2 staff-symbol-referencer.cc -- implement Staff_symbol_referencer
4 source file of the GNU LilyPond music typesetter
6 (c) 1999--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
9 #include "staff-symbol-referencer.hh"
12 #include "staff-symbol.hh"
13 #include "output-def.hh"
14 #include "libc-extension.hh"
17 Staff_symbol_referencer::line_count (Grob *me)
19 Grob *st = get_staff_symbol (me);
20 return st ? Staff_symbol::line_count (st) : 0;
24 Staff_symbol_referencer::on_line (Grob *me)
26 return on_line (me, (int) rint (get_position (me)));
30 Staff_symbol_referencer::on_staff_line (Grob *me)
32 return on_staff_line (me, (int) rint (get_position (me)));
36 Staff_symbol_referencer::on_line (Grob *me, int pos)
38 int sz = line_count (me) - 1;
39 return ((pos + sz) % 2) == 0;
43 Staff_symbol_referencer::on_staff_line (Grob *me, int pos)
45 return on_line (me, pos) && abs (pos) <= 2 * staff_radius (me);
49 Staff_symbol_referencer::get_staff_symbol (Grob *me)
51 if (Staff_symbol::has_interface (me))
54 SCM st = me->get_object ("staff-symbol");
55 return unsmob_grob (st);
59 Staff_symbol_referencer::staff_space (Grob *me)
61 Grob *st = get_staff_symbol (me);
63 return Staff_symbol::staff_space (st);
68 Staff_symbol_referencer::line_thickness (Grob *me)
70 Grob *st = get_staff_symbol (me);
72 return Staff_symbol::get_line_thickness (st);
73 return me->layout ()->get_dimension (ly_symbol2scm ("line-thickness"));
77 Staff_symbol_referencer::get_position (Grob *me)
80 Grob *st = get_staff_symbol (me);
81 Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
84 Real y = me->relative_coordinate (c, Y_AXIS)
85 - st->relative_coordinate (c, Y_AXIS);
87 p += 2.0 * y / Staff_symbol::staff_space (st);
91 return me->relative_coordinate (me->get_parent (Y_AXIS), Y_AXIS) * 2;
92 return robust_scm2double (me->get_property ("staff-position"), p);
96 Staff_symbol_referencer::get_rounded_position (Grob *me)
98 return int (rint (get_position (me)));
101 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer, callback, 1);
103 Staff_symbol_referencer::callback (SCM smob)
105 Grob *me = unsmob_grob (smob);
107 SCM pos = me->get_property ("staff-position");
109 if (scm_is_number (pos))
111 Real space = Staff_symbol_referencer::staff_space (me);
112 off = scm_to_double (pos) * space / 2.0;
113 me->set_property ("staff-position", scm_from_int (0));
116 return scm_from_double (off);
119 /* This sets the position relative to the center of the staff symbol.
121 The function is hairy, because it can be called in two situations:
123 1. There is no staff yet; we must set staff-position
125 2. There is a staff, and perhaps someone even applied a
126 translate_axis (). Then we must compensate for the translation
128 In either case, we set a callback to be sure that our new position
129 will be extracted from staff-position */
132 Staff_symbol_referencer::set_position (Grob *me, Real p)
134 Grob *st = get_staff_symbol (me);
136 if (st && me->common_refpoint (st, Y_AXIS))
138 oldpos = get_position (me);
142 Real ss = Staff_symbol_referencer::staff_space (me);
143 me->translate_axis ((p - oldpos) * ss * 0.5, Y_AXIS);
146 /* Half of the height, in staff space, i.e. 2.0 for a normal staff. */
148 Staff_symbol_referencer::staff_radius (Grob *me)
150 return (line_count (me) - 1) / 2.0;
154 compare_position (Grob *const &a, Grob *const &b)
156 return sign (Staff_symbol_referencer::get_position ((Grob *)a)
157 - Staff_symbol_referencer::get_position ((Grob *) b));
160 ADD_INTERFACE (Staff_symbol_referencer, "staff-symbol-referencer-interface",
161 "An object whose Y position is meant relative to a staff "
163 "These usually have @code{Staff_symbol_referencer::callback} "
164 "in their @code{Y-offset-callbacks}. ",