path: root/lily/tuplet-bracket.cc

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

  Copyright (C) 1997--2015 Jan Nieuwenhuizen <janneke@gnu.org>
  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.

  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/>.
*/

/*
  TODO:

  - tuplet bracket should probably be subject to the same rules as
  beam sloping/quanting.

  - There is no support for kneed brackets, or nested brackets.

  - number placement for parallel beams should be much more advanced:
  for sloped beams some extra horizontal offset must be introduced.

  - number placement is usually done over the center note, not the
  graphical center.
*/

/*
  TODO: quantise, we don't want to collide with staff lines.
  (or should we be above staff?)

  todo: handle breaking elegantly.
*/

#include "tuplet-bracket.hh"
#include "axis-group-interface.hh"
#include "line-interface.hh"
#include "beam.hh"
#include "warn.hh"
#include "output-def.hh"
#include "font-interface.hh"
#include "text-interface.hh"
#include "stem.hh"
#include "note-column.hh"
#include "pointer-group-interface.hh"
#include "directional-element-interface.hh"
#include "skyline.hh"
#include "spanner.hh"
#include "staff-symbol-referencer.hh"
#include "lookup.hh"
#include "paper-column.hh"
#include "moment.hh"

static Item *
get_x_bound_item (Grob *me_grob, Direction hdir, Direction my_dir)
{
  Spanner *me = dynamic_cast<Spanner *> (me_grob);
  Item *g = me->get_bound (hdir);
  if (has_interface<Note_column> (g)
      && Note_column::get_stem (g)
      && Note_column::dir (g) == my_dir)
    g = Note_column::get_stem (g);

  return g;
}

void
flatten_number_pair_property (Grob *me, Direction xdir, SCM sym)
{
  Drul_array<Real> zero (0, 0);
  Drul_array<Real> pair
    = robust_scm2drul (me->get_property (sym), zero);
  pair[xdir] = 0.0;

  me->set_property (sym, ly_interval2scm (pair));
}

/*
  Return beam that encompasses the span of the tuplet bracket.
*/
Grob *
Tuplet_bracket::parallel_beam (Grob *me_grob, vector<Grob *> const &cols,
                               bool *equally_long)
{
  Spanner *me = dynamic_cast<Spanner *> (me_grob);

  Item *left = me->get_bound (LEFT);
  Item *right = me->get_bound (RIGHT);
  if (!left || left->break_status_dir ()
      || !right || right->break_status_dir ())
    return 0;

  Drul_array<Grob *> stems (Note_column::get_stem (cols[0]),
                            Note_column::get_stem (cols.back ()));

  if (!stems[RIGHT]
      || !stems[LEFT]
      || (dynamic_cast<Item *> (stems[RIGHT])->get_column ()
          != me->get_bound (RIGHT)->get_column ()))
    return 0;

  Drul_array<Grob *> beams;
  for (LEFT_and_RIGHT (d))
    beams[d] = stems[d] ? Stem::get_beam (stems[d]) : 0;

  *equally_long = false;
  if (! (beams[LEFT] && (beams[LEFT] == beams[RIGHT]) && !me->is_broken ()))
    return 0;

  extract_grob_set (beams[LEFT], "stems", beam_stems);
  if (beam_stems.size () == 0)
    {
      programming_error ("beam under tuplet bracket has no stems");
      *equally_long = 0;
      return 0;
    }

  *equally_long
    = (beam_stems[0] == stems[LEFT]
       && beam_stems.back () == stems[RIGHT]);
  return beams[LEFT];
}

MAKE_SCHEME_CALLBACK (Tuplet_bracket, calc_connect_to_neighbors, 1);
SCM
Tuplet_bracket::calc_connect_to_neighbors (SCM smob)
{
  Spanner *me = unsmob<Spanner> (smob);

  Direction dir = get_grob_direction (me);
  Drul_array<Item *> bounds (get_x_bound_item (me, LEFT, dir),
                             get_x_bound_item (me, RIGHT, dir));

