X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fslur.cc;h=a35784eb3d2475e89965aa8375bce045f4454527;hb=58bcc84c9480dae1b21bc24d8396b91fe19e0131;hp=316774e37d9002d22f8981171a49bedbaaa8e7d4;hpb=fc3e875d6bf06f0680e897faffdcab36ad975a03;p=lilypond.git

diff --git a/lily/slur.cc b/lily/slur.cc
index 316774e37d..a35784eb3d 100644
--- a/lily/slur.cc
+++ b/lily/slur.cc
@@ -1,667 +1,238 @@
 /*
-  slur.cc -- implement  Slur
+  slur.cc -- implement external interface for Slur
 
   source file of the GNU LilyPond music typesetter
 
-  (c) 1996--2001 Han-Wen Nienhuys <hanwen@cs.uu.nl>
-    Jan Nieuwenhuizen <janneke@gnu.org>
+  (c) 1996--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
+  Jan Nieuwenhuizen <janneke@gnu.org>
 */
 
-/*
-  [TODO]
-    * fix broken interstaff slurs
-    * should avoid stafflines with horizontal part.
-    * begin and end should be treated as a/acknowledge Scripts.
-    * smart changing of endings
-    * smart changing of (Y-?)offsets to avoid ugly beziers
- (along-side-stem)
- */
+#include "slur.hh"
 
+#include <math.h>
+
+#include "beam.hh"
+#include "bezier.hh"
 #include "directional-element-interface.hh"
+#include "font-interface.hh"
 #include "group-interface.hh"
-#include "slur.hh"
 #include "lookup.hh"
-#include "paper-def.hh"
+#include "main.hh"		// DEBUG_SLUR_SCORING
 #include "note-column.hh"
-#include "stem.hh"
-#include "paper-column.hh"
-#include "molecule.hh"
-#include "debug.hh"
-#include "slur-bezier-bow.hh"
-#include "main.hh"
-#include "group-interface.hh"
-#include "staff-symbol-referencer.hh"
+#include "output-def.hh"
 #include "spanner.hh"
+#include "staff-symbol-referencer.hh"
+#include "staff-symbol.hh"
+#include "stem.hh"
+#include "text-item.hh"
+#include "warn.hh"
+#include "slur-scoring.hh"
 
-
-void
-Slur::set_interface (Grob*me)
-{
-  /* Copy to mutable list. */
-  me->set_grob_property ("attachment",
-			 ly_deep_copy (me->get_grob_property ("attachment")));
-}
-
-void
-Slur::add_column (Grob*me, Grob*n)
-{
-  if (!gh_pair_p (n->get_grob_property ("note-heads")))
-    warning (_ ("Putting slur over rest.  Ignoring."));
-  else
-    {
-      Pointer_group_interface::add_element (me, "note-columns",n);
-      me->add_dependency (n);
-    }
-
-  add_bound_item (dynamic_cast<Spanner*> (me), dynamic_cast<Item*> (n));
-}
-
-void
-Slur::de_uglyfy (Grob*me, Slur_bezier_bow* bb, Real default_height)
+MAKE_SCHEME_CALLBACK (Slur, height, 2);
+SCM
+Slur::height (SCM smob, SCM ax)
 {
-  Real length = bb->curve_.control_[3][X_AXIS] ; 
-  Real ff = bb->fit_factor ();
-  for (int i = 1; i < 3; i++)
-    {
-      Real ind = abs (bb->curve_.control_[ (i-1)*3][X_AXIS]
-		      - bb->curve_.control_[i][X_AXIS]) / length;
-      Real h = bb->curve_.control_[i][Y_AXIS] * ff / length;
-
-      Real f = default_height / length;
-      SCM up = me->get_grob_property ("de-uglify-parameters");
-      
-      Real c1 = gh_scm2double (gh_car (up));
-      Real c2 = gh_scm2double (gh_cadr (up));
-      Real c3 = gh_scm2double (gh_caddr (up)); 
-      
-      if (h > c1 * f)
-	{
-	  h = c1 * f; 
-	}
-      else if (h > c2 + c3 * ind)
-	{
-	  h = c2 + c3 * ind; 
-	}
-      
-      bb->curve_.control_[i][Y_AXIS] = h * length;
-    } 
-
-  bb->curve_.assert_sanity ();
-}
+  Axis a = (Axis)scm_to_int (ax);
+  Grob *me = unsmob_grob (smob);
+  assert (a == Y_AXIS);
 
