source file of the GNU LilyPond music typesetter
- (c) 2006 Joe Neeman <joeneeman@gmail.com>
+ (c) 2006--2007 Joe Neeman <joeneeman@gmail.com>
*/
#include "page-breaking.hh"
#include "system.hh"
#include "warn.hh"
+/* for each forbidden page break, merge the systems around it into one system. */
+static vector<Line_details>
+compress_lines (const vector<Line_details> &orig)
+{
+ vector<Line_details> ret;
+
+ for (vsize i = 0; i < orig.size (); i++)
+ {
+ if (ret.size () && !scm_is_symbol (ret.back ().page_permission_))
+ {
+ Line_details const &old = ret.back ();
+ Line_details compressed = orig[i];
+ compressed.extent_[DOWN] = old.extent_[DOWN];
+ compressed.extent_[UP] = old.extent_[UP] + orig[i].extent_.length () + old.padding_;
+ compressed.space_ += old.space_;
+ compressed.inverse_hooke_ += old.inverse_hooke_;
+
+ /* we don't need the force_ field for the vertical spacing,
+ so we use force_ = n to signal that the line was compressed,
+ reducing the number of lines by n (and force_ = 0 otherwise).
+ This makes uncompression much easier. */
+ compressed.force_ = old.force_ + 1;
+ ret.back () = compressed;
+ }
+ else
+ {
+ ret.push_back (orig[i]);
+ ret.back ().force_ = 0;
+ }
+ }
+ return ret;
+}
+
+/* translate the number of systems-per-page into something meaningful for
+ the uncompressed lines.
+*/
+static vector<vsize>
+uncompress_solution (vector<vsize> const &systems_per_page,
+ vector<Line_details> const &compressed)
+{
+ vector<vsize> ret;
+ vsize start_sys = 0;
+
+ for (vsize i = 0; i < systems_per_page.size (); i++)
+ {
+ int compressed_count = 0;
+ for (vsize j = start_sys; j < start_sys + systems_per_page[i]; j++)
+ compressed_count += (int)compressed[j].force_;
+
+ ret.push_back (systems_per_page[i] + compressed_count);
+ start_sys += systems_per_page[i];
+ }
+ return ret;
+}
+
/* for Page_breaking, the start index (when we are dealing with the stuff
between a pair of breakpoints) refers to the break_ index of the end of
the previous page. So the system index of the start of the current page
Page_breaking::Page_breaking (Paper_book *pb, Break_predicate is_break)
{
book_ = pb;
+ ragged_ = to_boolean (pb->paper_->c_variable ("ragged-bottom"));
+ ragged_last_ = to_boolean (pb->paper_->c_variable ("ragged-last-bottom"));
create_system_list ();
find_chunks_and_breaks (is_break);
}
{
}
+bool
+Page_breaking::ragged () const
+{
+ return ragged_;
+}
+
+bool
+Page_breaking::ragged_last () const
+{
+ return ragged_last_;
+}
+
/* translate indices into breaks_ into start-end parameters for the line breaker */
void
Page_breaking::line_breaker_args (vsize sys,
Page_breaking::break_into_pieces (vsize start_break, vsize end_break, Line_division const &div)
{
vector<Break_position> chunks = chunk_list (start_break, end_break);
- assert (chunks.size () == div.size () + 1);
+ bool ignore_div = false;
+ if (chunks.size () != div.size () + 1)
+ {
+ programming_error ("did not find a valid page breaking configuration");
+ ignore_div = true;
+ }
- for (vsize i = 0; i < chunks.size () - 1; i++)
+ for (vsize i = 0; i + 1 < chunks.size (); i++)
{
vsize sys = next_system (chunks[i]);
if (all_[sys].pscore_)
vsize end;
line_breaker_args (sys, chunks[i], chunks[i+1], &start, &end);
- vector<Column_x_positions> pos = line_breaking_[sys].get_solution (start, end, div[i]);
+ vector<Column_x_positions> pos = ignore_div
+ ? line_breaking_[sys].best_solution (start, end)
+ : line_breaking_[sys].solve (start, end, div[i]);
all_[sys].pscore_->root_system ()->break_into_pieces (pos);
}
}
{
if (all_[sys].pscore_)
{