  Drul_array<bool> connect_to_other (false, false);
  for (LEFT_and_RIGHT (d))
    {
      Direction break_dir = bounds[d]->break_status_dir ();
      Spanner *orig_spanner = dynamic_cast<Spanner *> (me->original ());
      vsize neighbor_idx = me->get_break_index () - break_dir;
      if (break_dir
          && d == RIGHT
          && neighbor_idx < orig_spanner->broken_intos_.size ())
        {
          Grob *neighbor = orig_spanner->broken_intos_[neighbor_idx];

          /* trigger possible suicide*/
          (void) neighbor->get_property ("positions");
        }

      connect_to_other[d]
        = (break_dir
           && neighbor_idx < orig_spanner->broken_intos_.size ()
           && orig_spanner->broken_intos_[neighbor_idx]->is_live ());
    }

  if (connect_to_other[LEFT] || connect_to_other[RIGHT])
    return scm_cons (scm_from_bool (connect_to_other[LEFT]),
                     scm_from_bool (connect_to_other[RIGHT]));

  return SCM_EOL;
}

Grob *
Tuplet_bracket::get_common_x (Spanner *me)
{
  extract_grob_set (me, "note-columns", columns);

  Grob *commonx = common_refpoint_of_array (columns, me, X_AXIS);
  commonx = commonx->common_refpoint (me->get_bound (LEFT), X_AXIS);
  commonx = commonx->common_refpoint (me->get_bound (RIGHT), X_AXIS);

  return commonx;
}

MAKE_SCHEME_CALLBACK (Tuplet_bracket, calc_x_positions, 1)
SCM
Tuplet_bracket::calc_x_positions (SCM smob)
{
  Spanner *me = unsmob<Spanner> (smob);
  extract_grob_set (me, "note-columns", columns);

  Grob *commonx = get_common_x (me);
  Direction dir = get_grob_direction (me);

  Drul_array<Item *> bounds;
  bounds[LEFT] = get_x_bound_item (me, LEFT, dir);
  bounds[RIGHT] = get_x_bound_item (me, RIGHT, dir);

  Drul_array<bool> connect_to_other
    = robust_scm2booldrul (me->get_property ("connect-to-neighbor"),
                           Drul_array<bool> (false, false));

  Interval x_span;
  for (LEFT_and_RIGHT (d))
    {
      x_span[d] = Axis_group_interface::generic_bound_extent (bounds[d], commonx, X_AXIS)[d];

      if (connect_to_other[d])
        {
          Interval overshoot (robust_scm2drul (me->get_property ("break-overshoot"),
                                               Interval (-0.5, 0.0)));

          if (d == RIGHT)
            x_span[d] += d * overshoot[d];
          else
            x_span[d] = (bounds[d]->break_status_dir ()
                         ? Axis_group_interface::generic_bound_extent (bounds[d], commonx, X_AXIS)[-d]
                         : robust_relative_extent (bounds[d], commonx, X_AXIS)[-d])
                        - overshoot[LEFT];
        }

      else if (d == RIGHT
               && (columns.empty ()
                   || (bounds[d]->get_column ()
                       != dynamic_cast<Item *> (columns.back ())->get_column ())))
        {
          /*
            We're connecting to a column, for the last bit of a broken
            fullLength bracket.
          */
          Real padding
            = robust_scm2double (me->get_property ("full-length-padding"), 1.0);

          if (bounds[d]->break_status_dir ())
            padding = 0.0;

          Real coord = bounds[d]->relative_coordinate (commonx, X_AXIS);
          if (to_boolean (me->get_property ("full-length-to-extent")))
            coord = robust_relative_extent (bounds[d], commonx, X_AXIS)[LEFT];

          coord = max (coord, x_span[LEFT]);

          x_span[d] = coord - padding;
        }
    }

  return ly_interval2scm (x_span - me->get_bound (LEFT)->relative_coordinate (commonx, X_AXIS));
}

