lily/timing-translator.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2011 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
  26 void
  27 Timing_translator::stop_translation_timestep ()
  28 {
  29   Global_context *global = get_global_context ();
  30
  31   if (to_boolean (get_property ("timing"))
  32       && !to_boolean (get_property ("skipBars")))
  33     {
  34       Moment barleft = (measure_length () - measure_position (context ()));
  35       Moment now = now_mom ();
  36
  37       if (barleft > Moment (0))
  38         {
  39           Moment nextmom = now + barleft;
  40           nextmom.grace_part_ = Rational (0);
  41           global->add_moment_to_process (nextmom);
  42         }
  43     }
  44 }
  45
  46 void
  47 Timing_translator::initialize ()
  48 {
  49   context ()->add_alias (ly_symbol2scm ("Timing"));
  50   context ()->set_property ("currentBarNumber", scm_from_int (1));
  51   context ()->set_property ("internalBarNumber", scm_from_int (1));
  52
  53   context ()->set_property ("timeSignatureFraction",
  54                             scm_cons (scm_from_int (4), scm_from_int (4)));
  55   /*
  56     Do not init measurePosition; this should be done from global
  57     context.
  58   */
  59   context ()->set_property ("measureLength",
  60                             Moment (Rational (1)).smobbed_copy ());
  61   context ()->set_property ("baseMoment",
  62                             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 void
  80 Timing_translator::start_translation_timestep ()
  81 {
  82   Global_context *global = get_global_context ();
  83
  84   Moment now = global->now_mom ();
  85   Moment dt = now - global->previous_moment ();
  86   if (dt < Moment (0))
  87     {
  88       programming_error ("moving backwards in time");
  89       dt = 0;
  90     }
  91   else if (dt.main_part_.is_infinity ())
  92     {
  93       programming_error ("moving infinitely to future");
  94       dt = 0;
  95     }
  96
  97   if (!dt.to_bool ())
  98     return;
  99
 100   Moment measposp;
 101
 102   SCM s = get_property ("measurePosition");
 103   if (unsmob_moment (s))
 104     measposp = *unsmob_moment (s);
 105   else
 106     {
 107       measposp = now;
 108       context ()->set_property ("measurePosition",
 109                                 measposp.smobbed_copy ());
 110     }
 111
 112   measposp += dt;
 113
 114   int current_barnumber = robust_scm2int (get_property ("currentBarNumber"), 0);
 115   int internal_barnumber = robust_scm2int (get_property ("internalBarNumber"), 0);
 116
 117   SCM cad = get_property ("timing");
 118   bool c = to_boolean (cad);
 119
 120   Rational len = measure_length ();
 121   while (c && measposp.main_part_ >= len)
 122     {
 123       measposp.main_part_ -= len;
 124       current_barnumber ++;
 125       internal_barnumber ++;
 126     }
 127
 128   context ()->set_property ("currentBarNumber", scm_from_int (current_barnumber));
 129   context ()->set_property ("internalBarNumber", scm_from_int (internal_barnumber));
 130   context ()->set_property ("measurePosition", measposp.smobbed_copy ());
 131 }
 132
 133 #include "translator.icc"
 134
 135 ADD_TRANSLATOR (Timing_translator,
 136                 /* doc */
 137                 "This engraver adds the alias @code{Timing} to its containing"
 138                 " context.  Responsible for synchronizing timing information"
 139                 " from staves.  Normally in @code{Score}.  In order to create"
 140                 " polyrhythmic music, this engraver should be removed from"
 141                 " @code{Score} and placed in @code{Staff}.",
 142
 143                 /* create */
 144                 "",
 145
 146                 /* read */
 147                 "internalBarNumber "
 148                 "currentBarNumber "
 149                 "measureLength "
 150                 "measurePosition ",
 151
 152                 /* write */
 153                 "baseMoment "
 154                 "currentBarNumber "
 155                 "internalBarNumber "
 156                 "measureLength "
 157                 "measurePosition "
 158                 "timeSignatureFraction "
 159                 );