- SCM lines = all_[sys].pscore_->root_system ()->get_paper_systems ();
- ret = scm_cons (scm_vector_to_list (lines), ret);
+ all_[sys].pscore_->root_system ()->do_break_substitution_and_fixup_refpoints ();
+ SCM lines = all_[sys].pscore_->root_system ()->get_broken_system_grobs ();
+ ret = scm_cons (lines, ret);
}
else
{
return scm_append (scm_reverse (ret));
}
-vector<Line_details>
-Page_breaking::line_details (vsize start_break, vsize end_break, Line_division const &div)
-{
- vector<Break_position> chunks = chunk_list (start_break, end_break);
- vector<Line_details> ret;
- assert (chunks.size () == div.size () + 1);
-
- for (vsize i = 0; i < chunks.size () - 1; i++)
- {
- vsize sys = next_system (chunks[i]);
- if (all_[sys].pscore_)
- {
- vsize start;
- vsize end;
- line_breaker_args (sys, chunks[i], chunks[i+1], &start, &end);
-
- vector<Line_details> details = line_breaking_[sys].get_details (start, end, div[i]);
- ret.insert (ret.end (), details.begin (), details.end ());
- }
- else
- {
- assert (div[i] == 1);
- ret.push_back (Line_details (all_[sys].prob_));
- }
- }
- return ret;
-}
-
Real
-Page_breaking::page_height (int page_num, bool last)
+Page_breaking::page_height (int page_num, bool last) const
{
SCM mod = scm_c_resolve_module ("scm page");
SCM calc_height = scm_c_module_lookup (mod, "calc-printable-height");
Page_breaking::make_pages (vector<vsize> lines_per_page, SCM systems)
{
SCM layout_module = scm_c_resolve_module ("scm layout-page-layout");
- SCM dump_module = scm_c_resolve_module ("scm layout-page-dump");
SCM page_module = scm_c_resolve_module ("scm page");
- SCM make_page = scm_c_module_lookup (layout_module, "make-page-from-systems");
- SCM write_page_breaks = scm_c_module_lookup (dump_module, "write-page-breaks");
+ SCM make_page = scm_c_module_lookup (layout_module, "stretch-and-draw-page");
SCM page_stencil = scm_c_module_lookup (page_module, "page-stencil");
make_page = scm_variable_ref (make_page);
- write_page_breaks = scm_variable_ref (write_page_breaks);
page_stencil = scm_variable_ref (page_stencil);
SCM book = book_->self_scm ();
- bool ragged_all = to_boolean (book_->paper_->c_variable ("ragged-bottom"));
- bool ragged_last = to_boolean (book_->paper_->c_variable ("ragged-last-bottom"));
int first_page_number = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
SCM ret = SCM_EOL;
{
SCM page_num = scm_from_int (i + first_page_number);
SCM last = scm_from_bool (i == lines_per_page.size () - 1);
- SCM ragged = scm_from_bool (ragged_all || (to_boolean (last) && ragged_last));
+ SCM rag = scm_from_bool (ragged () || (to_boolean (last) && ragged_last ()));
SCM line_count = scm_from_int (lines_per_page[i]);
SCM lines = scm_list_head (systems, line_count);
SCM page = scm_apply_0 (make_page,
- scm_list_n (book, lines, page_num, ragged, last, SCM_UNDEFINED));
+ scm_list_n (book, lines, page_num, rag, last, SCM_UNDEFINED));
scm_apply_1 (page_stencil, page, SCM_EOL);
ret = scm_cons (page, ret);
systems = scm_list_tail (systems, line_count);
}
ret = scm_reverse (ret);
-
- if (to_boolean (book_->paper_->c_variable ("write-page-layout")))
- scm_apply_1 (write_page_breaks, ret, SCM_EOL);
return ret;
}
{
if (all_[i].pscore_)
{
- vector<Grob*> cols = all_[i].pscore_->root_system ()->columns ();
+ vector<Grob*> cols = all_[i].pscore_->root_system ()->used_columns ();
vector<vsize> line_breaker_columns;
line_breaker_columns.push_back (0);
if ((break_point || chunk_end) && !last)
line_breaker_columns.push_back (j);
}
- line_breaking_.push_back (Constrained_breaking (line_breaker_columns));
- line_breaking_.back ().set_pscore (all_[i].pscore_);
