Gets vertical skylines from grob stencils

lily/skyline-pair.cc

 /*
   This file is part of LilyPond, the GNU music typesetter.
 
   Copyright (C) 2008--2012 Han-Wen Nienhuys <hanwen@lilypond.org>
 
 
   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 10 matching lines @@
 #include "skyline-pair.hh"
 
 #include "international.hh"
 #include "ly-smobs.icc"
 
 Skyline_pair::Skyline_pair ()
   : skylines_ (Skyline (DOWN), Skyline (UP))
 {
 }
 
-Skyline_pair::Skyline_pair (vector<Box> const &boxes, Real padding, Axis a)
-  : skylines_ (Skyline (boxes, padding, a, DOWN), Skyline (boxes, padding, a, UP))
-{
-}
-
-Skyline_pair::Skyline_pair (vector<Drul_array<Offset> > const &buildings, Real padding, Axis a)
-  : skylines_ (Skyline (buildings, padding, a, DOWN), Skyline (buildings, padding, a, UP))
-{
-}
-
-Skyline_pair::Skyline_pair (vector<Skyline_pair> const &skypairs, Real padding, Axis a)
-  : skylines_ (Skyline (skypairs, padding, a, DOWN), Skyline (skypairs, padding, a, UP))
-{
-}
-
-Skyline_pair::Skyline_pair (Box const &b, Real padding, Axis a)
-  : skylines_ (Skyline (b, padding, a, DOWN), Skyline (b, padding, a, UP))
+Skyline_pair::Skyline_pair (vector<Box> const &boxes, Axis a)
+  : skylines_ (Skyline (boxes, a, DOWN), Skyline (boxes, a, UP))
+{
+}
+
+Skyline_pair::Skyline_pair (vector<Drul_array<Offset> > const &buildings, Axis a)
+  : skylines_ (Skyline (buildings, a, DOWN), Skyline (buildings, a, UP))
+{
+}
+
+Skyline_pair::Skyline_pair (vector<Skyline_pair> const &skypairs)
+  : skylines_ (Skyline (skypairs, DOWN), Skyline (skypairs, UP))
+{
+}
+
+Skyline_pair::Skyline_pair (Box const &b, Axis a)
+  : skylines_ (Skyline (b, a, DOWN), Skyline (b, a, UP))
 {
 }
 
 void
 Skyline_pair::raise (Real r)
 {
   skylines_[UP].raise (r);
   skylines_[DOWN].raise (r);
 }
 
 void
+Skyline_pair::deholify ()
+{
+  skylines_[UP].deholify ();
+  skylines_[DOWN].deholify ();
+}
+
+void
 Skyline_pair::shift (Real r)
 {
   skylines_[UP].shift (r);
   skylines_[DOWN].shift (r);
 }
 
 void
-Skyline_pair::insert (Box const &b, Real padding, Axis a)
-{
-  skylines_[UP].insert (b, padding, a);
-  skylines_[DOWN].insert (b, padding, a);
+Skyline_pair::insert (Box const &b, Axis a)
+{
+  skylines_[UP].insert (b, a);
+  skylines_[DOWN].insert (b, a);
 }
 
 Real
-Skyline_pair::left ()
+Skyline_pair::left () const
 {
   return min (skylines_[UP].left (), skylines_[DOWN].left ());
 }
 
 Real
-Skyline_pair::right ()
+Skyline_pair::right () const
 {
   return max (skylines_[UP].right (), skylines_[DOWN].right ());
+}
+
+// This function comes with the same caveats as smallest_shift:
+// if the skylines are not contiguous, we may report false
+// intersections.
+bool
+Skyline_pair::intersects (Skyline_pair const &other) const
+{
+  return skylines_[UP].distance (other[DOWN]) > 0
+         && other[UP].distance (skylines_[DOWN]) > 0;
+}
+
+Real
+Skyline_pair::smallest_shift (Skyline_pair const &other, Direction d,
+                              Real h_pad, Real v_pad)
+{
+  // If skylines_[UP] avoids other[DOWN] or skylines_[DOWN] avoids
+  // other[UP] then we will not intersect.
+  // Note that this is not guaranteed to return the smallest shift
+  // if one Skyline_pair is not connected: the smallest_shift left
+  // in the case of
+  // AAA
+  // BBBBBB
+  //    AAA
+  // will result in
+  //    AAA
+  // BBBBBB
+  //       AAA
+  // even though the originals did not collide.  If it becomes necessary,
+  // this case could be handled by splitting the Skyline_pairs up into
+  // their connected components.
+
+  return d * min (d * skylines_[UP].smallest_shift (other[DOWN], d, h_pad, v_pad),
+                  d * skylines_[DOWN].smallest_shift (other[UP], d, h_pad, v_pad));
 }
 
 void
 Skyline_pair::merge (Skyline_pair const &other)
 {
   skylines_[UP].merge (other[UP]);
   skylines_[DOWN].merge (other[DOWN]);
 }
 
 void
 Skyline_pair::print () const
 {
   skylines_[UP].print ();
   skylines_[DOWN].print ();
 }
 
 void
 Skyline_pair::print_points () const
 {
   skylines_[UP].print_points ();
   skylines_[DOWN].print_points ();
 }
 
 bool
 Skyline_pair::is_empty () const
 {
   return skylines_[UP].is_empty ()
          && skylines_[DOWN].is_empty ();
+}
+
+bool
+Skyline_pair::is_singleton () const
+{
+  return skylines_[UP].is_singleton ()
+         && skylines_[DOWN].is_singleton ();
 }
 
 Skyline &
 Skyline_pair::operator [] (Direction d)
 {
   return skylines_[d];
 }
 
 Skyline const &
 Skyline_pair::operator [] (Direction d) const
@@ skipping 29 matching lines @@
   Direction dir = robust_scm2dir (dir_scm, UP);
 
   if (dir == CENTER)
     {
       warning (_f ("direction must not be CENTER in ly:skyline-pair::skyline"));
       dir = UP;
     }
 
   return (*sp)[dir].smobbed_copy ();
 }