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[lilypond/patrick.git] / lily / slur-scoring.cc

/*
  This file is part of LilyPond, the GNU music typesetter.

  Copyright (C) 1996--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
  Jan Nieuwenhuizen <janneke@gnu.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.

  LilyPond is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
*/


#include "slur-scoring.hh"

#include "accidental-interface.hh"
#include "beam.hh"
#include "directional-element-interface.hh"
#include "libc-extension.hh"
#include "main.hh"
#include "note-column.hh"
#include "output-def.hh"
#include "paper-column.hh"
#include "pitch.hh"
#include "pointer-group-interface.hh"
#include "slur-configuration.hh"
#include "slur.hh"
#include "spanner.hh"
#include "staff-symbol-referencer.hh"
#include "staff-symbol.hh"
#include "stem.hh"
#include "warn.hh"

/*
  TODO:

  - curve around flag for y coordinate

  - short-cut: try a smaller region first.

  - handle non-visible stems better.

  - try to prune number of scoring criteria

  - take encompass-objects more into account when determining
  slur shape

  - calculate encompass scoring directly after determining slur shape.

  - optimize.
*/
struct Slur_score_state;

Slur_score_state::Slur_score_state ()
{
  musical_dy_ = 0.0;
  valid_ = false;
  edge_has_beams_ = false;
  has_same_beam_ = false;
  is_broken_ = false;
  dir_ = CENTER;
  slur_ = 0;
  common_[X_AXIS] = 0;
  common_[Y_AXIS] = 0;
}

Slur_score_state::~Slur_score_state ()
{
  junk_pointers (configurations_);
}

/*
  If a slur is broken across a line break, the direction
  of the post-break slur must be the same as the pre-break
  slur.
*/
Direction
Slur_score_state::slur_direction () const
{
  Grob *left_neighbor = slur_->broken_neighbor (LEFT);

  if (left_neighbor && left_neighbor->is_live ())
    return get_grob_direction (left_neighbor);

  Direction dir = get_grob_direction (slur_);

  if (Grob *right_neighbor = slur_->broken_neighbor (RIGHT))
    set_grob_direction (right_neighbor, dir);

  return dir;
}

Encompass_info
Slur_score_state::get_encompass_info (Grob *col) const
{
  Grob *stem = unsmob_grob (col->get_object ("stem"));
  Encompass_info ei;

  if (!stem)
    {
      programming_error ("no stem for note column");
      ei.x_ = col->relative_coordinate (common_[X_AXIS], X_AXIS);
      ei.head_ = ei.stem_ = col->extent (common_[Y_AXIS],
                                         Y_AXIS)[dir_];
      return ei;
    }
  Direction stem_dir = get_grob_direction (stem);

  if (Grob *head = Note_column::first_head (col))
    ei.x_ = head->extent (common_[X_AXIS], X_AXIS).center ();
  else
    ei.x_ = col->extent (common_[X_AXIS], X_AXIS).center ();

  Grob *h = Stem::extremal_heads (stem)[Direction (dir_)];
  if (!h)
    {
      ei.head_ = ei.stem_ = col->extent (common_[Y_AXIS], Y_AXIS)[dir_];
      return ei;
    }

  ei.head_ = h->extent (common_[Y_AXIS], Y_AXIS)[dir_];

  if ((stem_dir == dir_)
      && !stem->extent (stem, Y_AXIS).is_empty ())
    {
      ei.stem_ = stem->extent (common_[Y_AXIS], Y_AXIS)[dir_];
      if (Grob *b = Stem::get_beam (stem))
        ei.stem_ += stem_dir * 0.5 * Beam::get_beam_thickness (b);

      Interval x = stem->extent (common_[X_AXIS], X_AXIS);
      ei.x_ = x.is_empty ()
        ? stem->relative_coordinate (common_[X_AXIS], X_AXIS)
        : x.center ();
    }
  else
    ei.stem_ = ei.head_;

  return ei;
}

Drul_array<Bound_info>
Slur_score_state::get_bound_info () const
{
  Drul_array<Bound_info> extremes;

