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<Score_element> 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 ;
66 optimal_paths[0] = first_node;
69 for (; break_idx< breaks.size (); break_idx++)
72 start with a short line, add measures. At some point
73 the line becomes infeasible. Then we don't try to add more
75 int minimal_start_idx = -1;
76 Column_x_positions minimal_sol;
77 Column_x_positions backup_sol;
79 Real minimal_demerits = infinity_f;
81 for (int start_idx = break_idx; start_idx--;)
83 Link_array<Score_element> line = all.slice (breaks[start_idx], breaks[break_idx]+1);
85 line[0] = dynamic_cast<Item*> (line[0]) ->find_prebroken_piece (RIGHT);
86 line.top () = dynamic_cast<Item*> (line.top ())->find_prebroken_piece (LEFT);
88 Column_x_positions cp;
92 = pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_);
93 Simple_spacer * sp = generate_spacing_problem (line, line_dims);
97 if (start_idx == break_idx - 1)
98 backup_sol = cp; // in case everything fucks up
99 if (!cp.satisfies_constraints_b_)
104 if (optimal_paths[start_idx].demerits_f_ >= infinity_f)
105 this_demerits = infinity_f;
107 this_demerits = combine_demerits (optimal_paths[start_idx].line_config_, cp)
108 + optimal_paths[start_idx].demerits_f_;
110 if (this_demerits < minimal_demerits)
112 minimal_start_idx = start_idx;
114 minimal_demerits = this_demerits;
118 int prev =break_idx - 1;
119 if (minimal_start_idx < 0)
121 optimal_paths[break_idx].demerits_f_ = infinity_f;
122 optimal_paths[break_idx].line_config_ = backup_sol;
126 prev = minimal_start_idx;
127 optimal_paths[break_idx].line_config_ = minimal_sol;
128 optimal_paths[break_idx].demerits_f_ = minimal_demerits;
130 optimal_paths[break_idx].prev_break_i_ = prev;
131 optimal_paths[break_idx].line_i_ = optimal_paths[prev].line_i_ + 1;
133 if (! (break_idx % HAPPY_DOTS_I))
134 progress_indication (String ("[") + to_str (break_idx) + "]");
137 /* do the last one */
138 if (break_idx % HAPPY_DOTS_I)
139 progress_indication (String ("[") + to_str (break_idx) + "]");
142 progress_indication ("\n");
144 Array<int> final_breaks;
145 Array<Column_x_positions> lines;
147 /* skip 0-th element, since it is a "dummy" elt*/
148 for (int i = optimal_paths.size ()-1; i> 0;)
150 final_breaks.push (i);
151 int prev = optimal_paths[i].prev_break_i_;
156 if (optimal_paths.top ().demerits_f_ >= infinity_f)
157 warning (_ ("No feasible line breaking found"));
159 for (int i= final_breaks.size (); i--;)
160 lines.push (optimal_paths[final_breaks[i]].line_config_);
166 Gourlay_breaking::Gourlay_breaking ()
173 TODO: uniformity parameter to control rel. importance of spacing differences.
176 Gourlay_breaking::combine_demerits (Column_x_positions const &prev,
177 Column_x_positions const &this_one) const
179 Real break_penalties = 0.0;
180 Score_element * pc = this_one.cols_.top ();
183 SCM pen = pc->get_elt_property ("penalty");
184 if (gh_number_p (pen))
186 break_penalties += gh_scm2double (pen);
190 return abs (this_one.force_f_) + abs (prev.force_f_ - this_one.force_f_)