-Direction
-Slur::get_default_dir (Grob*me) 
-{
-  Link_array<Grob> encompass_arr =
-    Pointer_group_interface__extract_elements (me, (Grob*)0, "note-columns");
-  
-  Direction d = DOWN;
-  for (int i=0; i < encompass_arr.size (); i ++) 
-    {
-      if (Note_column::dir (encompass_arr[i]) < 0) 
-	{
-	  d = UP;
-	  break;
-	}
-    }
-  return d;
+  SCM mol = me->get_uncached_stencil ();
+  Interval ext;
+  if (Stencil *m = unsmob_stencil (mol))
+    ext = m->extent (a);
+  return ly_interval2scm (ext);
 }
 
-
-MAKE_SCHEME_CALLBACK (Slur, after_line_breaking,1);
+/*
+  Ugh should have dash-length + dash-period
+*/
+MAKE_SCHEME_CALLBACK (Slur, print, 1);
 SCM
-Slur::after_line_breaking (SCM smob)
+Slur::print (SCM smob)
 {
   Grob *me = unsmob_grob (smob);
-  if (!scm_ilength (me->get_grob_property ("note-columns")))
+  if (!scm_ilength (me->get_property ("note-columns")))
     {
       me->suicide ();
-      return SCM_UNSPECIFIED;
-    }
-  set_extremities (me);
-  set_control_points (me);
-  return SCM_UNSPECIFIED;
-} 
-
-
-void
-Slur::check_slope (Grob *me)
-{
-  /*
-    Avoid too steep slurs.
-   */
-  SCM s = me->get_grob_property ("slope-limit");
-  if (gh_number_p (s))
-    {
-      Array<Offset> encompass = get_encompass_offset_arr (me);
-      Drul_array<Offset> attachment;
-      attachment[LEFT] = encompass[0];
-      attachment[RIGHT] = encompass.top ();
-
-      Real dx = attachment[RIGHT][X_AXIS] - attachment[LEFT][X_AXIS];
-      Real dy = attachment[RIGHT][Y_AXIS] - attachment[LEFT][Y_AXIS];
-      if (!dx)
-	return;
-      
-      Real slope = slope = abs (dy / dx);
-
-      Real limit = gh_scm2double (s);
-
-      if (slope > limit)
-	{
-	  Real staff_space = Staff_symbol_referencer::staff_space ((Grob*)me);
-	  Direction dir = (Direction)gh_scm2int (me->get_grob_property ("direction"));
-	  Direction d = (Direction) (- dir * (sign (dy)));
-	  SCM a = me->get_grob_property ("attachment-offset");
-	  Drul_array<Offset> o;
-	  o[LEFT] = ly_scm2offset (index_cell (a, LEFT));
-	  o[RIGHT] = ly_scm2offset (index_cell (a, RIGHT));
-	  o[d][Y_AXIS] -= (limit - slope) * dx * dir / staff_space;
-	  //o[d][Y_AXIS] = attachment[-d][Y_AXIS] + (dx * limit * dir / staff_space);
-	  me->set_grob_property ("attachment-offset",
-				gh_cons (ly_offset2scm (o[LEFT]),
-					 ly_offset2scm (o[RIGHT])));
-	}
-    }
-}
-
-void
-Slur::set_extremities (Grob *me)
-{
-  if (!Directional_element_interface::get (me))
-    Directional_element_interface::set (me, get_default_dir (me));
-
-  Direction dir = LEFT;
-  do 
-    {
-      if (!gh_symbol_p (index_cell (me->get_grob_property ("attachment"), dir)))
-	{
-	  for (SCM s = me->get_grob_property ("extremity-rules");
-	       s != SCM_EOL; s = gh_cdr (s))
-	    {
-	      SCM r = gh_call2 (gh_caar (s), me->self_scm (),
-				 gh_int2scm ((int)dir));
-	      if (r != SCM_BOOL_F)
-		{
-		  index_set_cell (me->get_grob_property ("attachment"), dir,
-				  gh_cdar (s));
-		  break;
-		}
-	    }
-	}
+      return SCM_EOL;
     }
-  while (flip (&dir) != LEFT);
 
