lily/timing-engraver.cc

   1 /*
   2   timing-grav.cc -- implement Timing_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2002 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8 #include "translator-group.hh"
   9 #include "command-request.hh"
  10 #include "grob-info.hh"
  11 #include "multi-measure-rest.hh"
  12 #include "timing-translator.hh"
  13 #include "engraver.hh"
  14
  15 /**
  16   Do time bookkeeping
  17  */
  18 class Timing_engraver : public Timing_translator, public Engraver
  19 {
  20 protected:
  21   /*
  22     Needed to know whether we're advancing in grace notes, or not.
  23    */
  24   Moment last_moment_;
  25
  26   virtual void start_translation_timestep ();
  27   virtual void stop_translation_timestep ();
  28
  29 public:
  30   TRANSLATOR_DECLARATIONS(Timing_engraver);
  31 };
  32
  33
  34 Timing_engraver::Timing_engraver ()
  35 {
  36   last_moment_.main_part_ = Rational (-1);
  37 }
  38
  39
  40
  41 void
  42 Timing_engraver::start_translation_timestep ()
  43 {
  44   Timing_translator::start_translation_timestep ();
  45
  46   SCM nonauto = get_property ("barNonAuto");
  47   Moment now = now_mom ();
  48   SCM which = get_property ("whichBar");
  49
  50   /*
  51     Set the first bar of the score?
  52    */
  53   if (!gh_string_p (which))
  54     which
  55       = (now.main_part_ || now.main_part_ == last_moment_.main_part_)
  56       ? SCM_EOL : ly_str02scm ("|");
  57
  58   if (!gh_string_p (which) && !to_boolean (nonauto))
  59     {
  60       SCM always = get_property ("barAlways");
  61       Moment mp = measure_position ();
  62       if ( (last_moment_.main_part_ != now.main_part_
  63             && !mp.main_part_)
  64            || (to_boolean (always)))
  65         {
  66           /* should this work, or be junked?  See input/bugs/no-bars.ly */
  67           which = get_property ("defaultBarType");
  68         }
  69     }
  70
  71   daddy_trans_l_->set_property ("whichBar", which);
  72 }
  73
  74 void
  75 Timing_engraver::stop_translation_timestep ()
  76 {
  77   Timing_translator::stop_translation_timestep ();
  78   daddy_trans_l_->set_property ("whichBar", SCM_EOL);
  79   last_moment_ = now_mom ();
  80 }
  81
  82
  83 ENTER_DESCRIPTION(Timing_engraver,
  84 /* descr */       " Responsible for synchronizing timing information from staves.
  85 Normally in @code{Score}.  In order to create polyrhythmic music,
  86 this engraver should be removed from @code{Score} and placed in
  87 @code{Staff}.",
  88 /* creats*/       "",
  89 /* acks  */       "",
  90 /* reads */       "timeSignatureFraction barCheckNoSynchronize barNonAuto whichBar barAlways defaultBarType skipBars timing oneBeat measureLength measurePosition currentBarNumber",
  91 /* write */       "");