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 = current_configuration (0);
49 Line_division best_division = ideal_line_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 if (systems_per_page () > 0)
59 best = space_systems_with_fixed_number_per_page (0, first_page_num);
61 best = space_systems_on_best_pages (0, first_page_num);
63 page_count = best.systems_per_page_.size ();
64 ideal_sys_count = best.system_count ();
65 min_sys_count = ideal_sys_count - best.systems_per_page_.back ();
67 if (page_count > 1 && best.systems_per_page_[page_count - 2] > 1)
68 min_sys_count -= best.systems_per_page_[page_count - 2];
72 /* TODO: the following line will spit out programming errors if the
73 ideal line spacing doesn't fit on PAGE_COUNT pages */
74 /* TODO: the interaction between systems_per_page and page_count needs to
76 best = space_systems_on_n_pages (0, page_count, first_page_num);
77 min_sys_count = page_count;
81 message (_ ("Fitting music on 1 page..."));
82 else if (scm_is_integer (forced_page_count))
83 message (_f ("Fitting music on %d pages...", (int)page_count));
85 message (_f ("Fitting music on %d or %d pages...", (int)page_count-1, (int)page_count));
87 /* try a smaller number of systems than the ideal number for line breaking */
88 Line_division bound = ideal_line_division;
89 for (vsize sys_count = ideal_sys_count; --sys_count >= min_sys_count;)
91 Page_spacing_result best_for_this_sys_count;
92 set_current_breakpoints (0, end, sys_count, Line_division (), bound);
94 for (vsize i = 0; i < current_configuration_count (); i++)
96 vsize min_p_count = min_page_count (i, first_page_num);
97 Page_spacing_result cur;
99 if (min_p_count == page_count || scm_is_integer (forced_page_count))
100 cur = space_systems_on_n_pages (i, page_count, first_page_num);
102 cur = space_systems_on_n_or_one_more_pages (i, page_count-1, first_page_num);
104 if (cur.demerits_ < best_for_this_sys_count.demerits_ || isinf (best_for_this_sys_count.demerits_))
106 best_for_this_sys_count = cur;
107 bound = current_configuration (i);
111 if (best_for_this_sys_count.demerits_ < best.demerits_ || isinf (best.demerits_))
113 best = best_for_this_sys_count;
114 best_division = bound;
117 /* if the pages are stretched on average, stop trying to reduce sys_count */
118 if (best_for_this_sys_count.page_count () < page_count
119 && best_for_this_sys_count.average_force () > 0)
123 if (isinf (best_for_this_sys_count.demerits_))
127 /* try a larger number of systems than the ideal line breaking number. This
128 is more or less C&P, but the loop bounds make it difficult to try something
129 like do {...} while (flip(&d) != UP). */
130 bound = ideal_line_division;
131 for (vsize sys_count = ideal_sys_count+1; sys_count <= max_sys_count; sys_count++)
133 Real best_demerits_for_this_sys_count = infinity_f;
134 set_current_breakpoints (0, end, sys_count, bound);
136 for (vsize i = 0; i < current_configuration_count (); i++)
138 vsize min_p_count = min_page_count (i, first_page_num);
139 Page_spacing_result cur;
141 if (min_p_count > page_count)
144 cur = space_systems_on_n_pages (i, page_count, first_page_num);
146 if (cur.demerits_ < best.demerits_ || isinf (best.demerits_))
149 best_division = current_configuration (i);
152 if (cur.demerits_ < best_demerits_for_this_sys_count || isinf (best_demerits_for_this_sys_count))
154 best_demerits_for_this_sys_count = cur.demerits_;
155 bound = current_configuration (i);
158 if (isinf (best_demerits_for_this_sys_count))
162 message (_ ("Drawing systems..."));
163 break_into_pieces (0, end, best_division);
164 SCM lines = systems ();
165 return make_pages (best.systems_per_page_, lines);