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--2006 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   vector<Grob*> ledgered_grobs_;
  18
  19 public:
  20   TRANSLATOR_DECLARATIONS (Ledger_line_engraver);
  21
  22 protected:
  23   virtual void finalize ();
  24   void process_music ();
  25
  26   DECLARE_ACKNOWLEDGER (ledgered);
  27   DECLARE_ACKNOWLEDGER (staff_symbol);
  28
  29   void start_spanner ();
  30   void stop_spanner ();
  31   void stop_translation_timestep ();
  32 };
  33
  34 Ledger_line_engraver::Ledger_line_engraver ()
  35 {
  36   span_ = 0;
  37 }
  38
  39 void
  40 Ledger_line_engraver::start_spanner ()
  41 {
  42   assert (!span_);
  43
  44   span_ = make_spanner ("LedgerLineSpanner", SCM_EOL);
  45   span_->set_bound (LEFT, unsmob_grob (get_property ("currentCommandColumn")));
  46 }
  47
  48 void
  49 Ledger_line_engraver::stop_translation_timestep ()
  50 {
  51   if (span_)
  52     {
  53       for (vsize i = 0; i < ledgered_grobs_.size (); i++)
  54         {
  55           if (!to_boolean (ledgered_grobs_[i]->get_property ("no-ledgers")))
  56             Pointer_group_interface::add_grob (span_,
  57                                                ly_symbol2scm ("note-heads"),
  58                                                ledgered_grobs_[i]);
  59         }
  60     }
  61
  62   ledgered_grobs_.clear ();
  63 }
  64
  65 void
  66 Ledger_line_engraver::process_music ()
  67 {
  68   /*
  69     Need to do this, otherwise the first note might miss ledgers.
  70   */
  71   if (!span_)
  72     start_spanner ();
  73 }
  74
  75 void
  76 Ledger_line_engraver::finalize ()
  77 {
  78   stop_spanner ();
  79 }
  80
  81 void
  82 Ledger_line_engraver::stop_spanner ()
  83 {
  84   if (span_)
  85     {
  86       span_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  87       Pointer_group_interface::set_ordered (span_, ly_symbol2scm ("elements"), false);
  88       span_ = 0;
  89     }
  90 }
  91
  92 void
  93 Ledger_line_engraver::acknowledge_staff_symbol (Grob_info s)
  94 {
  95   Spanner *sym = dynamic_cast<Spanner *> (s.grob ());
  96
  97   if (!span_
  98       || (span_->get_bound (LEFT) != sym->get_bound (LEFT)))
  99     {
 100       stop_spanner ();
 101       start_spanner ();
 102     }
 103 }
 104
 105 void
 106 Ledger_line_engraver::acknowledge_ledgered (Grob_info s)
 107 {
 108   ledgered_grobs_.push_back (s.grob ());
 109 }
 110
 111 #include "translator.icc"
 112
 113 ADD_ACKNOWLEDGER (Ledger_line_engraver, ledgered);
 114 ADD_ACKNOWLEDGER (Ledger_line_engraver, staff_symbol);
 115 ADD_TRANSLATOR (Ledger_line_engraver,
 116                 "Creates the spanner to draw ledger lines, and notices objects that need ledger lines",
 117                 /* create */ "LedgerLineSpanner",
 118                 /* read */ "",
 119                 /* write */ "")