lily/grace-spacing-engraver.cc

   1 /*
   2   grace-spacing-engraver.cc -- implement Grace_spacing_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2006 Han-Wen <hanwen@lilypond.org>
   7
   8 */
   9
  10 #include "engraver.hh"
  11 #include "spanner.hh"
  12 #include "pointer-group-interface.hh"
  13
  14 #include "translator.icc"
  15
  16 class Grace_spacing_engraver : public Engraver
  17 {
  18   TRANSLATOR_DECLARATIONS (Grace_spacing_engraver);
  19
  20 protected:
  21
  22   Moment last_moment_;
  23   Spanner *grace_spacing_;
  24
  25   void process_music ();
  26   void stop_translation_timestep ();
  27 };
  28
  29
  30 Grace_spacing_engraver::Grace_spacing_engraver ()
  31 {
  32   grace_spacing_ = 0;
  33 }
  34
  35 void
  36 Grace_spacing_engraver::process_music ()
  37 {
  38   Moment now = now_mom ();
  39   if (!last_moment_.grace_part_ and now.grace_part_)
  40     {
  41       grace_spacing_ = make_spanner ("GraceSpacing", SCM_EOL);
  42     }
  43
  44
  45   if (grace_spacing_ && (now.grace_part_ || last_moment_.grace_part_))
  46     {
  47       Grob *column = unsmob_grob (get_property ("currentMusicalColumn"));
  48       Pointer_group_interface::add_grob (grace_spacing_,
  49                                          ly_symbol2scm ("columns"),
  50                                          column);
  51
  52       column->set_object ("grace-spacing", grace_spacing_->self_scm ());
  53     }
  54 }
  55
  56 void
  57 Grace_spacing_engraver::stop_translation_timestep ()
  58 {
  59   last_moment_ = now_mom ();
  60
  61   if (!last_moment_.grace_part_)
  62     grace_spacing_ = 0;
  63 }
  64
  65
  66 ADD_TRANSLATOR (Grace_spacing_engraver,
  67                 "Bookkeeping of shortest starting and playing notes in grace note runs.",
  68
  69                 /* create */
  70                 "GraceSpacing ",
  71
  72                 /* accept */
  73                 "",
  74
  75                 /* read */
  76                 "currentMusicalColumn ",
  77
  78                 /* write */ "");