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--2009 Han-Wen Nienhuys <hanwen@xs4all.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   if (to_boolean (get_property ("timing"))
  23       && !to_boolean (get_property ("skipBars")))
  24     {
  25       Moment barleft = (measure_length () - measure_position (context ()));
  26       Moment now = now_mom ();
  27
  28       if (barleft > Moment (0))
  29         {
  30           Moment nextmom = now + barleft;
  31           nextmom.grace_part_ = Rational (0);
  32           global->add_moment_to_process (nextmom);
  33         }
  34     }
  35 }
  36
  37 void
  38 Timing_translator::initialize ()
  39 {
  40   context ()->add_alias (ly_symbol2scm ("Timing"));
  41   context ()->set_property ("currentBarNumber", scm_from_int (1));
  42   context ()->set_property ("internalBarNumber", scm_from_int (1));
  43
  44   context ()->set_property ("timeSignatureFraction",
  45                             scm_cons (scm_from_int (4), scm_from_int (4)));
  46   /*
  47     Do not init measurePosition; this should be done from global
  48     context.
  49   */
  50   context ()->set_property ("measureLength",
  51                             Moment (Rational (1)).smobbed_copy ());
  52   context ()->set_property ("beatLength",
  53                             Moment (Rational (1, 4)).smobbed_copy ());
  54 }
  55
  56 Rational
  57 Timing_translator::measure_length () const
  58 {
  59   SCM l = get_property ("measureLength");
  60   if (unsmob_moment (l))
  61     return unsmob_moment (l)->main_part_;
  62   else
  63     return Rational (1);
  64 }
  65
  66 Timing_translator::Timing_translator ()
  67 {
  68 }
  69
  70 void
  71 Timing_translator::start_translation_timestep ()
  72 {
  73   Global_context *global = get_global_context ();
  74
  75   Moment now = global->now_mom ();
  76   Moment dt = now - global->previous_moment ();
  77   if (dt < Moment (0))
  78     {
  79       programming_error ("moving backwards in time");
  80       dt = 0;
  81     }
  82   else if (dt.main_part_.is_infinity ())
  83     {
  84       programming_error ("moving infinitely to future");
  85       dt = 0;
  86     }
  87
  88   if (!dt.to_bool ())
  89     return;
  90
  91   Moment measposp;
  92
  93   SCM s = get_property ("measurePosition");
  94   if (unsmob_moment (s))
  95     measposp = *unsmob_moment (s);
  96   else
  97     {
  98       measposp = now;
  99       context ()->set_property ("measurePosition",
 100                                 measposp.smobbed_copy ());
 101     }
 102
 103   measposp += dt;
 104
 105   int current_barnumber = robust_scm2int (get_property ("currentBarNumber"), 0);
 106   int internal_barnumber = robust_scm2int (get_property ("internalBarNumber"), 0);
 107
 108   SCM cad = get_property ("timing");
 109   bool c = to_boolean (cad);
 110
 111   Rational len = measure_length ();
 112   while (c && measposp.main_part_ >= len)
 113     {
 114       measposp.main_part_ -= len;
 115       current_barnumber ++;
 116       internal_barnumber ++;
 117     }
 118
 119   context ()->set_property ("currentBarNumber", scm_from_int (current_barnumber));
 120   context ()->set_property ("internalBarNumber", scm_from_int (internal_barnumber));
 121   context ()->set_property ("measurePosition", measposp.smobbed_copy ());
 122 }
 123
 124 #include "translator.icc"
 125
 126 ADD_TRANSLATOR (Timing_translator,
 127                 /* doc */
 128                 "This engraver adds the alias @code{Timing} to its containing"
 129                 " context.  Responsible for synchronizing timing information"
 130                 " from staves.  Normally in @code{Score}.  In order to create"
 131                 " polyrhythmic music, this engraver should be removed from"
 132                 " @code{Score} and placed in @code{Staff}.",
 133
 134                 /* create */
 135                 "",
 136
 137                 /* read */
 138                 "internalBarNumber "
 139                 "currentBarNumber "
 140                 "measureLength "
 141                 "measurePosition ",
 142
 143                 /* write */
 144                 "internalBarNumber "
 145                 "currentBarNumber "
 146                 "measurePosition "
 147                 );