Allows slurs to break at barlines.

lily/phrasing-slur-engraver.cc

 /*
   This file is part of LilyPond, the GNU music typesetter.
 
   Copyright (C) 1997--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>
 
   LilyPond is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
@@ skipping 34 matching lines @@
   least, it is for phrasing slurs: a note can be both beginning and
   ending of a phrase.
 */
 class Phrasing_slur_engraver : public Engraver
 {
   vector<Stream_event *> start_events_;
   vector<Stream_event *> stop_events_;
   vector<Grob *> slurs_;
   vector<Grob *> end_slurs_;
   vector<Grob_info> objects_to_acknowledge_;
+  Stream_event *break_slur_;
 
 protected:
   DECLARE_TRANSLATOR_LISTENER (phrasing_slur);
+  DECLARE_TRANSLATOR_LISTENER (break_phrasing_slur);
   DECLARE_ACKNOWLEDGER (inline_accidental);
   DECLARE_ACKNOWLEDGER (fingering);
   DECLARE_ACKNOWLEDGER (note_column);
   DECLARE_ACKNOWLEDGER (slur);
   DECLARE_ACKNOWLEDGER (script);
   DECLARE_ACKNOWLEDGER (dots);
   DECLARE_ACKNOWLEDGER (text_script);
   DECLARE_END_ACKNOWLEDGER (tie);
   DECLARE_ACKNOWLEDGER (tuplet_number);
 
@@ skipping 27 matching lines @@
 {
   Direction d = to_dir (ev->get_property ("span-direction"));
   if (d == START)
     start_events_.push_back (ev);
   else if (d == STOP)
     stop_events_.push_back (ev);
   else ev->origin ()->warning (_f ("direction of %s invalid: %d",
                                      "phrasing-slur-event", int (d)));
 }
 
+IMPLEMENT_TRANSLATOR_LISTENER (Phrasing_slur_engraver, break_phrasing_slur);
+void
+Phrasing_slur_engraver::listen_break_phrasing_slur (Stream_event *ev)
+{
+  ASSIGN_EVENT_ONCE (break_slur_, ev);
+}
+
 void
 Phrasing_slur_engraver::acknowledge_note_column (Grob_info info)
 {
   Grob *e = info.grob ();
   for (vsize i = slurs_.size (); i--;)
     Slur::add_column (slurs_[i], e);
   for (vsize i = end_slurs_.size (); i--;)
     Slur::add_column (end_slurs_[i], e);
 }
 
@@ skipping 59 matching lines @@
     {
       slurs_[i]->warning (_ ("unterminated phrasing slur"));
       slurs_[i]->suicide ();
     }
   slurs_.clear ();
 }
 
 void
 Phrasing_slur_engraver::process_music ()
 {
+  if (break_slur_
+      && unsmob_grob (get_property ("currentCommandColumn")))
+    {
+      for (vsize i = slurs_.size (); i--;)
+        {
+          Grob *ccc = unsmob_grob (get_property ("currentCommandColumn"));
+          Spanner *s = dynamic_cast<Spanner *> (slurs_[i]);
+          s->set_bound (RIGHT, ccc);
+          announce_end_grob (s, SCM_EOL);
+          slurs_.erase (slurs_.begin () + i);
+          if (robust_scm2dir (break_slur_->get_property ("side-to-junk"), CENTER) == LEFT)
+            s->suicide ();
+
+          if (robust_scm2dir (break_slur_->get_property ("side-to-junk"), CENTER) != RIGHT)
+            {
+              SCM spanner_id = s->get_property ("spanner-id");
+              Spanner *slur = make_spanner ("Slur", s->self_scm ());
+              slur->set_property ("spanner-id", spanner_id);
+              if (scm_is_number (s->get_property_data ("direction")))
+                set_grob_direction (slur, robust_scm2dir (s->get_property ("direction"), UP));
+              slur->set_bound (LEFT, ccc);
+              slurs_.push_back (slur);
+            }
+        }
+    }
+  else if (to_boolean (get_property ("breakSlurHere")))
+    warning ("no current command column to break slur");
+
   for (vsize i = 0; i < stop_events_.size (); i++)
     {
       Stream_event *ev = stop_events_[i];
       string id = robust_scm2string (ev->get_property ("spanner-id"), "");
 
       // Find the slurs that are ended with this event (by checking the spanner-id)
       bool ended = false;
       for (vsize j = slurs_.size (); j--;)
         {
           if (id == robust_scm2string (slurs_[j]->get_property ("spanner-id"), ""))
@@ skipping 104 matching lines @@
       announce_end_grob (s, SCM_EOL);
     }
 
   for (vsize i = 0; i < objects_to_acknowledge_.size (); i++)
     Slur::auxiliary_acknowledge_extra_object (objects_to_acknowledge_[i], slurs_, end_slurs_);
 
   objects_to_acknowledge_.clear ();
   end_slurs_.clear ();
   start_events_.clear ();
   stop_events_.clear ();
+  break_slur_ = 0;
 }
 
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, inline_accidental);
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, fingering)
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, note_column);
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, slur);
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, script);
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, dots);
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, text_script);
 ADD_END_ACKNOWLEDGER (Phrasing_slur_engraver, tie);
 ADD_ACKNOWLEDGER (Phrasing_slur_engraver, tuplet_number);
 
 ADD_TRANSLATOR (Phrasing_slur_engraver,
                 /* doc */
                 "Print phrasing slurs.  Similar to @ref{Slur_engraver}.",
 
                 /* create */
                 "PhrasingSlur ",
 
                 /* read */
                 "",
 
                 /* write */
                 ""
                );