lily/partial-iterator.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2010--2011 Neil Puttock <n.puttock@gmail.com>
   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 "context.hh"
  21 #include "input.hh"
  22 #include "international.hh"
  23 #include "moment.hh"
  24 #include "music.hh"
  25 #include "simple-music-iterator.hh"
  26
  27 class Partial_iterator : public Simple_music_iterator
  28 {
  29 public:
  30   DECLARE_SCHEME_CALLBACK (constructor, ());
  31  protected:
  32   virtual void process (Moment);
  33 };
  34
  35 void
  36 Partial_iterator::process (Moment m)
  37 {
  38   if (Duration *dur
  39       = unsmob_duration (get_music ()->get_property ("partial-duration")))
  40     {
  41       Context *ctx = get_outlet ();
  42       Moment now = ctx->now_mom ();
  43       if (now.main_part_ > Rational (0))
  44         get_music ()->origin ()->
  45           warning (_ ("trying to use \\partial after the start of a piece"));
  46       Moment length = Moment (dur->get_length ());
  47       now = Moment (0, now.grace_part_);
  48       ctx->set_property ("measurePosition", (now - length).smobbed_copy ());
  49     }
  50   else
  51     programming_error ("invalid duration in \\partial");
  52
  53   Simple_music_iterator::process (m);
  54 }
  55
  56 IMPLEMENT_CTOR_CALLBACK (Partial_iterator);