2 gourlay-breaking.cc -- implement Gourlay_breaking
4 source file of the GNU LilyPond music typesetter
6 (c) 1997--2000 Han-Wen Nienhuys <hanwen@cs.uu.nl>
8 #include <math.h> // rint
10 #include "gourlay-breaking.hh"
11 #include "column-x-positions.hh"
13 #include "paper-column.hh"
14 #include "paper-score.hh"
15 #include "paper-def.hh"
16 #include "simple-spacer.hh"
17 #include "line-of-score.hh"
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
32 Which system number so far?
37 Column_x_positions line_config_;
48 This algorithms is adapted from the OSU Tech report on breaking lines.
50 this function is longish, but not very complicated.
53 Array<Column_x_positions>
54 Gourlay_breaking::do_solve () const
56 Array<Break_node> optimal_paths;
57 Link_array<Paper_column> all =
58 pscore_l_->line_l_->column_l_arr ();
60 Array<int> breaks = find_break_indices ();
62 optimal_paths.set_size (breaks.size ());
64 Break_node first_node ;
65 first_node.line_config_.energy_f_ = 0;
67 optimal_paths[0] = first_node;
70 for (; break_idx< breaks.size (); break_idx++)
73 start with a short line, add measures. At some point
74 the line becomes infeasible. Then we don't try to add more
76 int minimal_start_idx = -1;
77 Column_x_positions minimal_sol;
78 Column_x_positions backup_sol;
80 Real minimal_demerits = infinity_f;
82 for (int start_idx = break_idx; start_idx--;)
84 Link_array<Paper_column> line = all.slice (breaks[start_idx], breaks[break_idx]+1);
86 line[0] = dynamic_cast<Paper_column*>(line[0]->find_broken_piece (RIGHT));
87 line.top () = dynamic_cast<Paper_column*>(line.top ()->find_broken_piece (LEFT));
89 Column_x_positions cp;
93 = pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_);
94 Simple_spacer * sp = generate_spacing_problem (line, line_dims);
98 if (start_idx == break_idx - 1)
99 backup_sol = cp; // in case everything fucks up
100 if (!cp.satisfies_constraints_b_)
105 if (optimal_paths[start_idx].demerits_f_ >= infinity_f)
106 this_demerits = infinity_f;
108 this_demerits = combine_demerits (optimal_paths[start_idx].line_config_, cp)
109 + optimal_paths[start_idx].demerits_f_;
111 if (this_demerits < minimal_demerits)
113 minimal_start_idx = start_idx;
115 minimal_demerits = this_demerits;
119 int prev =break_idx - 1;
120 if (minimal_start_idx < 0)
122 optimal_paths[break_idx].demerits_f_ = infinity_f;
123 optimal_paths[break_idx].line_config_ = backup_sol;
127 prev = minimal_start_idx;
128 optimal_paths[break_idx].line_config_ = minimal_sol;
129 optimal_paths[break_idx].demerits_f_ = minimal_demerits;
131 optimal_paths[break_idx].prev_break_i_ = prev;
132 optimal_paths[break_idx].line_i_ = optimal_paths[prev].line_i_ + 1;
134 if (! (break_idx % HAPPY_DOTS_I))
135 progress_indication (String ("[") + to_str (break_idx) + "]");
138 /* do the last one */
139 if (break_idx % HAPPY_DOTS_I)
140 progress_indication (String ("[") + to_str (break_idx) + "]");
143 progress_indication ("\n");
145 Array<int> final_breaks;
146 Array<Column_x_positions> lines;
148 /* skip 0-th element, since it is a "dummy" elt*/
149 for (int i = optimal_paths.size ()-1; i> 0;)
151 final_breaks.push (i);
152 int prev = optimal_paths[i].prev_break_i_;
157 if (optimal_paths.top ().demerits_f_ >= infinity_f)
158 warning (_ ("No feasible line breaking found"));
160 for (int i= final_breaks.size (); i--;)
161 lines.push (optimal_paths[final_breaks[i]].line_config_);
167 Gourlay_breaking::Gourlay_breaking ()
169 energy_bound_f_ = infinity_f;
175 TODO: uniformity parameter to control rel. importance of spacing differences.
178 Gourlay_breaking::combine_demerits (Column_x_positions const &prev,
179 Column_x_positions const &this_one) const
181 Real break_penalties = 0.0;
182 Paper_column * pc = this_one.cols_.top ();
185 SCM pen = pc->get_elt_property ("penalty");
186 if (gh_number_p (pen))
188 break_penalties += gh_scm2double (pen);
192 return abs (this_one.force_f_) + abs (prev.force_f_ - this_one.force_f_)