lily/ledger-line-engraver.cc

   1 /*
   2   ledger-line-engraver.cc -- implement Ledger_line_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2004--2005 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "pointer-group-interface.hh"
  10 #include "spanner.hh"
  11 #include "engraver.hh"
  12 #include "staff-symbol.hh"
  13
  14 class Ledger_line_engraver : public Engraver
  15 {
  16   Spanner *span_;
  17
  18 public:
  19   TRANSLATOR_DECLARATIONS (Ledger_line_engraver);
  20
  21 protected:
  22   virtual void finalize ();
  23   void process_music ();
  24
  25   DECLARE_ACKNOWLEDGER (ledgered);
  26   DECLARE_ACKNOWLEDGER (staff_symbol);
  27
  28   void start_spanner ();
  29   void stop_spanner ();
  30 };
  31
  32 Ledger_line_engraver::Ledger_line_engraver ()
  33 {
  34   span_ = 0;
  35 }
  36
  37 void
  38 Ledger_line_engraver::start_spanner ()
  39 {
  40   assert (!span_);
  41   span_ = make_spanner ("LedgerLineSpanner", SCM_EOL);
  42
  43   span_->set_bound (LEFT, unsmob_grob (get_property ("currentCommandColumn")));
  44 }
  45
  46 void
  47 Ledger_line_engraver::process_music ()
  48 {
  49   if (!span_)
  50     start_spanner ();
  51 }
  52
  53 void
  54 Ledger_line_engraver::finalize ()
  55 {
  56   stop_spanner ();
  57 }
  58
  59 void
  60 Ledger_line_engraver::stop_spanner ()
  61 {
  62   if (span_)
  63     {
  64       span_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  65       span_ = 0;
  66     }
  67 }
  68
  69 void
  70 Ledger_line_engraver::acknowledge_staff_symbol (Grob_info s)
  71 {
  72   Spanner *sym = dynamic_cast<Spanner *> (s.grob ());
  73
  74   if (!span_
  75       || span_->get_bound (LEFT) != sym->get_bound (LEFT))
  76     {
  77       stop_spanner ();
  78       start_spanner ();
  79     }
  80 }
  81
  82 void
  83 Ledger_line_engraver::acknowledge_ledgered (Grob_info s)
  84 {
  85   if (span_)
  86     {
  87       if (!to_boolean (s.grob ()->get_property ("no-ledgers")))
  88         Pointer_group_interface::add_grob (span_, ly_symbol2scm ("note-heads"),
  89                                            s.grob ());
  90     }
  91 }
  92
  93 #include "translator.icc"
  94
  95 ADD_ACKNOWLEDGER (Ledger_line_engraver, ledgered);
  96 ADD_ACKNOWLEDGER (Ledger_line_engraver, staff_symbol);
  97 ADD_TRANSLATOR (Ledger_line_engraver,
  98                 "Creates the spanner to draw ledger lines, and notices objects that need ledger lines",
  99                 /* create */ "LedgerLineSpanner",
 100                 /* accept */ "",
 101                 /* read */ "",
 102                 /* write */ "")