lily/instrument-switch-engraver.cc

   1 /*
   2   instrument-switch-engraver.cc -- implement
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2006--2009 Han-Wen Nienhuys <hanwen@lilypond.org>
   7
   8 */
   9
  10 #include "engraver.hh"
  11 #include "item.hh"
  12 #include "text-interface.hh"
  13 #include "translator.icc"
  14
  15
  16 class Instrument_switch_engraver : public Engraver
  17 {
  18
  19   TRANSLATOR_DECLARATIONS (Instrument_switch_engraver);
  20 protected:
  21   Grob *text_;
  22   SCM cue_name_;
  23
  24   void stop_translation_time_step ();
  25   void process_music ();
  26 };
  27
  28
  29 Instrument_switch_engraver::Instrument_switch_engraver ()
  30 {
  31   cue_name_ = SCM_EOL;
  32   text_ = 0;
  33 }
  34
  35 /*
  36   TODO: should use an event.
  37  */
  38 void
  39 Instrument_switch_engraver::process_music ()
  40 {
  41   SCM cue_text = get_property ("instrumentCueName");
  42
  43   if (!scm_is_eq (cue_name_, cue_text))
  44     {
  45       if (Text_interface::is_markup (cue_text))
  46         {
  47           text_ = make_item ("InstrumentSwitch", SCM_EOL);
  48           text_->set_property ("text", cue_text);
  49         }
  50       cue_name_ = cue_text;
  51     }
  52 }
  53
  54 void
  55 Instrument_switch_engraver::stop_translation_time_step ()
  56 {
  57   text_ = 0;
  58 }
  59
  60 ADD_TRANSLATOR (Instrument_switch_engraver,
  61                 /* doc */
  62                 "Create a cue text for taking instrument.",
  63
  64                 /* create */
  65                 "InstrumentSwitch ",
  66
  67                 /* read */
  68                 "instrumentCueName ",
  69
  70                 /* write */
  71                 ""
  72                 );