2 constrained-breaking.hh -- declare a line breaker that
3 supports limits on the number of systems
5 source file of the GNU LilyPond music typesetter
7 (c) 2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
10 #ifndef CONSTRAINED_BREAKING_HH
11 #define CONSTRAINED_BREAKING_HH
13 #include "break-algorithm.hh"
23 Real extent_; /* Y-exent of the system */
24 Real padding_; /* compulsory space after this system (if we're not last on a page) */
25 Real space_; /* spring length (stretches over extent_ but not over padding_) */
35 Line_details::Line_details ()
42 line_break_ = DEFAULT;
43 page_break_ = DEFAULT;
52 Helper to trace back an optimal path
54 struct Constrained_break_node
56 /* the number of bars in all the systems before this one
60 /* unlike the Gourlay breaker, this is the sum of all demerits up to,
61 * and including, this line */
63 struct Line_details details_;
65 Constrained_break_node ()
68 demerits_ = infinity_f;
73 printf ("prev break %d, demerits %f\n", prev_, demerits_);
78 A dynamic programming solution to breaking scores into lines
80 class Constrained_breaking : public Break_algorithm
83 vector<Column_x_positions> solve ();
84 Constrained_breaking ();
85 Constrained_breaking (vector<vsize> const &start_col_posns);
87 vector<Column_x_positions> get_solution(vsize start, vsize end, vsize sys_count);
88 vector<Line_details> get_details (vsize start, vsize end, vsize sys_count);
89 int get_max_systems (vsize start, vsize end);
90 int get_min_systems (vsize start, vsize end);
92 void resize (vsize systems);
98 /* the (i,j)th entry is the configuration for breaking between
100 vector<Line_details> lines_;
103 /* the [i](j,k)th entry is the score for fitting the first k bars onto the
104 first j systems, starting at the i'th allowed starting column */
105 vector<vector<Constrained_break_node> > state_;
107 vector<vsize> start_; /* the columns at which we might be asked to start breaking */
108 vector<vsize> starting_breakpoints_; /* the corresponding index in breaks_ */
111 vector<vsize> breaks_;
113 Column_x_positions space_line (vsize start_col, vsize end_col);
114 void prepare_solution (vsize start, vsize end, vsize sys_count, vsize *rank, vsize *brk);
116 Real combine_demerits (Real force, Real prev_force);
118 bool calc_subproblem(vsize start, vsize systems, vsize max_break_index);
120 #endif /* CONSTRAINED_BREAKING_HH */