lily/rest-collision-engraver.cc

   1 /*
   2   rest-collision-reg.cc -- implement Rest_collision_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "warn.hh"
  10 #include "rest-collision.hh"
  11 #include "engraver.hh"
  12 #include "note-collision.hh"
  13 #include "note-column.hh"
  14
  15 class Rest_collision_engraver : public Engraver
  16 {
  17   Item* rest_collision_;
  18   int rest_count_;
  19   Link_array<Grob> note_columns_;
  20 protected:
  21   virtual void acknowledge_grob (Grob_info);
  22   virtual void process_acknowledged_grobs ();
  23   virtual void stop_translation_timestep ();
  24 public:
  25   TRANSLATOR_DECLARATIONS(Rest_collision_engraver);
  26 };
  27
  28
  29
  30 Rest_collision_engraver::Rest_collision_engraver ()
  31 {
  32   rest_collision_ =0;
  33   rest_count_ = 0;
  34 }
  35
  36 void
  37 Rest_collision_engraver::process_acknowledged_grobs ()
  38 {
  39   if (rest_collision_
  40       || note_columns_.is_empty ()
  41       || !rest_count_)
  42     return;
  43
  44   rest_collision_ = make_item ("RestCollision");
  45
  46   announce_grob(rest_collision_, SCM_EOL);
  47   for (int i=0; i < note_columns_.size (); i++)
  48     Rest_collision::add_column (rest_collision_,note_columns_[i]);
  49 }
  50
  51 void
  52 Rest_collision_engraver::acknowledge_grob (Grob_info i)
  53 {
  54   if (Note_column::has_interface (i.grob_))
  55     {
  56       note_columns_.push (i.grob_);
  57       if (Note_column::has_rests (i.grob_))
  58         rest_count_ ++;
  59     }
  60 }
  61
  62 void
  63 Rest_collision_engraver::stop_translation_timestep ()
  64 {
  65   if (rest_collision_)
  66     {
  67       typeset_grob (rest_collision_);
  68       rest_collision_ = 0;
  69     }
  70   note_columns_.clear ();
  71   rest_count_ = 0;
  72 }
  73
  74 ENTER_DESCRIPTION(Rest_collision_engraver,
  75 /* descr */       "Handles collisions of rests.",
  76 /* creats*/       "RestCollision",
  77 /* accepts */     "",
  78 /* acks  */      "note-column-interface",
  79 /* reads */       "",
  80 /* write */       "");