lily/self-aligment-interface.cc

   1 /*
   2   self-alignment-interface.cc -- implement Self_alignment_interface
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2004--2007 Han-Wen Nienhuys <hanwen@xs4all.nl>
   7 */
   8
   9 #include "self-alignment-interface.hh"
  10
  11 #include "warn.hh"
  12 #include "paper-column.hh"
  13 #include "grob.hh"
  14
  15 MAKE_SCHEME_CALLBACK (Self_alignment_interface, y_aligned_on_self, 1);
  16 SCM
  17 Self_alignment_interface::y_aligned_on_self (SCM element)
  18 {
  19   return aligned_on_self (unsmob_grob (element), Y_AXIS);
  20 }
  21
  22 MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_aligned_on_self, 1);
  23 SCM
  24 Self_alignment_interface::x_aligned_on_self (SCM element)
  25 {
  26   return aligned_on_self (unsmob_grob (element), X_AXIS);
  27 }
  28
  29 SCM
  30 Self_alignment_interface::aligned_on_self (Grob *me, Axis a)
  31 {
  32   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
  33     : ly_symbol2scm ("self-alignment-Y");
  34
  35   SCM align (me->internal_get_property (sym));
  36   if (scm_is_number (align))
  37     {
  38       Interval ext (me->extent (me, a));
  39       if (ext.is_empty ())
  40         programming_error ("cannot align on self: empty element");
  41       else
  42         return scm_from_double (- ext.linear_combination (scm_to_double (align)));
  43     }
  44   return scm_from_double (0.0);
  45 }
  46
  47
  48
  49 SCM
  50 Self_alignment_interface::centered_on_object (Grob *him, Axis a)
  51 {
  52   return scm_from_double (robust_relative_extent (him, him, a).center ());
  53 }
  54
  55
  56 MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_x_parent, 1);
  57 SCM
  58 Self_alignment_interface::centered_on_x_parent (SCM smob)
  59 {
  60   return centered_on_object (unsmob_grob (smob)->get_parent (X_AXIS), X_AXIS);
  61 }
  62
  63
  64 MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_y_parent, 1);
  65 SCM
  66 Self_alignment_interface::centered_on_y_parent (SCM smob)
  67 {
  68   return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), Y_AXIS);
  69 }
  70
  71
  72 MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_centered_on_y_parent, 1);
  73 SCM
  74 Self_alignment_interface::x_centered_on_y_parent (SCM smob)
  75 {
  76   return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), X_AXIS);
  77 }
  78
  79 MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_x_parent,1);
  80 SCM
  81 Self_alignment_interface::aligned_on_x_parent (SCM smob)
  82 {
  83   return aligned_on_parent (unsmob_grob (smob), X_AXIS);
  84 }
  85
  86 MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_y_parent,1);
  87 SCM
  88 Self_alignment_interface::aligned_on_y_parent (SCM smob)
  89 {
  90   return aligned_on_parent (unsmob_grob (smob), Y_AXIS);
  91 }
  92
  93 SCM
  94 Self_alignment_interface::aligned_on_parent (Grob *me, Axis a)
  95 {
  96   Grob *him = me->get_parent (a);
  97   if (Paper_column::has_interface (him))
  98     return scm_from_double (0.0);
  99
 100   Interval he = him->extent (him, a);
 101
 102   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
 103     : ly_symbol2scm ("self-alignment-Y");
 104   SCM align_prop (me->internal_get_property (sym));
 105
 106   if (!scm_is_number (align_prop))
 107     return scm_from_int (0);
 108
 109   Real x = 0.0;
 110   Real align = scm_to_double (align_prop);
 111
 112   Interval ext (me->extent (me, a));
 113   if (ext.is_empty ())
 114     programming_error ("cannot align on self: empty element");
 115   else
 116     x -= ext.linear_combination (align);
 117
 118   if (!he.is_empty ())
 119     x += he.linear_combination (align);
 120
 121   return scm_from_double (x);
 122 }
 123
 124 void
 125 Self_alignment_interface::set_center_parent (Grob *me, Axis a)
 126 {
 127   add_offset_callback (me,
 128                        (a==X_AXIS) ? centered_on_x_parent_proc : centered_on_y_parent_proc,
 129                        a);
 130 }
 131
 132 void
 133 Self_alignment_interface::set_align_self (Grob *me, Axis a)
 134 {
 135   add_offset_callback (me,
 136                        (a==X_AXIS) ? x_aligned_on_self_proc : y_aligned_on_self_proc,
 137                        a);
 138 }
 139
 140 ADD_INTERFACE (Self_alignment_interface,
 141                "Position this object on itself and/or on its parent.  To this"
 142                " end, the following functions are provided:\n"
 143                "\n"
 144                "@table @code\n"
 145                "@item Self_alignment_interface::[xy]_aligned_on_self\n"
 146                "Align self on reference point, using"
 147                " @code{self-alignment-X} and @code{self-alignment-Y}."
 148                "@item Self_alignment_interface::aligned_on_[xy]_parent\n"
 149                "@item Self_alignment_interface::centered_on_[xy]_parent\n"
 150                "Shift the object so its own reference point is centered on"
 151                " the extent of the parent\n"
 152                "@end table\n",
 153
 154                /* properties */
 155                "self-alignment-X "
 156                "self-alignment-Y "
 157                );
 158