lily/staff-symbol-engraver.cc

   1 /*
   2   staff-symbol-engraver.cc -- implement Staff_symbol_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "spanner.hh"
  10 #include "engraver.hh"
  11
  12 class Staff_symbol_engraver : public Engraver
  13 {
  14 public:
  15   TRANSLATOR_DECLARATIONS (Staff_symbol_engraver);
  16
  17 protected:
  18   Drul_array<Music *> span_events_;
  19   Spanner *span_;
  20   Spanner *finished_span_;
  21   bool first_start_;
  22
  23 protected:
  24   virtual void start_spanner ();
  25   virtual void stop_spanner ();
  26
  27   void stop_translation_timestep ();
  28   virtual bool try_music (Music *);
  29   virtual ~Staff_symbol_engraver ();
  30   DECLARE_ACKNOWLEDGER (grob);
  31   virtual void finalize ();
  32   void process_music ();
  33 };
  34
  35 Staff_symbol_engraver::~Staff_symbol_engraver ()
  36 {
  37   assert (!span_);
  38 }
  39
  40 Staff_symbol_engraver::Staff_symbol_engraver ()
  41 {
  42   finished_span_ = 0;
  43   first_start_ = true;
  44   span_ = 0;
  45   span_events_[LEFT] = 0;
  46   span_events_[RIGHT] = 0;
  47 }
  48
  49 bool
  50 Staff_symbol_engraver::try_music (Music *music)
  51 {
  52   Direction d = to_dir (music->get_property ("span-direction"));
  53   if (d)
  54     {
  55       span_events_[d] = music;
  56       return true;
  57     }
  58
  59   return false;
  60 }
  61
  62 void
  63 Staff_symbol_engraver::process_music ()
  64 {
  65   if (span_events_[STOP])
  66     {
  67       finished_span_ = span_;
  68       span_ = 0;
  69       if (first_start_)
  70         first_start_ = false;
  71     }
  72
  73   if (span_events_[START]
  74       || (first_start_ && !span_events_[STOP]))
  75     start_spanner ();
  76 }
  77
  78 void
  79 Staff_symbol_engraver::start_spanner ()
  80 {
  81   if (!span_)
  82     {
  83       span_ = make_spanner ("StaffSymbol", SCM_EOL);
  84       span_->set_bound (LEFT,
  85                         unsmob_grob (get_property ("currentCommandColumn")));
  86     }
  87 }
  88
  89 void
  90 Staff_symbol_engraver::stop_spanner ()
  91 {
  92   if (!finished_span_)
  93     return;
  94
  95   if (!finished_span_->get_bound (RIGHT))
  96     finished_span_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  97
  98   announce_end_grob (finished_span_,
  99                      span_events_[STOP]
 100                      ? span_events_[STOP]->self_scm ()
 101                      : SCM_EOL);
 102
 103   finished_span_ = 0;
 104 }
 105
 106 void
 107 Staff_symbol_engraver::stop_translation_timestep ()
 108 {
 109   if ((span_events_[START] || first_start_)
 110       && span_)
 111     {
 112       first_start_ = false;
 113     }
 114
 115   span_events_[START] = 0;
 116   span_events_[STOP] = 0;
 117   stop_spanner ();
 118 }
 119
 120 void
 121 Staff_symbol_engraver::finalize ()
 122 {
 123   finished_span_ = span_;
 124   span_ = 0;
 125   stop_spanner ();
 126 }
 127
 128 /*
 129   Todo: staff-symbol-referencer iface.
 130 */
 131 void
 132 Staff_symbol_engraver::acknowledge_grob (Grob_info s)
 133 {
 134   /*
 135     Perhaps should try to take SeparationItem as bound of the staff
 136     symbol?
 137   */
 138   if (span_ || finished_span_)
 139     {
 140       Spanner *my = span_ ? span_ : finished_span_;
 141       s.grob ()->set_object ("staff-symbol", my->self_scm ());
 142     }
 143 }
 144
 145 #include "translator.icc"
 146
 147 ADD_ACKNOWLEDGER (Staff_symbol_engraver, grob);
 148
 149 ADD_TRANSLATOR (Staff_symbol_engraver,
 150                 /* doc */ "Create the constellation of five (default) "
 151                 "staff lines.",
 152                 /* create */ "StaffSymbol",
 153                 /* accept */ "staff-span-event",
 154                 /* read */ "",
 155                 /* write */ "");