  Direction d = LEFT;
  Direction dir = dir_;

  do
    {
      extremes[d].bound_ = slur_->get_bound (d);
      if (Note_column::has_interface (extremes[d].bound_))
        {
          extremes[d].note_column_ = extremes[d].bound_;
          extremes[d].stem_ = Note_column::get_stem (extremes[d].note_column_);
          if (extremes[d].stem_)
            {
              extremes[d].stem_dir_ = get_grob_direction (extremes[d].stem_);

              for (int a = X_AXIS; a < NO_AXES; a++)
                {
                  Axis ax = Axis (a);
                  Interval s = extremes[d].stem_->extent (common_[ax], ax);
                  if (s.is_empty ())
                    {
                      /*
                        do not issue warning. This happens for rests and
                        whole notes.
                      */
                      s = Interval (0, 0)
                        + extremes[d].stem_->relative_coordinate (common_[ax], ax);
                    }
                  extremes[d].stem_extent_[ax] = s;
                }

              extremes[d].slur_head_
                = Stem::extremal_heads (extremes[d].stem_)[dir];
              if (!extremes[d].slur_head_
                  && Note_column::has_rests (extremes[d].bound_))
                extremes[d].slur_head_ = Note_column::get_rest (extremes[d].bound_);
              extremes[d].staff_ = Staff_symbol_referencer
                ::get_staff_symbol (extremes[d].stem_);
              extremes[d].staff_space_ = Staff_symbol_referencer
                ::staff_space (extremes[d].stem_);
            }

          if (extremes[d].slur_head_)
            extremes[d].slur_head_x_extent_
              = extremes[d].slur_head_->extent (common_[X_AXIS], X_AXIS);

        }
    }
  while (flip (&d) != LEFT);

  return extremes;
}

void
Slur_score_state::fill (Grob *me)
{
  slur_ = dynamic_cast<Spanner *> (me);
  columns_
    = internal_extract_grob_array (me, ly_symbol2scm ("note-columns"));
  
  if (columns_.empty ())
    {
      me->suicide ();
      return;
    }

  Slur::replace_breakable_encompass_objects (me);
  staff_space_ = Staff_symbol_referencer::staff_space (me);
  Real lt = me->layout ()->get_dimension (ly_symbol2scm ("line-thickness"));
  thickness_ = robust_scm2double (me->get_property ("thickness"), 1.0) * lt;

  dir_ = slur_direction ();
  parameters_.fill (me);

  extract_grob_set (me, "note-columns", columns);
  extract_grob_set (me, "encompass-objects", extra_objects);

  Spanner *sp = dynamic_cast<Spanner *> (me);

  for (int i = X_AXIS; i < NO_AXES; i++)
    {
      Axis a = (Axis)i;
      common_[a] = common_refpoint_of_array (columns, me, a);
      common_[a] = common_refpoint_of_array (extra_objects, common_[a], a);

      Direction d = LEFT;
      do
        {
          /*
            If bound is not in note-columns, we don't want to know about
            its Y-position
          */
          if (a != Y_AXIS)
            common_[a] = common_[a]->common_refpoint (sp->get_bound (d), a);
        }
      while (flip (&d) != LEFT);
    }

  extremes_ = get_bound_info ();
  is_broken_ = (!extremes_[LEFT].note_column_
                || !extremes_[RIGHT].note_column_);

  has_same_beam_
    = (extremes_[LEFT].stem_ && extremes_[RIGHT].stem_
       && Stem::get_beam (extremes_[LEFT].stem_) == Stem::get_beam (extremes_[RIGHT].stem_));

  base_attachments_ = get_base_attachments ();

  Drul_array<Real> end_ys
    = get_y_attachment_range ();

  configurations_ = enumerate_attachments (end_ys);
  for (vsize i = 0; i < columns_.size (); i++)
    encompass_infos_.push_back (get_encompass_info (columns_[i]));

  extra_encompass_infos_ = get_extra_encompass_infos ();
  valid_ = true;

  musical_dy_ = 0.0;
  Direction d = LEFT;
  do
    {
      if (!is_broken_
          && extremes_[d].slur_head_)
        musical_dy_ += d
          * extremes_[d].slur_head_->relative_coordinate (common_[Y_AXIS], Y_AXIS);
    }
  while (flip (&d) != LEFT);

  edge_has_beams_
    = (extremes_[LEFT].stem_ && Stem::get_beam (extremes_[LEFT].stem_))
    || (extremes_[RIGHT].stem_ && Stem::get_beam (extremes_[RIGHT].stem_));

  if (is_broken_)
    musical_dy_ = 0.0;
}


MAKE_SCHEME_CALLBACK (Slur, calc_control_points, 1)
SCM
Slur::calc_control_points (SCM smob)
{
  Spanner *me = unsmob_spanner (smob);

