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 #include "libc-extension.hh"
  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 LY_DEFINE(ly_grob_staff_position,
  79           "ly:grob-staff-position",
  80           1, 0,0, (SCM sg),
  81           "Return the Y-position of this grob relative to the staff.")
  82 {
  83   Grob * g = unsmob_grob (sg);
  84
  85   SCM_ASSERT_TYPE (g, sg, SCM_ARG1, __FUNCTION__, "grob");
  86   Real pos = Staff_symbol_referencer::get_position (g);
  87
  88   if (fabs (rint (pos) -pos) < 1e-6) // ugh.
  89     return gh_int2scm ((int) my_round (pos));
  90   else
  91     return gh_double2scm (pos);
  92 }
  93
  94
  95 /*
  96   should use offset callback!
  97  */
  98 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer,callback,2);
  99 SCM
 100 Staff_symbol_referencer::callback (SCM element_smob, SCM)
 101 {
 102   Grob *me = unsmob_grob (element_smob);
 103
 104
 105   SCM pos = me->get_grob_property ("staff-position");
 106   Real off =0.0;
 107   if (gh_number_p (pos))
 108     {
 109       Real space = Staff_symbol_referencer::staff_space (me);
 110       off = gh_scm2double (pos) * space/2.0;
 111       me->set_grob_property ("staff-position", gh_int2scm (0));
 112     }
 113
 114   return gh_double2scm (off);
 115 }
 116
 117  /*
 118
 119   This sets the position relative to the center of the staff symbol.
 120
 121   The function is hairy, because it can be callled in two situations:
 122
 123   1.  There is no staff yet; we must set staff-position
 124
 125   2.  There is a staff, and perhaps someone even applied a
 126   translate_axis (). Then we must compensate for the translation
 127
 128   In either case, we set a callback to be sure that our new position
 129   will be extracted from staff-position
 130
 131  */
 132 void
 133 Staff_symbol_referencer::set_position (Grob*me,Real p)
 134 {
 135   Grob * st = get_staff_symbol (me);
 136   if (st && me->common_refpoint (st, Y_AXIS))
 137     {
 138       Real oldpos = get_position (me);
 139       me->set_grob_property ("staff-position", gh_double2scm (p - oldpos));
 140     }
 141   else
 142     {
 143       me->set_grob_property ("staff-position",
 144                             gh_double2scm (p));
 145
 146     }
 147
 148   if (me->has_offset_callback_b (Staff_symbol_referencer::callback_proc, Y_AXIS))
 149     return ;
 150
 151   me->add_offset_callback (Staff_symbol_referencer::callback_proc, Y_AXIS);
 152 }
 153
 154 /*
 155   Half of the height, in staff space, i.e. 2.0 for a normal staff.
 156 */
 157 Real
 158 Staff_symbol_referencer::staff_radius (Grob*me)
 159 {
 160   return (line_count (me) -1) / 2.0;
 161 }
 162
 163
 164 int
 165 compare_position (Grob *const  &a, Grob * const &b)
 166 {
 167   return sign (Staff_symbol_referencer::get_position ((Grob*)a) -
 168     Staff_symbol_referencer::get_position ((Grob*)b));
 169 }
 170
 171 ADD_INTERFACE (Staff_symbol_referencer,"staff-symbol-referencer-interface",
 172   "Object whose Y position is meaning with reference to a staff "
 173 "symbol. Objects that have this interface should include "
 174 "Staff_symbol_referencer::callback in their Y-offset-callback. "
 175 ,
 176   "staff-position");