2 staff-symbol-referencer.cc -- implement Staff_symbol_referencer
4 source file of the GNU LilyPond music typesetter
6 (c) 1999--2005 Han-Wen Nienhuys <hanwen@cs.uu.nl>
9 #include "staff-symbol-referencer.hh"
14 #include "staff-symbol.hh"
15 #include "output-def.hh"
16 #include "libc-extension.hh"
19 Staff_symbol_referencer::line_count (Grob *me)
21 Grob *st = get_staff_symbol (me);
22 return st ? Staff_symbol::line_count (st) : 0;
26 Staff_symbol_referencer::on_staffline (Grob *me)
28 return on_staffline (me, (int) rint (get_position (me)));
32 This does not take size into account.
33 maybe rename: on_virtual_staffline, on_staff_or_ledger_line?
36 Staff_symbol_referencer::on_staffline (Grob *me, int pos)
38 int sz = line_count (me) - 1;
39 return ((pos + sz) % 2) == 0;
43 Staff_symbol_referencer::get_staff_symbol (Grob *me)
45 if (Staff_symbol::has_interface (me))
48 SCM st = me->get_object ("staff-symbol");
49 return unsmob_grob (st);
53 Staff_symbol_referencer::staff_space (Grob *me)
55 Grob *st = get_staff_symbol (me);
57 return Staff_symbol::staff_space (st);
62 Staff_symbol_referencer::line_thickness (Grob *me)
64 Grob *st = get_staff_symbol (me);
66 return Staff_symbol::get_line_thickness (st);
67 return me->get_layout ()->get_dimension (ly_symbol2scm ("linethickness"));
71 Staff_symbol_referencer::get_position (Grob *me)
74 Grob *st = get_staff_symbol (me);
75 Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
78 Real y = me->relative_coordinate (c, Y_AXIS)
79 - st->relative_coordinate (c, Y_AXIS);
81 p += 2.0 * y / Staff_symbol::staff_space (st);
85 return me->relative_coordinate (me->get_parent (Y_AXIS), Y_AXIS) * 2;
86 return robust_scm2double (me->get_property ("staff-position"), p);
90 Staff_symbol_referencer::get_rounded_position (Grob *me)
92 return int (rint (get_position (me)));
95 LY_DEFINE (ly_grob_staff_position, "ly:grob-staff-position",
97 "Return the Y-position of @var{sg} relative to the staff.")
99 Grob *g = unsmob_grob (sg);
101 SCM_ASSERT_TYPE (g, sg, SCM_ARG1, __FUNCTION__, "grob");
102 Real pos = Staff_symbol_referencer::get_position (g);
104 if (fabs (rint (pos) -pos) < 1e-6) // ugh.
105 return scm_from_int ((int) my_round (pos));
107 return scm_from_double (pos);
110 /* should use offset callback! */
111 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer, callback, 2);
113 Staff_symbol_referencer::callback (SCM element_smob, SCM)
115 Grob *me = unsmob_grob (element_smob);
117 SCM pos = me->get_property ("staff-position");
119 if (scm_is_number (pos))
121 Real space = Staff_symbol_referencer::staff_space (me);
122 off = scm_to_double (pos) * space / 2.0;
123 me->set_property ("staff-position", scm_from_int (0));
126 return scm_from_double (off);
129 /* This sets the position relative to the center of the staff symbol.
131 The function is hairy, because it can be called in two situations:
133 1. There is no staff yet; we must set staff-position
135 2. There is a staff, and perhaps someone even applied a
136 translate_axis (). Then we must compensate for the translation
138 In either case, we set a callback to be sure that our new position
139 will be extracted from staff-position */
142 Staff_symbol_referencer::set_position (Grob *me, Real p)
144 Grob *st = get_staff_symbol (me);
145 if (st && me->common_refpoint (st, Y_AXIS))
147 Real oldpos = get_position (me);
148 me->set_property ("staff-position", scm_from_double (p - oldpos));
151 me->set_property ("staff-position", scm_from_double (p));
153 me->add_offset_callback (Staff_symbol_referencer::callback_proc, Y_AXIS);
156 /* Half of the height, in staff space, i.e. 2.0 for a normal staff. */
158 Staff_symbol_referencer::staff_radius (Grob *me)
160 return (line_count (me) - 1) / 2.0;
164 compare_position (Grob *const &a, Grob *const &b)
166 return sign (Staff_symbol_referencer::get_position ((Grob *)a)
167 - Staff_symbol_referencer::get_position ((Grob *) b));
170 ADD_INTERFACE (Staff_symbol_referencer, "staff-symbol-referencer-interface",
171 "An object whose Y position is meant relative to a staff "
173 "These usually have @code{Staff_symbol_referencer::callback} "
174 "in their @code{Y-offset-callbacks}. ",