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 #include "grob.hh"
  15
  16 /**
  17   Do time bookkeeping
  18  */
  19 class Timing_engraver : public Timing_translator, public Engraver
  20 {
  21 protected:
  22   /*
  23     Needed to know whether we're advancing in grace notes, or not.
  24    */
  25   Moment last_moment_;
  26
  27   virtual void start_translation_timestep ();
  28   virtual void stop_translation_timestep ();
  29
  30 public:
  31   TRANSLATOR_DECLARATIONS(Timing_engraver);
  32 };
  33
  34
  35 Timing_engraver::Timing_engraver ()
  36 {
  37   last_moment_.main_part_ = Rational (-1);
  38 }
  39
  40
  41
  42 void
  43 Timing_engraver::start_translation_timestep ()
  44 {
  45   Timing_translator::start_translation_timestep ();
  46
  47   SCM nonauto = get_property ("barNonAuto");
  48   Moment now = now_mom ();
  49   SCM which = get_property ("whichBar");
  50
  51   /*
  52     Set the first bar of the score?
  53    */
  54   if (!gh_string_p (which))
  55     which
  56       = (now.main_part_ || now.main_part_ == last_moment_.main_part_)
  57       ? SCM_EOL : scm_makfrom0str ("|");
  58
  59   Moment mp = measure_position ();
  60   bool start_of_measure = (last_moment_.main_part_ != now.main_part_&& !mp.main_part_  );
  61
  62   if (start_of_measure)
  63     {
  64       Moment mlen = Moment(measure_length ());
  65       unsmob_grob (get_property ("currentCommandColumn"))->set_grob_property ("measure-length", mlen.smobbed_copy());
  66     }
  67
  68   if (!gh_string_p (which) && !to_boolean (nonauto))
  69     {
  70       SCM always = get_property ("barAlways");
  71
  72       if ( start_of_measure || (to_boolean (always)))
  73         {
  74           /* should this work, or be junked?  See input/bugs/no-bars.ly */
  75           which = get_property ("defaultBarType");
  76         }
  77     }
  78
  79   daddy_trans_->set_property ("whichBar", which);
  80 }
  81
  82 void
  83 Timing_engraver::stop_translation_timestep ()
  84 {
  85   Timing_translator::stop_translation_timestep ();
  86   daddy_trans_->set_property ("whichBar", SCM_EOL);
  87   last_moment_ = now_mom ();
  88
  89 }
  90
  91
  92 ENTER_DESCRIPTION(Timing_engraver,
  93 /* descr */       " Responsible for synchronizing timing information from staves.
  94 Normally in @code{Score}.  In order to create polyrhythmic music,
  95 this engraver should be removed from @code{Score} and placed in
  96 @code{Staff}.",
  97 /* creats*/       "",
  98 /* acks  */       "",
  99 /* reads */       "timeSignatureFraction barNonAuto whichBar barAlways defaultBarType skipBars timing oneBeat measureLength measurePosition currentBarNumber",
 100 /* write */       "");