doc: NR 2.1.7 Chants..: rework

[lilypond.git] / lily / optimal-page-breaking.cc

diff --git a/lily/optimal-page-breaking.cc b/lily/optimal-page-breaking.cc
index 13b2669aafd4a7d4f0a9f8b8bbe0d441b3fac3d5..e9010aec09345ef715d247a20a0a854d34bc5956 100644 (file)
--- a/lily/optimal-page-breaking.cc
+++ b/lily/optimal-page-breaking.cc
@@ -1,11 +1,20 @@
 /*
-  optimal-page-breaking.cc -- implement a page-breaker that
-  will break pages in such a way that both horizontal and
-  vertical spacing will be acceptable
+  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--2009 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 "international.hh"
@@ -17,19 +26,8 @@
 #include "prob.hh"
 #include "system.hh"
 
-static bool
-is_break (Grob *)
-{
-  return false;
-}
-
-// FIXME: divide the page breaking into subproblems wherever there is a page break.
-// This will allow us to tweak line-breaking independently on both sides of a
-// page break (currently, we only get to request a number of systems for an entire score
-// at a time), which is necessary for min-systems-per-page and \pageBreak to interact
-// correctly.
 Optimal_page_breaking::Optimal_page_breaking (Paper_book *pb)
-  : Page_breaking (pb, is_break)
+  : Page_breaking (pb, 0, 0)
 {
 }
 
@@ -37,17 +35,19 @@ Optimal_page_breaking::~Optimal_page_breaking ()
 {
 }
 
+extern bool debug_page_breaking_scoring;
+
 SCM
 Optimal_page_breaking::solve ()
 {
   vsize end = last_break_position ();
   vsize max_sys_count = max_system_count (0, end);
   vsize first_page_num = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
-  SCM forced_page_count = book_->paper_->c_variable ("page-count");
 
   set_to_ideal_line_configuration (0, end);
 
   Page_spacing_result best;
+  SCM forced_page_count = book_->paper_->c_variable ("page-count");
   vsize page_count = robust_scm2int (forced_page_count, 1);
   Line_division ideal_line_division = current_configuration (0);
   Line_division best_division = ideal_line_division;
@@ -97,15 +97,17 @@ Optimal_page_breaking::solve ()
       Page_spacing_result best_for_this_sys_count;
       set_current_breakpoints (0, end, sys_count, Line_division (), bound);
 
+      if (debug_page_breaking_scoring)
+       message (_f ("trying %d systems", (int)sys_count));
+
       for (vsize i = 0; i < current_configuration_count (); i++)
        {
-         vsize min_p_count = min_page_count (i, first_page_num);
          Page_spacing_result cur;
 
-         if (min_p_count == page_count || scm_is_integer (forced_page_count))
+         if (scm_is_integer (forced_page_count))
            cur = space_systems_on_n_pages (i, page_count, first_page_num);
          else
-           cur = space_systems_on_n_or_one_more_pages (i, page_count-1, first_page_num);
+           cur = space_systems_on_best_pages (i, first_page_num);
 
          if (cur.demerits_ < best_for_this_sys_count.demerits_)
            {
@@ -114,6 +116,9 @@ Optimal_page_breaking::solve ()
            }
        }
 
+      if (debug_page_breaking_scoring)
+       message (_f ("best score for this sys-count: %f", best_for_this_sys_count.demerits_));
+
       if (best_for_this_sys_count.demerits_ < best.demerits_)
        {
          best = best_for_this_sys_count;
@@ -146,6 +151,9 @@ Optimal_page_breaking::solve ()
       Real best_demerits_for_this_sys_count = infinity_f;
       set_current_breakpoints (0, end, sys_count, bound);
 
+      if (debug_page_breaking_scoring)
+       message (_f ("trying %d systems", (int)sys_count));
+
       for (vsize i = 0; i < current_configuration_count (); i++)
        {
          vsize min_p_count = min_page_count (i, first_page_num);
@@ -153,8 +161,10 @@ Optimal_page_breaking::solve ()
 
          if (min_p_count > page_count)
            continue;
-         else
+         else if (scm_is_integer (forced_page_count))
            cur = space_systems_on_n_pages (i, page_count, first_page_num);
+         else
+           cur = space_systems_on_best_pages (i, first_page_num);
 
          if (cur.demerits_ < best.demerits_)
            {
@@ -168,6 +178,10 @@ Optimal_page_breaking::solve ()
              bound = current_configuration (i);
            }
        }
+
+      if (debug_page_breaking_scoring)
+       message (_f ("best score for this sys-count: %f", best_demerits_for_this_sys_count));
+
       if (best_demerits_for_this_sys_count >= BAD_SPACING_PENALTY
        && !(best.system_count_status_ & SYSTEM_COUNT_TOO_FEW))
        break;