lily/timing-translator.cc

   1 /*
   2   timing-translator.cc -- implement Timing_translator
   3
   4
   5   source file of the GNU LilyPond music typesetter
   6
   7   (c) 1997--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   8 */
   9
  10 #include "timing-translator.hh"
  11
  12 #include "warn.hh"
  13 #include "translator-group.hh"
  14 #include "global-context.hh"
  15 #include "multi-measure-rest.hh"
  16
  17 void
  18 Timing_translator::stop_translation_timestep ()
  19 {
  20   Global_context *global = get_global_context ();
  21
  22   /* allbars == ! skipbars */
  23   SCM sb = get_property ("skipBars");
  24   bool allbars = !to_boolean (sb);
  25
  26   // urg: multi bar rests: should always process whole of first bar?
  27   SCM tim = get_property ("timing");
  28   bool timb = to_boolean (tim);
  29   if (timb && allbars)
  30     {
  31       Moment barleft = (measure_length () - measure_position ());
  32       Moment now = now_mom ();
  33
  34       if (barleft > Moment (0)
  35           /*
  36             Hmm. We insert the bar moment every time we process a
  37             moment.  A waste of cpu?
  38           */
  39           && !now.grace_part_)
  40         global->add_moment_to_process (now + barleft);
  41     }
  42 }
  43
  44 void
  45 Timing_translator::initialize ()
  46 {
  47
  48   /*
  49     move this to engraver-init.ly?
  50   */
  51   context ()->add_alias (ly_symbol2scm ("Timing"));
  52   context ()->set_property ("timing", SCM_BOOL_T);
  53   context ()->set_property ("currentBarNumber", scm_int2num (1));
  54
  55   context ()->set_property ("timeSignatureFraction",
  56                             scm_cons (scm_int2num (4), scm_int2num (4)));
  57   /*
  58     Do not init measurePosition; this should be done from global
  59     context.
  60   */
  61   context ()->set_property ("measureLength", Moment (Rational (1)).smobbed_copy ());
  62   context ()->set_property ("beatLength", Moment (Rational (1, 4)).smobbed_copy ());
  63 }
  64
  65 Rational
  66 Timing_translator::measure_length () const
  67 {
  68   SCM l = get_property ("measureLength");
  69   if (unsmob_moment (l))
  70     return unsmob_moment (l)->main_part_;
  71   else
  72     return Rational (1);
  73 }
  74
  75 Timing_translator::Timing_translator ()
  76 {
  77 }
  78
  79 Moment
  80 Timing_translator::measure_position () const
  81 {
  82   SCM sm = get_property ("measurePosition");
  83
  84   Moment m = 0;
  85   if (unsmob_moment (sm))
  86     {
  87       m = *unsmob_moment (sm);
  88       while (m.main_part_ < Rational (0))
  89         m.main_part_ += measure_length ();
  90     }
  91
  92   return m;
  93 }
  94
  95 void
  96 Timing_translator::start_translation_timestep ()
  97 {
  98   Global_context *global = get_global_context ();
  99
 100   Moment now = global->now_mom ();
 101   Moment dt = now - global->previous_moment ();
 102   if (dt < Moment (0))
 103     {
 104       programming_error ("moving backwards in time");
 105       dt = 0;
 106     }
 107   else if (dt.main_part_.is_infinity ())
 108     {
 109       programming_error ("moving infinitely to future");
 110       dt = 0;
 111     }
 112
 113   if (!dt.to_bool ())
 114     return;
 115
 116   Moment measposp;
 117
 118   SCM s = get_property ("measurePosition");
 119   if (unsmob_moment (s))
 120     {
 121       measposp = *unsmob_moment (s);
 122     }
 123   else
 124     {
 125       measposp = now;
 126       context ()->set_property ("measurePosition",
 127                                 measposp.smobbed_copy ());
 128     }
 129
 130   measposp += dt;
 131
 132   SCM barn = get_property ("currentBarNumber");
 133   int b = 0;
 134   if (scm_is_number (barn))
 135     {
 136       b = scm_to_int (barn);
 137     }
 138
 139   SCM cad = get_property ("timing");
 140   bool c = to_boolean (cad);
 141
 142   Rational len = measure_length ();
 143   while (c && measposp.main_part_ >= len)
 144     {
 145       measposp.main_part_ -= len;
 146       b++;
 147     }
 148
 149   context ()->set_property ("currentBarNumber", scm_int2num (b));
 150   context ()->set_property ("measurePosition", measposp.smobbed_copy ());
 151 }
 152
 153 ADD_TRANSLATOR (Timing_translator,
 154                 "This engraver adds the alias "
 155                 "@code{Timing} to its containing context.",
 156
 157                 "", "", "", "", "");