return scm_from_double (offset + staff_space * shift);
}
+/*
+ Estimate the position of a rest under a beam,
+ as the average position of its neighboring heads.
+*/
MAKE_SCHEME_CALLBACK_WITH_OPTARGS (Beam, pure_rest_collision_callback, 4, 1, "");
SCM
Beam::pure_rest_collision_callback (SCM smob,
- SCM, /* prev_offset */
+ SCM prev_offset,
SCM, /* start */
SCM /* end */)
{
- Real amount = 0.0;
+ Real previous = robust_scm2double (prev_offset, 0.0);
Grob *me = unsmob_grob (smob);
Grob *stem = unsmob_grob (me->get_object ("stem"));
if (!stem)
- return scm_from_double (amount);
+ return scm_from_double (previous);
Grob *beam = unsmob_grob (stem->get_object ("beam"));
if (!beam
|| !Beam::normal_stem_count (beam)
|| !is_direction (beam->get_property_data ("direction")))
- return scm_from_double (amount);
+ return scm_from_double (previous);
Real ss = Staff_symbol_referencer::staff_space (me);
/*
This gives the extrema of rest positions.
- In general, beams are never typeset more than one staff space away
- from the staff in either direction.
+ Even with noteheads on ledgers, beams typically remain within the staff,
+ and push rests at most one staff-space (2 positions) from the staff.
*/
Grob *staff = Staff_symbol_referencer::get_staff_symbol (me);
Interval rest_max_pos = staff ? Staff_symbol::line_span (staff) : Interval (0.0, 0.0);
- rest_max_pos.widen (1);
- rest_max_pos *= ss / 2;
+ rest_max_pos.widen (2);
extract_grob_set (beam, "stems", stems);
vector<Grob *> my_stems;
Grob *right;
if (idx == (vsize) - 1 || my_stems.size () == 1)
- return scm_from_double (amount);
+ return scm_from_double (previous);
else if (idx == 0)
left = right = my_stems[1];
else if (idx == my_stems.size () - 1)
right = my_stems[idx + 1];
}
Direction beamdir = get_grob_direction (beam);
- /*
- Take the position between the two bounding head_positions,
- then bound it by the minimum and maximum positions outside the staff.
- 4.0 = 2.0 to get out of staff space * 2.0 for the average
- */
- amount = min (max ((Stem::head_positions (left)[beamdir] + Stem::head_positions (right)[beamdir]) / 4.0, rest_max_pos[DOWN]), rest_max_pos[UP]);
- return scm_from_double (amount);
+ /* In stems with several heads, use the one closest to the beam. */
+ Real shift = min (max ( (Stem::head_positions (left)[beamdir]
+ + Stem::head_positions (right)[beamdir]) / 2.0,
+ rest_max_pos[DOWN]),
+ rest_max_pos[UP]
+ ) * ss / 2.0
+ - previous;
+ /* Always move by a whole number of staff spaces */
+ shift = ceil (fabs (shift / ss)) * ss * sign (shift);
+
+ return scm_from_double (previous + shift);
}
bool