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--1998 Han-Wen Nienhuys <hanwen@stack.nl>
   7 */
   8
   9 #include "word-wrap.hh"
  10 #include "paper-def.hh"
  11 #include "p-score.hh"
  12 #include "debug.hh"
  13 #include "p-col.hh"
  14 #include "spring-spacer.hh"
  15
  16
  17 /** el stupido.
  18
  19
  20    A Dynamic Programming type of algorithm
  21    similar to TeX's is in Gourlay_breaking
  22
  23    */
  24 Array<Col_hpositions>
  25 Word_wrap::do_solve() const
  26 {
  27   problem_OK();
  28
  29   PCursor<Paper_column*> curcol (pscore_l_->col_p_list_.top());
  30   Array<Col_hpositions> breaking;
  31   Line_of_cols breakpoints (find_breaks());
  32   assert (breakpoints.size()>=2);
  33
  34   int break_idx_i=0;
  35   int line_no_i = 0;
  36   while (break_idx_i < breakpoints.size() -1)
  37     {
  38       Col_hpositions minimum;
  39       Col_hpositions current;
  40
  41       // do  another line
  42       line_no_i ++;
  43       Paper_column *post = breakpoints[break_idx_i]->postbreak_l();
  44       int start_break_idx = break_idx_i;
  45       current.add (post);
  46       curcol++;         // skip the breakable.
  47       break_idx_i++;
  48
  49       while (break_idx_i < breakpoints.size())
  50         {
  51
  52           // add another measure.
  53           while (breakpoints[break_idx_i] != curcol.ptr())
  54             {
  55               current.add (curcol);
  56               curcol++;
  57             }
  58           current.add (breakpoints[break_idx_i]->prebreak_l());
  59
  60           current.spacer_l_ = generate_spacing_problem (current.cols,
  61             pscore_l_->paper_l_->line_dimensions_int (line_no_i));
  62
  63           // try to solve
  64           if (!feasible (current.cols))
  65             {
  66               if (!minimum.cols.size())
  67                 {
  68                   warning (_("Ugh, this measure is too long, breakpoint: ")
  69                            + String (break_idx_i) +
  70                            _(" (generating stupido solution)"));
  71                   current.stupid_solution();
  72                   current.energy_f_ = - 1; // make sure we break out.
  73                 }
  74               else
  75                 current.energy_f_ = infinity_f; // make sure we go back
  76             }
  77           else
  78             {
  79               current.solve_line();
  80               current.print();
  81             }
  82
  83           delete current.spacer_l_;
  84           current.spacer_l_ =0;
  85
  86           if (!current.satisfies_constraints_b_ && start_break_idx == break_idx_i - 1)
  87             {
  88               warning ( _ ("I don't fit.  Put me on Montignac"));
  89               minimum = current;
  90               break;
  91             }
  92
  93           if (current.energy_f_ < minimum.energy_f_ || current.energy_f_ < 0)
  94             {
  95               minimum = current;
  96             }
  97           else {                // we're one col too far.
  98             break_idx_i--;
  99             while (curcol.ptr() != breakpoints[break_idx_i])
 100               curcol --;
 101             break;              // do the next line.
 102           }
 103
 104
 105           // add nobreak version of breakable column
 106           current.cols.top()=breakpoints[break_idx_i];
 107           curcol ++;
 108           break_idx_i++;
 109         }
 110
 111       *mlog << "[" <<break_idx_i<<"]"<<flush;
 112       breaking.push (minimum);
 113     }
 114   return breaking;
 115 }
 116
 117 Word_wrap::Word_wrap()
 118 {
 119   get_line_spacer = Spring_spacer::constructor;
 120 }