lily/page-turn-page-breaking.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2006--2010 Joe Neeman <joeneeman@gmail.com>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "page-turn-page-breaking.hh"
  21
  22 #include "international.hh"
  23 #include "item.hh"
  24 #include "output-def.hh"
  25 #include "page-spacing.hh"
  26 #include "paper-book.hh"
  27 #include "paper-score.hh"
  28 #include "paper-system.hh"
  29 #include "system.hh"
  30 #include "warn.hh"
  31
  32 static bool
  33 is_break (Grob *g)
  34 {
  35   bool turnable = scm_is_symbol (g->get_property ("page-turn-permission"));
  36
  37   if (turnable &&
  38       (!scm_is_symbol (g->get_property ("page-break-permission"))
  39        || !scm_is_symbol (g->get_property ("line-break-permission"))))
  40     {
  41       programming_error ("found a page-turnable place which was not breakable");
  42       turnable = false;
  43     }
  44
  45   return turnable;
  46 }
  47
  48 Page_turn_page_breaking::Page_turn_page_breaking (Paper_book *pb)
  49   : Page_breaking (pb, is_break)
  50 {
  51 }
  52
  53 Page_turn_page_breaking::~Page_turn_page_breaking ()
  54 {
  55 }
  56
  57 Page_turn_page_breaking::Break_node
  58 Page_turn_page_breaking::put_systems_on_pages (vsize start,
  59                                                vsize end,
  60                                                vsize configuration,
  61                                                vsize page_number)
  62 {
  63   vsize min_p_count = min_page_count (configuration, page_number);
  64   bool auto_first = to_boolean (book_->paper_->c_variable ("auto-first-page-number"));
  65
  66   /* If [START, END] does not contain an intermediate
  67      breakpoint, we may need to consider solutions that result in a bad turn.
  68      In this case, we won't abort if the min_page_count is too big */
  69   if (start < end - 1 && min_p_count + (auto_first ? 0 : (page_number % 2)) > 2)
  70     return Break_node ();
  71
  72   /* if PAGE-NUMBER is odd, we are starting on a right hand page. That is, we
  73      have the options
  74      PAGE-NUMBER odd:
  75        - even number of pages + a blank page
  76        - odd number of pages
  77      PAGE-NUMBER even:
  78        - odd number of pages + a blank page
  79        - even number of pages
  80
  81      No matter which case PAGE-NUMBER falls into, we take the second choice if
  82      min_p_count has that evenness. (For example, if PAGE-NUMBER is even and
  83      min_p_count is even, we don't even consider the blank page option). */
  84
  85   Page_spacing_result result;
  86   if (start == 0 && auto_first)
  87     {
  88       if (min_p_count % 2)
  89         result = space_systems_on_n_or_one_more_pages (configuration, min_p_count, page_number, 0);
  90       else
  91         result = space_systems_on_n_pages (configuration, min_p_count, page_number);
  92     }
  93   else if (page_number % 2 == min_p_count % 2)
  94     result = space_systems_on_n_pages (configuration, min_p_count, page_number);
  95   else
  96     result = space_systems_on_n_or_one_more_pages (configuration, min_p_count, page_number, blank_page_penalty ());
  97
  98   Break_node ret;
  99   ret.prev_ = start - 1;
 100   ret.break_pos_ = end;
 101   ret.page_count_ = result.force_.size ();
 102   ret.first_page_number_ = page_number;
 103   if (auto_first && start == 0)
 104     ret.first_page_number_ += 1 - (ret.page_count_ % 2);
 105
 106   ret.div_ = current_configuration (configuration);
 107   ret.system_count_ = result.systems_per_page_;
 108
 109   ret.too_many_lines_ = all_lines_stretched (configuration);
 110   ret.demerits_ = result.demerits_;
 111   if (start > 0)
 112     ret.demerits_ += state_[start-1].demerits_;
 113
 114   return ret;
 115 }
 116
 117 /* The number of pages taken up by a Break_node, including
 118    the blank page if there is one */
 119 vsize
 120 Page_turn_page_breaking::total_page_count (Break_node const &b)
 121 {
 122   vsize end = b.first_page_number_ + b.page_count_;
 123   return end - 1 + (end % 2) - b.first_page_number_;
 124 }
 125
 126 extern bool debug_page_breaking_scoring;
 127
 128 void
 129 Page_turn_page_breaking::calc_subproblem (vsize ending_breakpoint)
 130 {
 131   vsize end = ending_breakpoint + 1;
 132   Break_node best;
 133   Break_node cur;
 134   Break_node this_start_best;
 135   vsize prev_best_system_count = 0;
 136
 137   for (vsize start = end; start--;)
 138     {
 139       if (start < end-1
 140           && breakpoint_property (start+1, "page-turn-permission") == ly_symbol2scm ("force"))
 141         break;
 142
 143       if (start > 0 && best.demerits_ < state_[start-1].demerits_)
 144         continue;
 145
 146       int p_num = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
 147       if (start > 0)
 148         {
 149           /* except possibly for the first page, enforce the fact that first_page_number_
 150              should always be even (left hand page).
