+bool
+operator <(Beam_stem_segment const &a,
+ Beam_stem_segment const &b)
+{
+ return a.rank_ < b.rank_;
+}
+
+typedef map<int, vector<Beam_stem_segment> > Position_stem_segments_map;
+
+// TODO - should store result in a property?
+vector<Beam_segment>
+Beam::get_beam_segments (Grob *me_grob, Grob **common)
+{
+ /* ugh, this has a side-effect that we need to ensure that
+ Stem #'beaming is correct */
+ (void) me_grob->get_property ("beaming");
+
+ Spanner *me = dynamic_cast<Spanner*> (me_grob);
+
+ extract_grob_set (me, "stems", stems);
+ Grob *commonx = common_refpoint_of_array (stems, me, X_AXIS);
+
+ commonx = me->get_bound (LEFT)->common_refpoint (commonx, X_AXIS);
+ commonx = me->get_bound (RIGHT)->common_refpoint (commonx, X_AXIS);
+
+ *common = commonx;
+
+ int gap_count = robust_scm2int (me->get_property ("gap-count"), 0);
+ Real gap_length = robust_scm2double (me->get_property ("gap"), 0.0);
+
+ Position_stem_segments_map stem_segments;
+ Real lt = me->layout ()->get_dimension (ly_symbol2scm ("line-thickness"));
+
+ /* There are two concepts of "rank" that are used in the following code.
+ The beam_rank is the vertical position of the beam (larger numbers are
+ closer to the noteheads). Beam_stem_segment.rank_, on the other hand,
+ is the horizontal position of the segment (this is incremented by two
+ for each stem; the beam segment on the right side of the stem has
+ a higher rank (by one) than its neighbour to the left). */
+ Slice ranks;
+ for (vsize i = 0; i < stems.size (); i++)
+ {
+ Grob *stem = stems[i];
+ Real stem_width = robust_scm2double (stem->get_property ("thickness"), 1.0) * lt;
+ Real stem_x = stem->relative_coordinate (commonx, X_AXIS);
+ SCM beaming = stem->get_property ("beaming");
+ Direction d = LEFT;
+ do
+ {
+ // Find the maximum and minimum beam ranks.
+ // Given that RANKS is never reset to empty, the interval will always be
+ // smallest for the left beamlet of the first stem, and then it might grow.
+ // Do we really want this? (It only affects the tremolo gaps) --jneem
+ for (SCM s = index_get_cell (beaming, d);
+ scm_is_pair (s); s = scm_cdr (s))
+ {
+ if (!scm_is_integer (scm_car (s)))
+ continue;
+
+ int beam_rank = scm_to_int (scm_car (s));
+ ranks.add_point (beam_rank);
+ }
+
+ for (SCM s = index_get_cell (beaming, d);
+ scm_is_pair (s); s = scm_cdr (s))
+ {
+ if (!scm_is_integer (scm_car (s)))
+ continue;
+
+ int beam_rank = scm_to_int (scm_car (s));
+ Beam_stem_segment seg;
+ seg.stem_ = stem;
+ seg.stem_x_ = stem_x;
+ seg.rank_ = 2 * i + (d+1)/2;
+ seg.width_ = stem_width;
+ seg.stem_index_ = i;
+ seg.dir_ = d;
+ seg.max_connect_ = robust_scm2int (stem->get_property ("max-beam-connect"), 1000);
+
+ Direction stem_dir = get_grob_direction (stem);
+
+ seg.gapped_
+ = (stem_dir * beam_rank < (stem_dir * ranks[-stem_dir] + gap_count));
+ stem_segments[beam_rank].push_back (seg);
+ }
+ }
+ while (flip (&d) != LEFT);
+ }
+
+ Drul_array<Real> break_overshoot
+ = robust_scm2drul (me->get_property ("break-overshoot"),
+ Drul_array<Real> (-0.5, 0.0));
+
+ vector<Beam_segment> segments;
+ for (Position_stem_segments_map::const_iterator i (stem_segments.begin ());
+ i != stem_segments.end (); i++)
+ {
+ vector<Beam_stem_segment> segs = (*i).second;
+ vector_sort (segs, less<Beam_stem_segment> ());
+
+ Beam_segment current;
+
+ // Iterate over all of the segments of the current beam rank,
+ // merging the adjacent Beam_stem_segments into one Beam_segment
+ // when appropriate.
