2 optimal-page-breaking.cc -- implement a page-breaker that
3 will break pages in such a way that both horizontal and
4 vertical spacing will be acceptable
6 source file of the GNU LilyPond music typesetter
8 (c) 2006--2007 Joe Neeman <joeneeman@gmail.com>
11 #include "international.hh"
12 #include "optimal-page-breaking.hh"
13 #include "output-def.hh"
14 #include "page-spacing.hh"
15 #include "paper-book.hh"
16 #include "paper-score.hh"
23 (void) g; /* shutup warning */
27 Optimal_page_breaking::Optimal_page_breaking (Paper_book *pb)
28 : Page_breaking (pb, is_break)
32 Optimal_page_breaking::~Optimal_page_breaking ()
37 Optimal_page_breaking::solve ()
39 vsize end = breaks_.size () - 1;
40 vsize min_sys_count = 0;
41 vsize ideal_sys_count = 0;
42 vsize max_sys_count = max_system_count (0, end);
44 Line_division ideal_line_division;
45 Line_division best_division;
47 vsize first_page_num = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
49 /* find out the ideal number of pages */
50 message (_ ("Finding the ideal number of pages..."));
51 set_to_ideal_line_configuration (0, end);
52 ideal_line_division = current_configuration (0);
54 Spacing_result best = space_systems_on_best_pages (0, first_page_num);
55 page_count = best.systems_per_page_.size ();
56 best_division = ideal_line_division;
58 for (vsize i = 0; i < page_count; i++)
59 ideal_sys_count += best.systems_per_page_[i];
61 min_sys_count = ideal_sys_count - best.systems_per_page_.back ();
63 min_sys_count -= best.systems_per_page_[page_count - 2];
65 message (_f ("Fitting music on %d (or one fewer) pages...", (int)page_count));
66 /* try a smaller number of systems than the ideal number for line breaking */
67 bound = ideal_line_division;
68 for (vsize sys_count = ideal_sys_count; --sys_count >= min_sys_count;)
70 Spacing_result best_for_this_sys_count;
71 set_current_breakpoints (0, end, sys_count, Line_division (), bound);
73 for (vsize i = 0; i < current_configuration_count (); i++)
75 vsize min_p_count = min_page_count (i, first_page_num);
78 if (min_p_count > page_count)
80 else if (min_p_count == page_count)
81 cur = space_systems_on_n_pages (i, page_count, first_page_num);
83 cur = space_systems_on_n_or_one_more_pages (i, page_count-1, first_page_num);
85 if (cur.demerits_ < best_for_this_sys_count.demerits_ || isinf (best_for_this_sys_count.demerits_))
87 best_for_this_sys_count = cur;
88 bound = current_configuration (i);
92 if (best_for_this_sys_count.demerits_ < best.demerits_ || isinf (best.demerits_))
94 best = best_for_this_sys_count;
95 best_division = bound;
98 if (best_for_this_sys_count.systems_per_page_.size () < page_count)
100 /* if the pages are stretched on average, stop trying to reduce sys_count */
102 for (vsize i = 0; i < best_for_this_sys_count.systems_per_page_.size (); i++)
103 avg_f += best_for_this_sys_count.systems_per_page_[i];
108 if (isinf (best_for_this_sys_count.demerits_))
112 /* try a larger number of systems than the ideal line breaking number. This
113 is more or less C&P, but the loop bounds make it difficult to try something
114 like do {...} while (flip(&d) != UP). */
115 bound = ideal_line_division;
116 for (vsize sys_count = ideal_sys_count+1; sys_count <= max_sys_count; sys_count++)
118 Real best_demerits_for_this_sys_count = infinity_f;
119 set_current_breakpoints (0, end, sys_count, bound);
121 for (vsize i = 0; i < current_configuration_count (); i++)
123 vsize min_p_count = min_page_count (i, first_page_num);
126 if (min_p_count > page_count)
129 cur = space_systems_on_n_pages (i, page_count, first_page_num);
131 if (cur.demerits_ < best.demerits_ || isinf (best.demerits_))
134 best_division = current_configuration (i);
137 if (cur.demerits_ < best_demerits_for_this_sys_count || isinf (best_demerits_for_this_sys_count))
139 best_demerits_for_this_sys_count = cur.demerits_;
140 bound = current_configuration (i);
143 if (isinf (best_demerits_for_this_sys_count))
147 message ("Drawing systems...");
148 break_into_pieces (0, end, best_division);
149 SCM lines = systems ();
150 return make_pages (best.systems_per_page_, lines);