/*
- page-spacing.cc - implement routines for spacing
- systems vertically on pages
+ This file is part of LilyPond, the GNU music typesetter.
- source file of the GNU LilyPond music typesetter
+ Copyright (C) 2006--2010 Joe Neeman <joeneeman@gmail.com>
- (c) 2006--2007 Joe Neeman <joeneeman@gmail.com>
+ LilyPond is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ LilyPond is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with LilyPond. If not, see <http://www.gnu.org/licenses/>.
*/
#include "page-spacing.hh"
void
Page_spacing::calc_force ()
{
- /* If the first system is a title, we add back in the page-top-space. */
- Real height = first_line_.title_ ? page_height_ + page_top_space_ : page_height_;
+ Real height = page_height_
+ - breaker_->min_whitespace_at_top_of_page (first_line_)
+ - breaker_->min_whitespace_at_bottom_of_page (last_line_);
if (rod_height_ + last_line_.bottom_padding_ >= height)
- force_ = infinity_f;
+ force_ = -infinity_f;
else
force_ = (height - rod_height_ - last_line_.bottom_padding_ - spring_len_)
/ max (0.1, inverse_spring_k_);
void
Page_spacing::append_system (const Line_details &line)
{
- if (!rod_height_)
- first_line_ = line;
-
- rod_height_ += last_line_.padding_;
+ if (rod_height_)
+ {
+ rod_height_ += line.tallness_;
+ }
+ else
+ {
+ rod_height_ += line.full_height ();
+ first_line_ = line;
+ }
- rod_height_ += line.extent_.length ();
- spring_len_ += line.space_;
+ // line.space_ measures the spring which goes from the bottom refpoint
+ // of one system to the top refpoint of the next. spring_len_ measures
+ // how much of that is stretchable.
+ Real refpoint_dist = last_line_.tallness_
+ + last_line_.refpoint_extent_[DOWN]
+ - line.refpoint_extent_[UP];
+ Real space = line.title_ ? last_line_.title_space_ : last_line_.space_;
+ spring_len_ += max (0.0, space - refpoint_dist);
inverse_spring_k_ += line.inverse_hooke_;
last_line_ = line;
void
Page_spacing::prepend_system (const Line_details &line)
{
- if (rod_height_)
- rod_height_ += line.padding_;
- else
+ if (!rod_height_)
last_line_ = line;
- rod_height_ += line.extent_.length ();
- spring_len_ += line.space_;
+ rod_height_ -= first_line_.full_height ();
+ rod_height_ += first_line_.tallness_;
+ rod_height_ += line.full_height();
+
+ Real refpoint_dist = line.tallness_
+ + line.refpoint_extent_[DOWN]
+ - first_line_.refpoint_extent_[UP];
+ Real space = first_line_.title_ ? line.title_space_ : line.space_;
+ spring_len_ += max (0.0, space - refpoint_dist);
inverse_spring_k_ += line.inverse_hooke_;
first_line_ = line;
ragged_last_ = breaker->is_last () && breaker->ragged_last ();
}
+Page_spacing_result
+Page_spacer::solve ()
+{
+ if (simple_state_.empty ())
+ {
+ simple_state_.resize (lines_.size ());
+ for (vsize i = 0; i < lines_.size (); ++i)
+ calc_subproblem (VPOS, i);
+ }
+
+ Page_spacing_result ret;
+ ret.penalty_ = simple_state_.back ().penalty_
+ + lines_.back ().page_penalty_ + lines_.back ().turn_penalty_;