  Slur_score_state state;
  state.fill (me);

  if (!state.valid_)
    return SCM_EOL;

  state.generate_curves ();

  SCM end_ys = me->get_property ("positions");
  Bezier best;

  if (is_number_pair (end_ys))
    best = state.configurations_[state.get_closest_index (end_ys)]->curve_;
  else
    best = state.get_best_curve ();

  SCM controls = SCM_EOL;
  for (int i = 4; i--;)
    {
      Offset o = best.control_[i]
        - Offset (me->relative_coordinate (state.common_[X_AXIS], X_AXIS),
                  me->relative_coordinate (state.common_[Y_AXIS], Y_AXIS));
      controls = scm_cons (ly_offset2scm (o), controls);
    }

  return controls;
}

Bezier
Slur_score_state::get_best_curve ()
{
  int opt_idx = -1;
  Real opt = 1e6;

#if DEBUG_SLUR_SCORING
  bool debug_slurs = to_boolean (slur_->layout ()
                                 ->lookup_variable (ly_symbol2scm ("debug-slur-scoring")));
  SCM inspect_quants = slur_->get_property ("inspect-quants");
  SCM inspect_index = slur_->get_property ("inspect-index");
  if (debug_slurs
      && scm_is_integer (inspect_index))
    {
      opt_idx = scm_to_int (inspect_index);
      configurations_[opt_idx]->calculate_score (*this);
      opt = configurations_[opt_idx]->score ();
    }
  else if (debug_slurs
           && scm_is_pair (inspect_quants))
    {
      opt_idx = get_closest_index (inspect_quants);
      configurations_[opt_idx]->calculate_score (*this);
      opt = configurations_[opt_idx]->score ();
    }
  else
#endif
    {
      for (vsize i = 0; i < configurations_.size (); i++)
        configurations_[i]->calculate_score (*this);
      for (vsize i = 0; i < configurations_.size (); i++)
        {
          if (configurations_[i]->score () < opt)
            {
              opt = configurations_[i]->score ();
              opt_idx = i;
            }
        }
    }

#if DEBUG_SLUR_SCORING
  if (debug_slurs)
    {
      string total;
      if (opt_idx >= 0)
        {
          total = configurations_[opt_idx]->card ();
          total += to_string (" TOTAL=%.2f idx=%d", configurations_[opt_idx]->score (), opt_idx); 
        }
      else
        {
          total = "no sol?";
        }
  
      slur_->set_property ("quant-score",
                           ly_string2scm (total));
    }
#endif

  if (opt_idx < 0)
    {
      opt_idx = 0;
      programming_error ("No optimal slur found. Guessing 0.");
    }
  
  return configurations_[opt_idx]->curve_;
}

Grob *
Slur_score_state::breakable_bound_item (Direction d) const
{
  Grob *col = slur_->get_bound (d)->get_column ();

  extract_grob_set (slur_, "encompass-objects", extra_encompasses);

  for (vsize i = 0; i < extra_encompasses.size (); i++)
    {
      Item *item = dynamic_cast<Item*> (extra_encompasses[i]);
      if (item && col == item->get_column ())
        return item;
    }

  return 0;
}

int
Slur_score_state::get_closest_index (SCM inspect_quants) const
{
  Drul_array<Real> ins = ly_scm2interval (inspect_quants);

  int opt_idx = -1;
  Real mindist = 1e6;
  for (vsize i = 0; i < configurations_.size (); i++)
    {
      Real d = fabs (configurations_[i]->attachment_[LEFT][Y_AXIS] - ins[LEFT])
        + fabs (configurations_[i]->attachment_[RIGHT][Y_AXIS] - ins[RIGHT]);
      if (d < mindist)
        {
          opt_idx = i;
          mindist = d;
        }
    }
  if (mindist > 1e5)
    programming_error ("cannot find quant");
  return opt_idx;
}

/*
  TODO: should analyse encompasses to determine sensible region, and
  should limit slopes available.
*/