+ line_breaking_.push_back (Constrained_breaking (all_[i].pscore_, line_breaker_columns));
}
else
{
breaks_.push_back (Break_position (i));
chunks_.push_back (Break_position (i));
- line_breaking_.push_back (Constrained_breaking ());
+ line_breaking_.push_back (Constrained_breaking (NULL));
}
}
}
Line_division ret;
ret.resize (chunks.size () - 1, 1);
- for (vsize i = 0; i < chunks.size () - 1; i++)
+ for (vsize i = 0; i + 1 < chunks.size (); i++)
{
vsize sys = next_system (chunks[i]);
if (all_[sys].pscore_)
vsize end;
line_breaker_args (sys, chunks[i], chunks[i+1], &start, &end);
ret[i] = min
- ? line_breaking_[sys].get_min_systems (start, end)
- : line_breaking_[sys].get_max_systems (start, end);
+ ? line_breaking_[sys].min_system_count (start, end)
+ : line_breaking_[sys].max_system_count (start, end);
}
}
return ret;
}
-vector<Page_breaking::Line_division>
-Page_breaking::line_divisions (vsize start,
- vsize end,
- vsize system_count,
- Line_division lower_bound,
- Line_division upper_bound)
+void
+Page_breaking::set_current_breakpoints (vsize start,
+ vsize end,
+ vsize system_count,
+ Line_division lower_bound,
+ Line_division upper_bound)
{
- vector<Break_position> chunks = chunk_list (start, end);
+ current_chunks_ = chunk_list (start, end);
+ current_start_breakpoint_ = start;
+ current_end_breakpoint_ = end;
+ clear_line_details_cache ();
if (!lower_bound.size ())
- lower_bound = system_count_bounds (chunks, true);
+ lower_bound = system_count_bounds (current_chunks_, true);
if (!upper_bound.size ())
- upper_bound = system_count_bounds (chunks, false);
+ upper_bound = system_count_bounds (current_chunks_, false);
- assert (lower_bound.size () == chunks.size () - 1);
- assert (upper_bound.size () == chunks.size () - 1);
+ assert (lower_bound.size () == current_chunks_.size () - 1);
+ assert (upper_bound.size () == current_chunks_.size () - 1);
- vector<Line_division> ret;
Line_division work_in_progress;
-
+ current_configurations_.clear ();
line_divisions_rec (system_count,
lower_bound,
upper_bound,
- &ret,
&work_in_progress);
- return ret;
+
+ /* we only consider a constant number of configurations. Otherwise,
+ this becomes slow when there are many small scores. The constant
+ 5 is somewhat arbitrary. */
+ if (current_configurations_.size () > 5)
+ {
+ vector<pair<Real,vsize> > dems_and_indices;
+
+ for (vsize i = 0; i < current_configurations_.size (); i++)
+ {
+ cache_line_details (i);
+ Real dem = 0;
+ for (vsize j = 0; j < cached_line_details_.size (); j++)
+ dem += cached_line_details_[j].force_ * cached_line_details_[j].force_
+ + cached_line_details_[j].break_penalty_;
+
+ dems_and_indices.push_back (pair<Real,vsize> (dem, i));
+ }
+ vector_sort (dems_and_indices, less<pair<Real,vsize> > ());
+
+ vector<Line_division> best_5_configurations;
+ for (vsize i = 0; i < 5; i++)
+ best_5_configurations.push_back (current_configurations_[dems_and_indices[i].second]);
+
+ clear_line_details_cache ();
+ current_configurations_ = best_5_configurations;
+ }
+}
+
+void
+Page_breaking::set_to_ideal_line_configuration (vsize start, vsize end)
+{
+ current_chunks_ = chunk_list (start, end);
+ current_start_breakpoint_ = start;
+ current_end_breakpoint_ = end;
+ clear_line_details_cache ();
+
+ Line_division div;
+ for (vsize i = 0; i+1 < current_chunks_.size (); i++)
+ {
+ vsize sys = next_system (current_chunks_[i]);
+ if (all_[sys].pscore_)
+ {
+ line_breaker_args (sys, current_chunks_[i], current_chunks_[i+1], &start, &end);
+ div.push_back (line_breaking_[sys].best_solution (start, end).size ());
+ }
+ else
+ div.push_back (1);
