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 "group-interface.hh"
  10 #include "spanner.hh"
  11 #include "engraver.hh"
  12
  13 class Ledger_line_engraver : public Engraver
  14 {
  15   Spanner *span_;
  16
  17 public:
  18   TRANSLATOR_DECLARATIONS (Ledger_line_engraver);
  19
  20 protected:
  21   virtual void finalize ();
  22   virtual void process_music ();
  23   virtual void acknowledge_grob (Grob_info);
  24 };
  25
  26 Ledger_line_engraver::Ledger_line_engraver ()
  27 {
  28   span_ = 0;
  29 }
  30
  31 void
  32 Ledger_line_engraver::process_music ()
  33 {
  34   if (!span_)
  35     {
  36       span_ = make_spanner ("LedgerLineSpanner", SCM_EOL);
  37
  38       span_->set_bound (LEFT, unsmob_grob (get_property ("currentCommandColumn")));
  39     }
  40 }
  41
  42 void
  43 Ledger_line_engraver::finalize ()
  44 {
  45   if (span_)
  46     span_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  47 }
  48
  49 void
  50 Ledger_line_engraver::acknowledge_grob (Grob_info s)
  51 {
  52   if (!to_boolean (s.grob_->get_property ("no-ledgers")))
  53     Pointer_group_interface::add_grob (span_, ly_symbol2scm ("note-heads"),
  54                                        s.grob_);
  55 }
  56 ADD_TRANSLATOR (Ledger_line_engraver,
  57                 "Creates the spanner to draw ledger lines, and notices objects that need ledger lines",
  58                 /* creats*/ "LedgerLineSpanner",
  59                 /* accepts */ "",
  60                 /* acks  */ "ledgered-interface", // ledgered-interface?
  61                 /* reads */ "",
  62                 /* write */ "")