lily/timing-translator.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2010 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "timing-translator.hh"
  21
  22 #include "warn.hh"
  23 #include "translator-group.hh"
  24 #include "global-context.hh"
  25 #include "multi-measure-rest.hh"
  26
  27 void
  28 Timing_translator::stop_translation_timestep ()
  29 {
  30   Global_context *global = get_global_context ();
  31
  32   if (to_boolean (get_property ("timing"))
  33       && !to_boolean (get_property ("skipBars")))
  34     {
  35       Moment barleft = (measure_length () - measure_position (context ()));
  36       Moment now = now_mom ();
  37
  38       if (barleft > Moment (0))
  39         {
  40           Moment nextmom = now + barleft;
  41           nextmom.grace_part_ = Rational (0);
  42           global->add_moment_to_process (nextmom);
  43         }
  44     }
  45 }
  46
  47 void
  48 Timing_translator::initialize ()
  49 {
  50   context ()->add_alias (ly_symbol2scm ("Timing"));
  51   context ()->set_property ("currentBarNumber", scm_from_int (1));
  52   context ()->set_property ("internalBarNumber", scm_from_int (1));
  53
  54   context ()->set_property ("timeSignatureFraction",
  55                             scm_cons (scm_from_int (4), scm_from_int (4)));
  56   /*
  57     Do not init measurePosition; this should be done from global
  58     context.
  59   */
  60   context ()->set_property ("measureLength",
  61                             Moment (Rational (1)).smobbed_copy ());
  62   context ()->set_property ("beatLength",
  63                             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 void
  81 Timing_translator::start_translation_timestep ()
  82 {
  83   Global_context *global = get_global_context ();
  84
  85   Moment now = global->now_mom ();
  86   Moment dt = now - global->previous_moment ();
  87   if (dt < Moment (0))
  88     {
  89       programming_error ("moving backwards in time");
  90       dt = 0;
  91     }
  92   else if (dt.main_part_.is_infinity ())
  93     {
  94       programming_error ("moving infinitely to future");
  95       dt = 0;
  96     }
  97
  98   if (!dt.to_bool ())
  99     return;
 100
 101   Moment measposp;
 102
 103   SCM s = get_property ("measurePosition");
 104   if (unsmob_moment (s))
 105     measposp = *unsmob_moment (s);
 106   else
 107     {
 108       measposp = now;
 109       context ()->set_property ("measurePosition",
 110                                 measposp.smobbed_copy ());
 111     }
 112
 113   measposp += dt;
 114
 115   int current_barnumber = robust_scm2int (get_property ("currentBarNumber"), 0);
 116   int internal_barnumber = robust_scm2int (get_property ("internalBarNumber"), 0);
 117
 118   SCM cad = get_property ("timing");
 119   bool c = to_boolean (cad);
 120
 121   Rational len = measure_length ();
 122   while (c && measposp.main_part_ >= len)
 123     {
 124       measposp.main_part_ -= len;
 125       current_barnumber ++;
 126       internal_barnumber ++;
 127     }
 128
 129   context ()->set_property ("currentBarNumber", scm_from_int (current_barnumber));
 130   context ()->set_property ("internalBarNumber", scm_from_int (internal_barnumber));
 131   context ()->set_property ("measurePosition", measposp.smobbed_copy ());
 132 }
 133
 134 #include "translator.icc"
 135
 136 ADD_TRANSLATOR (Timing_translator,
 137                 /* doc */
 138                 "This engraver adds the alias @code{Timing} to its containing"
 139                 " context.  Responsible for synchronizing timing information"
 140                 " from staves.  Normally in @code{Score}.  In order to create"
 141                 " polyrhythmic music, this engraver should be removed from"
 142                 " @code{Score} and placed in @code{Staff}.",
 143
 144                 /* create */
 145                 "",
 146
 147                 /* read */
 148                 "internalBarNumber "
 149                 "currentBarNumber "
 150                 "measureLength "
 151                 "measurePosition ",
 152
 153                 /* write */
 154                 "internalBarNumber "
 155                 "currentBarNumber "
 156                 "measurePosition "
 157                 );