-  check_slope (me);
-}
+  Real base_thick = robust_scm2double (me->get_property ("thickness"), 1);
+  Real thick = base_thick * Staff_symbol_referencer::line_thickness (me);
 
+  Real ss = Staff_symbol_referencer::staff_space (me);
+  Bezier one = get_curve (me);
 
-Real
-Slur::get_first_notecolumn_y (Grob *me, Direction dir)
-{
-  Grob *col = dir == LEFT
-    ? unsmob_grob (gh_car (scm_reverse (me->get_grob_property
- ("note-columns"))))
-    : unsmob_grob
- (gh_car (me->get_grob_property ("note-columns")));
-  
-  Grob *common[] =
-  {
-    0,
-    me->common_refpoint (col, Y_AXIS)
-  };
-  Real y;
-  if (col == ((Spanner*)me)->get_bound (dir))
-    {
-      y = get_attachment (me, dir, common)[Y_AXIS];
-    }
-  else
-    {
-      y = encompass_offset (me, col, common)[Y_AXIS]
-	- me->relative_coordinate (common[Y_AXIS], Y_AXIS); 
-    }
-  return y;
-}
+  Stencil a;
 
-Offset
-Slur::broken_trend_offset (Grob *me, Direction dir)
-{
   /*
-    A broken slur should maintain the same vertical trend
-    the unbroken slur would have had.
+    TODO: replace dashed with generic property.
   */
-  Offset o;
-  if (Spanner *mother =  dynamic_cast<Spanner*> (me->original_l_))
-    {
-      for (int i = dir == LEFT ? 0 : mother->broken_into_l_arr_.size () - 1;
-	   dir == LEFT ? i < mother->broken_into_l_arr_.size () : i > 0;
-	   dir == LEFT ? i++ : i--)
-	{
-	  if (mother->broken_into_l_arr_[i - dir] == me)
-	    {
-	      Grob *neighbour = mother->broken_into_l_arr_[i];
-	      if (dir == RIGHT)
-		neighbour->set_grob_property ("direction",
-					     me->get_grob_property ("direction"));
-	      Real neighbour_y = get_first_notecolumn_y (neighbour, dir);
-	      Real y = get_first_notecolumn_y (me, -dir);
-	      int neighbour_cols = scm_ilength (neighbour->get_grob_property ("note-columns"));
-	      int cols = scm_ilength (me->get_grob_property ("note-columns"));
-	      o = Offset (0, (y*neighbour_cols + neighbour_y*cols) /
- (cols + neighbour_cols));
-	      break;
-	    }
-	}
-    }
-  return o;
-}
-
-Offset
-Slur::get_attachment (Grob *me, Direction dir,
-		      Grob **common) 
-{
-  SCM s = me->get_grob_property ("attachment");
-  if (!gh_symbol_p (index_cell (s, dir)))
-    {
-      set_extremities (me);
-      s = me->get_grob_property ("attachment");
-    }
-  SCM a = dir == LEFT ? gh_car (s) : gh_cdr (s);
-  Spanner*sp = dynamic_cast<Spanner*> (me);
-  String str = ly_symbol2string (a);
-  Real staff_space = Staff_symbol_referencer::staff_space ((Grob*)me);
-  Real hs = staff_space / 2.0;
-  Offset o;
-  
-  Grob *stem = 0;
-  if (Note_column::has_interface (sp->get_bound (dir)))