/*
  TODO:

  in the case that there is no bracket, but there is a (single) beam,
  follow beam precisely for determining tuplet number location.
*/
MAKE_SCHEME_CALLBACK (Tuplet_bracket, print, 1);
SCM
Tuplet_bracket::print (SCM smob)
{
  Spanner *me = unsmob<Spanner> (smob);
  Stencil mol;

  extract_grob_set (me, "note-columns", columns);
  bool equally_long = false;
  Grob *par_beam = parallel_beam (me, columns, &equally_long);

  bool bracket_visibility = !(par_beam && equally_long); // Flag, print/don't print tuplet bracket.
  /*
    FIXME: The type of this prop is sucky.
  */
  SCM bracket_vis_prop = me->get_property ("bracket-visibility");
  bool bracket_prop = ly_scm2bool (bracket_vis_prop); // Flag, user has set bracket-visibility prop.
  bool bracket = scm_is_eq (bracket_vis_prop, ly_symbol2scm ("if-no-beam"));
  if (scm_is_bool (bracket_vis_prop))
    bracket_visibility = bracket_prop;
  else if (bracket)
    bracket_visibility = !par_beam;

  /*
    Don't print a tuplet bracket and number if
    no X or Y positions were calculated.
  */
  SCM scm_x_span = me->get_property ("X-positions");
  SCM scm_positions = me->get_property ("positions");
  if (!scm_is_pair (scm_x_span) || !scm_is_pair (scm_positions))
    {
      me->suicide ();
      return SCM_EOL;
    }
  /*  if the tuplet does not span any time, i.e. a single-note tuplet, hide
      the bracket, but still let the number be displayed.
      Only do this if the user has not explicitly specified bracket-visibility = #t.
  */
  if (!to_boolean (bracket_vis_prop)
      && (robust_scm2moment (me->get_bound (LEFT)->get_column ()->get_property ("when"), Moment (0))
          == robust_scm2moment (me->get_bound (RIGHT)->get_column ()->get_property ("when"), Moment (0))))
    bracket_visibility = false;

  Interval x_span = robust_scm2interval (scm_x_span, Interval (0.0, 0.0));
  Interval positions = robust_scm2interval (scm_positions, Interval (0.0, 0.0));

  Drul_array<Offset> points;
  for (LEFT_and_RIGHT (d))
    points[d] = Offset (x_span[d], positions[d]);

  Output_def *pap = me->layout ();

  Grob *number_grob = unsmob<Grob> (me->get_object ("tuplet-number"));

  /*
    Don't print the bracket when it would be smaller than the number.
    ...Unless the user has coded bracket-visibility = #t, that is.
  */
  Real gap = 0.;
  if (bracket_visibility && number_grob)
    {
      Interval ext = number_grob->extent (number_grob, X_AXIS);
      if (!ext.is_empty ())
        {
          gap = ext.length () + 1.0;

          if ((0.75 * x_span.length () < gap) && !bracket_prop)
            bracket_visibility = false;
        }
    }

  if (bracket_visibility)
    {
      Drul_array<Real> zero (0, 0);
      Real ss = Staff_symbol_referencer::staff_space (me);
      Drul_array<Real> height
        = robust_scm2drul (me->get_property ("edge-height"), zero);
      Drul_array<Real> flare
        = robust_scm2drul (me->get_property ("bracket-flare"), zero);
      Drul_array<Real> shorten
        = robust_scm2drul (me->get_property ("shorten-pair"), zero);
      Drul_array<Stencil> edge_stencils;

      Direction dir = get_grob_direction (me);

      scale_drul (&height, -ss * dir);
      scale_drul (&flare, ss);
      scale_drul (&shorten, ss);

      Drul_array<bool> connect_to_other
        = robust_scm2booldrul (me->get_property ("connect-to-neighbor"),
                               Drul_array<bool> (false, false));

      for (LEFT_and_RIGHT (d))
        {
          if (connect_to_other[d])
            {
              height[d] = 0.0;
              flare[d] = 0.0;
              shorten[d] = 0.0;

              SCM edge_text = me->get_property ("edge-text");

              if (scm_is_pair (edge_text))
                {
                  SCM properties = Font_interface::text_font_alist_chain (me);
                  SCM text = index_get_cell (edge_text, d);
                  if (Text_interface::is_markup (text))
                    {
                      SCM t
                        = Text_interface::interpret_markup (pap->self_scm (),
                                                            properties, text);

