--- /dev/null
+/*
+ This file is part of LilyPond, the GNU music typesetter.
+
+ Copyright (C) 2016 Paul Morris
+
+ 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 "international.hh"
+#include "one-page-breaking.hh"
+#include "output-def.hh"
+#include "page-spacing.hh"
+#include "paper-book.hh"
+#include "paper-score.hh"
+#include "system.hh"
+
+One_page_breaking::One_page_breaking (Paper_book *pb)
+ : Page_breaking (pb, 0, 0)
+{
+}
+
+One_page_breaking::~One_page_breaking ()
+{
+}
+
+SCM
+One_page_breaking::read_spacing_alist (SCM spec, SCM sym)
+{
+ SCM pair = scm_sloppy_assq (sym, spec);
+ if (scm_is_pair (pair) && scm_is_number (scm_cdr (pair)))
+ return scm_cdr (pair);
+ else
+ return scm_from_int (0);
+}
+
+/*
+ This is a somewhat unconventional page-breaking algorithm. The
+ @code{paper-height} setting (in the paper block) is automatically
+ modified to fit the height of the content so that everything exactly
+ fits on a single page with no compression. As usual (in the paper
+ block) the width of the page can be customized with
+ @code{paper-width} or @code{set-paper-size}, and the spacing between
+ the footer and the last system (or top level markup) can be customized
+ with @code{last-bottom-spacing}.
+
+ It works by (1) temporarily setting the page height to a very large
+ value, (2) doing line breaking and page breaking, much like in
+ @code{ly:minimal-line-breaking}, (3) calculate and set the final
+ height of the page based on the results, taking last-bottom-spacing,
+ footer, top and bottom margins, etc. into account.
+*/
+SCM
+One_page_breaking::solve ()
+{
+ // TEMPORARILY SET VERY LARGE PAPER HEIGHT
+ // Stencil::translate throws a programming error (for the tagline
+ // position) if this is set any larger than 1e6
+ book_->paper_->set_variable (ly_symbol2scm ("paper-height"), scm_from_double (1e6));
+
+ // LINE BREAKING
+ message (_ ("Calculating line breaks..."));
+ vsize end = last_break_position ();
+ set_to_ideal_line_configuration (0, end);
+ break_into_pieces (0, end, current_configuration (0));
+
+ // PAGE BREAKING
+ message (_ ("Fitting music on 1 page..."));
+ vsize first_page_num = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
+ Page_spacing_result res = space_systems_on_n_pages (0, 1, first_page_num);
+ SCM lines = systems ();
+ SCM pages = make_pages (res.systems_per_page_, lines);
+
+ // GET VERTICAL POSITIONS
+ // Larger values are lower on the page. We can't just use the last
+ // one, because the last does not necessarily have the lowest bound.
+ vector<Real> line_posns;
+ SCM lowest_line_pos = scm_from_int (0);
+
+ Prob *page_pb = unsmob<Prob> (scm_car (pages));
+ SCM config = page_pb->internal_get_property (ly_symbol2scm ("configuration"));
+
+ for (SCM c = config; scm_is_pair (c); c = scm_cdr (c))
+ {
+ SCM this_pos = scm_car (c);
+ line_posns.push_back (scm_to_double (this_pos));
+ if (scm_gr_p (this_pos, lowest_line_pos))
+ lowest_line_pos = this_pos;
+ }
+
+ // CALCULATE THE LOWEST LOWER BOUND OF ALL LINES ON THE PAGE
+ vector<Real> line_heights;
+ for (vsize i = 0; i < system_specs_.size (); i++)
+ {
+ if (Paper_score *ps = system_specs_[i].pscore_)
+ {
+ // musical systems
+ vsize broken_intos_size = ps->root_system ()->broken_intos_.size ();
+ for (vsize s = 0; s < broken_intos_size; s++)
+ {
+ Grob *system = ps->root_system ()->broken_intos_[s];
+ line_heights.push_back (system->extent (system, Y_AXIS).length ());
+ }
+ }
+ else if (Prob *pb = system_specs_[i].prob_)
+ {
+ // top-level markups
+ Stencil *stil = unsmob<Stencil> (pb->internal_get_property (ly_symbol2scm ("stencil")));
+ line_heights.push_back (stil->extent (Y_AXIS).length ());
+ }
+ }
+
+ Real lowest_bound = 0;
+ for (vsize i = 0; i < line_heights.size (); i++)
+ {
+ Real low_bound = line_heights[i] + line_posns[i];
+ if (low_bound > lowest_bound)
+ lowest_bound = low_bound;
+ }
+
+ // HANDLE LAST-BOTTOM-SPACING
+ SCM last_bottom = book_->paper_->c_variable ("last-bottom-spacing");
+
+ SCM padding = read_spacing_alist (last_bottom, ly_symbol2scm("padding"));
+ lowest_bound += scm_to_double (padding);
+
+ SCM basic_dist = read_spacing_alist (last_bottom, ly_symbol2scm("basic-distance"));
+ SCM minimum_dist = read_spacing_alist (last_bottom, ly_symbol2scm("minimum-distance"));
+ SCM max_dist = scm_max (basic_dist, minimum_dist);
+
+ // If the last line is a musical system get the distance between its
+ // refpoint and its upper bound. If it is a top level markup its
+ // refpoint is 0.
+ SCM refpoint_dist = scm_from_int (0);
+
+ SCM lines_probs = page_pb->internal_get_property (ly_symbol2scm ("lines"));
+ Prob *last_line_pb = unsmob<Prob> (scm_list_ref (lines_probs, scm_oneminus (scm_length (lines_probs))));
+
+ SCM refpoint_extent = last_line_pb->internal_get_property (ly_symbol2scm ("staff-refpoint-extent"));
+
+ if (scm_is_pair (refpoint_extent) && scm_is_number (scm_car (refpoint_extent)))
+ refpoint_dist = scm_product (scm_car (refpoint_extent), scm_from_int (-1));
+
+ Real last_bottom_bound = scm_to_double (scm_sum (lowest_line_pos, scm_sum (refpoint_dist, max_dist)));
+ if (last_bottom_bound > lowest_bound)
+ lowest_bound = last_bottom_bound;
+
+ // SET FINAL PAPER HEIGHT
+ Stencil *foot_stil = unsmob<Stencil> (page_pb->internal_get_property (ly_symbol2scm ("foot-stencil")));
+ Real foot_height = foot_stil->extent (Y_AXIS).length ();
+
+ SCM top_margin = book_->paper_->c_variable ("top-margin");
+ SCM bottom_margin = book_->paper_->c_variable ("bottom-margin");
+ SCM margins = scm_sum (top_margin, bottom_margin);
+
+ SCM ppr_height = scm_sum (margins, scm_from_double (lowest_bound + foot_height));
+
+ book_->paper_->set_variable (ly_symbol2scm ("paper-height"), ppr_height);
+
+ // bottom-edge determines placement of footer (tagline, footnotes, etc.)
+ page_pb->set_property ("bottom-edge", scm_difference (ppr_height, bottom_margin));
+
+ return pages;
+}
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