-    {
-      Grob * n =sp->get_bound (dir);
-      if ((stem = Note_column::stem_l (n)))
-	{
-
-	  if (str == "head")
-	    {
-	      o = Offset (0, Stem::head_positions (stem)
-			  [Directional_element_interface::get (me)] * hs);
-	      /*
-		Default position is centered in X, on outer side of head Y
-	       */
-	      o += Offset (0.5 * n->extent (n,X_AXIS).length (),
-			   0.5 * staff_space
-			   * Directional_element_interface::get (me));
-	    }
-	  else if (str == "alongside-stem")
-	    {
-	      o = Offset (0, Stem::chord_start_f (stem));
-	      /*
-		Default position is on stem X, on outer side of head Y
-	       */
-	      o += Offset (n->extent (n,X_AXIS).length ()
-			   * (1 + Stem::get_direction (stem)),
-			   0.5 * staff_space
-			   * Directional_element_interface::get (me));
-	    }
-	  else if (str == "stem")
-	    {
-	      o = Offset (0, Stem::stem_end_position (stem) * hs);
-	      /*
-		Default position is on stem X, at stem end Y
-	       */
-	      o += Offset (0.5 *
- (n->extent (n,X_AXIS).length ()
-			    - stem->extent (stem,X_AXIS).length ())
-			    * (1 + Stem::get_direction (stem)),
-			    0);
-	    }
-	}
-    }
-  else if (str == "loose-end")
-    {
-      SCM other_a = dir == LEFT ? gh_cdr (s) : gh_car (s);
-      if (ly_symbol2string (other_a) != "loose-end")
-	{
-#if 0
-	  /*
-	    The braindead way: horizontal
-	  */
-	  o = Offset (0, get_attachment (me, -dir, common)[Y_AXIS]);
-#else
-	  o = broken_trend_offset (me, dir);
-#endif
-
-	  
-	}
-	
-    }
+  SCM p = me->get_property ("dash-period");
+  SCM f = me->get_property ("dash-fraction");
+  if (scm_is_number (p) && scm_is_number (f))
+    a = Lookup::dashed_slur (one, thick, robust_scm2double (p, 1.0),
+			     robust_scm2double (f, 0));
+  else
+    a = Lookup::slur (one, get_grob_direction (me) * base_thick * ss / 10.0,
+		      thick);
 
-  SCM alist = me->get_grob_property ("extremity-offset-alist");
-int stemdir = stem ? Stem::get_direction (stem) : 1;
-  int slurdir = gh_scm2int (me->get_grob_property ("direction"));
-  SCM l = scm_assoc
- (scm_listify (a,
-                gh_int2scm (stemdir * dir),
-                gh_int2scm (slurdir * dir),
-                  SCM_UNDEFINED), alist);
+#if DEBUG_SLUR_SCORING
+  SCM quant_score = me->get_property ("quant-score");
 
-  if (l != SCM_BOOL_F)
+  if (to_boolean (me->get_layout ()
+		  ->lookup_variable (ly_symbol2scm ("debug-slur-scoring")))
+      && scm_is_string (quant_score))
     {
-      o += ly_scm2offset (gh_cdr (l)) * staff_space * dir;
-    }
+      String str;
+      SCM properties = Font_interface::text_font_alist_chain (me);
 