                      Stencil *edge_text = unsmob<Stencil> (t);
                      edge_text->translate_axis (x_span[d] - x_span[LEFT],
                                                 X_AXIS);
                      edge_stencils[d] = *edge_text;
                    }
                }
            }
        }

      Stencil brack = make_bracket (me, Y_AXIS,
                                    points[RIGHT] - points[LEFT],
                                    height,
                                    /*
                                      0.1 = more space at right due to italics
                                      TODO: use italic correction of font.
                                    */
                                    Interval (-0.5, 0.5) * gap + 0.1,
                                    flare, shorten);

      for (LEFT_and_RIGHT (d))
        {
          if (!edge_stencils[d].is_empty ())
            brack.add_stencil (edge_stencils[d]);
        }

      mol.add_stencil (brack);
    }

  mol.translate (points[LEFT]);
  return mol.smobbed_copy ();
}

/*
  should move to lookup?

  TODO: this will fail for very short (shorter than the flare)
  brackets.
*/
Stencil
Tuplet_bracket::make_bracket (Grob *me, // for line properties.
                              Axis protrusion_axis,
                              Offset dz,
                              Drul_array<Real> height,
                              Interval gap,
                              Drul_array<Real> flare,
                              Drul_array<Real> shorten)
{
  Drul_array<Offset> corners (Offset (0, 0), dz);

  Real length = dz.length ();
  Drul_array<Offset> gap_corners;

  Axis bracket_axis = other_axis (protrusion_axis);

  Drul_array<Offset> straight_corners = corners;

  for (LEFT_and_RIGHT (d))
    straight_corners[d] += -d * shorten[d] / length * dz;

  if (!gap.is_empty ())
    {
      for (LEFT_and_RIGHT (d))
        gap_corners[d] = (dz * 0.5) + gap[d] / length * dz;
    }

  Drul_array<Offset> flare_corners = straight_corners;
  for (LEFT_and_RIGHT (d))
    {
      flare_corners[d][bracket_axis] = straight_corners[d][bracket_axis];
      flare_corners[d][protrusion_axis] += height[d];
      straight_corners[d][bracket_axis] += -d * flare[d];
    }

  Stencil m;
  if (!gap.is_empty ())
    for (LEFT_and_RIGHT (d))
      m.add_stencil (Line_interface::line (me, straight_corners[d],
                                           gap_corners[d]));
  else
    m.add_stencil (Line_interface::line (me, straight_corners[LEFT],
                                         straight_corners[RIGHT]));

  if (scm_is_number (me->get_property ("dash-fraction")))
    me->set_property ("dash-fraction", scm_from_double (1.0));
  for (LEFT_and_RIGHT (d))
    m.add_stencil (Line_interface::line (me, straight_corners[d],
                                         flare_corners[d]));
  return m;
}

void
Tuplet_bracket::get_bounds (Grob *me, Grob **left, Grob **right)
{
  extract_grob_set (me, "note-columns", columns);
  vsize l = 0;
  while (l < columns.size () && Note_column::has_rests (columns[l]))
    l++;

  vsize r = columns.size ();
  while (r > l && Note_column::has_rests (columns[r - 1]))
    r--;

  *left = *right = 0;

  if (l < r)
    {
      *left = columns[l];
      *right = columns[r - 1];
    }
}

/*
  use first -> last note for slope, and then correct for disturbing
  notes in between.  */
void
Tuplet_bracket::calc_position_and_height (Grob *me_grob, Real *offset, Real *dy)
{
  Spanner *me = dynamic_cast<Spanner *> (me_grob);

  extract_grob_set (me, "note-columns", columns);
  extract_grob_set (me, "tuplets", tuplets);

  Grob *commony = common_refpoint_of_array (columns, me, Y_AXIS);
  commony = common_refpoint_of_array (tuplets, commony, Y_AXIS);
  if (Grob *st = Staff_symbol_referencer::get_staff_symbol (me))
    commony = st->common_refpoint (commony, Y_AXIS);
  Real my_offset = me->relative_coordinate (commony, Y_AXIS);

