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 = last_break_position ();
40 vsize max_sys_count = max_system_count (0, end);
41 vsize first_page_num = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
42 SCM forced_page_count = book_->paper_->c_variable ("page-count");
44 set_to_ideal_line_configuration (0, end);
46 Page_spacing_result best;
47 vsize page_count = robust_scm2int (forced_page_count, 1);
48 Line_division ideal_line_division;
49 Line_division best_division;
50 vsize min_sys_count = 1;
51 vsize ideal_sys_count = system_count ();
53 if (!scm_is_integer (forced_page_count))
55 /* find out the ideal number of pages */
56 message (_ ("Finding the ideal number of pages..."));
58 best = space_systems_on_best_pages (0, first_page_num);
59 page_count = best.systems_per_page_.size ();
60 ideal_line_division = current_configuration (0);
61 best_division = ideal_line_division;
63 ideal_sys_count = best.system_count ();
64 min_sys_count = ideal_sys_count - best.systems_per_page_.back ();
66 if (page_count > 1 && best.systems_per_page_[page_count - 2] > 1)
67 min_sys_count -= best.systems_per_page_[page_count - 2];
71 message (_ ("Fitting music on 1 page..."));
72 else if (scm_is_integer (forced_page_count))
73 message (_f ("Fitting music on %d pages...", (int)page_count));
75 message (_f ("Fitting music on %d or %d pages...", (int)page_count-1, (int)page_count));
77 /* try a smaller number of systems than the ideal number for line breaking */
78 Line_division bound = ideal_line_division;
79 for (vsize sys_count = ideal_sys_count; --sys_count >= min_sys_count;)
81 Page_spacing_result best_for_this_sys_count;
82 set_current_breakpoints (0, end, sys_count, Line_division (), bound);
84 for (vsize i = 0; i < current_configuration_count (); i++)
86 vsize min_p_count = min_page_count (i, first_page_num);
87 Page_spacing_result cur;
89 if (min_p_count > page_count)
91 else if (min_p_count == page_count)
92 cur = space_systems_on_n_pages (i, page_count, first_page_num);
94 cur = space_systems_on_n_or_one_more_pages (i, page_count-1, first_page_num);
96 if (cur.demerits_ < best_for_this_sys_count.demerits_ || isinf (best_for_this_sys_count.demerits_))
98 best_for_this_sys_count = cur;
99 bound = current_configuration (i);
103 if (best_for_this_sys_count.demerits_ < best.demerits_ || isinf (best.demerits_))
105 best = best_for_this_sys_count;
106 best_division = bound;
109 /* if the pages are stretched on average, stop trying to reduce sys_count */
110 if (best_for_this_sys_count.page_count () < page_count
111 && best_for_this_sys_count.average_force () > 0)
115 if (isinf (best_for_this_sys_count.demerits_))
119 /* try a larger number of systems than the ideal line breaking number. This
120 is more or less C&P, but the loop bounds make it difficult to try something
121 like do {...} while (flip(&d) != UP). */
122 bound = ideal_line_division;
123 for (vsize sys_count = ideal_sys_count+1; sys_count <= max_sys_count; sys_count++)
125 Real best_demerits_for_this_sys_count = infinity_f;
126 set_current_breakpoints (0, end, sys_count, bound);
128 for (vsize i = 0; i < current_configuration_count (); i++)
130 vsize min_p_count = min_page_count (i, first_page_num);
131 Page_spacing_result cur;
133 if (min_p_count > page_count)
136 cur = space_systems_on_n_pages (i, page_count, first_page_num);
138 if (cur.demerits_ < best.demerits_ || isinf (best.demerits_))
141 best_division = current_configuration (i);
144 if (cur.demerits_ < best_demerits_for_this_sys_count || isinf (best_demerits_for_this_sys_count))
146 best_demerits_for_this_sys_count = cur.demerits_;
147 bound = current_configuration (i);
150 if (isinf (best_demerits_for_this_sys_count))
154 message ("Drawing systems...");
155 break_into_pieces (0, end, best_division);
156 SCM lines = systems ();
157 return make_pages (best.systems_per_page_, lines);