+#include "stem.hh"
+#include "warn.hh"
+
+MAKE_SCHEME_CALLBACK (Stem_tremolo, calc_slope, 1)
+SCM
+Stem_tremolo::calc_slope (SCM smob)
+{
+ Grob *me = unsmob_grob (smob);
+ Grob *stem = unsmob_grob (me->get_object ("stem"));
+ Spanner *beam = Stem::get_beam (stem);
+
+ if (beam)
+ {
+ Real dy = 0;
+ SCM s = beam->get_property ("quantized-positions");
+ if (is_number_pair (s))
+ dy = - scm_to_double (scm_car (s)) + scm_to_double (scm_cdr (s));
+
+ Grob *s2 = Beam::last_normal_stem (beam);
+ Grob *s1 = Beam::first_normal_stem (beam);
+
+ Grob *common = s1->common_refpoint (s2, X_AXIS);
+ Real dx = s2->relative_coordinate (common, X_AXIS)
+ - s1->relative_coordinate (common, X_AXIS);
+
+ return scm_from_double (dx ? dy / dx : 0);
+ }
+ else
+ /* down stems with flags should have more sloped trems (helps avoid
+ flag/stem collisions without making the stem very long) */
+ return scm_from_double ((Stem::duration_log (stem) >= 3 && get_grob_direction (stem) == DOWN)
+ ? 0.40 : 0.25);
+}
+
+MAKE_SCHEME_CALLBACK (Stem_tremolo, calc_width, 1)
+SCM
+Stem_tremolo::calc_width (SCM smob)
+{
+ Grob *me = unsmob_grob (smob);
+ Grob *stem = unsmob_grob (me->get_object ("stem"));
+ Direction stemdir = get_grob_direction (stem);
+ bool beam = Stem::get_beam (stem);
+ bool flag = Stem::duration_log (stem) >= 3 && !beam;
+
+ /* beamed stems and up-stems with flags have shorter tremolos */
+ return scm_from_double (((stemdir == UP && flag) || beam) ? 1.0 : 1.5);
+}
+
+MAKE_SCHEME_CALLBACK (Stem_tremolo, calc_style, 1)
+SCM
+Stem_tremolo::calc_style (SCM smob)
+{
+ Grob *me = unsmob_grob (smob);
+ Grob *stem = unsmob_grob (me->get_object ("stem"));
+ Direction stemdir = get_grob_direction (stem);
+ bool beam = Stem::get_beam (stem);
+ bool flag = Stem::duration_log (stem) >= 3 && !beam;
+
+ return ly_symbol2scm (((stemdir == UP && flag) || beam) ? "rectangle" : "default");
+}
+
+Real
+Stem_tremolo::get_beam_translation (Grob *me)
+{
+ Grob *stem = unsmob_grob (me->get_object ("stem"));
+ Spanner *beam = Stem::get_beam (stem);
+
+ return (beam && beam->is_live ())
+ ? Beam::get_beam_translation (beam)
+ : (Staff_symbol_referencer::staff_space (me)
+ * robust_scm2double (me->get_property ("length-fraction"), 1.0) * 0.81);
+}
+
+Stencil
+Stem_tremolo::raw_stencil (Grob *me, Real slope, Direction stemdir)
+{
+ Real ss = Staff_symbol_referencer::staff_space (me);
+ Real thick = robust_scm2double (me->get_property ("beam-thickness"), 1);
+ Real width = robust_scm2double (me->get_property ("beam-width"), 1);
+ Real blot = me->layout ()->get_dimension (ly_symbol2scm ("blot-diameter"));
+ SCM style = me->get_property ("style");
+ if (!scm_is_symbol (style))
+ style = ly_symbol2scm ("default");
+
+ width *= ss;
+ thick *= ss;
+
+ Stencil a;
+ if (style == ly_symbol2scm ("rectangle"))
+ a = Lookup::rotated_box (slope, width, thick, blot);
+ else
+ a = Lookup::beam (slope, width, thick, blot);
+
+ a.align_to (X_AXIS, CENTER);
+ a.align_to (Y_AXIS, CENTER);
+
+ int tremolo_flags = robust_scm2int (me->get_property ("flag-count"), 0);
+ if (!tremolo_flags)
+ {
+ programming_error ("no tremolo flags");
+
+ me->suicide ();
+ return Stencil ();
+ }
+
+ Real beam_translation = get_beam_translation (me);
+
+ Stencil mol;
+ for (int i = 0; i < tremolo_flags; i++)
+ {
+ Stencil b (a);
+ b.translate_axis (beam_translation * i * stemdir * -1, Y_AXIS);
+ mol.add_stencil (b);
+ }
+ return mol;
+}
+
+MAKE_SCHEME_CALLBACK (Stem_tremolo, pure_height, 3);
+SCM
+Stem_tremolo::pure_height (SCM smob, SCM, SCM)
+{
+ Item *me = unsmob_item (smob);
+
+ /*
+ Cannot use the real slope, since it looks at the Beam.
+ */
+ Stencil s1 (untranslated_stencil (me, 0.35));
+ Item *stem = unsmob_item (me->get_object ("stem"));
+ if (!stem)
+ return ly_interval2scm (s1.extent (Y_AXIS));