lily/keep-alive-together-engraver.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2010--2015 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 "context.hh"
  21 #include "dispatcher.hh"
  22 #include "engraver.hh"
  23 #include "grob.hh"
  24 #include "grob-array.hh"
  25 #include "international.hh"
  26
  27 #include "translator.icc"
  28
  29 class Keep_alive_together_engraver: public Engraver
  30 {
  31   vector<Grob *> group_spanners_;
  32
  33 public:
  34   TRANSLATOR_DECLARATIONS (Keep_alive_together_engraver);
  35   void acknowledge_hara_kiri_group_spanner (Grob_info);
  36
  37   virtual void finalize ();
  38 };
  39
  40 Keep_alive_together_engraver::Keep_alive_together_engraver ()
  41 {
  42 }
  43
  44 void
  45 Keep_alive_together_engraver::acknowledge_hara_kiri_group_spanner (Grob_info i)
  46 {
  47   group_spanners_.push_back (i.grob ());
  48 }
  49
  50 void
  51 Keep_alive_together_engraver::finalize ()
  52 {
  53   for (vsize i = 0; i < group_spanners_.size (); ++i)
  54     {
  55       SCM this_layer = group_spanners_[i]->get_property ("remove-layer");
  56       if (scm_is_false (this_layer))
  57         continue;
  58
  59       SCM live_scm = Grob_array::make_array ();
  60       Grob_array *live = unsmob<Grob_array> (live_scm);
  61       SCM dead_scm = Grob_array::make_array ();
  62       Grob_array *dead = unsmob<Grob_array> (dead_scm);
  63
  64       for (vsize j = 0; j < group_spanners_.size (); ++j)
  65         {
  66           if (i == j)
  67             continue;
  68
  69           if (scm_is_symbol (this_layer))
  70             {
  71               if (scm_is_eq (this_layer, ly_symbol2scm ("any")))
  72                 {
  73                   // layer is kept alive by any other layer
  74                   live->add (group_spanners_[j]);
  75                   continue;
  76                 }
  77               else if (scm_is_eq (this_layer, ly_symbol2scm ("above")))
  78                 {
  79                   // layer is kept alive by the layer preceding it
  80                   if (i == j + 1)
  81                     live->add (group_spanners_[j]);
  82                   continue;
  83                 }
  84               else if (scm_is_eq (this_layer, ly_symbol2scm ("below")))
  85                 {
  86                   // layer is kept alive by the layer following it
  87                   if (i == j - 1)
  88                     live->add (group_spanners_[j]);
  89                   continue;
  90                 }
  91               else
  92                 {
  93                   group_spanners_[i]->warning (_f ("unknown remove-layer value `%s'",
  94                                                    ly_symbol2string (this_layer).c_str ()));
  95                   continue;
  96                 }
  97             }
  98
  99           SCM that_layer = group_spanners_[j]->get_property ("remove-layer");
 100
 101           if (scm_is_false (that_layer))
 102             continue;
 103           if (!scm_is_integer (this_layer))
 104             {
 105               // unset layers are kept alive by all but ignored layers
 106               live->add (group_spanners_[j]);
 107               continue;
 108             }
 109           // an explicit layer is only affected by explicit layers
 110           if (!scm_is_integer (that_layer))
 111             continue;
 112           if (scm_is_true (scm_num_eq_p (that_layer, this_layer)))
 113             live->add (group_spanners_[j]);
 114           else if (scm_is_true (scm_less_p (that_layer, this_layer)))
 115             dead->add (group_spanners_[j]);
 116         }
 117       if (!live->empty ())
 118         group_spanners_[i]->set_object ("keep-alive-with", live_scm);
 119       if (!dead->empty ())
 120         group_spanners_[i]->set_object ("make-dead-when", dead_scm);
 121     }
 122 }
 123
 124
 125 void
 126 Keep_alive_together_engraver::boot ()
 127 {
 128   ADD_ACKNOWLEDGER (Keep_alive_together_engraver, hara_kiri_group_spanner);
 129 }
 130
 131 ADD_TRANSLATOR (Keep_alive_together_engraver,
 132                 /* doc */
 133                 "This engraver collects all @code{Hara_kiri_group_spanner}s "
 134                 "that are created in contexts at or below its own.  "
 135                 "These spanners are then tied together so that one will "
 136                 "be removed only if all are removed.  For example, "
 137                 "if a @code{StaffGroup} uses this engraver, then the staves "
 138                 "in the group will all be visible as long as there is a note "
 139                 "in at least one of them.",
 140
 141                 /* create */
 142                 "",
 143
 144                 /* read */
 145                 "",
 146
 147                 /* write */
 148                 ""
 149                );