+ ret.system_count_status_ = simple_state_.back ().system_count_status_;
+
+ vsize system = lines_.size () - 1;
+ while (system != VPOS)
+ {
+ Page_spacing_node const& cur = simple_state_[system];
+ vsize system_count = (cur.prev_ == VPOS) ? system + 1 : system - cur.prev_;
+
+ ret.force_.push_back (cur.force_);
+ ret.systems_per_page_.push_back (system_count);
+ ret.demerits_ += cur.force_ * cur.force_;
+ system = cur.prev_;
+ }
+
+ reverse (ret.force_);
+ reverse (ret.systems_per_page_);
+ return ret;
+}
+
Page_spacing_result
Page_spacer::solve (vsize page_count)
{
resize (page_count);
Page_spacing_result ret;
- ret.force_.resize (page_count);
- ret.systems_per_page_.resize (page_count);
vsize system = lines_.size () - 1;
- vsize tack_onto_the_end = 0;
+ vsize extra_systems = 0;
+ vsize extra_pages = 0;
if (isinf (state_.at (system, page_count-1).demerits_))
{
if (i)
{
- tack_onto_the_end = system - i;
+ extra_systems = system - i;
system = i;
}
else
- return Page_spacing_result (); /* couldn't salvage it -- probably going to crash */
+ {
+ /* try chopping off pages from the end */
+ vsize j;
+ for (j = page_count; j && isinf (state_.at (system, j-1).demerits_); j--)
+ ;
+
+ if (j)
+ {
+ extra_pages = page_count - j;
+ page_count = j;
+ }
+ else
+ return Page_spacing_result (); /* couldn't salvage it -- probably going to crash */
+ }
}
+ ret.force_.resize (page_count);
+ ret.systems_per_page_.resize (page_count);
+ ret.system_count_status_ = state_.at (system, page_count-1).system_count_status_;
ret.penalty_ = state_.at (system, page_count-1).penalty_
+ lines_.back ().page_penalty_ + lines_.back ().turn_penalty_;
if (p == 0)
ret.systems_per_page_[p] = system + 1;
else
- ret.systems_per_page_[p] = system - ps.prev_ + tack_onto_the_end;
+ ret.systems_per_page_[p] = system - ps.prev_;
system = ps.prev_;
}
- ret.demerits_ += ret.penalty_;
+
+ if (extra_systems)
+ {
+ ret.systems_per_page_.back () += extra_systems;
+ ret.force_.back () = BAD_SPACING_PENALTY;
+ }
+ if (extra_pages)
+ {
+ ret.force_.insert (ret.force_.end (), extra_pages, BAD_SPACING_PENALTY);
+ ret.systems_per_page_.insert (ret.systems_per_page_.end (), extra_pages, 0);
+ }
+
return ret;
}
max_page_count_ = page_count;
}
+// Carries out one step in the dynamic programming algorithm for putting systems
+// on a fixed number of pages. One call to this routine calculates the best
+// configuration for putting lines 0 through LINE-1 on PAGE+1 pages, provided that
+// we have previously called calc_subproblem(page-1, k) for every k < LINE.
+//
+// This algorithm is similar to the constrained-breaking algorithm.
+//
+// If page == VPOS, we act on simple_state_ instead of state_. This is useful if
+// we don't want to constrain the number of pages that the solution has. In this
+// case, the algorithm looks more like the page-turn-page-breaking algorithm. But
+// the subproblems look similar for both, so we reuse this method.