+ }
+ current_configurations_.clear ();
+ current_configurations_.push_back (div);
+}
+
+vsize
+Page_breaking::current_configuration_count () const
+{
+ return current_configurations_.size ();
+}
+
+void
+Page_breaking::cache_line_details (vsize configuration_index)
+{
+ if (cached_configuration_index_ != configuration_index)
+ {
+ SCM padding_scm = book_->paper_->c_variable ("page-breaking-between-system-padding");
+ if (!scm_is_number (padding_scm))
+ padding_scm = book_->paper_->c_variable ("between-system-padding");
+ Real padding = robust_scm2double (padding_scm, 0.0);
+
+ Line_division &div = current_configurations_[configuration_index];
+ uncompressed_line_details_.clear ();
+ for (vsize i = 0; i + 1 < current_chunks_.size (); i++)
+ {
+ vsize sys = next_system (current_chunks_[i]);
+ if (all_[sys].pscore_)
+ {
+ vsize start;
+ vsize end;
+ line_breaker_args (sys, current_chunks_[i], current_chunks_[i+1], &start, &end);
+
+ vector<Line_details> details = line_breaking_[sys].line_details (start, end, div[i]);
+ uncompressed_line_details_.insert (uncompressed_line_details_.end (), details.begin (), details.end ());
+ }
+ else
+ {
+ assert (div[i] == 1);
+ uncompressed_line_details_.push_back (Line_details (all_[sys].prob_));
+ uncompressed_line_details_.back ().padding_ = padding;
+ }
+ }
+ cached_line_details_ = compress_lines (uncompressed_line_details_);
+ }
+}
+
+void
+Page_breaking::clear_line_details_cache ()
+{
+ cached_configuration_index_ = VPOS;
+ cached_line_details_.clear ();
+ uncompressed_line_details_.clear ();
}
void
Page_breaking::line_divisions_rec (vsize system_count,
Line_division const &min_sys,
Line_division const &max_sys,
- vector<Line_division > *result,
Line_division *cur_division)
{
vsize my_index = cur_division->size ();
{
cur_division->push_back (i);
if (my_index == min_sys.size () - 1)
- result->push_back (*cur_division);
+ current_configurations_.push_back (*cur_division);
else
- line_divisions_rec (system_count - i, min_sys, max_sys, result, cur_division);
+ line_divisions_rec (system_count - i, min_sys, max_sys, cur_division);
cur_division->pop_back ();
}
}
+
+vsize
+Page_breaking::min_page_count (vsize configuration, vsize first_page_num)
+{
+ vsize ret = 1;
+ Real cur_rod_height = 0;
+ Real cur_spring_height = 0;
+ Real cur_page_height = page_height (first_page_num, false);
+
+ cache_line_details (configuration);
+ for (vsize i = 0; i < cached_line_details_.size (); i++)
+ {
+ Real ext_len = cached_line_details_[i].extent_.length ();
+ Real next_rod_height = cur_rod_height + ext_len
+ + ((cur_rod_height > 0) ? cached_line_details_[i].padding_: 0);
+ Real next_spring_height = cur_spring_height + line_space (cached_line_details_[i]);
+ Real next_height = next_rod_height + (ragged () ? next_spring_height : 0);
+
+
+ if ((next_height > cur_page_height && cur_rod_height > 0)
+ || (i > 0
+ && cached_line_details_[i-1].page_permission_ == ly_symbol2scm ("force")))
+ {
+ cur_rod_height = ext_len;
+ cur_spring_height = line_space (cached_line_details_[i]);
+ cur_page_height = page_height (first_page_num + ret, false);
+ ret++;
+ }
+ else
+ {
+ cur_rod_height = next_rod_height;
+ cur_spring_height = next_spring_height;
+ }
+ }
+
+ /* there are two potential problems with the last page (because we didn't know
+ it was the last page until after we managed to fit all the systems to it):
+ - we are ragged-last but the last page has a compressed spring
+ - the value returned by page_height (num, true) is smaller than the
+ value returned by page_height (num, false) and it causes the page not to
+ fit.
