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--2003 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
  16
  17 int
  18 Staff_symbol_referencer::line_count (Grob*me)
  19 {
  20   Grob *st = get_staff_symbol (me);
  21   return st  ?  Staff_symbol::line_count (st) : 0;
  22 }
  23
  24 bool
  25 Staff_symbol_referencer::on_staffline (Grob*me)
  26 {
  27   return on_staffline (me, (int) rint (get_position (me)));
  28 }
  29
  30 bool
  31 Staff_symbol_referencer::on_staffline (Grob*me, int pos)
  32 {
  33   int sz = line_count (me)-1;
  34   return ((pos + sz) % 2) == 0;
  35 }
  36
  37 Grob*
  38 Staff_symbol_referencer::get_staff_symbol (Grob*me)
  39 {
  40   SCM st = me->get_grob_property ("staff-symbol");
  41   return unsmob_grob (st);
  42 }
  43
  44 Real
  45 Staff_symbol_referencer::staff_space (Grob*me)
  46 {
  47   Grob * st = get_staff_symbol (me);
  48   if (st)
  49     return Staff_symbol::staff_space (st);
  50
  51   return 1.0;
  52 }
  53
  54 Real
  55 Staff_symbol_referencer::get_position (Grob*me)
  56 {
  57   Real p =0.0;
  58   Grob * st = get_staff_symbol (me);
  59   Grob * c = st ? me->common_refpoint (st, Y_AXIS) : 0;
  60   if (st && c)
  61     {
  62       Real y = me->relative_coordinate (c, Y_AXIS)
  63         - st->relative_coordinate (c, Y_AXIS);
  64
  65       p += 2.0 * y / Staff_symbol::staff_space (st);
  66     }
  67   else
  68     {
  69       SCM pos = me->get_grob_property ("staff-position");
  70       if (gh_number_p (pos))
  71         return gh_scm2double (pos);
  72     }
  73
  74   return  p;
  75 }
  76
  77
  78
  79 /*
  80   should use offset callback!
  81  */
  82 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer,callback,2);
  83 SCM
  84 Staff_symbol_referencer::callback (SCM element_smob, SCM)
  85 {
  86   Grob *me = unsmob_grob (element_smob);
  87
  88
  89   SCM pos = me->get_grob_property ("staff-position");
  90   Real off =0.0;
  91   if (gh_number_p (pos))
  92     {
  93       Real space = Staff_symbol_referencer::staff_space (me);
  94       off = gh_scm2double (pos) * space/2.0;
  95       me->set_grob_property ("staff-position", gh_double2scm (0.0));
  96     }
  97
  98   return gh_double2scm (off);
  99 }
 100
 101  /*
 102
 103   This sets the position relative to the center of the staff symbol.
 104
 105   The function is hairy, because it can be callled in two situations:
 106
 107   1.  There is no staff yet; we must set staff-position
 108
 109   2.  There is a staff, and perhaps someone even applied a
 110   translate_axis (). Then we must compensate for the translation
 111
 112   In either case, we set a callback to be sure that our new position
 113   will be extracted from staff-position
 114
 115  */
 116 void
 117 Staff_symbol_referencer::set_position (Grob*me,Real p)
 118 {
 119   Grob * st = get_staff_symbol (me);
 120   if (st && me->common_refpoint (st, Y_AXIS))
 121     {
 122       Real oldpos = get_position (me);
 123       me->set_grob_property ("staff-position", gh_double2scm (p - oldpos));
 124     }
 125   else
 126     {
 127       me->set_grob_property ("staff-position",
 128                             gh_double2scm (p));
 129
 130     }
 131
 132   if (me->has_offset_callback_b (Staff_symbol_referencer::callback_proc, Y_AXIS))
 133     return ;
 134
 135   me->add_offset_callback (Staff_symbol_referencer::callback_proc, Y_AXIS);
 136 }
 137
 138 /*
 139   Half of the height, in staff space, i.e. 2.0 for a normal staff.
 140 */
 141 Real
 142 Staff_symbol_referencer::staff_radius (Grob*me)
 143 {
 144   return (line_count (me) -1) / 2.0;
 145 }
 146
 147
 148 int
 149 compare_position (Grob *const  &a, Grob * const &b)
 150 {
 151   return sign (Staff_symbol_referencer::get_position ((Grob*)a) -
 152     Staff_symbol_referencer::get_position ((Grob*)b));
 153 }
 154
 155 ADD_INTERFACE (Staff_symbol_referencer,"staff-symbol-referencer-interface",
 156   "Object whose Y position is meaning with reference to a staff "
 157 "symbol. Objects that have this interface should include "
 158 "Staff_symbol_referencer::callback in their Y-offset-callback. "
 159 ,
 160   "staff-position");