-  /*
-    What if get_bound () is not a note-column?
-   */
-  if (str != "loose-end"
-      && sp->get_bound (dir)->common_refpoint (common[Y_AXIS], Y_AXIS) == common[Y_AXIS])
-    {      
-      o[Y_AXIS] += sp->get_bound (dir)->relative_coordinate (common[Y_AXIS], Y_AXIS) 
-	- me->relative_coordinate (common[Y_AXIS], Y_AXIS);
+      Stencil tm = *unsmob_stencil (Text_interface::interpret_markup
+				    (me->get_layout ()->self_scm (), properties,
+				     quant_score));
+      a.add_at_edge (Y_AXIS, get_grob_direction (me), tm, 1.0, 0);
     }
+#endif
 
-  o += ly_scm2offset (index_cell (me->get_grob_property ("attachment-offset"),
-				  dir)) * staff_space;
-  return o;
+  return a.smobbed_copy ();
 }
 
-Offset
-Slur::encompass_offset (Grob*me,
-			Grob* col,
-			Grob **common) 
+Bezier
+Slur::get_curve (Grob *me)
 {
-  Offset o;
-  Grob* stem_l = unsmob_grob (col->get_grob_property ("stem"));
-  
-  Direction dir = Directional_element_interface::get (me);
-  
-  if (!stem_l)
-    {
-      warning (_ ("Slur over rest?"));
-      o[X_AXIS] = col->relative_coordinate (common[X_AXIS], X_AXIS);
-      o[Y_AXIS] = col->relative_coordinate (common[Y_AXIS], Y_AXIS);
-      return o;  
-    }
-  Direction stem_dir = Directional_element_interface::get (stem_l);
-  o[X_AXIS] = stem_l->relative_coordinate (0, X_AXIS);
-
-  /*
-    Simply set x to middle of notehead
-   */
-
-  o[X_AXIS] -= 0.5 * stem_dir * col->extent (col,X_AXIS).length ();
-
-  if ((stem_dir == dir)
-      && !stem_l->extent (stem_l, Y_AXIS).empty_b ())
-    {
-      o[Y_AXIS] = stem_l->extent (common[Y_AXIS], Y_AXIS)[dir];
-    }
-  else
-    {
-      o[Y_AXIS] = col->extent (common[Y_AXIS], Y_AXIS)[dir];
-    }
+  Bezier b;
+  int i = 0;
+  for (SCM s = me->get_property ("control-points"); s != SCM_EOL;
+       s = scm_cdr (s))
+    b.control_[i++] = ly_scm2offset (scm_car (s));
 
-  /*
-   leave a gap: slur mustn't touch head/stem
-   */
-  o[Y_AXIS] += dir * gh_scm2double (me->get_grob_property ("y-free")) *
-    1.0;
-  return o;
+  return b;
 }
 
-Array<Offset>
-Slur::get_encompass_offset_arr (Grob *me)
+void
+Slur::add_column (Grob *me, Grob *n)
 {
-  Spanner*sp = dynamic_cast<Spanner*> (me);
-  SCM eltlist = me->get_grob_property ("note-columns");
-  Grob *common[] = {me->common_refpoint (eltlist, X_AXIS),
-			     me->common_refpoint (eltlist, Y_AXIS)};
-
-
-  common[X_AXIS] = common[X_AXIS]->common_refpoint (sp->get_bound (RIGHT), X_AXIS);
-  common[X_AXIS] = common[X_AXIS]->common_refpoint (sp->get_bound (LEFT), X_AXIS);
-  
-  Link_array<Grob>  encompass_arr;
-  while (gh_pair_p (eltlist))
-    {
-      encompass_arr.push (unsmob_grob (gh_car (eltlist)));      
-      eltlist =gh_cdr (eltlist);
-    }
-  encompass_arr.reverse ();
-
-  
-  Array<Offset> offset_arr;
-
-  Offset origin (me->relative_coordinate (common[X_AXIS], X_AXIS),
-		 me->relative_coordinate (common[Y_AXIS], Y_AXIS)); 
-
-  int first = 1;
-  int last = encompass_arr.size () - 2;
-
-  offset_arr.push (get_attachment (me, LEFT, common));
-
-  /*
-    left is broken edge
-  */
-
-  if (encompass_arr[0] != sp->get_bound (LEFT))
-    {
-      first--;
-
-      // ?
-      offset_arr[0][Y_AXIS] -=
-	encompass_arr[0]->relative_coordinate (common[Y_AXIS], Y_AXIS) 
-	- me->relative_coordinate (common[Y_AXIS], Y_AXIS); 
-    }
-
-  /*
-    right is broken edge
-  */
-  if (encompass_arr.top () != sp->get_bound (RIGHT))
-    {
-      last++;
-    }
-
-  for (int i = first; i <= last; i++)
-    {
-      Offset o (encompass_offset (me, encompass_arr[i], common));
-      offset_arr.push (o - origin);
-    }
-
-  offset_arr.push (Offset (sp->spanner_length (), 0) + get_attachment (me, RIGHT,common));
-
-  if (encompass_arr[0] != sp->get_bound (LEFT))
-    {
-      offset_arr.top ()[Y_AXIS] -= encompass_arr.top ()->relative_coordinate (common[Y_AXIS], Y_AXIS) 
-	- me->relative_coordinate (common[Y_AXIS], Y_AXIS);
-    }
-
-  return offset_arr;
+  Pointer_group_interface::add_grob (me, ly_symbol2scm ("note-columns"), n);
+  add_bound_item (dynamic_cast<Spanner *> (me), dynamic_cast<Item *> (n));
 }
 