+
+ In either case, we just need to add one more page. This is because the last
+ line will always fit on the extra page and by adding one more page to the
+ end, the previous page is no longer the last page, so our previous
+ calculations that treated it as a non-last page were ok.
+ */
+
+ cur_page_height = page_height (first_page_num + ret - 1, true);
+ Real cur_height = cur_rod_height + ((ragged_last () || ragged ()) ? cur_spring_height : 0);
+ if (cur_height > cur_page_height
+ /* don't increase the page count if the last page had only one system */
+ && cur_rod_height > cached_line_details_.back ().extent_.length ())
+ ret++;
+
+ assert (ret <= cached_line_details_.size ());
+ return ret;
+}
+
+Spacing_result
+Page_breaking::space_systems_on_n_pages (vsize configuration, vsize n, vsize first_page_num)
+{
+ Spacing_result ret;
+ assert (n >= min_page_count (configuration, first_page_num));
+
+ cache_line_details (configuration);
+ if (n > cached_line_details_.size ())
+ return Spacing_result ();
+ if (n == 1)
+ ret = space_systems_on_1_page (cached_line_details_,
+ page_height (first_page_num, last ()),
+ ragged () || (last () && ragged_last ()));
+ else if (n == 2)
+ ret = space_systems_on_2_pages (configuration, first_page_num);
+ else
+ {
+ Page_spacer ps (cached_line_details_, first_page_num, this);
+ ret = ps.solve (n);
+ }
+
+ return finalize_spacing_result (configuration, ret);
+}
+
+Real
+Page_breaking::blank_page_penalty () const
+{
+ SCM penalty_sym = last () ? ly_symbol2scm ("blank-last-page-force") : ly_symbol2scm ("blank-page-force");
+ return robust_scm2double (book_->paper_->lookup_variable (penalty_sym), 0.0);
+}
+
+Spacing_result
+Page_breaking::space_systems_on_n_or_one_more_pages (vsize configuration, vsize n, vsize first_page_num)
+{
+ Spacing_result n_res;
+ Spacing_result m_res;
+
+ if (n <= 2)
+ {
+ n_res = space_systems_on_n_pages (configuration, n, first_page_num);
+ m_res = space_systems_on_n_pages (configuration, n+1, first_page_num);
+ }
+ else
+ {
+ cache_line_details (configuration);
+
+ vsize min_p_count = min_page_count (configuration, first_page_num);
+ Page_spacer ps (cached_line_details_, first_page_num, this);
+ if (n >= min_p_count)
+ n_res = ps.solve (n);
+ if (n < cached_line_details_.size ())
+ m_res = ps.solve (n+1);
+ }
+
+ Real penalty = blank_page_penalty ();
+ n_res.demerits_ += penalty;
+ n_res.force_.back () += penalty;
+
+ if (m_res.demerits_ < n_res.demerits_)
+ return m_res;
+ return n_res;
+}
+
+Spacing_result
+Page_breaking::space_systems_on_best_pages (vsize configuration, vsize first_page_num)
+{
+ vsize min_p_count = min_page_count (configuration, first_page_num);
+ Real odd_pages_penalty = blank_page_penalty ();
+
+ cache_line_details (configuration);
+ Page_spacer ps (cached_line_details_, first_page_num, this);
+ Spacing_result best = ps.solve (min_p_count);
+ best.force_.back () += (min_p_count % 2) ? odd_pages_penalty : 0;
+ best.demerits_ += (min_p_count % 2) ? odd_pages_penalty : 0;
+
+ for (vsize i = min_p_count+1; i <= cached_line_details_.size (); i++)