+ int vertical_count = (*i).first;
+ for (vsize j = 0; j < segs.size (); j++)
+ {
+ // Keeping track of the different directions here is a little tricky.
+ // segs[j].dir_ is the direction of the beam segment relative to the stem
+ // (ie. segs[j].dir_ == LEFT if the beam segment sticks out to the left of
+ // its stem) whereas event_dir refers to the edge of the beam segment that
+ // we are currently looking at (ie. if segs[j].dir_ == event_dir then we
+ // are looking at that edge of the beam segment that is furthest from its
+ // stem).
+ Direction event_dir = LEFT;
+ Beam_stem_segment const& seg = segs[j];
+ do
+ {
+ Beam_stem_segment const& neighbor_seg = segs[j + event_dir];
+ // TODO: make names clearer? --jneem
+ // on_line_bound: whether the current segment is on the boundary of the WHOLE beam
+ // on_beam_bound: whether the current segment is on the boundary of just that part
+ // of the beam with the current beam_rank
+ bool on_line_bound = (seg.dir_ == LEFT) ? seg.stem_index_ == 0
+ : seg.stem_index_ == stems.size() - 1;
+ bool on_beam_bound = (event_dir == LEFT) ? j == 0 :
+ j == segs.size () - 1;
+ bool inside_stem = (event_dir == LEFT)
+ ? seg.stem_index_ > 0
+ : seg.stem_index_ + 1 < stems.size () ;
+
+ bool event = on_beam_bound
+ || abs (seg.rank_ - neighbor_seg.rank_) > 1
+ || (abs (vertical_count) >= seg.max_connect_
+ || abs (vertical_count) >= neighbor_seg.max_connect_);
+
+ if (!event)
+ // Then this edge of the current segment is irrelevent because it will
+ // be connected with the next segment in the event_dir direction.
+ continue;
+
+ current.vertical_count_ = vertical_count;
+ current.horizontal_[event_dir] = seg.stem_x_;
+ if (seg.dir_ == event_dir)
+ // then we are examining the edge of a beam segment that is furthest
+ // from its stem.
+ {
+ if (on_line_bound
+ && me->get_bound (event_dir)->break_status_dir ())
+ {
+ current.horizontal_[event_dir]
+ = (robust_relative_extent (me->get_bound (event_dir),
+ commonx, X_AXIS)[RIGHT]
+ + event_dir * break_overshoot[event_dir]);
+ }
+ else
+ {
+ Grob *stem = stems[seg.stem_index_];
+ Drul_array<Real> beamlet_length =
+ robust_scm2interval (stem->get_property ("beamlet-default-length"), Interval (1.1, 1.1));
+ Drul_array<Real> max_proportion =
+ robust_scm2interval (stem->get_property ("beamlet-max-length-proportion"), Interval (0.75, 0.75));
+ Real length = beamlet_length[seg.dir_];
+
+ if (inside_stem)
+ {
+ Grob *neighbor_stem = stems[seg.stem_index_ + event_dir];
+ Real neighbor_stem_x = neighbor_stem->relative_coordinate (commonx, X_AXIS);
+
+ length = min (length,
+ fabs (neighbor_stem_x - seg.stem_x_) * max_proportion[seg.dir_]);
+ }
+ current.horizontal_[event_dir] += event_dir * length;
+ }
+ }
+ else
+ // we are examining the edge of a beam segment that is closest
+ // (ie. touching, unless there is a gap) its stem.
+ {
+ current.horizontal_[event_dir] += event_dir * seg.width_/2;
+ if (seg.gapped_)
+ {
+ current.horizontal_[event_dir] -= event_dir * gap_length;
+
+ if (Stem::is_invisible (seg.stem_))
+ {
+ /*
+ Need to do this in case of whole notes. We don't want the
+ heads to collide with the beams.
+ */
+ extract_grob_set (seg.stem_, "note-heads", heads);
+
+ for (vsize k = 0; k < heads.size (); k ++)
+ current.horizontal_[event_dir]
+ = event_dir * min (event_dir * current.horizontal_[event_dir],
+ - gap_length/2
+ + event_dir
+ * heads[k]->extent (commonx,
+ X_AXIS)[-event_dir]);
+ }
+ }
+ }
+
+ if (event_dir == RIGHT)
+ {
+ segments.push_back (current);
+ current = Beam_segment ();
+ }
+ }
+ while (flip (&event_dir) != LEFT);
+ }
+
+ }
+
+ return segments;
+}