lily/page-turn-page-breaking.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2006--2011 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 template<typename T>
  33 static bool
  34 is_break (T *g)
  35 {
  36   bool turnable = scm_is_symbol (g->get_property ("page-turn-permission"));
  37
  38   if (turnable &&
  39       (!scm_is_symbol (g->get_property ("page-break-permission"))
  40        || !scm_is_symbol (g->get_property ("line-break-permission"))))
  41     {
  42       programming_error ("found a page-turnable place which was not breakable");
  43       turnable = false;
  44     }
  45
  46   return turnable;
  47 }
  48
  49 Page_turn_page_breaking::Page_turn_page_breaking (Paper_book *pb)
  50   : Page_breaking (pb, is_break<Grob>, is_break<Prob>)
  51 {
  52 }
  53
  54 Page_turn_page_breaking::~Page_turn_page_breaking ()
  55 {
  56 }
  57
  58 Page_turn_page_breaking::Break_node
  59 Page_turn_page_breaking::put_systems_on_pages (vsize start,
  60                                                vsize end,
  61                                                vsize configuration,
  62                                                vsize page_number)
  63 {
  64   vsize min_p_count = min_page_count (configuration, page_number);
  65   bool auto_first = to_boolean (book_->paper_->c_variable ("auto-first-page-number"));
  66
  67   /* If [START, END] does not contain an intermediate
  68      breakpoint, we may need to consider solutions that result in a bad turn.
  69      In this case, we won't abort if the min_page_count is too big */
  70   if (start < end - 1 && min_p_count + (auto_first ? 0 : (page_number % 2)) > 2)
  71     return Break_node ();
  72
  73   /* if PAGE-NUMBER is odd, we are starting on a right hand page. That is, we
  74      have the options
  75      PAGE-NUMBER odd:
  76        - even number of pages + a blank page
  77        - odd number of pages
  78      PAGE-NUMBER even:
  79        - odd number of pages + a blank page
  80        - even number of pages
  81
  82      No matter which case PAGE-NUMBER falls into, we take the second choice if
  83      min_p_count has that evenness. (For example, if PAGE-NUMBER is even and
  84      min_p_count is even, we don't even consider the blank page option). */
  85
  86   Page_spacing_result result;
  87   if (start == 0 && auto_first)
  88     {
  89       if (min_p_count % 2)
  90         result = space_systems_on_n_or_one_more_pages (configuration, min_p_count, page_number, 0);
  91       else
  92         result = space_systems_on_n_pages (configuration, min_p_count, page_number);
  93     }
  94   else if (page_number % 2 == min_p_count % 2)
  95     result = space_systems_on_n_pages (configuration, min_p_count, page_number);
  96   else
  97     result = space_systems_on_n_or_one_more_pages (configuration, min_p_count, page_number, blank_page_penalty ());
  98
  99   Break_node ret;
 100   ret.prev_ = start - 1;
 101   ret.break_pos_ = end;
 102   ret.page_count_ = result.force_.size ();
 103   ret.first_page_number_ = page_number;
 104   if (auto_first && start == 0)
 105     ret.first_page_number_ += 1 - (ret.page_count_ % 2);
 106
 107   ret.div_ = current_configuration (configuration);
 108   ret.system_count_ = result.systems_per_page_;
 109
 110   ret.too_many_lines_ = all_lines_stretched (configuration);
 111   ret.demerits_ = result.demerits_;
 112   if (start > 0)
 113     ret.demerits_ += state_[start-1].demerits_;
 114
 115   return ret;
 116 }
 117
 118 /* The number of pages taken up by a Break_node, including
 119    the blank page if there is one */
 120 vsize
 121 Page_turn_page_breaking::total_page_count (Break_node const &b)
 122 {
 123   vsize end = b.first_page_number_ + b.page_count_;
 124   return end - 1 + (end % 2) - b.first_page_number_;
 125 }
 126
 127 extern bool debug_page_breaking_scoring;
 128
 129 void
 130 Page_turn_page_breaking::calc_subproblem (vsize ending_breakpoint)
 131 {
 132   vsize end = ending_breakpoint + 1;
 133   Break_node best;
 134   Break_node cur;
 135   Break_node this_start_best;
 136   vsize prev_best_system_count = 0;
 137
 138   for (vsize start = end; start--;)
 139     {
 140       if (start < end-1
 141           && breakpoint_property (start+1, "page-turn-permission") == ly_symbol2scm ("force"))
 142         break;
 143
 144       if (start > 0 && best.demerits_ < state_[start-1].demerits_)
 145         continue;
 146
 147       int p_num = robust_scm2int (book_->paper_->c_variable ("first-page-number"), 1);
 148       if (start > 0)
 149         {
 150           /* except possibly for the first page, enforce the fact that first_page_number_
 151              should always be even (left hand page).