Drul_array<Real>
Slur_score_state::get_y_attachment_range () const
{
  Drul_array<Real> end_ys;
  Direction d = LEFT;
  do
    {
      if (extremes_[d].note_column_)
        {
          end_ys[d] = dir_
            * max (max (dir_ * (base_attachments_[d][Y_AXIS]
                                + parameters_.region_size_ * dir_),
                        dir_ * (dir_ + extremes_[d].note_column_->extent (common_[Y_AXIS], Y_AXIS)[dir_])),
                   dir_ * base_attachments_[-d][Y_AXIS]);
        }
      else
        end_ys[d] = base_attachments_[d][Y_AXIS] + parameters_.region_size_ * dir_;
    }
  while (flip (&d) != LEFT);

  return end_ys;
}

bool
spanner_less (Spanner *s1, Spanner *s2)
{
  Slice b1, b2;
  Direction d = LEFT;
  do
    {
      b1[d] = s1->get_bound (d)->get_column ()->get_rank ();
      b2[d] = s2->get_bound (d)->get_column ()->get_rank ();
    }
  while (flip (&d) != LEFT);

  return b2[LEFT] <= b1[LEFT] && b2[RIGHT] >= b1[RIGHT]
    && (b2[LEFT] != b1[LEFT] || b2[RIGHT] != b1[RIGHT]);
}

Drul_array<Offset>
Slur_score_state::get_base_attachments () const
{
  Drul_array<Offset> base_attachment;
  Direction d = LEFT;
  do
    {
      Grob *stem = extremes_[d].stem_;
      Grob *head = extremes_[d].slur_head_;

      Real x = 0.0;
      Real y = 0.0;
      if (extremes_[d].note_column_)
        {

          /*
            fixme: X coord should also be set in this case.
          */
          if (stem
              && !Stem::is_invisible (stem)
              && extremes_[d].stem_dir_ == dir_
              && Stem::get_beaming (stem, -d)
              && Stem::get_beam (stem)
              && (!spanner_less (slur_, Stem::get_beam (stem))
                  || has_same_beam_))
            y = extremes_[d].stem_extent_[Y_AXIS][dir_];
          else if (head)
            y = head->extent (common_[Y_AXIS], Y_AXIS)[dir_];
          y += dir_ * 0.5 * staff_space_;

          y = move_away_from_staffline (y, head);

          Grob *fh = Note_column::first_head (extremes_[d].note_column_);
          x
            = (fh ? fh->extent (common_[X_AXIS], X_AXIS)
               : extremes_[d].bound_->extent (common_[X_AXIS], X_AXIS))
            .linear_combination (CENTER);
        }
      base_attachment[d] = Offset (x, y);
    }
  while (flip (&d) != LEFT);

  do
    {
      if (!extremes_[d].note_column_)
        {
          Real x = 0;
          Real y = 0;

          if (Grob *g = breakable_bound_item (d))
            {
              x = robust_relative_extent (g, common_[X_AXIS], X_AXIS)[RIGHT];
            }
          else if (d == RIGHT)
            x = robust_relative_extent (extremes_[d].bound_, common_[X_AXIS], X_AXIS)[d];
          else
            x = slur_->get_broken_left_end_align ();
          
          Grob *col = (d == LEFT) ? columns_[0] : columns_.back ();

          if (extremes_[-d].bound_ != col)
            {
              y = robust_relative_extent (col, common_[Y_AXIS], Y_AXIS)[dir_];
              y += dir_ * 0.5 * staff_space_;

              if (get_grob_direction (col) == dir_
                  && Note_column::get_stem (col)
                  && !Stem::is_invisible (Note_column::get_stem (col)))
                y -= dir_ * 1.5 * staff_space_;
            }
          else
            y = base_attachment[-d][Y_AXIS];

          y = move_away_from_staffline (y, col);

          base_attachment[d] = Offset (x, y);
        }
    }
  while (flip (&d) != LEFT);

  do
    {
      for (int a = X_AXIS; a < NO_AXES; a++)
        {
          Real &b = base_attachment[d][Axis (a)];

          if (isinf (b) || isnan (b))
            {
              programming_error ("slur attachment is inf/nan");
              b = 0.0;
            }
        }
    }
  while (flip (&d) != LEFT);

  return base_attachment;
}

Real
Slur_score_state::move_away_from_staffline (Real y,
                                            Grob *on_staff) const
{
  if (!on_staff)
    return y;
  
  Grob *staff_symbol = Staff_symbol_referencer::get_staff_symbol (on_staff);
  if (!staff_symbol)
    return y;

