2 gourlay-breaking.cc -- implement Gourlay_breaking
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--1999 Han-Wen Nienhuys <hanwen@cs.uu.nl>
9 #include "gourlay-breaking.hh"
11 #include "spring-spacer.hh"
13 #include "paper-column.hh"
14 #include "paper-score.hh"
15 #include "paper-def.hh"
17 #include "killing-cons.tcc"
19 /// How often to print operator pacification marks?
20 const int HAPPY_DOTS_I = 3;
23 Helper to trace back an optimal path
26 /** this was the previous. If negative, this break should not be
27 considered: this path has infinite energy
33 Column_x_positions line_config_;
42 This algorithms is adapted from the OSU Tech report on breaking lines.
46 Array<Column_x_positions>
47 Gourlay_breaking::do_solve () const
49 Array<Break_node> optimal_paths;
50 Line_of_cols all = pscore_l_->col_l_arr_ ;
51 Array<int> breaks = find_break_indices ();
53 optimal_paths.set_size (breaks.size ());
55 Break_node first_node ;
56 first_node.prev_break_i_ = -1;
57 first_node.line_config_.energy_f_ = 0;
58 first_node.line_i_ = 0;
60 optimal_paths[0] = first_node;
64 for (; break_idx< breaks.size (); break_idx++)
66 Array<int> candidates;
67 Array<Column_x_positions> candidate_lines;
68 Cons_list<Line_spacer> spacer_p_list;
71 start with a short line, add measures. At some point
72 the line becomes infeasible. Then we don't try to add more
74 for (int start_idx = break_idx; start_idx--;)
76 if (break_idx - start_idx > max_measures_i_)
79 if (optimal_paths[start_idx].prev_break_i_ < 0
80 && optimal_paths[start_idx].line_config_.energy_f_)
84 Line_of_cols line = all.slice (breaks[start_idx], breaks[break_idx]+1);
86 line[0] = dynamic_cast<Paper_column*>(line[0]->find_prebroken_piece (RIGHT));
87 line.top () = dynamic_cast<Paper_column*>(line.top ()->find_prebroken_piece (LEFT));
92 Column_x_positions approx;
95 approx.spacer_l_ = generate_spacing_problem (line,
96 pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_));
97 spacer_p_list.append (new Killing_cons<Line_spacer> (approx.spacer_l_,0));
99 ( (Break_algorithm*)this)->approx_stats_.add (approx.cols);
100 approx.approximate_solve_line ();
102 if (approx.energy_f_ > energy_bound_f_)
108 // this is a likely candidate. Store it.
109 candidate_lines.push (approx);
110 candidates.push (start_idx);
115 Real minimal_energy = infinity_f;
116 for (int j=0; j < candidates.size (); j++)
118 int start = candidates[j];
119 if (optimal_paths[start].line_config_.energy_f_
120 + candidate_lines[j].energy_f_ > minimal_energy)
124 if (!candidate_lines[j].satisfies_constraints_b_)
126 candidate_lines[j].solve_line ();
127 ( (Break_algorithm*)this)->exact_stats_.add (candidate_lines[j].cols);
131 = optimal_paths[start].line_config_.energy_f_
132 + candidate_lines[j].energy_f_ ;
134 if (this_energy < minimal_energy)
137 minimal_energy = this_energy;
143 optimal_paths[break_idx].prev_break_i_ = -1;
144 optimal_paths[break_idx].line_config_.energy_f_ = infinity_f;
148 optimal_paths[break_idx].prev_break_i_ = candidates[minimal_j];
149 optimal_paths[break_idx].line_config_ = candidate_lines[minimal_j];
150 optimal_paths[break_idx].line_i_ =
151 optimal_paths[optimal_paths[break_idx].prev_break_i_].line_i_ + 1;
154 if (! (break_idx % HAPPY_DOTS_I))
155 *mlog << "[" << break_idx << "]" << flush;
157 spacer_p_list.junk ();
160 if (break_idx % HAPPY_DOTS_I)
161 *mlog << "[" << break_idx << "]" << flush;
163 Array<int> final_breaks;
165 Array<Column_x_positions> lines;
167 /* skip 0-th element, since it is a "dummy" elt*/
168 for (int i = optimal_paths.size ()-1; i> 0;)
170 final_breaks.push (i);
171 assert (i > optimal_paths[i].prev_break_i_);
173 // there was no "feasible path"
174 if (!optimal_paths[i].line_config_.config.size ()) {
175 final_breaks.set_size (0);
178 i = optimal_paths[i].prev_break_i_;
182 for (int i= final_breaks.size (); i--;)
183 lines.push (optimal_paths[final_breaks[i]].line_config_);
189 Gourlay_breaking::Gourlay_breaking ()
191 get_line_spacer = Spring_spacer::constructor;
192 energy_bound_f_ = infinity_f;
193 max_measures_i_ = INT_MAX;
197 Gourlay_breaking::do_set_pscore ()
199 energy_bound_f_ = pscore_l_->paper_l_->get_var ("gourlay_energybound");
200 max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));