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--2009 Joe Neeman <joeneeman@gmail.com>
10 #ifndef CONSTRAINED_BREAKING_HH
11 #define CONSTRAINED_BREAKING_HH
13 #include "lily-guile.hh"
19 Interval extent_; /* Y-extent of the system */
21 Real padding_; /* compulsory space after this system (if we're not
24 Real space_; /* spring length */
27 SCM break_permission_;
36 /* The page-breaker deals with forbidden page breaks by "compressing"
37 two Line_detailses into one. The following fields are used by the
38 page-breaker to keep track of this. If the number of fields needed
39 by the page-breaker grows, it might be a good idea to create a separate
41 int compressed_lines_count_;
42 int compressed_nontitle_lines_count_;
51 break_permission_ = ly_symbol2scm ("allow");
52 page_permission_ = ly_symbol2scm ("allow");
53 turn_permission_ = ly_symbol2scm ("allow");
58 compressed_lines_count_ = 1;
59 compressed_nontitle_lines_count_ = 1;
62 Line_details (Prob *pb)
65 extent_ = unsmob_stencil (pb->get_property ("stencil")) ->extent (Y_AXIS);
66 padding_ = robust_scm2double (pb->get_property ("next-padding"), 0);
68 space_ = robust_scm2double (pb->get_property ("next-space"), 1.0);
70 break_permission_ = ly_symbol2scm ("allow");
71 page_permission_ = pb->get_property ("page-break-permission");
72 turn_permission_ = pb->get_property ("page-turn-permission");
74 page_penalty_ = robust_scm2double (pb->get_property ("page-break-penalty"), 0);
75 turn_penalty_ = robust_scm2double (pb->get_property ("page-turn-penalty"), 0);
76 title_ = to_boolean (pb->get_property ("is-title"));
77 compressed_lines_count_ = 1;
78 compressed_nontitle_lines_count_ = title_ ? 0 : 1;
83 Helper to trace back an optimal path
85 struct Constrained_break_node
87 /* the number of bars in all the systems before this one
91 /* unlike the Gourlay breaker, this is the sum of all demerits up to,
92 * and including, this line */
94 struct Line_details details_;
96 Constrained_break_node ()
99 demerits_ = infinity_f;
104 printf ("prev break %d, demerits %f\n", prev_, demerits_);
109 A dynamic programming solution to breaking scores into lines
111 class Constrained_breaking
114 vector<Column_x_positions> solve (vsize start, vsize end, vsize sys_count);
115 vector<Column_x_positions> best_solution (vsize start, vsize end);
116 vector<Line_details> line_details (vsize start, vsize end, vsize sys_count);
118 Constrained_breaking (Paper_score *ps);
119 Constrained_breaking (Paper_score *ps, vector<vsize> const &start_col_posns);
121 int max_system_count (vsize start, vsize end);
122 int min_system_count (vsize start, vsize end);
125 Paper_score *pscore_;
126 vsize valid_systems_;
131 /* the (i,j)th entry is the configuration for breaking between
133 Matrix<Line_details> lines_;
135 /* the [i](j,k)th entry is the score for fitting the first k bars onto the
136 first j systems, starting at the i'th allowed starting column */
137 vector<Matrix<Constrained_break_node> > state_;
139 vector<vsize> start_; /* the columns at which we might be asked to start breaking */
140 vector<vsize> starting_breakpoints_; /* the corresponding index in breaks_ */
143 vector<vsize> breaks_;
146 void resize (vsize systems);
148 Column_x_positions space_line (vsize start_col, vsize end_col);
149 vsize prepare_solution (vsize start, vsize end, vsize sys_count);
151 Real combine_demerits (Real force, Real prev_force);
153 bool calc_subproblem(vsize start, vsize systems, vsize max_break_index);
155 #endif /* CONSTRAINED_BREAKING_HH */