-
-MAKE_SCHEME_CALLBACK (Slur,set_spacing_rods,1);
-SCM
-Slur::set_spacing_rods (SCM smob)
+void
+Slur::add_extra_encompass (Grob *me, Grob *n)
 {
-  Grob*me = unsmob_grob (smob);
-
-  Rod r;
-  Spanner*sp = dynamic_cast<Spanner*> (me);
-  r.item_l_drul_[LEFT] = sp->get_bound (LEFT);
-  r.item_l_drul_[RIGHT] = sp->get_bound (RIGHT);
-  r.distance_f_ =
-    gh_scm2double (me->get_grob_property ("minimum-length"))
-    * 1.0;
-
-  r.add_to_cols ();
-  return SCM_UNSPECIFIED;
+  Pointer_group_interface::add_grob (me, ly_symbol2scm ("encompass-objects"), n);
 }
 
-
-/*
-  ugh ?
- */
-MAKE_SCHEME_CALLBACK (Slur, height, 2);
+MAKE_SCHEME_CALLBACK (Slur, outside_slur_callback, 2);
 SCM
-Slur::height (SCM smob, SCM ax)
+Slur::outside_slur_callback (SCM grob, SCM axis)
 {
-  Axis a = (Axis)gh_scm2int (ax);
-  Grob * me = unsmob_grob (smob);
+  Grob *script = unsmob_grob (grob);
+  Axis a = Axis (scm_to_int (axis));
   assert (a == Y_AXIS);
 
-  SCM mol = me->get_uncached_molecule ();
-  return ly_interval2scm (unsmob_molecule (mol)->extent (a));
-}
+  Grob *slur = unsmob_grob (script->get_property ("slur"));
 
-/*
-  Ugh should have dash-length + dash-period
- */
-MAKE_SCHEME_CALLBACK (Slur, brew_molecule,1);
-SCM
-Slur::brew_molecule (SCM smob)
-{
-  Grob * me = unsmob_grob (smob);
-  if (!scm_ilength (me->get_grob_property ("note-columns")))
-    {
-      me->suicide ();
-      return SCM_EOL;
-    }
+  if (!slur)
+    return scm_from_int (0);
 
-  Real thick = me->paper_l ()->get_var ("stafflinethickness") *
-    gh_scm2double (me->get_grob_property ("thickness"));
-  Bezier one = get_curve (me);
+  Grob *cx = script->common_refpoint (slur, X_AXIS);
+  Grob *cy = script->common_refpoint (slur, Y_AXIS);
 
