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--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   8 */
   9
  10 #include "warn.hh"
  11 #include "timing-translator.hh"
  12
  13 #include "translator-group.hh"
  14 #include "global-context.hh"
  15 #include "multi-measure-rest.hh"
  16
  17
  18 void
  19 Timing_translator::stop_translation_timestep ()
  20 {
  21   Global_context *global = get_global_context ();
  22
  23   /* allbars == ! skipbars */
  24   SCM sb = get_property ("skipBars");
  25   bool allbars = !to_boolean (sb);
  26
  27   // urg: multi bar rests: should always process whole of first bar?
  28   SCM tim = get_property ("timing");
  29   bool timb = to_boolean (tim);
  30   if (timb && allbars)
  31     {
  32       Moment barleft = (measure_length () - measure_position ());
  33       Moment now = now_mom ();
  34
  35       if (barleft > Moment (0)
  36           /*
  37             Hmm. We insert the bar moment every time we process a
  38             moment.  A waste of cpu?
  39            */
  40           && !now.grace_part_)
  41         global->add_moment_to_process (now + barleft);
  42     }
  43 }
  44
  45 void
  46 Timing_translator::initialize ()
  47 {
  48
  49   /*
  50     move this to engraver-init.ly?
  51    */
  52   daddy_context_->add_alias (ly_symbol2scm ("Timing"));
  53   daddy_context_->set_property ("timing" , SCM_BOOL_T);
  54   daddy_context_->set_property ("currentBarNumber" , gh_int2scm (1));
  55
  56   daddy_context_->set_property ("timeSignatureFraction",
  57                                 gh_cons (gh_int2scm (4), gh_int2scm (4)));
  58   /*
  59     Do not init measurePosition; this should be done from global
  60     context.
  61    */
  62   daddy_context_->set_property ("measureLength", Moment (Rational (1)).smobbed_copy ());
  63   daddy_context_->set_property ("beatLength", Moment (Rational (1,4)).smobbed_copy ());
  64 }
  65
  66 Rational
  67 Timing_translator::measure_length () const
  68 {
  69   SCM l = get_property ("measureLength");
  70   if (unsmob_moment (l))
  71     return unsmob_moment (l)->main_part_;
  72   else
  73     return Rational (1);
  74 }
  75
  76 Timing_translator::Timing_translator ()
  77 {
  78
  79 }
  80
  81 Moment
  82 Timing_translator::measure_position () const
  83 {
  84   SCM sm = get_property ("measurePosition");
  85
  86   Moment m   =0;
  87   if (unsmob_moment (sm))
  88     {
  89       m = *unsmob_moment (sm);
  90       while (m.main_part_ < Rational (0))
  91         m.main_part_ += measure_length ();
  92     }
  93
  94   return m;
  95 }
  96
  97 void
  98 Timing_translator::start_translation_timestep ()
  99 {
 100   Global_context *global =get_global_context ();
 101
 102   Moment now = global->now_mom ();
 103   Moment dt = now  - global->previous_moment ();
 104   if (dt < Moment (0))
 105     {
 106       programming_error ("Moving backwards in time");
 107       dt = 0;
 108     }
 109   else if (dt.main_part_.is_infinity ())
 110     {
 111       programming_error ("Moving infinitely to future");
 112       dt = 0;
 113     }
 114
 115   if (!dt.to_bool ())
 116     return;
 117
 118   Moment measposp;
 119
 120   SCM s = get_property ("measurePosition");
 121   if (unsmob_moment (s))
 122     {
 123       measposp = *unsmob_moment (s);
 124     }
 125   else
 126     {
 127       measposp = now;
 128       daddy_context_->set_property ("measurePosition",
 129                                     measposp.smobbed_copy ());
 130     }
 131
 132   measposp += dt;
 133
 134   SCM barn = get_property ("currentBarNumber");
 135   int b = 0;
 136   if (gh_number_p (barn))
 137     {
 138       b = gh_scm2int (barn);
 139     }
 140
 141   SCM cad = get_property ("timing");
 142   bool c= to_boolean (cad);
 143
 144   Rational len = measure_length ();
 145   while (c && measposp.main_part_ >= len)
 146     {
 147       measposp.main_part_ -= len;
 148       b ++;
 149     }
 150
 151   daddy_context_->set_property ("currentBarNumber", gh_int2scm (b));
 152   daddy_context_->set_property ("measurePosition", measposp.smobbed_copy ());
 153 }
 154
 155 ENTER_DESCRIPTION (Timing_translator,
 156                    "This engraver adds the alias "
 157                    "@code{Timing} to its containing context."
 158                    ,
 159
 160                    "","","","","");