bool
Page_spacer::calc_subproblem (vsize page, vsize line)
{
bool last = line == lines_.size () - 1;
- Page_spacing space (breaker_->page_height (page + first_page_num_, last),
- breaker_->page_top_space ());
- Page_spacing_node &cur = state_.at (line, page);
+
+ // Note: if page == VPOS then we don't actually know yet which page number we're
+ // working on, so we have to recalculate the page height in the loop. Therefore
+ // our early-exit condition from the loop depends on paper_height rather than
+ // page_height (ie. we break only if we would overfill a page without margins
+ // or headers/footers). Otherwise, the algorithm would not be optimal:
+ // if our page has a very large header then perhaps
+ // we should look ahead a few systems in order to find the best solution. A
+ // good example of this is input/regression/page-spacing-tall-headfoot.ly
+ vsize page_num = page == VPOS ? 0 : page;
+ Real paper_height = breaker_->paper_height ();
+ Page_spacing space (breaker_->page_height (page_num + first_page_num_, last),
+ breaker_);
+ Page_spacing_node &cur = page == VPOS ? simple_state_[line] : state_.at (line, page);
bool ragged = ragged_ || (ragged_last_ && last);
+ int line_count = 0;
- for (vsize page_start = line+1; page_start > page && page_start--;)
+ for (vsize page_start = line+1; page_start > page_num && page_start--;)
{
- Page_spacing_node const *prev = page > 0 ? &state_.at (page_start-1, page-1) : 0;
+ Page_spacing_node const *prev = 0;
+
+ if (page == VPOS)
+ {
+ if (page_start > 0)
+ {
+ prev = &simple_state_[page_start-1];
+ space.resize (breaker_->page_height (prev->page_ + 1, last));
+ }
+ else
+ space.resize (breaker_->page_height (first_page_num_, last));
+ }
+ else if (page > 0)
+ prev = &state_.at (page_start-1, page-1);
space.prepend_system (lines_[page_start]);
- if (page_start < line && (isinf (space.force_) || (space.force_ < 0 && ragged)))
+
+ bool overfull = (space.rod_height_ > paper_height
+ || (ragged
+ && (space.rod_height_ + space.spring_len_ > paper_height)));
+ // This 'if' statement is a little hard to parse. It won't consider this configuration
+ // if it is overfull unless the current configuration is the first one with this start
+ // point. We also make an exception (and consider this configuration) if the previous
+ // configuration we tried had fewer lines than min-systems-per-page.
+ if (!breaker_->too_few_lines (line_count)
+ && page_start < line
+ && overfull)
break;
+ line_count += lines_[page_start].compressed_nontitle_lines_count_;
if (page > 0 || page_start == 0)
{
- if (line == lines_.size () - 1 && ragged_last_ && space.force_ > 0)
+ // If the last page is ragged, set its force to zero. This way, we will leave
+ // the last page half-empty rather than trying to balance things out
+ // (which only makes sense in non-ragged situations).
+ if (line == lines_.size () - 1 && ragged && last && space.force_ > 0)
space.force_ = 0;
- /* we may have to deal with single lines that are taller than a page */
- if (isinf (space.force_) && page_start == line)
- space.force_ = -200000;
+ Real demerits = space.force_ * space.force_;
+
+ // Clamp the demerits at BAD_SPACING_PENALTY, even if the page
+ // is overfull. This ensures that TERRIBLE_SPACING_PENALTY takes
+ // precedence over overfull pages.
+ demerits = min (demerits, BAD_SPACING_PENALTY);
+ demerits += (prev ? prev->demerits_ : 0);
- Real dem = fabs (space.force_) + (prev ? prev->demerits_ : 0);
- Real penalty = 0;
+ Real penalty = breaker_->line_count_penalty (line_count);
if (page_start > 0)
- penalty = lines_[page_start-1].page_penalty_
+ penalty += lines_[page_start-1].page_penalty_
+ (page % 2 == 0) ? lines_[page_start-1].turn_penalty_ : 0;
- dem += penalty;
- if (dem < cur.demerits_ || page_start == line)
+ /* Deal with widow/orphan lines */
+ /* Last line of paragraph is first line on the new page */
+ if ((page_start > 0) &&
+ (page_start < lines_.size ()) &&
+ (lines_[page_start].last_markup_line_))
+ penalty += breaker_->orphan_penalty ();
+ /* First line of paragraph is last line on the previous page */
+ if ((page_start > 0) &&
+ (page_start < lines_.size ()) &&
+ (lines_[page_start-1].first_markup_line_))
+ penalty += breaker_->orphan_penalty ();
+
+ demerits += penalty;
+ if (demerits < cur.demerits_ || page_start == line)
{
- cur.demerits_ = dem;
+ cur.demerits_ = demerits;
cur.force_ = space.force_;
cur.penalty_ = penalty + (prev ? prev->penalty_ : 0);
+ cur.system_count_status_ = breaker_->line_count_status (line_count)
+ | (prev ? prev->system_count_status_ : 0);
cur.prev_ = page_start - 1;
+ cur.page_ = prev ? prev->page_ + 1 : first_page_num_;
}
}
projects / lilypond.git / blobdiff