2 staff-symbol-referencer.cc -- implement Staff_symbol_referencer
4 source file of the GNU LilyPond music typesetter
6 (c) 1999--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
11 #include "staff-symbol-referencer.hh"
12 #include "staff-symbol.hh"
13 #include "paper-def.hh"
14 #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 Staff_symbol_referencer::on_staffline (Grob*me, int pos)
33 int sz = line_count (me)-1;
34 return ((pos + sz) % 2) == 0;
38 Staff_symbol_referencer::get_staff_symbol (Grob*me)
40 SCM st = me->get_grob_property ("staff-symbol");
41 return unsmob_grob (st);
45 Staff_symbol_referencer::staff_space (Grob*me)
47 Grob * st = get_staff_symbol (me);
49 return Staff_symbol::staff_space (st);
55 Staff_symbol_referencer::line_thickness (Grob*me)
57 Grob * st = get_staff_symbol (me);
59 return Staff_symbol::get_line_thickness (st);
61 return me->get_paper ()->get_realvar (ly_symbol2scm ("linethickness"));
65 Staff_symbol_referencer::get_position (Grob*me)
68 Grob * st = get_staff_symbol (me);
69 Grob * c = st ? me->common_refpoint (st, Y_AXIS) : 0;
72 Real y = me->relative_coordinate (c, Y_AXIS)
73 - st->relative_coordinate (c, Y_AXIS);
75 p += 2.0 * y / Staff_symbol::staff_space (st);
79 return robust_scm2double ( me->get_grob_property ("staff-position"), p);
83 LY_DEFINE(ly_grob_staff_position,
84 "ly:grob-staff-position",
86 "Return the Y-position of this grob relative to the staff.")
88 Grob * g = unsmob_grob (sg);
90 SCM_ASSERT_TYPE (g, sg, SCM_ARG1, __FUNCTION__, "grob");
91 Real pos = Staff_symbol_referencer::get_position (g);
93 if (fabs (rint (pos) -pos) < 1e-6) // ugh.
94 return gh_int2scm ((int) my_round (pos));
96 return gh_double2scm (pos);
101 should use offset callback!
103 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer,callback,2);
105 Staff_symbol_referencer::callback (SCM element_smob, SCM)
107 Grob *me = unsmob_grob (element_smob);
109 SCM pos = me->get_grob_property ("staff-position");
111 if (gh_number_p (pos))
113 Real space = Staff_symbol_referencer::staff_space (me);
114 off = gh_scm2double (pos) * space/2.0;
115 me->set_grob_property ("staff-position", gh_int2scm (0));
118 return gh_double2scm (off);
123 This sets the position relative to the center of the staff symbol.
125 The function is hairy, because it can be callled in two situations:
127 1. There is no staff yet; we must set staff-position
129 2. There is a staff, and perhaps someone even applied a
130 translate_axis (). Then we must compensate for the translation
132 In either case, we set a callback to be sure that our new position
133 will be extracted from staff-position
137 Staff_symbol_referencer::set_position (Grob*me,Real p)
139 Grob * st = get_staff_symbol (me);
140 if (st && me->common_refpoint (st, Y_AXIS))
142 Real oldpos = get_position (me);
143 me->set_grob_property ("staff-position", gh_double2scm (p - oldpos));
147 me->set_grob_property ("staff-position",
152 if (me->has_offset_callback_b (Staff_symbol_referencer::callback_proc, Y_AXIS))
155 me->add_offset_callback (Staff_symbol_referencer::callback_proc, Y_AXIS);
159 Half of the height, in staff space, i.e. 2.0 for a normal staff.
162 Staff_symbol_referencer::staff_radius (Grob*me)
164 return (line_count (me) -1) / 2.0;
169 compare_position (Grob *const &a, Grob * const &b)
171 return sign (Staff_symbol_referencer::get_position ((Grob*)a) -
172 Staff_symbol_referencer::get_position ((Grob*)b));
175 ADD_INTERFACE (Staff_symbol_referencer,"staff-symbol-referencer-interface",
176 "Object whose Y position is meaning with reference to a staff "
177 "symbol. Objects that have this interface should include "
178 "Staff_symbol_referencer::callback in their Y-offset-callback. "