  Grob *commonx = get_common_x (me);
  commonx = common_refpoint_of_array (tuplets, commonx, Y_AXIS);

  Interval staff;
  Grob *st = Staff_symbol_referencer::get_staff_symbol (me);

  /* staff-padding doesn't work correctly on cross-staff tuplets
     because it only considers one staff symbol. Until this works,
     disable it. */
  if (st && !to_boolean (me->get_property ("cross-staff")))
    {
      Real pad = robust_scm2double (me->get_property ("staff-padding"), -1.0);
      if (pad >= 0.0)
        {
          staff = st->extent (commony, Y_AXIS) - my_offset;
          staff.widen (pad);
        }
    }

  Direction dir = get_grob_direction (me);

  bool equally_long = false;
  Grob *par_beam = parallel_beam (me, columns, &equally_long);

  Item *lgr = get_x_bound_item (me, LEFT, dir);
  Item *rgr = get_x_bound_item (me, RIGHT, dir);
  Real x0 = robust_relative_extent (lgr, commonx, X_AXIS)[LEFT];
  Real x1 = robust_relative_extent (rgr, commonx, X_AXIS)[RIGHT];
  bool follow_beam = par_beam
                     && get_grob_direction (par_beam) == dir
                     && !Beam::is_knee (par_beam);

  vector<Offset> points;
  if (columns.size ()
      && follow_beam
      && Note_column::get_stem (columns[0])
      && Note_column::get_stem (columns.back ()))
    {
      Drul_array<Grob *> stems (Note_column::get_stem (columns[0]),
                                Note_column::get_stem (columns.back ()));

      Interval poss;
      for (LEFT_and_RIGHT (side))
        {
          // Trigger setting of stem lengths if necessary.
          if (Grob *beam = Stem::get_beam (stems[side]))
            (void) beam->get_property ("quantized-positions");
          poss[side] = stems[side]->extent (stems[side], Y_AXIS)[get_grob_direction (stems[side])]
                       + stems[side]->get_parent (Y_AXIS)->relative_coordinate (commony, Y_AXIS);
        }

      *dy = poss[RIGHT] - poss[LEFT];
      points.push_back (Offset (stems[LEFT]->relative_coordinate (commonx, X_AXIS) - x0, poss[LEFT]));
      points.push_back (Offset (stems[RIGHT]->relative_coordinate (commonx, X_AXIS) - x0, poss[RIGHT]));
    }
  else
    {
      /*
        Use outer non-rest columns to determine slope
      */
      Grob *left_col = 0;
      Grob *right_col = 0;
      get_bounds (me, &left_col, &right_col);
      if (left_col && right_col)
        {
          Interval rv = Note_column::cross_staff_extent (right_col, commony);
          Interval lv = Note_column::cross_staff_extent (left_col, commony);
          rv.unite (staff);
          lv.unite (staff);

          Real graphical_dy = rv[dir] - lv[dir];

          Slice ls = Note_column::head_positions_interval (left_col);
          Slice rs = Note_column::head_positions_interval (right_col);

          Interval musical_dy;
          musical_dy[UP] = rs[UP] - ls[UP];
          musical_dy[DOWN] = rs[DOWN] - ls[DOWN];
          if (sign (musical_dy[UP]) != sign (musical_dy[DOWN]))
            *dy = 0.0;
          else if (sign (graphical_dy) != sign (musical_dy[DOWN]))
            *dy = 0.0;
          else
            *dy = graphical_dy;
        }
      else
        *dy = 0;

      for (vsize i = 0; i < columns.size (); i++)
        {
          Interval note_ext = Note_column::cross_staff_extent (columns[i],
                                                               commony);
          Real x = columns[i]->relative_coordinate (commonx, X_AXIS) - x0;

          points.push_back (Offset (x, note_ext[dir]));
        }
    }

  if (!follow_beam)
    {
      points.push_back (Offset (x0 - x0, staff[dir]));
      points.push_back (Offset (x1 - x0, staff[dir]));
    }

  /*
    This is a slight hack. We compute two encompass points from the
    bbox of the smaller tuplets.

