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