lily/self-alignment-interface.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2004--2010 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 "self-alignment-interface.hh"
  21
  22 #include "grob.hh"
  23 #include "paper-column.hh"
  24 #include "warn.hh"
  25
  26 MAKE_SCHEME_CALLBACK (Self_alignment_interface, y_aligned_on_self, 1);
  27 SCM
  28 Self_alignment_interface::y_aligned_on_self (SCM element)
  29 {
  30   return aligned_on_self (unsmob_grob (element), Y_AXIS, false, 0, 0);
  31 }
  32
  33 MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_aligned_on_self, 1);
  34 SCM
  35 Self_alignment_interface::x_aligned_on_self (SCM element)
  36 {
  37   return aligned_on_self (unsmob_grob (element), X_AXIS, false, 0, 0);
  38 }
  39
  40 MAKE_SCHEME_CALLBACK (Self_alignment_interface, pure_y_aligned_on_self, 3);
  41 SCM
  42 Self_alignment_interface::pure_y_aligned_on_self (SCM smob, SCM start, SCM end)
  43 {
  44   return aligned_on_self (unsmob_grob (smob), Y_AXIS, true, robust_scm2int (start, 0), robust_scm2int (end, INT_MAX));
  45 }
  46
  47 SCM
  48 Self_alignment_interface::aligned_on_self (Grob *me, Axis a, bool pure, int start, int end)
  49 {
  50   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
  51     : ly_symbol2scm ("self-alignment-Y");
  52
  53   SCM align (me->internal_get_property (sym));
  54   if (scm_is_number (align))
  55     {
  56       Interval ext (me->maybe_pure_extent (me, a, pure, start, end));
  57       if (ext.is_empty ())
  58         programming_error ("cannot align on self: empty element");
  59       else
  60         return scm_from_double (- ext.linear_combination (scm_to_double (align)));
  61     }
  62   return scm_from_double (0.0);
  63 }
  64
  65
  66 SCM
  67 Self_alignment_interface::centered_on_object (Grob *him, Axis a)
  68 {
  69   return scm_from_double (robust_relative_extent (him, him, a).center ());
  70 }
  71
  72 MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_x_parent, 1);
  73 SCM
  74 Self_alignment_interface::centered_on_x_parent (SCM smob)
  75 {
  76   return centered_on_object (unsmob_grob (smob)->get_parent (X_AXIS), X_AXIS);
  77 }
  78
  79 MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_y_parent, 1);
  80 SCM
  81 Self_alignment_interface::centered_on_y_parent (SCM smob)
  82 {
  83   return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), Y_AXIS);
  84 }
  85
  86 MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_centered_on_y_parent, 1);
  87 SCM
  88 Self_alignment_interface::x_centered_on_y_parent (SCM smob)
  89 {
  90   return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), X_AXIS);
  91 }
  92
  93 MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_x_parent,1);
  94 SCM
  95 Self_alignment_interface::aligned_on_x_parent (SCM smob)
  96 {
  97   return aligned_on_parent (unsmob_grob (smob), X_AXIS);
  98 }
  99
 100 MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_y_parent,1);
 101 SCM
 102 Self_alignment_interface::aligned_on_y_parent (SCM smob)
 103 {
 104   return aligned_on_parent (unsmob_grob (smob), Y_AXIS);
 105 }
 106
 107 SCM
 108 Self_alignment_interface::aligned_on_parent (Grob *me, Axis a)
 109 {
 110   Grob *him = me->get_parent (a);
 111   if (Paper_column::has_interface (him))
 112     return scm_from_double (0.0);
 113
 114   Interval he = him->extent (him, a);
 115
 116   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
 117     : ly_symbol2scm ("self-alignment-Y");
 118   SCM align_prop (me->internal_get_property (sym));
 119
 120   if (!scm_is_number (align_prop))
 121     return scm_from_int (0);
 122
 123   Real x = 0.0;
 124   Real align = scm_to_double (align_prop);
 125
 126   Interval ext (me->extent (me, a));
 127   if (ext.is_empty ())
 128     programming_error ("cannot align on self: empty element");
 129   else
 130     x -= ext.linear_combination (align);
 131
 132   if (!he.is_empty ())
 133     x += he.linear_combination (align);
 134
 135   return scm_from_double (x);
 136 }
 137
 138 void
 139 Self_alignment_interface::set_center_parent (Grob *me, Axis a)
 140 {
 141   add_offset_callback (me,
 142                        (a == X_AXIS) ? centered_on_x_parent_proc : centered_on_y_parent_proc,
 143                        a);
 144 }
 145
 146 void
 147 Self_alignment_interface::set_align_self (Grob *me, Axis a)
 148 {
 149   add_offset_callback (me,
 150                        (a == X_AXIS) ? x_aligned_on_self_proc : y_aligned_on_self_proc,
 151                        a);
 152 }
 153
 154 ADD_INTERFACE (Self_alignment_interface,
 155                "Position this object on itself and/or on its parent.  To this"
 156                " end, the following functions are provided:\n"
 157                "\n"
 158                "@table @code\n"
 159                "@item Self_alignment_interface::[xy]_aligned_on_self\n"
 160                "Align self on reference point, using"
 161                " @code{self-alignment-X} and @code{self-alignment-Y}."
 162                "@item Self_alignment_interface::aligned_on_[xy]_parent\n"
 163                "@item Self_alignment_interface::centered_on_[xy]_parent\n"
 164                "Shift the object so its own reference point is centered on"
 165                " the extent of the parent\n"
 166                "@end table\n",
 167
 168                /* properties */
 169                "self-alignment-X "
 170                "self-alignment-Y "
 171                );