    We assume that the smaller bracket is 1.0 space high.
  */
  Real ss = Staff_symbol_referencer::staff_space (me);
  for (vsize i = 0; i < tuplets.size (); i++)
    {
      Interval tuplet_x (tuplets[i]->extent (commonx, X_AXIS));
      Interval tuplet_y (tuplets[i]->extent (commony, Y_AXIS));

      if (!tuplets[i]->is_live ())
        continue;

      Drul_array<Real> positions
        = robust_scm2interval (tuplets[i]->get_property ("positions"),
                               Interval (0, 0));

      Real other_dy = positions[RIGHT] - positions[LEFT];

      for (LEFT_and_RIGHT (d))
        {
          Real y
            = tuplet_y.linear_combination (d * sign (other_dy));

          /*
            We don't take padding into account for nested tuplets.
            the edges can come very close to the stems, likewise for
            nested tuplets?
          */

          points.push_back (Offset (tuplet_x[d] - x0, y));
        }

      // Check for number-on-bracket collisions
      Grob *number = unsmob<Grob> (tuplets[i]->get_object ("tuplet-number"));
      if (number)
        {
          Interval x_ext = robust_relative_extent (number, commonx, X_AXIS);
          Interval y_ext = robust_relative_extent (number, commony, Y_AXIS);
          points.push_back (Offset (x_ext.center () - x0, y_ext[dir]));
        }
    }

  if (to_boolean (me->get_property ("avoid-scripts"))
      && !scm_is_number (me->get_property ("outside-staff-priority")))
    {
      extract_grob_set (me, "scripts", scripts);
      for (vsize i = 0; i < scripts.size (); i++)
        {
          if (!scripts[i]->is_live ())
            continue;
          if (scm_is_number (scripts[i]->get_property ("outside-staff-priority")))
            continue;

          // assume that if a script is avoiding slurs, it should not get placed
          // under a tuplet bracket
          if (unsmob<Grob> (scripts[i]->get_object ("slur")))
            continue;

          Interval script_x
            = robust_relative_extent (scripts[i], commonx, X_AXIS);
          Interval script_y
            = robust_relative_extent (scripts[i], commony, Y_AXIS);

          points.push_back (Offset (script_x.center () - x0,
                                    script_y[dir]));
        }
    }

  *offset = -dir * infinity_f;
  Real factor = (columns.size () > 1) ? 1 / (x1 - x0) : 1.0;
  for (vsize i = 0; i < points.size (); i++)
    {
      Real x = points[i][X_AXIS];
      Real tuplety = (*dy) * x * factor + my_offset;

      if (points[i][Y_AXIS] * dir > (*offset + tuplety) * dir)
        *offset = points[i][Y_AXIS] - tuplety;
    }

  *offset += scm_to_double (me->get_property ("padding")) * dir;

  /*
    horizontal brackets should not collide with staff lines.

    This doesn't seem to support cross-staff tuplets atm.
  */
  if (*dy == 0)
    {
      // quantize, then do collision check.
      *offset /= 0.5 * ss;

      Interval staff_span = Staff_symbol_referencer::staff_span (me);
      if (staff_span.contains (*offset))
        {
          *offset = rint (*offset);
          if (Staff_symbol_referencer::on_line (me, int (*offset)))
            *offset += dir;
        }

      *offset *= 0.5 * ss;
    }
}

MAKE_SCHEME_CALLBACK (Tuplet_bracket, calc_direction, 1);
SCM
Tuplet_bracket::calc_direction (SCM smob)
{
  Grob *me = unsmob<Grob> (smob);
  Direction dir = Tuplet_bracket::get_default_dir (me);
  return scm_from_int (dir);
}

MAKE_SCHEME_CALLBACK (Tuplet_bracket, calc_positions, 1);
SCM
Tuplet_bracket::calc_positions (SCM smob)
{
  Spanner *me = unsmob<Spanner> (smob);

  Real dy = 0.0;
  Real offset = 0.0;
  calc_position_and_height (me, &offset, &dy);

