lily/default-bar-line-engraver.cc

   1 /*
   2   timing-engraver.cc -- implement Default_bar_line_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "engraver.hh"
  10 #include "context.hh"
  11 #include "multi-measure-rest.hh"
  12 #include "grob.hh"
  13 #include "warn.hh"
  14
  15 class Default_bar_line_engraver : public Engraver
  16 {
  17 protected:
  18   /* Need to know whether we're advancing in grace notes, or not. */
  19   Moment last_moment_;
  20
  21   void start_translation_timestep ();
  22   void stop_translation_timestep ();
  23
  24 public:
  25   TRANSLATOR_DECLARATIONS (Default_bar_line_engraver);
  26 };
  27
  28 #include "translator.icc"
  29
  30 ADD_TRANSLATOR (Default_bar_line_engraver,
  31                 /* doc */
  32                 "This engraver determines what kind of automatic bar lines"
  33                 " should be produced, and sets @code{whichBar} accordingly."
  34                 "  It should be at the same level as @ref{Timing_translator}.",
  35
  36                 /* create */
  37                 "",
  38
  39                 /* read */
  40                 "automaticBars "
  41                 "barAlways "
  42                 "defaultBarType "
  43                 "measureLength "
  44                 "whichBar "
  45                 "measurePosition ",
  46
  47                 /* write */
  48                 "automaticBars "
  49                 );
  50
  51 Default_bar_line_engraver::Default_bar_line_engraver ()
  52 {
  53   last_moment_.main_part_ = Rational (-1);
  54 }
  55
  56 void
  57 Default_bar_line_engraver::start_translation_timestep ()
  58 {
  59   SCM automatic_bars = get_property ("automaticBars");
  60   Moment now = now_mom ();
  61   SCM which = get_property ("whichBar");
  62
  63   /* Set the first bar of the score? */
  64   if (!scm_is_string (which))
  65     which = SCM_EOL;
  66
  67   Moment mp = measure_position (context ());
  68   bool start_of_measure = (last_moment_.main_part_ != now.main_part_
  69                            && !mp.main_part_);
  70
  71   if (!scm_is_string (which) && to_boolean (automatic_bars))
  72     {
  73       SCM always = get_property ("barAlways");
  74
  75       if ((start_of_measure && last_moment_.main_part_ >= Moment (0))
  76           || to_boolean (always))
  77         {
  78           /* should this work, or be junked?  See input/bugs/no-bars.ly */
  79           which = get_property ("defaultBarType");
  80         }
  81     }
  82
  83   context ()->set_property ("whichBar", which);
  84 }
  85
  86 void
  87 Default_bar_line_engraver::stop_translation_timestep ()
  88 {
  89   context ()->set_property ("whichBar", SCM_EOL);
  90   last_moment_ = now_mom ();
  91 }