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 (Context *c)
  41   : Engraver (c)
  42 {
  43 }
  44
  45 void
  46 Keep_alive_together_engraver::acknowledge_hara_kiri_group_spanner (Grob_info i)
  47 {
  48   group_spanners_.push_back (i.grob ());
  49 }
  50
  51 void
  52 Keep_alive_together_engraver::finalize ()
  53 {
  54   for (vsize i = 0; i < group_spanners_.size (); ++i)
  55     {
  56       SCM this_layer = group_spanners_[i]->get_property ("remove-layer");
  57       if (scm_is_false (this_layer))
  58         continue;
  59
  60       SCM live_scm = Grob_array::make_array ();
  61       Grob_array *live = unsmob<Grob_array> (live_scm);
  62       SCM dead_scm = Grob_array::make_array ();
  63       Grob_array *dead = unsmob<Grob_array> (dead_scm);
  64
  65       for (vsize j = 0; j < group_spanners_.size (); ++j)
  66         {
  67           if (i == j)
  68             continue;
  69
  70           if (scm_is_symbol (this_layer))
  71             {
  72               if (scm_is_eq (this_layer, ly_symbol2scm ("any")))
  73                 {
  74                   // layer is kept alive by any other layer
  75                   live->add (group_spanners_[j]);
  76                   continue;
  77                 }
  78               else if (scm_is_eq (this_layer, ly_symbol2scm ("above")))
  79                 {
  80                   // layer is kept alive by the layer preceding it
  81                   if (i == j + 1)
  82                     live->add (group_spanners_[j]);
  83                   continue;
  84                 }
  85               else if (scm_is_eq (this_layer, ly_symbol2scm ("below")))
  86                 {
  87                   // layer is kept alive by the layer following it
  88                   if (i == j - 1)
  89                     live->add (group_spanners_[j]);
  90                   continue;
  91                 }
  92               else
  93                 {
  94                   group_spanners_[i]->warning (_f ("unknown remove-layer value `%s'",
  95                                                    ly_symbol2string (this_layer).c_str ()));
  96                   continue;
  97                 }
  98             }
  99
 100           SCM that_layer = group_spanners_[j]->get_property ("remove-layer");
 101
 102           if (scm_is_false (that_layer))
 103             continue;
 104           if (!scm_is_integer (this_layer))
 105             {
 106               // unset layers are kept alive by all but ignored layers
 107               live->add (group_spanners_[j]);
 108               continue;
 109             }
 110           // an explicit layer is only affected by explicit layers
 111           if (!scm_is_integer (that_layer))
 112             continue;
 113           if (scm_is_true (scm_num_eq_p (that_layer, this_layer)))
 114             live->add (group_spanners_[j]);
 115           else if (scm_is_true (scm_less_p (that_layer, this_layer)))
 116             dead->add (group_spanners_[j]);
 117         }
 118       if (!live->empty ())
 119         group_spanners_[i]->set_object ("keep-alive-with", live_scm);
 120       if (!dead->empty ())
 121         group_spanners_[i]->set_object ("make-dead-when", dead_scm);
 122     }
 123 }
 124
 125
 126 void
 127 Keep_alive_together_engraver::boot ()
 128 {
 129   ADD_ACKNOWLEDGER (Keep_alive_together_engraver, hara_kiri_group_spanner);
 130 }
 131
 132 ADD_TRANSLATOR (Keep_alive_together_engraver,
 133                 /* doc */
 134                 "This engraver collects all @code{Hara_kiri_group_spanner}s "
 135                 "that are created in contexts at or below its own.  "
 136                 "These spanners are then tied together so that one will "
 137                 "be removed only if all are removed.  For example, "
 138                 "if a @code{StaffGroup} uses this engraver, then the staves "
 139                 "in the group will all be visible as long as there is a note "
 140                 "in at least one of them.",
 141
 142                 /* create */
 143                 "",
 144
 145                 /* read */
 146                 "",
 147
 148                 /* write */
 149                 ""
 150                );