lily/grid-line-span-engraver.cc

   1 /*
   2   grid-line-span-engraver.cc --  implement Grid_line_span_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7
   8 */
   9
  10 #include "engraver.hh"
  11 #include "item.hh"
  12 #include "grid-line-interface.hh"
  13
  14 class Grid_line_span_engraver : public Engraver
  15 {
  16   Item *spanline_;
  17   Link_array<Item> lines_;
  18
  19 public:
  20   TRANSLATOR_DECLARATIONS (Grid_line_span_engraver);
  21 protected:
  22   virtual void acknowledge_grob (Grob_info);
  23   virtual void stop_translation_timestep ();
  24 };
  25
  26 Grid_line_span_engraver::Grid_line_span_engraver ()
  27 {
  28   spanline_ = 0;
  29 }
  30
  31 void
  32 Grid_line_span_engraver::acknowledge_grob (Grob_info i)
  33 {
  34   int depth = i.origin_contexts (this).size ();
  35   if (depth && i.grob ()->internal_has_interface (ly_symbol2scm ("grid-point-interface")))
  36     {
  37       Item *it = dynamic_cast<Item *> (i.grob ());
  38       lines_.push (it);
  39
  40       if (lines_.size () >= 2 && !spanline_)
  41         {
  42           spanline_ = make_item ("GridLine", SCM_EOL);
  43           spanline_->set_parent (lines_[0], X_AXIS);
  44         }
  45     }
  46 }
  47
  48 void
  49 Grid_line_span_engraver::stop_translation_timestep ()
  50 {
  51   if (spanline_)
  52     {
  53       for (int i = 0; i < lines_.size (); i++)
  54         Grid_line_interface::add_grid_point (spanline_, lines_[i]);
  55
  56       spanline_ = 0;
  57     }
  58   lines_.set_size (0);
  59 }
  60
  61 ADD_TRANSLATOR (Grid_line_span_engraver,
  62                 /* descr */ "This engraver makes cross-staff linelines: It catches all normal "
  63                 "line lines, and draws a single span-line across them.",
  64                 /* creats*/ "GridLine",
  65                 /* accepts */ "",
  66                 /* acks  */ "grid-point-interface",
  67                 /* reads */ "",
  68                 /* write */ "");