breaking::do_solve () const
  52 {
  53   Array<Break_node> optimal_paths;
  54   Line_of_cols all = pscore_l_->col_l_arr_ ;
  55   Array<int> breaks = find_break_indices ();
  56
  57   optimal_paths.set_size (breaks.size ());
  58
  59   Break_node first_node ;
  60   first_node.line_config_.energy_f_ = 0;
  61
  62   optimal_paths[0] = first_node;
  63   int break_idx=1;
  64
  65   for (; break_idx< breaks.size (); break_idx++)
  66     {
  67       /*
  68         start with a short line, add measures. At some point
  69         the line becomes infeasible. Then we don't try to add more
  70         */
  71       int minimal_start_idx = -1;
  72       Column_x_positions minimal_sol;
  73       Column_x_positions backup_sol;
  74
  75       Real minimal_demerits = infinity_f;
  76
  77       for (int start_idx = break_idx; start_idx--;)
  78         {
  79           Line_of_cols line = all.slice (breaks[start_idx], breaks[break_idx]+1);
  80
  81           line[0] = dynamic_cast<Paper_column*>(line[0]->find_broken_piece (RIGHT));
  82           line.top () =  dynamic_cast<Paper_column*>(line.top ()->find_broken_piece (LEFT));
  83
  84           Column_x_positions cp;
  85           cp.cols_ = line;
  86
  87           Interval line_dims
  88             = pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_);
  89           Simple_spacer * sp = generate_spacing_problem (line, line_dims);
  90           sp->solve (&cp);
  91           delete sp;
  92
  93           if (start_idx == break_idx - 1)
  94             backup_sol = cp;    // in case everything fucks up
  95           if (!cp.satisfies_constraints_b_)
  96             break;
  97
  98
  99           Real this_demerits;
 100           if (optimal_paths[start_idx].demerits_f_ >= infinity_f)
 101             this_demerits = infinity_f;
 102           else
 103             this_demerits = combine_demerits (optimal_paths[start_idx].line_config_, cp)
 104               + optimal_paths[start_idx].demerits_f_;
 105
 106           if (this_demerits < minimal_demerits)
 107             {
 108               minimal_start_idx = start_idx;
 109               minimal_sol = cp;
 110               minimal_demerits = this_demerits;
 111             }
 112         }
 113
 114       int prev =break_idx - 1;
 115       if (minimal_start_idx < 0)
 116         {
 117           optimal_paths[break_idx].demerits_f_ = infinity_f;
 118           optimal_paths[break_idx].line_config_ = backup_sol;
 119         }
 120       else
 121         {
 122           prev = minimal_start_idx;
 123           optimal_paths[break_idx].line_config_ = minimal_sol;
 124           optimal_paths[break_idx].demerits_f_ = minimal_demerits;
 125         }
 126       optimal_paths[break_idx].prev_break_i_ = prev;
 127       optimal_paths[break_idx].line_i_ = optimal_paths[prev].line_i_ + 1;
 128
 129       if (! (break_idx % HAPPY_DOTS_I))
 130         *mlog << "[" << break_idx << "]" << flush;
 131     }
 132
 133   /* do the last one */
 134   if  (break_idx % HAPPY_DOTS_I)
 135     *mlog << "[" << break_idx << "]";
 136
 137   *mlog << endl;
 138
 139   Array<int> final_breaks;
 140   Array<Column_x_positions> lines;
 141
 142   /* skip 0-th element, since it is a "dummy" elt*/
 143   for (int i = optimal_paths.size ()-1; i> 0;)
 144     {
 145       final_breaks.push (i);
 146       int prev = optimal_paths[i].prev_break_i_;
 147       assert (i > prev);
 148       i = prev;
 149     }
 150
 151   if (optimal_paths.top ().demerits_f_ >= infinity_f)
 152     warning (_ ("No feasible line breaking found"));
 153
 154   for (int i= final_breaks.size (); i--;)
 155     lines.push (optimal_paths[final_breaks[i]].line_config_);
 156
 157   return lines;
 158 }
 159
 160
 161 Gourlay_breaking::Gourlay_breaking ()
 162 {
 163   energy_bound_f_ = infinity_f;
 164   max_measures_i_ = INT_MAX;
 165 }
 166
 167 void
 168 Gourlay_breaking::do_set_pscore ()
 169 {
 170   max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));
 171 }
 172
 173
 174 /*
 175   TODO: uniformity parameter to control rel. importance of spacing differences.
 176  */
 177 Real
 178 Gourlay_breaking::combine_demerits (Column_x_positions const &prev,
 179                                     Column_x_positions const &this_one) const
 180 {
 181   Real break_penalties = 0.0;
 182   Paper_column * pc = this_one.cols_.top ();
 183   if (pc->original_l_)
 184     {
 185       SCM pen = pc->get_elt_property (penalty_scm_sym);
 186       if (pen != SCM_BOOL_F)
 187         {
 188           break_penalties += gh_scm2double (SCM_CDR(pen));
 189         }
 190     }
 191
 192   return abs (this_one.force_f_) + abs (prev.force_f_ - this_one.force_f_)
 193     + break_penalties;
 194 }