lily/staff-symbol-referencer.cc

   1 /*
   2   staff-symbol-referencer.cc -- implement Staff_symbol_referencer
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1999--2009 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "staff-symbol-referencer.hh"
  10
  11 #include "staff-symbol.hh"
  12 #include "grob.hh"
  13 #include "output-def.hh"
  14 #include "libc-extension.hh"
  15
  16 int
  17 Staff_symbol_referencer::line_count (Grob *me)
  18 {
  19   Grob *st = get_staff_symbol (me);
  20   return st ? Staff_symbol::line_count (st) : 0;
  21 }
  22
  23 bool
  24 Staff_symbol_referencer::on_line (Grob *me, int pos)
  25 {
  26   Grob *st = get_staff_symbol (me);
  27   return st ? Staff_symbol::on_line (st, pos) : false;
  28 }
  29
  30 bool
  31 Staff_symbol_referencer::on_staff_line (Grob *me, int pos)
  32 {
  33   return on_line (me, pos) && abs (pos) <= 2 * staff_radius (me);
  34 }
  35
  36 Grob *
  37 Staff_symbol_referencer::get_staff_symbol (Grob *me)
  38 {
  39   if (Staff_symbol::has_interface (me))
  40     return me;
  41
  42   SCM st = me->get_object ("staff-symbol");
  43   return unsmob_grob (st);
  44 }
  45
  46 Real
  47 Staff_symbol_referencer::staff_space (Grob *me)
  48 {
  49   Grob *st = get_staff_symbol (me);
  50   if (st)
  51     return Staff_symbol::staff_space (st);
  52   return 1.0;
  53 }
  54
  55 Real
  56 Staff_symbol_referencer::line_thickness (Grob *me)
  57 {
  58   Grob *st = get_staff_symbol (me);
  59   if (st)
  60     return Staff_symbol::get_line_thickness (st);
  61   return me->layout ()->get_dimension (ly_symbol2scm ("line-thickness"));
  62 }
  63
  64 Real
  65 Staff_symbol_referencer::get_position (Grob *me)
  66 {
  67   Real p = 0.0;
  68   Grob *st = get_staff_symbol (me);
  69   Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
  70   if (st && c)
  71     {
  72       Real y = me->relative_coordinate (c, Y_AXIS)
  73         - st->relative_coordinate (c, Y_AXIS);
  74
  75       p += 2.0 * y / Staff_symbol::staff_space (st);
  76       return p;
  77     }
  78   else if (!st)
  79     return me->relative_coordinate (me->get_parent (Y_AXIS), Y_AXIS) * 2;
  80   return robust_scm2double (me->get_property ("staff-position"), p);
  81 }
  82
  83
  84 Interval
  85 Staff_symbol_referencer::extent_in_staff (Grob *me)
  86 {
  87   Grob *st = get_staff_symbol (me);
  88   Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
  89
  90   Interval retval;
  91   if (st && c)
  92     {
  93       retval  = me->extent (c, Y_AXIS)
  94         - st->relative_coordinate (c, Y_AXIS);
  95     }
  96
  97   return retval;
  98 }
  99
 100 int
 101 Staff_symbol_referencer::get_rounded_position (Grob *me)
 102 {
 103   return int (rint (get_position (me)));
 104 }
 105
 106 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer, callback, 1);
 107 SCM
 108 Staff_symbol_referencer::callback (SCM smob)
 109 {
 110   Grob *me = unsmob_grob (smob);
 111
 112   SCM pos = me->get_property ("staff-position");
 113   Real off = 0.0;
 114   if (scm_is_number (pos))
 115     {
 116       Real space = Staff_symbol_referencer::staff_space (me);
 117       off = scm_to_double (pos) * space / 2.0;
 118     }
 119
 120   return scm_from_double (off);
 121 }
 122
 123 /*  This sets the position relative to the center of the staff symbol.
 124
 125 The function is hairy, because it can be called in two situations:
 126
 127 1. There is no staff yet; we must set staff-position
 128
 129 2. There is a staff, and perhaps someone even applied a
 130 translate_axis (). Then we must compensate for the translation
 131
 132 In either case, we set a callback to be sure that our new position
 133 will be extracted from staff-position */
 134
 135 void
 136 Staff_symbol_referencer::set_position (Grob *me, Real p)
 137 {
 138   Grob *st = get_staff_symbol (me);
 139   Real oldpos = 0.0;
 140   if (st && me->common_refpoint (st, Y_AXIS))
 141     {
 142       oldpos = get_position (me);
 143     }
 144
 145
 146   Real ss = Staff_symbol_referencer::staff_space (me);
 147   me->translate_axis ((p  - oldpos) * ss * 0.5, Y_AXIS);
 148 }
 149
 150 /* Half of the height, in staff space, i.e. 2.0 for a normal staff. */
 151 Real
 152 Staff_symbol_referencer::staff_radius (Grob *me)
 153 {
 154   return (line_count (me) - 1) / 2.0;
 155 }
 156
 157 int
 158 compare_position (Grob *const &a, Grob *const &b)
 159 {
 160   return sign (Staff_symbol_referencer::get_position ((Grob *)a)
 161                - Staff_symbol_referencer::get_position ((Grob *) b));
 162 }
 163
 164 bool
 165 position_less (Grob *const &a, Grob *const &b)
 166 {
 167   return Staff_symbol_referencer::get_position (a)
 168     < Staff_symbol_referencer::get_position (b);
 169 }
 170
 171 ADD_INTERFACE (Staff_symbol_referencer,
 172                "An object whose Y@tie{}position is meant relative to a staff"
 173                " symbol.  These usually"
 174                " have @code{Staff_symbol_referencer::callback} in their"
 175                " @code{Y-offset-callbacks}.",
 176
 177                /* properties */
 178                "staff-position "
 179                );