+ {
+ Spacing_result cur = ps.solve (i);
+ cur.demerits_ += (i % 2) ? odd_pages_penalty : 0;
+ if (cur.demerits_ < best.demerits_)
+ best = cur;
+ }
+
+ return finalize_spacing_result (configuration, best);
+}
+
+/* Calculate demerits and fix res.systems_per_page_ so that
+ it refers to the original line numbers, not the ones given by compress_lines (). */
+Spacing_result
+Page_breaking::finalize_spacing_result (vsize configuration, Spacing_result res)
+{
+ cache_line_details (configuration);
+ res.systems_per_page_ = uncompress_solution (res.systems_per_page_, cached_line_details_);
+
+ Real line_force = 0;
+ Real line_penalty = 0;
+ Real page_force = 0;
+ Real page_weighting = robust_scm2double (book_->paper_->c_variable ("page-spacing-weight"), 10);
+
+ for (vsize i = 0; i < uncompressed_line_details_.size (); i++)
+ {
+ line_force += uncompressed_line_details_[i].force_ * uncompressed_line_details_[i].force_;
+ line_penalty += uncompressed_line_details_[i].break_penalty_;
+ }
+
+ for (vsize i = 0; i < res.force_.size (); i++)
+ {
+ Real f = res.force_[i];
+ if (isinf (f) && res.systems_per_page_[i] == 1)
+ f = 20000;
+
+ page_force += f * f;
+ }
+
+ /* for a while we tried averaging page and line forces across pages instead
+ of summing them, but it caused a problem: if there is a single page
+ with a very bad page force (for example because of a forced page break),
+ the page breaker will put in a _lot_ of pages so that the bad force
+ becomes averaged out over many pages. */
+ res.demerits_ = line_force + line_penalty + (page_force + res.penalty_) * page_weighting;
+ return res;
+
+}
+
+/* the cases for page_count = 1 or 2 can be done in O (n) time. Since they
+ are by far the most common cases, we have special functions for them.
+
+ space_systems_on_1_page has a different calling convention than most of the
+ space_systems functions. This is because space_systems_on_1_page is (unlike
+ the other space_systems functions) sometimes called on subsets of a full
+ configuration. */
+Spacing_result
+Page_breaking::space_systems_on_1_page (vector<Line_details> const &lines, Real page_height, bool ragged)
+{
+ Page_spacing space (page_height);
+ Spacing_result ret;
+
+ for (vsize i = 0; i < lines.size (); i++)
+ space.append_system (lines[i]);
+
+ ret.systems_per_page_.push_back (lines.size ());
+ ret.force_.push_back (ragged ? min (space.force_, 0.0) : space.force_);
+ ret.penalty_ = lines.back ().page_penalty_ + lines.back ().turn_penalty_;
+
+ /* don't do finalize_spacing_result () because we are only an internal function */
+ return ret;
+}
+
+Spacing_result
+Page_breaking::space_systems_on_2_pages (vsize configuration, vsize first_page_num)
+{
+ Real page1_height = page_height (first_page_num, false);
+ Real page2_height = page_height (first_page_num+1, last ());
+ bool ragged1 = ragged ();
+ bool ragged2 = ragged () || (last () && ragged_last ());
+
+ /* if there is a forced break, this reduces to 2 1-page problems */
+ cache_line_details (configuration);
+ for (vsize i = 0; i + 1 < cached_line_details_.size (); i++)
