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--2008 Han-Wen <hanwen@lilypond.org>
   7
   8 */
   9
  10 #include "engraver.hh"
  11 #include "moment.hh"
  12 #include "pointer-group-interface.hh"
  13 #include "spanner.hh"
  14
  15 #include "translator.icc"
  16
  17 class Grace_spacing_engraver : public Engraver
  18 {
  19   TRANSLATOR_DECLARATIONS (Grace_spacing_engraver);
  20
  21 protected:
  22
  23   Moment last_moment_;
  24   Spanner *grace_spacing_;
  25
  26   void process_music ();
  27   void stop_translation_timestep ();
  28 };
  29
  30
  31 Grace_spacing_engraver::Grace_spacing_engraver ()
  32 {
  33   grace_spacing_ = 0;
  34 }
  35
  36 void
  37 Grace_spacing_engraver::process_music ()
  38 {
  39   Moment now = now_mom ();
  40   if (!last_moment_.grace_part_ and now.grace_part_)
  41     {
  42       grace_spacing_ = make_spanner ("GraceSpacing", SCM_EOL);
  43     }
  44
  45
  46   if (grace_spacing_ && (now.grace_part_ || last_moment_.grace_part_))
  47     {
  48       Grob *column = unsmob_grob (get_property ("currentMusicalColumn"));
  49       Pointer_group_interface::add_grob (grace_spacing_,
  50                                          ly_symbol2scm ("columns"),
  51                                          column);
  52
  53       column->set_object ("grace-spacing", grace_spacing_->self_scm ());
  54
  55       if (!grace_spacing_->get_bound (LEFT))
  56         grace_spacing_->set_bound (LEFT, column);
  57       else
  58         grace_spacing_->set_bound (RIGHT, column);
  59     }
  60 }
  61
  62 void
  63 Grace_spacing_engraver::stop_translation_timestep ()
  64 {
  65   last_moment_ = now_mom ();
  66
  67   if (!last_moment_.grace_part_)
  68     grace_spacing_ = 0;
  69 }
  70
  71
  72 ADD_TRANSLATOR (Grace_spacing_engraver,
  73                 "Bookkeeping of shortest starting and playing notes in grace"
  74                 " note runs.",
  75
  76                 /* create */
  77                 "GraceSpacing ",
  78
  79                 /* read */
  80                 "currentMusicalColumn ",
  81
  82                 /* write */
  83                 ""
  84                 );