-  // get_curve may suicide
-  if (!scm_ilength (me->get_grob_property ("note-columns")))
-    return SCM_EOL;
+  Bezier curve = Slur::get_curve (slur);
 
-  Molecule a;
-  SCM d =  me->get_grob_property ("dashed");
-  if (gh_number_p (d))
-    a = Lookup::dashed_slur (one, thick, thick * gh_scm2double (d));
-  else
-    a = Lookup::slur (one, Directional_element_interface::get (me) * thick, thick);
+  curve.translate (Offset (slur->relative_coordinate (cx, X_AXIS),
+			   slur->relative_coordinate (cy, Y_AXIS)));
 
-  return a.smobbed_copy ();
-}
+  Interval yext = robust_relative_extent (script, cy, Y_AXIS);
+  Interval xext = robust_relative_extent (script, cx, X_AXIS);
 
-void
-Slur::set_control_points (Grob*me)
-{
-  Real staff_space = Staff_symbol_referencer::staff_space ((Grob*)me);
+  Real slur_padding = robust_scm2double (script->get_property ("slur-padding"),
+					 0.0);	// todo: slur property, script property?
+  yext.widen (slur_padding);
+  Real EPS = 1e-3;
 
-  SCM details = me->get_grob_property ("details");
-  SCM h_inf_scm = scm_assq (ly_symbol2scm ("height-limit"), details);
-  SCM r_0_scm = scm_assq (ly_symbol2scm ("ratio"), details);
+  Interval bezext (curve.control_[0][X_AXIS],
+		   curve.control_[3][X_AXIS]);
 
-  Real r_0 = gh_scm2double (gh_cdr (r_0_scm));
-  Real h_inf = staff_space * gh_scm2double (gh_cdr (h_inf_scm));
-  
-  Slur_bezier_bow bb (get_encompass_offset_arr (me),
-		      Directional_element_interface::get (me),
-		      h_inf, r_0);
+  bool consider[] = { false, false, false };
+  Real ys[] = {0, 0, 0};
+  int k = 0;
+  bool do_shift = false;
 
-  if (bb.fit_factor () > 1.0)
+  for (int d = LEFT; d <= RIGHT; d++)
     {
-      Real length = bb.curve_.control_[3][X_AXIS]; 
-      Real default_height = slur_height (length, h_inf, r_0);
-
-      SCM ssb = me->get_grob_property ("beautiful");
-      Real sb = 0;
-      if (gh_number_p (ssb))
-	sb = gh_scm2double (ssb);
-
-      bb.minimise_enclosed_area (sb, details);
-      SCM sbf = scm_assq (ly_symbol2scm ("force-blowfit"), details);
-      Real bff = 1.0;
-      if (gh_pair_p (sbf) && gh_number_p (gh_cdr (sbf)))
-	  bff = gh_scm2double (gh_cdr (sbf));
-
-      bb.curve_.control_[1][Y_AXIS] *= bff;
-      bb.curve_.control_[2][Y_AXIS] *= bff;
-      bb.blow_fit ();
-
-      
-      Real beautiful = length * default_height * sb;
-      Real area = bb.enclosed_area_f ();
-      
-      /*
-	Slurs that fit beautifully are not ugly
-      */
-      if (area > beautiful)
-	de_uglyfy (me, &bb, default_height);
-    }
-
-  Bezier b = bb.get_bezier ();
-
+      Real x = xext.linear_combination ((Direction) d);
+      consider[k] = bezext.contains (x);
 