+ if (cached_line_details_[i].page_permission_ == ly_symbol2scm ("force"))
+ {
+ vector<Line_details> lines1 (cached_line_details_.begin (), cached_line_details_.begin () + i + 1);
+ vector<Line_details> lines2 (cached_line_details_.begin () + i + 1, cached_line_details_.end ());
+ Spacing_result p1 = space_systems_on_1_page (lines1, page1_height, ragged1);
+ Spacing_result p2 = space_systems_on_1_page (lines2, page2_height, ragged2);
+
+ p1.systems_per_page_.push_back (p2.systems_per_page_[0]);
+ p1.force_.push_back (p2.force_[0]);
+ p1.penalty_ += p2.penalty_ - cached_line_details_[i].turn_penalty_;
+ return p1;
+ }
+
+ vector<Real> page1_force;
+ vector<Real> page2_force;
+ Page_spacing page1 (page1_height);
+ Page_spacing page2 (page2_height);
+
+ page1_force.resize (cached_line_details_.size () - 1, infinity_f);
+ page2_force.resize (cached_line_details_.size () - 1, infinity_f);
+
+ /* find the page 1 and page 2 forces for each page-breaking position */
+ for (vsize i = 0; i < page1_force.size (); i++)
+ {
+ page1.append_system (cached_line_details_[i]);
+ page2.prepend_system (cached_line_details_[cached_line_details_.size () - 1 - i]);
+ page1_force[i] = (ragged1 && page1.force_ < 0 && i > 0) ? infinity_f : page1.force_;
+
+ if (ragged2)
+ page2_force[page2_force.size () - 1 - i] =
+ (page2.force_ < 0 && i + 1 < page1_force.size ()) ? infinity_f : 0;
+ else
+ page2_force[page2_force.size () - 1 - i] = page2.force_;
+ }
+
+ /* find the position that minimises the sum of the page forces */
+ vsize best_sys_count = 1;
+ Real best_demerits = infinity_f;
+ for (vsize i = 0; i < page1_force.size (); i++)
+ {
+ Real f = page1_force[i] * page1_force[i] + page2_force[i] * page2_force[i];
+ Real uneven = 2 * (page1_force[i] - page2_force[i]);
+ Real dem = uneven * uneven + f
+ + cached_line_details_[i+1].page_penalty_
+ + cached_line_details_.back ().page_penalty_ + cached_line_details_.back ().turn_penalty_;
+ if (dem < best_demerits)
+ {
+ best_demerits = dem;
+ best_sys_count = i+1;
+ }
+ }
+
+ Spacing_result ret;
+ ret.systems_per_page_.push_back (best_sys_count);
+ ret.systems_per_page_.push_back (cached_line_details_.size () - best_sys_count);
+ ret.force_.push_back (page1_force[best_sys_count-1]);
+ ret.force_.push_back (page2_force[best_sys_count-1]);
+ ret.penalty_ = cached_line_details_[best_sys_count-1].page_penalty_
+ + cached_line_details_.back ().page_penalty_
+ + cached_line_details_.back ().turn_penalty_;
+
+ /* don't do finalize_spacing_result () because we are only an internal function */
+ return ret;
+}
+
+bool
+Page_breaking::all_lines_stretched (vsize configuration)
+{
+ cache_line_details (configuration);
+ for (vsize i = 0; i < cached_line_details_.size (); i++)
+ if (cached_line_details_[i].force_ < 0)
+ return false;
+
+ return true;
+}
+
+Page_breaking::Line_division
+Page_breaking::current_configuration (vsize configuration_index) const
+{
+ return current_configurations_[configuration_index];
+}
+
+bool Page_breaking::last () const
+{
+ return current_end_breakpoint_ == breaks_.size () - 1;
+}