lily/staff-symbol-referencer.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1999--2011 Han-Wen Nienhuys <hanwen@xs4all.nl>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "staff-symbol-referencer.hh"
  21
  22 #include "staff-symbol.hh"
  23 #include "grob.hh"
  24 #include "output-def.hh"
  25 #include "libc-extension.hh"
  26
  27 int
  28 Staff_symbol_referencer::line_count (Grob *me)
  29 {
  30   Grob *st = get_staff_symbol (me);
  31   return st ? Staff_symbol::line_count (st) : 0;
  32 }
  33
  34 bool
  35 Staff_symbol_referencer::on_line (Grob *me, int pos)
  36 {
  37   Grob *st = get_staff_symbol (me);
  38   return st ? Staff_symbol::on_line (st, pos) : false;
  39 }
  40
  41 bool
  42 Staff_symbol_referencer::on_staff_line (Grob *me, int pos)
  43 {
  44   return on_line (me, pos) && abs (pos) <= 2 * staff_radius (me);
  45 }
  46
  47 Grob *
  48 Staff_symbol_referencer::get_staff_symbol (Grob *me)
  49 {
  50   if (Staff_symbol::has_interface (me))
  51     return me;
  52
  53   SCM st = me->get_object ("staff-symbol");
  54   return unsmob_grob (st);
  55 }
  56
  57 Real
  58 Staff_symbol_referencer::staff_space (Grob *me)
  59 {
  60   Grob *st = get_staff_symbol (me);
  61   if (st)
  62     return Staff_symbol::staff_space (st);
  63   return 1.0;
  64 }
  65
  66 Real
  67 Staff_symbol_referencer::line_thickness (Grob *me)
  68 {
  69   Grob *st = get_staff_symbol (me);
  70   if (st)
  71     return Staff_symbol::get_line_thickness (st);
  72   return me->layout ()->get_dimension (ly_symbol2scm ("line-thickness"));
  73 }
  74
  75 Real
  76 Staff_symbol_referencer::get_position (Grob *me)
  77 {
  78   Real p = 0.0;
  79   Grob *st = get_staff_symbol (me);
  80   Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
  81   if (st && c)
  82     {
  83       Real y = me->relative_coordinate (c, Y_AXIS)
  84                - st->relative_coordinate (c, Y_AXIS);
  85       Real space = Staff_symbol::staff_space (st);
  86       p = (space == 0) ? 0 : 2.0 * y / space;
  87       return p;
  88     }
  89   else if (!st)
  90     return me->relative_coordinate (me->get_parent (Y_AXIS), Y_AXIS) * 2;
  91   return robust_scm2double (me->get_property ("staff-position"), p);
  92 }
  93
  94
  95 Interval
  96 Staff_symbol_referencer::extent_in_staff (Grob *me)
  97 {
  98   Grob *st = get_staff_symbol (me);
  99   Grob *c = st ? me->common_refpoint (st, Y_AXIS) : 0;
 100
 101   Interval retval;
 102   if (st && c)
 103     {
 104       retval  = me->extent (c, Y_AXIS)
 105         - st->relative_coordinate (c, Y_AXIS);
 106     }
 107
 108   return retval;
 109 }
 110
 111 int
 112 Staff_symbol_referencer::get_rounded_position (Grob *me)
 113 {
 114   return int (rint (get_position (me)));
 115 }
 116
 117 MAKE_SCHEME_CALLBACK (Staff_symbol_referencer, callback, 1);
 118 SCM
 119 Staff_symbol_referencer::callback (SCM smob)
 120 {
 121   Grob *me = unsmob_grob (smob);
 122
 123   SCM pos = me->get_property ("staff-position");
 124   Real off = 0.0;
 125   if (scm_is_number (pos))
 126     {
 127       Real space = Staff_symbol_referencer::staff_space (me);
 128       off = scm_to_double (pos) * space / 2.0;
 129     }
 130
 131   return scm_from_double (off);
 132 }
 133
 134 /*  This sets the position relative to the center of the staff symbol.
 135
 136 The function is hairy, because it can be called in two situations:
 137
 138 1. There is no staff yet; we must set staff-position
 139
 140 2. There is a staff, and perhaps someone even applied a
 141 translate_axis (). Then we must compensate for the translation
 142
 143 In either case, we set a callback to be sure that our new position
 144 will be extracted from staff-position */
 145
 146 void
 147 Staff_symbol_referencer::set_position (Grob *me, Real p)
 148 {
 149   Grob *st = get_staff_symbol (me);
 150   Real oldpos = 0.0;
 151   if (st && me->common_refpoint (st, Y_AXIS))
 152     {
 153       oldpos = get_position (me);
 154     }
 155
 156   Real ss = Staff_symbol_referencer::staff_space (me);
 157   me->translate_axis ((p  - oldpos) * ss * 0.5, Y_AXIS);
 158 }
 159
 160 /* Half of the height, in staff space, i.e. 2.0 for a normal staff. */
 161 Real
 162 Staff_symbol_referencer::staff_radius (Grob *me)
 163 {
 164   return (line_count (me) - 1) / 2.0;
 165 }
 166
 167 int
 168 compare_position (Grob *const &a, Grob *const &b)
 169 {
 170   return sign (Staff_symbol_referencer::get_position ((Grob *)a)
 171                - Staff_symbol_referencer::get_position ((Grob *) b));
 172 }
 173
 174 bool
 175 position_less (Grob *const &a, Grob *const &b)
 176 {
 177   return Staff_symbol_referencer::get_position (a)
 178     < Staff_symbol_referencer::get_position (b);
 179 }
 180
 181 ADD_INTERFACE (Staff_symbol_referencer,
 182                "An object whose Y@tie{}position is meant relative to a staff"
 183                " symbol.  These usually"
 184                " have @code{Staff_symbol_referencer::callback} in their"
 185                " @code{Y-offset-callbacks}.",
 186
 187                /* properties */
 188                "staff-position "
 189                );