lily/default-bar-line-engraver.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
   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 "engraver.hh"
  21 #include "context.hh"
  22 #include "multi-measure-rest.hh"
  23 #include "grob.hh"
  24 #include "warn.hh"
  25
  26 class Default_bar_line_engraver : public Engraver
  27 {
  28 protected:
  29   /* Need to know whether we're advancing in grace notes, or not. */
  30   Moment last_moment_;
  31
  32   void start_translation_timestep ();
  33   void stop_translation_timestep ();
  34
  35 public:
  36   TRANSLATOR_DECLARATIONS (Default_bar_line_engraver);
  37 };
  38
  39 #include "translator.icc"
  40
  41 ADD_TRANSLATOR (Default_bar_line_engraver,
  42                 /* doc */
  43                 "This engraver determines what kind of automatic bar lines"
  44                 " should be produced, and sets @code{whichBar} accordingly."
  45                 "  It should be at the same level as @ref{Timing_translator}.",
  46
  47                 /* create */
  48                 "",
  49
  50                 /* read */
  51                 "automaticBars "
  52                 "barAlways "
  53                 "defaultBarType "
  54                 "measureLength "
  55                 "whichBar "
  56                 "measurePosition ",
  57
  58                 /* write */
  59                 "automaticBars "
  60                 );
  61
  62 Default_bar_line_engraver::Default_bar_line_engraver ()
  63 {
  64   last_moment_.main_part_ = Rational (-1);
  65 }
  66
  67 void
  68 Default_bar_line_engraver::start_translation_timestep ()
  69 {
  70   SCM automatic_bars = get_property ("automaticBars");
  71   Moment now = now_mom ();
  72   SCM which = get_property ("whichBar");
  73
  74   /* Set the first bar of the score? */
  75   if (!scm_is_string (which))
  76     which = SCM_EOL;
  77
  78   Moment mp = measure_position (context ());
  79   bool start_of_measure = (last_moment_.main_part_ != now.main_part_
  80                            && !mp.main_part_);
  81
  82   if (!scm_is_string (which) && to_boolean (automatic_bars))
  83     {
  84       SCM always = get_property ("barAlways");
  85
  86       if ((start_of_measure && last_moment_.main_part_ >= Moment (0))
  87           || to_boolean (always))
  88         {
  89           /* should this work, or be junked?  See input/bugs/no-bars.ly */
  90           which = get_property ("defaultBarType");
  91         }
  92     }
  93
  94   context ()->set_property ("whichBar", which);
  95 }
  96
  97 void
  98 Default_bar_line_engraver::stop_translation_timestep ()
  99 {
 100   context ()->set_property ("whichBar", SCM_EOL);
 101   last_moment_ = now_mom ();
 102 }