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--2002 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7  */
   8
   9 #include <math.h>
  10
  11 #include "staff-symbol-referencer.hh"
  12 #include "staff-symbol.hh"
  13 #include "paper-def.hh"
  14
  15 bool
  16 Staff_symbol_referencer::has_interface (Grob*e)
  17 {
  18   return unsmob_grob (e->get_grob_property ("staff-symbol"))
  19     || gh_number_p (e->get_grob_property ("staff-position"));
  20 }
  21
  22 int
  23 Staff_symbol_referencer::line_count (Grob*me)
  24 {
  25   Grob *st = get_staff_symbol (me);
  26   return st  ?  Staff_symbol::line_count (st) : 0;
  27 }
  28
  29 bool
  30 Staff_symbol_referencer::on_staffline (Grob*me)
  31 {
  32   return on_staffline (me, (int) rint (get_position (me)));
  33 }
  34
  35 bool
  36 Staff_symbol_referencer::on_staffline (Grob*me, int pos)
  37 {
  38   int sz = line_count (me)-1;
  39   return ((pos + sz) % 2) == 0;
  40 }
  41
  42 Grob*
  43 Staff_symbol_referencer::get_staff_symbol (Grob*me)
  44 {
  45   SCM st = me->get_grob_property ("staff-symbol");
  46   return unsmob_grob (st);
  47 }
  48
  49 Real
  50 Staff_symbol_referencer::staff_space (Grob*me)
  51 {
  52   Grob * st = get_staff_symbol (me);
  53   if (st)
  54     return Staff_symbol::staff_space (st);
  55
  56   return 1.0;
  57 }
  58
  59 Real
  60 Staff_symbol_referencer::get_position (Grob*me)
  61 {
  62   Real p =0.0;
  63   Grob * st = get_staff_symbol (me);
  64   Grob * c = st ? me->common_refpoint (st, Y_AXIS) : 0;
  65   if (st && c)
  66     {
  67       Real y = me->relative_coordinate (c, Y_AXIS)
  68         - st->relative_coordinate (c, Y_AXIS);
  69
  70       p += 2.0 * y / Staff_symbol::staff_space (st);
  71     }
  72   else
  73     {
  74       SCM pos = me->get_grob_property ("staff-position");
  75       if (gh_number_p (pos))
  76         return gh_scm2double (pos);
  77     }
  78
  79   return  p;
  80 }
  81
  82
  83
  84 /*
  85   should use offset callback!
  86  */
  87 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer,callback,2);
  88 SCM
  89 Staff_symbol_referencer::callback (SCM element_smob, SCM)
  90 {
  91   Grob *me = unsmob_grob (element_smob);
  92
  93
  94   SCM pos = me->get_grob_property ("staff-position");
  95   Real off =0.0;
  96   if (gh_number_p (pos))
  97     {
  98       Real space = Staff_symbol_referencer::staff_space (me);
  99       off = gh_scm2double (pos) * space/2.0;
 100       me->set_grob_property ("staff-position", gh_double2scm (0.0));
 101     }
 102
 103   return gh_double2scm (off);
 104 }
 105
 106  /*
 107
 108   This sets the position relative to the center of the staff symbol.
 109
 110   The function is hairy, because it can be callled in two situations:
 111
 112   1.  There is no staff yet; we must set staff-position
 113
 114   2.  There is a staff, and perhaps someone even applied a
 115   translate_axis (). Then we must compensate for the translation
 116
 117   In either case, we set a callback to be sure that our new position
 118   will be extracted from staff-position
 119
 120  */
 121 void
 122 Staff_symbol_referencer::set_position (Grob*me,Real p)
 123 {
 124   Grob * st = get_staff_symbol (me);
 125   if (st && me->common_refpoint (st, Y_AXIS))
 126     {
 127       Real oldpos = get_position (me);
 128       me->set_grob_property ("staff-position", gh_double2scm (p - oldpos));
 129     }
 130   else
 131     {
 132       me->set_grob_property ("staff-position",
 133                             gh_double2scm (p));
 134
 135     }
 136
 137   if (me->has_offset_callback_b (Staff_symbol_referencer::callback_proc, Y_AXIS))
 138     return ;
 139
 140   me->add_offset_callback (Staff_symbol_referencer::callback_proc, Y_AXIS);
 141 }
 142
 143 /*
 144   half  of the height, in staff space.
 145  */
 146 Real
 147 Staff_symbol_referencer::staff_radius (Grob*me)
 148 {
 149   return (line_count (me) -1) / 2;
 150 }
 151
 152
 153 int
 154 compare_position (Grob *const  &a, Grob * const &b)
 155 {
 156   return sign (Staff_symbol_referencer::get_position ((Grob*)a) -
 157     Staff_symbol_referencer::get_position ((Grob*)b));
 158 }
 159
 160
 161
 162
 163 #define has_interface ugly_hack
 164 ADD_INTERFACE (Staff_symbol_referencer,"staff-symbol-referencer-interface",
 165   "Object whose Y position is meaning with reference to a staff
 166 symbol. Objects that have this interface should include
 167 Staff_symbol_referencer::callback in their Y-offset-callback.
 168 ",
 169   "staff-position");