-  SCM controls = SCM_EOL;
-  for (int i= 4; i--;)
+      if (consider[k])
+	{
+	  ys[k]
+	    = (fabs (bezext[LEFT] - x) < EPS)
+	    ? curve.control_[0][Y_AXIS]
+	    : ((fabs (bezext[RIGHT] - x) < EPS)
+	       ? curve.control_[3][Y_AXIS]
+	       : curve.get_other_coordinate (X_AXIS, x));
+	  consider[k] = true;
+
+	  if (yext.contains (ys[k]))
+	    do_shift = true;
+	}
+    }
+  Real offset = 0.0;
+  if (do_shift)
     {
-      controls = gh_cons (ly_offset2scm (b.control_[i]), controls);
-      /*
-	BRRR WHURG.
-	All these null control-points, where do they all come from?
-      */
-      if (i && b.control_[i][X_AXIS] == 0)
+      k = 0;
+      Direction dir = get_grob_direction (script);
+      for (int d = LEFT; d <= RIGHT; d++)
 	{
-	  me->suicide ();
-	  return;
+	  offset = dir * (dir * offset >? dir
+			  * (ys[k] - yext[-dir] + dir * slur_padding));
+	  k++;
 	}
     }
 
-  me->set_grob_property ("control-points", controls);
+  return scm_make_real (offset);
 }
-  
-Bezier
-Slur::get_curve (Grob*me) 
-{
-  Bezier b;
-  int i = 0;
 
-  if (!Directional_element_interface::get (me)
-      || ! gh_symbol_p (index_cell (me->get_grob_property ("attachment"), LEFT))
-      || ! gh_symbol_p (index_cell (me->get_grob_property ("attachment"), RIGHT)))
-    set_extremities (me);
-  
-  if (!gh_pair_p (me->get_grob_property ("control-points")))
-    set_control_points (me);
-
-  // set_control_points may suicide
-  if (!scm_ilength (me->get_grob_property ("note-columns")))
-    return b;
-
-  for (SCM s= me->get_grob_property ("control-points"); s != SCM_EOL; s = gh_cdr (s))
-    {
-      b.control_[i] = ly_scm2offset (gh_car (s));
-      i++;
-    }
-
-  Array<Offset> enc (get_encompass_offset_arr (me));
-  Direction dir = Directional_element_interface::get (me);
-  
-  Real x1 = enc[0][X_AXIS];
-  Real x2 = enc.top ()[X_AXIS];
+static Direction
+get_default_dir (Grob *me)
+{
+  Link_array<Grob> encompasses
+    = extract_grob_array (me, ly_symbol2scm ("note-columns"));
 
-  Real off = 0.0;
-  for (int i=1; i < enc.size ()-1; i++)
+  Direction d = DOWN;
+  for (int i = 0; i < encompasses.size (); i++)
     {
-      Real x = enc[i][X_AXIS];
-      if (x > x1 && x <x2)
+      if (Note_column::dir (encompasses[i]) < 0)
 	{
-	  Real y = b.get_other_coordinate (X_AXIS, x);
-	  off = off >? dir * (enc[i][Y_AXIS] - y);
+	  d = UP;
+	  break;
 	}
     }
-  b.translate (Offset (0, dir * off));
-  return b;
+  return d;
 }
 
-
-bool
-Slur::has_interface (Grob*me)
+MAKE_SCHEME_CALLBACK (Slur, after_line_breaking, 1);
+SCM
+Slur::after_line_breaking (SCM smob)
 {
-  return me->has_interface (ly_symbol2scm ("slur-interface"));
+  Spanner *me = dynamic_cast<Spanner *> (unsmob_grob (smob));
+  if (!scm_ilength (me->get_property ("note-columns")))
+    {
+      me->suicide ();
+      return SCM_UNSPECIFIED;
+    }
+
+  if (!get_grob_direction (me))
+    set_grob_direction (me, get_default_dir (me));
+
+  if (scm_ilength (me->get_property ("control-points")) < 4)
+    set_slur_control_points (me);
+
+  return SCM_UNSPECIFIED;
 }
 
+ADD_INTERFACE (Slur, "slur-interface",
+	       "A slur",
+	       "positions quant-score excentricity encompass-objects control-points dash-period dash-fraction slur-details direction height-limit note-columns ratio thickness");