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       Column_x_positions backup_sol;
  76
  77       Real minimal_demerits = infinity_f;
  78
  79       for (int start_idx = break_idx; start_idx--;)
  80         {
  81           Line_of_cols line = all.slice (breaks[start_idx], breaks[break_idx]+1);
  82
  83           line[0] = dynamic_cast<Paper_column*>(line[0]->find_broken_piece (RIGHT));
  84           line.top () =  dynamic_cast<Paper_column*>(line.top ()->find_broken_piece (LEFT));
  85
  86           Column_x_positions cp;
  87           cp.cols_ = line;
  88
  89           Interval line_dims
  90             = pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_);
  91           Simple_spacer * sp = generate_spacing_problem (line, line_dims);
  92           sp->solve (&cp);
  93           delete sp;
  94
  95           if (start_idx == break_idx - 1)
  96             backup_sol = cp;    // in case everything fucks up
  97           if (!cp.satisfies_constraints_b_)
  98             break;
  99
 100
 101           Real this_demerits;
 102           if (optimal_paths[start_idx].demerits_f_ >= infinity_f)
 103             this_demerits = infinity_f;
 104           else
 105             this_demerits = combine_demerits (optimal_paths[start_idx].line_config_, cp)
 106               + optimal_paths[start_idx].demerits_f_;
 107
 108           if (this_demerits < minimal_demerits)
 109             {
 110               minimal_start_idx = start_idx;
 111               minimal_sol = cp;
 112               minimal_demerits = this_demerits;
 113             }
 114         }
 115
 116       int prev =break_idx - 1;
 117       if (minimal_start_idx < 0)
 118         {
 119           optimal_paths[break_idx].demerits_f_ = infinity_f;
 120           optimal_paths[break_idx].line_config_ = backup_sol;
 121         }
 122       else
 123         {
 124           prev = minimal_start_idx;
 125           optimal_paths[break_idx].line_config_ = minimal_sol;
 126           optimal_paths[break_idx].demerits_f_ = minimal_demerits;
 127         }
 128       optimal_paths[break_idx].prev_break_i_ = prev;
 129       optimal_paths[break_idx].line_i_ = optimal_paths[prev].line_i_ + 1;
 130
 131       if (! (break_idx % HAPPY_DOTS_I))
 132         *mlog << "[" << break_idx << "]" << flush;
 133     }
 134
 135   /* do the last one */
 136   if  (break_idx % HAPPY_DOTS_I)
 137     *mlog << "[" << break_idx << "]";
 138
 139   *mlog << endl;
 140
 141   Array<int> final_breaks;
 142   Array<Column_x_positions> lines;
 143
 144   /* skip 0-th element, since it is a "dummy" elt*/
 145   for (int i = optimal_paths.size ()-1; i> 0;)
 146     {
 147       final_breaks.push (i);
 148       int prev = optimal_paths[i].prev_break_i_;
 149       assert (i > prev);
 150       i = prev;
 151     }
 152
 153   if (optimal_paths.top ().demerits_f_ >= infinity_f)
 154     warning (_ ("No feasible line breaking found"));
 155
 156   for (int i= final_breaks.size (); i--;)
 157     lines.push (optimal_paths[final_breaks[i]].line_config_);
 158
 159   return lines;
 160 }
 161
 162
 163 Gourlay_breaking::Gourlay_breaking ()
 164 {
 165   energy_bound_f_ = infinity_f;
 166   max_measures_i_ = INT_MAX;
 167 }
 168
 169 void
 170 Gourlay_breaking::do_set_pscore ()
 171 {
 172   max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));
 173 }
 174
 175
 176 /*
 177   TODO: uniformity parameter to control rel. importance of spacing differences.
 178  */
 179 Real
 180 Gourlay_breaking::combine_demerits (Column_x_positions const &prev,
 181                                     Column_x_positions const &this_one) const
 182 {
 183   Real break_penalties = 0.0;
 184   Paper_column * pc = this_one.cols_.top ();
 185   if (pc->original_l_)
 186     {
 187       SCM pen = pc->get_elt_property (penalty_scm_sym);
 188       if (pen != SCM_BOOL_F)
 189         {
 190           break_penalties += gh_scm2double (SCM_CDR(pen));
 191         }
 192     }
 193
 194   return abs (this_one.force_f_) + abs (prev.force_f_ - this_one.force_f_)
 195     + break_penalties;
 196 }