2 staff-symbol-referencer.cc -- implement Staff_symbol_referencer
4 source file of the GNU LilyPond music typesetter
6 (c) 1999--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
9 #include "staff-symbol-referencer.hh"
13 #include "staff-symbol.hh"
14 #include "output-def.hh"
15 #include "libc-extension.hh"
18 Staff_symbol_referencer::line_count (Grob *me)
20 Grob *st = get_staff_symbol (me);
21 return st ? Staff_symbol::line_count (st) : 0;
25 Staff_symbol_referencer::on_staffline (Grob *me)
27 return on_staffline (me, (int) rint (get_position (me)));
31 This does not take size into account.
32 maybe rename: on_virtual_staffline, on_staff_or_ledger_line?
35 Staff_symbol_referencer::on_staffline (Grob *me, int pos)
37 int sz = line_count (me) - 1;
38 return ((pos + sz) % 2) == 0;
42 Staff_symbol_referencer::get_staff_symbol (Grob *me)
44 if (Staff_symbol::has_interface (me))
47 SCM st = me->get_property ("staff-symbol");
48 return unsmob_grob (st);
52 Staff_symbol_referencer::staff_space (Grob *me)
54 Grob *st = get_staff_symbol (me);
56 return Staff_symbol::staff_space (st);
61 Staff_symbol_referencer::line_thickness (Grob *me)
63 Grob *st = get_staff_symbol (me);
65 return Staff_symbol::get_line_thickness (st);
66 return me->get_layout ()->get_dimension (ly_symbol2scm ("linethickness"));
70 Staff_symbol_referencer::get_position (Grob *me)
73 Grob *st = get_staff_symbol (me);
74 Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
77 Real y = me->relative_coordinate (c, Y_AXIS)
78 - st->relative_coordinate (c, Y_AXIS);
80 p += 2.0 * y / Staff_symbol::staff_space (st);
85 return me->relative_coordinate (me->get_parent (Y_AXIS), Y_AXIS) * 2;
87 return robust_scm2double (me->get_property ("staff-position"), p);
91 Staff_symbol_referencer::get_rounded_position (Grob*me)
93 return int (rint (get_position (me)));
96 LY_DEFINE (ly_grob_staff_position, "ly:grob-staff-position",
98 "Return the Y-position of @var{sg} relative to the staff.")
100 Grob *g = unsmob_grob (sg);
102 SCM_ASSERT_TYPE (g, sg, SCM_ARG1, __FUNCTION__, "grob");
103 Real pos = Staff_symbol_referencer::get_position (g);
105 if (fabs (rint (pos) -pos) < 1e-6) // ugh.
106 return scm_int2num ((int) my_round (pos));
108 return scm_make_real (pos);
112 /* should use offset callback! */
113 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer,callback,2);
115 Staff_symbol_referencer::callback (SCM element_smob, SCM)
117 Grob *me = unsmob_grob (element_smob);
119 SCM pos = me->get_property ("staff-position");
121 if (scm_is_number (pos))
123 Real space = Staff_symbol_referencer::staff_space (me);
124 off = scm_to_double (pos) * space / 2.0;
125 me->set_property ("staff-position", scm_int2num (0));
128 return scm_make_real (off);
131 /* This sets the position relative to the center of the staff symbol.
133 The function is hairy, because it can be called in two situations:
135 1. There is no staff yet; we must set staff-position
137 2. There is a staff, and perhaps someone even applied a
138 translate_axis (). Then we must compensate for the translation
140 In either case, we set a callback to be sure that our new position
141 will be extracted from staff-position */
144 Staff_symbol_referencer::set_position (Grob *me, Real p)
146 Grob *st = get_staff_symbol (me);
147 if (st && me->common_refpoint (st, Y_AXIS))
149 Real oldpos = get_position (me);
150 me->set_property ("staff-position", scm_make_real (p - oldpos));
153 me->set_property ("staff-position", scm_make_real (p));
155 me->add_offset_callback (Staff_symbol_referencer::callback_proc, Y_AXIS);
158 /* Half of the height, in staff space, i.e. 2.0 for a normal staff. */
160 Staff_symbol_referencer::staff_radius (Grob *me)
162 return (line_count (me) - 1) / 2.0;
166 compare_position (Grob *const &a, Grob *const &b)
168 return sign (Staff_symbol_referencer::get_position ((Grob*)a)
169 - Staff_symbol_referencer::get_position ((Grob*) b));
172 ADD_INTERFACE (Staff_symbol_referencer,"staff-symbol-referencer-interface",
173 "An object whose Y position is meant relative to a staff "
175 "These usually have @code{Staff_symbol_referencer::callback} "
176 "in their @code{Y-offset-callbacks}. "