+/*
+ fall-engraver.cc -- implement Fall_engraver
+
+ (c) 2006 Han-Wen Nienhuys
+
+
+*/
+
+#include "engraver.hh"
+#include "item.hh"
+#include "spanner.hh"
+
+class Fall_engraver : public Engraver
+{
+public:
+ TRANSLATOR_DECLARATIONS (Fall_engraver);
+ DECLARE_ACKNOWLEDGER (note_head);
+
+protected:
+ virtual bool try_music (Music *event);
+ void process_music ();
+ void stop_translation_timestep ();
+ void start_translation_timestep ();
+ void stop_fall ();
+
+private:
+ Moment stop_moment_;
+ Music *fall_event_;
+ Spanner *fall_;
+ Grob *note_head_;
+};
+
+void
+Fall_engraver::stop_fall ()
+{
+ bool bar = scm_is_string (get_property ("whichBar"));
+
+
+ fall_->set_bound (RIGHT, unsmob_grob (
+ bar
+ ? get_property ("currentCommandColumn")
+ : get_property ("currentMusicalColumn")));
+ fall_ = 0;
+ note_head_ = 0;
+ fall_event_ = 0;
+}
+
+void
+Fall_engraver::stop_translation_timestep ()
+{
+ if (fall_ && !fall_->get_bound (LEFT))
+ {
+ fall_->set_bound (LEFT, note_head_);
+ fall_->set_parent (note_head_, Y_AXIS);
+ }
+}
+
+void
+Fall_engraver::start_translation_timestep ()
+{
+ if (fall_ && now_mom ().main_part_ >= stop_moment_.main_part_)
+ {
+ stop_fall ();
+ }
+}
+
+void
+Fall_engraver::acknowledge_note_head (Grob_info info)
+{
+ if (!fall_event_)
+ return;
+
+ if (note_head_ && fall_)
+ {
+ stop_fall ();
+ }
+
+ note_head_ = info.grob ();
+ stop_moment_ = now_mom () + info.music_cause ()->get_length ();
+}
+
+Fall_engraver::Fall_engraver ()
+{
+ fall_ = 0;
+ note_head_ = 0;
+ fall_event_ = 0;
+}
+
+bool
+Fall_engraver::try_music (Music *r)
+{
+ fall_event_ = r;
+ return true;
+}
+
+void
+Fall_engraver::process_music ()
+{
+ if (fall_event_ && !fall_)
+ {
+ fall_ = make_spanner ("BendAfter", fall_event_->self_scm ());
+ fall_->set_property ("delta-position",
+ scm_from_double (robust_scm2double (fall_event_->get_property ("delta-pitch"), 0) * 0.5));
+ }
+}
+
+#include "translator.icc"
+
+
+ADD_ACKNOWLEDGER (Fall_engraver, note_head);
+
+
+ADD_TRANSLATOR (Fall_engraver,
+ /* doc */ "Create fall spanners.",
+ /* create */ "BendAfter",
+ /* accept */ "bend-after-event",
+ /* read */ "",
+ /* write */ "");