lily/word-wrap.cc

   1 /*
   2   word-wrap.cc -- implement Word_wrap
   3
   4   source file of the LilyPond music typesetter
   5
   6   (c) 1997 Han-Wen Nienhuys <hanwen@stack.nl>
   7 */
   8
   9 #include "word-wrap.hh"
  10 #include "p-score.hh"
  11 #include "debug.hh"
  12 #include "p-col.hh"
  13 #include "spring-spacer.hh"
  14
  15
  16 /** el stupido.
  17
  18
  19    A Dynamic Programming type of algorithm
  20    similar to TeX's is in Gourlay_breaking
  21
  22    */
  23 Array<Col_hpositions>
  24 Word_wrap::do_solve() const
  25 {
  26   problem_OK();
  27
  28   PCursor<Paper_column*> curcol (pscore_l_->col_p_list_.top());
  29   Array<Col_hpositions> breaking;
  30   Line_of_cols breakpoints (find_breaks());
  31   assert (breakpoints.size()>=2);
  32
  33   int break_idx_i=0;
  34   while (break_idx_i < breakpoints.size() -1)
  35     {
  36       Col_hpositions minimum;
  37       Col_hpositions current;
  38
  39       // do  another line
  40       Paper_column *post = breakpoints[break_idx_i]->postbreak_l();
  41       current.add (post);
  42       curcol++;         // skip the breakable.
  43       break_idx_i++;
  44
  45       while (break_idx_i < breakpoints.size())
  46         {
  47
  48           // add another measure.
  49           while (breakpoints[break_idx_i] != curcol.ptr())
  50             {
  51               current.add (curcol);
  52               curcol++;
  53             }
  54           current.add (breakpoints[break_idx_i]->prebreak_l());
  55
  56           current.spacer_l_ = generate_spacing_problem (current.cols);
  57
  58           // try to solve
  59           if (!feasible (current.cols))
  60             {
  61               if (!minimum.cols.size())
  62                 {
  63                   warning ("Ugh, this measure is too long, breakpoint: "
  64                            + String (break_idx_i) +
  65                            " (generating stupido solution)");
  66                   current.stupid_solution();
  67                   current.energy_f_ = - 1; // make sure we break out.
  68                 }
  69               else
  70                 current.energy_f_ = infinity_f; // make sure we go back
  71             }
  72           else
  73             {
  74
  75               current.solve_line();
  76               current.print();
  77             }
  78
  79           delete current.spacer_l_;
  80           current.spacer_l_ =0;
  81
  82           // update minimum, or backup.
  83           if (current.energy_f_ < minimum.energy_f_ || current.energy_f_ < 0)
  84             {
  85               minimum = current;
  86             }
  87           else {                // we're one col too far.
  88             break_idx_i--;
  89             while (curcol.ptr() != breakpoints[break_idx_i])
  90               curcol --;
  91             break;              // do the next line.
  92           }
  93
  94
  95           // add nobreak version of breakable column
  96           current.cols.top()=breakpoints[break_idx_i];
  97           curcol ++;
  98           break_idx_i++;
  99         }
 100
 101       *mlog << "[" <<break_idx_i<<"]"<<flush;
 102       breaking.push (minimum);
 103     }
 104   print_stats();
 105   return breaking;
 106 }
 107
 108 Word_wrap::Word_wrap()
 109 {
 110   get_line_spacer = Spring_spacer::constructor;
 111 }