 151              TODO: are there different conventions in right-to-left languages?
 152           */
 153           p_num = state_[start-1].first_page_number_ + state_[start-1].page_count_;
 154           p_num += p_num % 2;
 155         }
 156
 157       Line_division min_division;
 158       Line_division max_division;
 159
 160       vsize min_sys_count = min_system_count (start, end);
 161       vsize max_sys_count = max_system_count (start, end);
 162       this_start_best.demerits_ = infinity_f;
 163
 164       bool ok_page = true;
 165
 166       if (debug_page_breaking_scoring)
 167         message (_f ("page-turn-page-breaking: breaking from %d to %d", (int) start, (int) end));
 168
 169       /* heuristic: we've just added a breakpoint, we'll need at least as
 170          many systems as before */
 171       min_sys_count = max (min_sys_count, prev_best_system_count);
 172       for (vsize sys_count = min_sys_count; sys_count <= max_sys_count && ok_page; sys_count++)
 173         {
 174           set_current_breakpoints (start, end, sys_count, min_division, max_division);
 175           bool found = false;
 176
 177           for (vsize i = 0; i < current_configuration_count (); i++)
 178             {
 179               cur = put_systems_on_pages (start, end, i, p_num);
 180
 181               if (isinf (cur.demerits_)
 182                   || (cur.page_count_  + (p_num % 2) > 2
 183                       && (!isinf (this_start_best.demerits_))
 184                       && total_page_count (cur) > total_page_count (this_start_best)))
 185                 {
 186                   ok_page = false;
 187                   break;
 188                 }
 189
 190               if (cur.demerits_ < this_start_best.demerits_)
 191                 {
 192                   if (debug_page_breaking_scoring)
 193                     print_break_node (cur);
 194
 195                   found = true;
 196                   this_start_best = cur;
 197                   prev_best_system_count = sys_count;
 198
 199                   /* heuristic: if we increase the number of systems, we can bound the
 200                      division from below by our current best division */
 201                   min_division = current_configuration (i);
 202                 }
 203             }
 204           if (!found && this_start_best.too_many_lines_)
 205             break;
 206         }
 207       if (isinf (this_start_best.demerits_))
 208         {
 209           assert (!isinf (best.demerits_) && start < end - 1);
 210           break;
 211         }
 212
 213       if (start == 0 && end == 1
 214           && this_start_best.first_page_number_ == 1
 215           && this_start_best.page_count_ > 1)
 216         warning (_ ("cannot fit the first page turn onto a single page.  "
 217                     "Consider setting first-page-number to an even number."));
 218
 219       if (this_start_best.demerits_ < best.demerits_)
 220         best = this_start_best;
 221     }
 222   state_.push_back (best);
 223 }
 224
 225 SCM
 226 Page_turn_page_breaking::solve ()
 227 {
 228   state_.clear ();
 229   message (_f ("Calculating page and line breaks (%d possible page breaks)...",
 230                (int) last_break_position ()));
 231   for (vsize i = 0; i < last_break_position (); i++)
 232     {
 233       calc_subproblem (i);
 234       progress_indication (string ("[") + to_string (i + 1) + "]");
 235     }
 236   progress_indication ("\n");
 237
 238   vector<Break_node> breaking;
 239   int i = state_.size () - 1;
 240   while (i >= 0)
 241     {
 242       breaking.push_back (state_[i]);
 243       i = state_[i].prev_;
 244     }
 245   reverse (breaking);
 246
 247   message (_ ("Drawing systems..."));
 248   SCM systems = make_lines (&breaking);
 249   return make_pages (breaking, systems);
 250 }
 251
 252 /* do the line breaking in all the scores and return a big list of systems */
 253 SCM
 254 Page_turn_page_breaking::make_lines (vector<Break_node> *psoln)
 255 {
 256   vector<Break_node> &soln = *psoln;
 257   for (vsize n = 0; n < soln.size (); n++)
 258     {
 259       vsize start = n > 0 ? soln[n-1].break_pos_ : 0;
 260       vsize end = soln[n].break_pos_;
 261
 262       break_into_pieces (start, end, soln[n].div_);
 263     }
 264
 265   return systems ();
 266 }
 267
 268 SCM
 269 Page_turn_page_breaking::make_pages (vector<Break_node> const &soln, SCM systems)
 270 {
 271   vector<vsize> lines_per_page;
 272   for (vsize i = 0; i < soln.size (); i++)
 273     {
 274       for (vsize j = 0; j < soln[i].page_count_; j++)
 275         lines_per_page.push_back (soln[i].system_count_[j]);
 276
 277       if (i + 1 < soln.size () && (soln[i].first_page_number_ + soln[i].page_count_) % 2)
 278         /* add a blank page */
 279         lines_per_page.push_back (0);
 280     }
 281
 282   /* this should only actually modify first-page-number if
 283      auto-first-page-number was true. */
 284   book_->paper_->set_variable (ly_symbol2scm ("first-page-number"),
 285                                scm_from_int (soln[0].first_page_number_));
 286   return Page_breaking::make_pages (lines_per_page, systems);
 287 }
 288
 289 void
 290 Page_turn_page_breaking::print_break_node (Break_node const &node)
 291 {
 292   int system_count = 0;
 293   for (vsize i = 0; i < node.system_count_.size (); i++)
 294     system_count += node.system_count_[i];
 295
 296   message (_f ("break starting at page %d", (int) node.first_page_number_));
 297   message (_f ("\tdemerits: %f", node.demerits_));
 298   message (_f ("\tsystem count: %d", system_count));
 299   message (_f ("\tpage count: %d", (int) node.page_count_));
 300   message (_f ("\tprevious break: %d", (int) node.prev_));
 301 }