lily/default-bar-line-engraver.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2011 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 "grob.hh"
  23 #include "warn.hh"
  24
  25 class Default_bar_line_engraver : public Engraver
  26 {
  27 protected:
  28   /* Need to know whether we're advancing in grace notes, or not. */
  29   Moment last_moment_;
  30
  31   void start_translation_timestep ();
  32   void stop_translation_timestep ();
  33
  34 public:
  35   TRANSLATOR_DECLARATIONS (Default_bar_line_engraver);
  36 };
  37
  38 #include "translator.icc"
  39
  40 ADD_TRANSLATOR (Default_bar_line_engraver,
  41                 /* doc */
  42                 "This engraver determines what kind of automatic bar lines"
  43                 " should be produced, and sets @code{whichBar} accordingly."
  44                 "  It should be at the same level as @ref{Timing_translator}.",
  45
  46                 /* create */
  47                 "",
  48
  49                 /* read */
  50                 "automaticBars "
  51                 "barAlways "
  52                 "defaultBarType "
  53                 "measureLength "
  54                 "whichBar "
  55                 "measurePosition ",
  56
  57                 /* write */
  58                 "automaticBars "
  59                 );
  60
  61 Default_bar_line_engraver::Default_bar_line_engraver ()
  62 {
  63   last_moment_.main_part_ = Rational (-1);
  64 }
  65
  66 void
  67 Default_bar_line_engraver::start_translation_timestep ()
  68 {
  69   SCM automatic_bars = get_property ("automaticBars");
  70   Moment now = now_mom ();
  71   SCM which = get_property ("whichBar");
  72
  73   /* Set the first bar of the score? */
  74   if (!scm_is_string (which))
  75     which = SCM_EOL;
  76
  77   Moment mp = measure_position (context ());
  78   bool start_of_measure = (last_moment_.main_part_ != now.main_part_
  79                            && !mp.main_part_);
  80
  81   if (!scm_is_string (which) && to_boolean (automatic_bars))
  82     {
  83       SCM always = get_property ("barAlways");
  84
  85       if ((start_of_measure && last_moment_.main_part_ >= Moment (0))
  86           || to_boolean (always))
  87         {
  88           /* should this work, or be junked?  See input/bugs/no-bars.ly */
  89           which = get_property ("defaultBarType");
  90         }
  91     }
  92
  93   context ()->set_property ("whichBar", which);
  94 }
  95
  96 void
  97 Default_bar_line_engraver::stop_translation_timestep ()
  98 {
  99   context ()->set_property ("whichBar", SCM_EOL);
 100   last_moment_ = now_mom ();
 101 }