  Real pos
    = (y - staff_symbol->relative_coordinate (common_[Y_AXIS],
                                              Y_AXIS))
    * 2.0 / staff_space_;

  if (fabs (pos - my_round (pos)) < 0.2
      && Staff_symbol_referencer::on_line (on_staff, (int) rint (pos))
      && Staff_symbol_referencer::line_count (on_staff) - 1 >= rint (pos))
    y += 1.5 * staff_space_ * dir_ / 10;

  return y;
}

vector<Offset>
Slur_score_state::generate_avoid_offsets () const
{
  vector<Offset> avoid;
  vector<Grob*> encompasses = columns_;

  for (vsize i = 0; i < encompasses.size (); i++)
    {
      if (extremes_[LEFT].note_column_ == encompasses[i]
          || extremes_[RIGHT].note_column_ == encompasses[i])
        continue;

      Encompass_info inf (get_encompass_info (encompasses[i]));
      Real y = dir_ * (max (dir_ * inf.head_, dir_ * inf.stem_));

      avoid.push_back (Offset (inf.x_, y + dir_ * parameters_.free_head_distance_));
    }

  extract_grob_set (slur_, "encompass-objects", extra_encompasses);
  for (vsize i = 0; i < extra_encompasses.size (); i++)
    {
      if (Slur::has_interface (extra_encompasses[i]))
        {
          Grob *small_slur = extra_encompasses[i];
          Bezier b = Slur::get_curve (small_slur);

          Offset z = b.curve_point (0.5);
          z += Offset (small_slur->relative_coordinate (common_[X_AXIS], X_AXIS),
                       small_slur->relative_coordinate (common_[Y_AXIS], Y_AXIS));

          z[Y_AXIS] += dir_ * parameters_.free_slur_distance_;
          avoid.push_back (z);
        }
      else if (extra_encompasses[i]->get_property ("avoid-slur") == ly_symbol2scm ("inside"))
        {
          Grob *g = extra_encompasses [i];
          Interval xe = g->extent (common_[X_AXIS], X_AXIS);
          Interval ye = g->extent (common_[Y_AXIS], Y_AXIS);

          if (!xe.is_empty ()
              && !ye.is_empty ())
            avoid.push_back (Offset (xe.center (), ye[dir_]));
        }
    }  
  return avoid;
}

void
Slur_score_state::generate_curves () const
{
  Real r_0 = robust_scm2double (slur_->get_property ("ratio"), 0.33);
  Real h_inf = staff_space_ * scm_to_double (slur_->get_property ("height-limit"));

  vector<Offset> avoid = generate_avoid_offsets ();
  for (vsize i = 0; i < configurations_.size (); i++)
    configurations_[i]->generate_curve (*this, r_0, h_inf, avoid);
}

vector<Slur_configuration*>
Slur_score_state::enumerate_attachments (Drul_array<Real> end_ys) const
{
  vector<Slur_configuration*> scores;

  Drul_array<Offset> os;
  os[LEFT] = base_attachments_[LEFT];
  Real minimum_length = staff_space_
    * robust_scm2double (slur_->get_property ("minimum-length"), 2.0);

  for (int i = 0; dir_ * os[LEFT][Y_AXIS] <= dir_ * end_ys[LEFT]; i++)
    {
      os[RIGHT] = base_attachments_[RIGHT];
      for (int j = 0; dir_ * os[RIGHT][Y_AXIS] <= dir_ * end_ys[RIGHT]; j++)
        {
          Slur_configuration s;
          Direction d = LEFT;
          Drul_array<bool> attach_to_stem (false, false);
          do
            {
              os[d][X_AXIS] = base_attachments_[d][X_AXIS];
              if (extremes_[d].stem_
                  && !Stem::is_invisible (extremes_[d].stem_)
                  && extremes_[d].stem_dir_ == dir_)
                {
                  Interval stem_y = extremes_[d].stem_extent_[Y_AXIS];
                  stem_y.widen (0.25 * staff_space_);
                  if (stem_y.contains (os[d][Y_AXIS]))
                    {
                      os[d][X_AXIS] = extremes_[d].stem_extent_[X_AXIS][-d]
                        - d * 0.3;
                      attach_to_stem[d] = true;
                    }
                  else if (dir_ * extremes_[d].stem_extent_[Y_AXIS][dir_]
                           < dir_ * os[d][Y_AXIS]
                           && !extremes_[d].stem_extent_[X_AXIS].is_empty ())

                    os[d][X_AXIS] = extremes_[d].stem_extent_[X_AXIS].center ();
                }
            }
          while (flip (&d) != LEFT);

          Offset dz;
          dz = os[RIGHT] - os[LEFT];
          if (dz[X_AXIS] < minimum_length
              || fabs (dz[Y_AXIS] / dz[X_AXIS]) > parameters_.max_slope_)
            {
              do
                {
                  if (extremes_[d].slur_head_
                      && !extremes_[d].slur_head_x_extent_.is_empty ())
                    {
                      os[d][X_AXIS] = extremes_[d].slur_head_x_extent_.center ();
                      attach_to_stem[d] = false;
                    }
                }
              while (flip (&d) != LEFT);
            }

          dz = os[RIGHT] - os[LEFT];
          do
            {
              if (extremes_[d].slur_head_
                  && !attach_to_stem[d])
                {
                  /* Horizontally move tilted slurs a little.  Move
                     more for bigger tilts.

