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--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8 #include "translator-group.hh"
   9
  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   /* Needed to know whether we're advancing in grace notes, or not. */
  23   Moment last_moment_;
  24
  25   virtual void start_translation_timestep ();
  26   virtual void stop_translation_timestep ();
  27
  28 public:
  29   TRANSLATOR_DECLARATIONS (Timing_engraver);
  30 };
  31
  32
  33 Timing_engraver::Timing_engraver ()
  34 {
  35   last_moment_.main_part_ = Rational (-1);
  36 }
  37
  38
  39
  40 void
  41 Timing_engraver::start_translation_timestep ()
  42 {
  43   Timing_translator::start_translation_timestep ();
  44
  45   SCM automatic_bars = get_property ("automaticBars");
  46   Moment now = now_mom ();
  47   SCM which = get_property ("whichBar");
  48
  49   /* Set the first bar of the score? */
  50   if (!gh_string_p (which))
  51     which
  52       = (now.main_part_ || now.main_part_ == last_moment_.main_part_)
  53       ? SCM_EOL : scm_makfrom0str ("|");
  54
  55   Moment mp = measure_position ();
  56   bool start_of_measure = (last_moment_.main_part_ != now.main_part_
  57                            && !mp.main_part_);
  58
  59   if (start_of_measure)
  60     {
  61       Moment mlen = Moment (measure_length ());
  62       unsmob_grob (get_property ("currentCommandColumn"))
  63         ->set_grob_property ("measure-length", mlen.smobbed_copy ());
  64     }
  65
  66   if (!gh_string_p (which) && to_boolean (automatic_bars))
  67     {
  68       SCM always = get_property ("barAlways");
  69
  70       if ( start_of_measure || (to_boolean (always)))
  71         {
  72           /* should this work, or be junked?  See input/bugs/no-bars.ly */
  73           which = get_property ("defaultBarType");
  74         }
  75     }
  76
  77   daddy_trans_->set_property ("whichBar", which);
  78 }
  79
  80 void
  81 Timing_engraver::stop_translation_timestep ()
  82 {
  83   Timing_translator::stop_translation_timestep ();
  84   daddy_trans_->set_property ("whichBar", SCM_EOL);
  85   last_moment_ = now_mom ();
  86
  87 }
  88
  89
  90 ENTER_DESCRIPTION (Timing_engraver,
  91 /* descr */       " Responsible for synchronizing timing information from staves.  "
  92 "Normally in @code{Score}.  In order to create polyrhythmic music, "
  93 "this engraver should be removed from @code{Score} and placed in "
  94 "@code{Staff}.",
  95 /* creats*/       "",
  96 /* accepts */     "",
  97 /* acks  */      "",
  98 /* reads */       "timeSignatureFraction automaticBars whichBar barAlways defaultBarType skipBars timing measureLength measurePosition currentBarNumber",
  99 /* write */       "");