 152              TODO: are there different conventions in right-to-left languages?
 153           */
 154           p_num = state_[start-1].first_page_number_ + state_[start-1].page_count_;
 155           p_num += p_num % 2;
 156         }
 157
 158       Line_division min_division;
 159       Line_division max_division;
 160
 161       vsize min_sys_count = min_system_count (start, end);
 162       vsize max_sys_count = max_system_count (start, end);
 163       this_start_best.demerits_ = infinity_f;
 164
 165       bool ok_page = true;
 166
 167       if (debug_page_breaking_scoring)
 168         message (_f ("page-turn-page-breaking: breaking from %d to %d", (int) start, (int) end));
 169
 170       /* heuristic: we've just added a breakpoint, we'll need at least as
 171          many systems as before */
 172       min_sys_count = max (min_sys_count, prev_best_system_count);
 173       for (vsize sys_count = min_sys_count; sys_count <= max_sys_count && ok_page; sys_count++)
 174         {
 175           set_current_breakpoints (start, end, sys_count, min_division, max_division);
 176           bool found = false;
 177
 178           for (vsize i = 0; i < current_configuration_count (); i++)
 179             {
 180               cur = put_systems_on_pages (start, end, i, p_num);
 181
 182               if (isinf (cur.demerits_)
 183                   || (cur.page_count_  + (p_num % 2) > 2
 184                       && (!isinf (this_start_best.demerits_))
 185                       && total_page_count (cur) > total_page_count (this_start_best)))
 186                 {
 187                   ok_page = false;
 188                   break;
 189                 }
 190
 191               if (cur.demerits_ < this_start_best.demerits_)
 192                 {
 193                   if (debug_page_breaking_scoring)
 194                     print_break_node (cur);
 195
 196                   found = true;
 197                   this_start_best = cur;
 198                   prev_best_system_count = sys_count;
 199
 200                   /* heuristic: if we increase the number of systems, we can bound the
 201                      division from below by our current best division */
 202                   min_division = current_configuration (i);
 203                 }
 204             }
 205           if (!found && this_start_best.too_many_lines_)
 206             break;
 207         }
 208       if (isinf (this_start_best.demerits_))
 209         {
 210           assert (!isinf (best.demerits_) && start < end - 1);
 211           break;
 212         }
 213
 214       if (start == 0 && end == 1
 215           && this_start_best.first_page_number_ == 1
 216           && this_start_best.page_count_ > 1)
 217         warning (_ ("cannot fit the first page turn onto a single page."
 218                     "  Consider setting first-page-number to an even number."));
 219
 220       if (this_start_best.demerits_ < best.demerits_)
 221         best = this_start_best;
 222     }
 223   state_.push_back (best);
 224 }
 225
 226 SCM
 227 Page_turn_page_breaking::solve ()
 228 {
 229   state_.clear ();
 230   message (_f ("Calculating page and line breaks (%d possible page breaks)...",
 231                (int) last_break_position ()));
 232   for (vsize i = 0; i < last_break_position (); i++)
 233     {
 234       calc_subproblem (i);
 235       progress_indication (string ("[") + to_string (i + 1) + "]");
 236     }
 237   progress_indication ("\n");
 238
 239   vector<Break_node> breaking;
 240   int i = state_.size () - 1;
 241   while (i >= 0)
 242     {
 243       breaking.push_back (state_[i]);
 244       i = state_[i].prev_;
 245     }
 246   reverse (breaking);
 247
 248   message (_ ("Drawing systems..."));
 249   SCM systems = make_lines (&breaking);
 250   return make_pages (breaking, systems);
 251 }
 252
 253 /* do the line breaking in all the scores and return a big list of systems */
 254 SCM
 255 Page_turn_page_breaking::make_lines (vector<Break_node> *psoln)
 256 {
 257   vector<Break_node> &soln = *psoln;
 258   for (vsize n = 0; n < soln.size (); n++)
 259     {
 260       vsize start = n > 0 ? soln[n-1].break_pos_ : 0;
 261       vsize end = soln[n].break_pos_;
 262
 263       break_into_pieces (start, end, soln[n].div_);
 264     }
 265
 266   return systems ();
 267 }
 268
 269 SCM
 270 Page_turn_page_breaking::make_pages (vector<Break_node> const &soln, SCM systems)
 271 {
 272   if (scm_is_null (systems))
 273     return SCM_EOL;
 274
 275   vector<vsize> lines_per_page;
 276   for (vsize i = 0; i < soln.size (); i++)
 277     {
 278       for (vsize j = 0; j < soln[i].page_count_; j++)
 279         lines_per_page.push_back (soln[i].system_count_[j]);
 280
 281       if (i + 1 < soln.size () && (soln[i].first_page_number_ + soln[i].page_count_) % 2)
 282         /* add a blank page */
 283         lines_per_page.push_back (0);
 284     }
 285
 286   /* this should only actually modify first-page-number if
 287      auto-first-page-number was true. */
 288   book_->paper_->set_variable (ly_symbol2scm ("first-page-number"),
 289                                scm_from_int (soln[0].first_page_number_));
 290   return Page_breaking::make_pages (lines_per_page, systems);
 291 }
 292
 293 void
 294 Page_turn_page_breaking::print_break_node (Break_node const &node)
 295 {
 296   int system_count = 0;
 297   for (vsize i = 0; i < node.system_count_.size (); i++)
 298     system_count += node.system_count_[i];
 299
 300   message (_f ("break starting at page %d", (int) node.first_page_number_));
 301   message (_f ("\tdemerits: %f", node.demerits_));
 302   message (_f ("\tsystem count: %d", system_count));
 303   message (_f ("\tpage count: %d", (int) node.page_count_));
 304   message (_f ("\tprevious break: %d", (int) node.prev_));
 305 }