                     TODO: parameter */
                  os[d][X_AXIS]
                    -= dir_ * extremes_[d].slur_head_x_extent_.length ()
                    * sin (dz.arg ()) / 3;
                }
            }
          while (flip (&d) != LEFT);

          s.attachment_ = os;
          s.index_ = scores.size ();

          scores.push_back (new Slur_configuration (s));

          os[RIGHT][Y_AXIS] += dir_ * staff_space_ / 2;
        }

      os[LEFT][Y_AXIS] += dir_ * staff_space_ / 2;
    }

  assert (scores.size () > 0);
  return scores;
}

vector<Extra_collision_info>
Slur_score_state::get_extra_encompass_infos () const
{
  extract_grob_set (slur_, "encompass-objects", encompasses);
  vector<Extra_collision_info> collision_infos;
  for (vsize i = encompasses.size (); i--;)
    {
      if (Slur::has_interface (encompasses[i]))
        {
          Spanner *small_slur = dynamic_cast<Spanner *> (encompasses[i]);
          Bezier b = Slur::get_curve (small_slur);

          Offset relative (small_slur->relative_coordinate (common_[X_AXIS], X_AXIS),
                           small_slur->relative_coordinate (common_[Y_AXIS], Y_AXIS));

          for (int k = 0; k < 3; k++)
            {
              Direction hdir = Direction (k - 1);

              /*
                Only take bound into account if small slur starts
                together with big slur.
              */
              if (hdir && small_slur->get_bound (hdir) != slur_->get_bound (hdir))
                continue;

              Offset z = b.curve_point (k / 2.0);
              z += relative;

              Interval yext;
              yext.set_full ();
              yext[dir_] = z[Y_AXIS] + dir_ * thickness_ * 1.0;

              Interval xext (-1, 1);
              xext = xext * (thickness_ * 2) + z[X_AXIS];
              Extra_collision_info info (small_slur,
                                         hdir,
                                         xext,
                                         yext,
                                         parameters_.extra_object_collision_penalty_);
              collision_infos.push_back (info);
            }
        }
      else
        {
          Grob *g = encompasses [i];
          Interval xe = g->extent (common_[X_AXIS], X_AXIS);
          Interval ye = g->extent (common_[Y_AXIS], Y_AXIS);

          Real xp = 0.0;
          Real penalty = parameters_.extra_object_collision_penalty_;
          if (Accidental_interface::has_interface (g))
            {
              penalty = parameters_.accidental_collision_;

              Rational alt = ly_scm2rational (g->get_property ("alteration"));
              SCM scm_style = g->get_property ("style");
              if (!scm_is_symbol (scm_style)
                  && !to_boolean (g->get_property ("parenthesized"))
                  && !to_boolean (g->get_property ("restore-first")))
                {
                  /* End copy accidental.cc */
                  if (alt == FLAT_ALTERATION
                      || alt == DOUBLE_FLAT_ALTERATION)
                    xp = LEFT;
                  else if (alt == SHARP_ALTERATION)
                    xp = 0.5 * dir_;
                  else if (alt == NATURAL_ALTERATION)
                    xp = -dir_;
                }
            }

          ye.widen (thickness_ * 0.5);
          xe.widen (thickness_ * 1.0);
          Extra_collision_info info (g, xp, xe, ye, penalty);
          collision_infos.push_back (info);
        }
    }

  return collision_infos;
}
 
Extra_collision_info::Extra_collision_info (Grob *g, Real idx, Interval x, Interval y, Real p)
{
  idx_ = idx;
  extents_[X_AXIS] = x;
  extents_[Y_AXIS] = y;
  penalty_ = p;
  grob_ = g;
  type_ = g->get_property ("avoid-slur");
}

Extra_collision_info::Extra_collision_info ()
{
  idx_ = 0.0;
  penalty_ = 0.;
  grob_ = 0;
  type_ = SCM_EOL; 
}