source file of the GNU LilyPond music typesetter
- (c) 2006--2007 Joe Neeman <joeneeman@gmail.com>
+ (c) 2006--2009 Joe Neeman <joeneeman@gmail.com>
*/
#include "page-spacing.hh"
#include "page-breaking.hh"
#include "warn.hh"
-/* In order to prevent possible division by zero, we require every line
- to have a spring of non-zero length. */
-Real
-line_space (const Line_details &line)
-{
- return max (0.1, line.space_);
-}
-
void
Page_spacing::calc_force ()
{
- if (rod_height_ + last_line_.bottom_padding_ >= page_height_ || !inverse_spring_k_)
+ 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;
else
- force_ = (page_height_ - rod_height_ - last_line_.bottom_padding_ - spring_len_) / inverse_spring_k_;
+ force_ = (height - rod_height_ - last_line_.bottom_padding_ - spring_len_)
+ / max (0.1, inverse_spring_k_);
+}
+
+void
+Page_spacing::resize (Real new_height)
+{
+ page_height_ = new_height;
+ calc_force ();
}
void
Page_spacing::append_system (const Line_details &line)
{
+ if (!rod_height_)
+ first_line_ = line;
+
rod_height_ += last_line_.padding_;
rod_height_ += line.extent_.length ();
- spring_len_ += line_space (line);
- inverse_spring_k_ += max (0.1, line.inverse_hooke_);
+ spring_len_ += line.space_;
+ inverse_spring_k_ += line.inverse_hooke_;
last_line_ = line;
last_line_ = line;
rod_height_ += line.extent_.length ();
- spring_len_ += line_space (line);
- inverse_spring_k_ += max (0.1, line.inverse_hooke_);
+ spring_len_ += line.space_;
+ inverse_spring_k_ += line.inverse_hooke_;
+
+ first_line_ = line;
calc_force ();
}
breaker_ = breaker;
max_page_count_ = 0;
ragged_ = breaker->ragged ();
- ragged_last_ = breaker->last () && breaker->ragged_last ();
+ ragged_last_ = breaker->is_last () && breaker->ragged_last ();
}
-Spacing_result
+Page_spacing_result
Page_spacer::solve (vsize page_count)
{
if (page_count > max_page_count_)
resize (page_count);
- Spacing_result ret;
- ret.force_.resize (page_count);
- ret.systems_per_page_.resize (page_count);
+ Page_spacing_result ret;
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_))
{
All the systems that don't fit get tacked onto the last page.
*/
vsize i;
- for (i = system; isinf (state_.at (i, page_count-1).demerits_) && i--; )
+ for (i = system; isinf (state_.at (i, page_count-1).demerits_) && i; i--)
;
if (i)
{
- tack_onto_the_end = system - i;
+ extra_systems = system - i;
system = i;
}
else
- return 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.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.
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));
+ Page_spacing space (breaker_->page_height (page + first_page_num_, last),
+ breaker_);
Page_spacing_node &cur = 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--;)
{
Page_spacing_node const *prev = page > 0 ? &state_.at (page_start-1, page-1) : 0;
space.prepend_system (lines_[page_start]);
- if (page_start < line && (isinf (space.force_) || (space.force_ < 0 && ragged)))
+
+ // 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
+ && (isinf (space.force_) || (space.force_ < 0 && ragged)))
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 */
+ Real demerits = space.force_ * space.force_;
+ /* If a single line is taller than a page, we need to consider it as
+ a possible solution (but we give it a very bad score). */
if (isinf (space.force_) && page_start == line)
- space.force_ = -200000;
+ 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)
+ 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;
}
}
projects / lilypond.git / blobdiff