  SCM x = scm_cons (scm_from_double (offset),
                    scm_from_double (offset + dy));

  return x;
}

/*
  similar to beam ?
*/
Direction
Tuplet_bracket::get_default_dir (Grob *me)
{
  Drul_array<int> dirs (0, 0);
  extract_grob_set (me, "note-columns", columns);
  for (vsize i = 0; i < columns.size (); i++)
    {
      Grob *nc = columns[i];
      if (Note_column::has_rests (nc))
        continue;
      Direction d = Note_column::dir (nc);
      if (d)
        dirs[d]++;
    }

  if (dirs[UP] == dirs[DOWN])
    {
      if (dirs[UP] == 0)
        return UP;
      Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
      if (!staff)
        return UP;
      Interval staff_extent = staff->extent (staff, Y_AXIS);
      Interval extremal_positions;
      extremal_positions.set_empty ();
      for (vsize i = 0; i < columns.size (); i++)
        {
          Direction d = Note_column::dir (columns[i]);
          extremal_positions[d] = minmax (d, 1.0 * Note_column::head_positions_interval (columns[i])[d], extremal_positions[d]);
        }
      for (LEFT_and_RIGHT (d))
        extremal_positions[d] = -d * (staff_extent[d] - extremal_positions[d]);

      return extremal_positions[UP] <= extremal_positions[DOWN] ? UP : DOWN;
    }

  return dirs[UP] > dirs[DOWN] ? UP : DOWN;
}

void
Tuplet_bracket::add_column (Grob *me, Item *n)
{
  Pointer_group_interface::add_grob (me, ly_symbol2scm ("note-columns"), n);
  add_bound_item (dynamic_cast<Spanner *> (me), n);
}

void
Tuplet_bracket::add_script (Grob *me, Item *s)
{
  Pointer_group_interface::add_grob (me, ly_symbol2scm ("scripts"), s);
}

void
Tuplet_bracket::add_tuplet_bracket (Grob *me, Grob *bracket)
{
  Pointer_group_interface::add_grob (me, ly_symbol2scm ("tuplets"), bracket);
}

MAKE_SCHEME_CALLBACK (Tuplet_bracket, calc_cross_staff, 1);
SCM
Tuplet_bracket::calc_cross_staff (SCM smob)
{
  Grob *me = unsmob<Grob> (smob);
  extract_grob_set (me, "note-columns", cols);
  extract_grob_set (me, "tuplets", tuplets);

  Grob *commony = common_refpoint_of_array (cols, me, Y_AXIS);
  commony = common_refpoint_of_array (tuplets, commony, Y_AXIS);
  if (Grob *st = Staff_symbol_referencer::get_staff_symbol (me))
    commony = st->common_refpoint (commony, Y_AXIS);
  if (me->check_cross_staff (commony))
    return SCM_BOOL_T;

  bool equally_long = false;
  Grob *par_beam = parallel_beam (me, cols, &equally_long);

  if (par_beam && to_boolean (par_beam->get_property ("cross-staff")))
    return SCM_BOOL_T;

  for (vsize i = 0; i < cols.size (); i++)
    {
      Grob *stem = unsmob<Grob> (cols[i]->get_object ("stem"));
      if (stem && to_boolean (stem->get_property ("cross-staff")))
        return SCM_BOOL_T;
    }

  return SCM_BOOL_F;
}

ADD_INTERFACE (Tuplet_bracket,
               "A bracket with a number in the middle, used for tuplets."
               "  When the bracket spans a line break, the value of"
               " @code{break-overshoot} determines how far it extends"
               " beyond the staff.  At a line break, the markups in the"
               " @code{edge-text} are printed at the edges.",

               /* properties */
               "avoid-scripts "
               "bracket-flare "
               "bracket-visibility "
               "break-overshoot "
               "connect-to-neighbor "
               "direction "
               "edge-height "
               "edge-text "
               "full-length-padding "
               "full-length-to-extent "
               "gap "
               "positions "
               "note-columns "
               "padding "
               "tuplet-number "
               "scripts "
               "shorten-pair "
               "staff-padding "
               "thickness "
               "tuplets "
               "X-positions "
              );