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 Han-Wen Nienhuys <hanwen@lilypond.org>
   7
   8 */
   9
  10 #include "engraver.hh"
  11 #include "item.hh"
  12 #include "translator.icc"
  13
  14
  15 class Instrument_switch_engraver : public Engraver
  16 {
  17
  18   TRANSLATOR_DECLARATIONS(Instrument_switch_engraver);
  19 protected:
  20   Grob *text_;
  21   SCM cue_name_;
  22
  23   void stop_translation_time_step ();
  24   void process_music ();
  25 };
  26
  27
  28 Instrument_switch_engraver::Instrument_switch_engraver ()
  29 {
  30   cue_name_ = SCM_EOL;
  31   text_ = 0;
  32 }
  33
  34 void
  35 Instrument_switch_engraver::process_music ()
  36 {
  37   SCM cue_text = get_property ("instrumentCueName");
  38
  39   if (!scm_is_eq (cue_name_, cue_text))
  40     {
  41       text_ = make_item ("InstrumentSwitch", SCM_EOL);
  42       text_->set_property ("text", cue_text);
  43       cue_name_ = cue_text;
  44     }
  45 }
  46
  47 void
  48 Instrument_switch_engraver::stop_translation_time_step ()
  49 {
  50   text_ = 0;
  51 }
  52
  53 ADD_TRANSLATOR(Instrument_switch_engraver,
  54                "Create a cue text for taking instrument.",
  55
  56                "InstrumentSwitch ",
  57
  58                "",
  59
  60                "instrumentCueName",
  61
  62                "");