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--2009 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, false, 0, 0);
  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, false, 0, 0);
  27 }
  28
  29 MAKE_SCHEME_CALLBACK (Self_alignment_interface, pure_y_aligned_on_self, 3);
  30 SCM
  31 Self_alignment_interface::pure_y_aligned_on_self (SCM smob, SCM start, SCM end)
  32 {
  33   return aligned_on_self (unsmob_grob (smob), Y_AXIS, true, robust_scm2int (start, 0), robust_scm2int (end, INT_MAX));
  34 }
  35
  36 SCM
  37 Self_alignment_interface::aligned_on_self (Grob *me, Axis a, bool pure, int start, int end)
  38 {
  39   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
  40     : ly_symbol2scm ("self-alignment-Y");
  41
  42   SCM align (me->internal_get_property (sym));
  43   if (scm_is_number (align))
  44     {
  45       Interval ext (me->maybe_pure_extent (me, a, pure, start, end));
  46       if (ext.is_empty ())
  47         programming_error ("cannot align on self: empty element");
  48       else
  49         return scm_from_double (- ext.linear_combination (scm_to_double (align)));
  50     }
  51   return scm_from_double (0.0);
  52 }
  53
  54
  55
  56 SCM
  57 Self_alignment_interface::centered_on_object (Grob *him, Axis a)
  58 {
  59   return scm_from_double (robust_relative_extent (him, him, a).center ());
  60 }
  61
  62
  63 MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_x_parent, 1);
  64 SCM
  65 Self_alignment_interface::centered_on_x_parent (SCM smob)
  66 {
  67   return centered_on_object (unsmob_grob (smob)->get_parent (X_AXIS), X_AXIS);
  68 }
  69
  70
  71 MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_y_parent, 1);
  72 SCM
  73 Self_alignment_interface::centered_on_y_parent (SCM smob)
  74 {
  75   return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), Y_AXIS);
  76 }
  77
  78
  79 MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_centered_on_y_parent, 1);
  80 SCM
  81 Self_alignment_interface::x_centered_on_y_parent (SCM smob)
  82 {
  83   return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), X_AXIS);
  84 }
  85
  86 MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_x_parent,1);
  87 SCM
  88 Self_alignment_interface::aligned_on_x_parent (SCM smob)
  89 {
  90   return aligned_on_parent (unsmob_grob (smob), X_AXIS);
  91 }
  92
  93 MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_y_parent,1);
  94 SCM
  95 Self_alignment_interface::aligned_on_y_parent (SCM smob)
  96 {
  97   return aligned_on_parent (unsmob_grob (smob), Y_AXIS);
  98 }
  99
 100 SCM
 101 Self_alignment_interface::aligned_on_parent (Grob *me, Axis a)
 102 {
 103   Grob *him = me->get_parent (a);
 104   if (Paper_column::has_interface (him))
 105     return scm_from_double (0.0);
 106
 107   Interval he = him->extent (him, a);
 108
 109   SCM sym = (a == X_AXIS) ? ly_symbol2scm ("self-alignment-X")
 110     : ly_symbol2scm ("self-alignment-Y");
 111   SCM align_prop (me->internal_get_property (sym));
 112
 113   if (!scm_is_number (align_prop))
 114     return scm_from_int (0);
 115
 116   Real x = 0.0;
 117   Real align = scm_to_double (align_prop);
 118
 119   Interval ext (me->extent (me, a));
 120   if (ext.is_empty ())
 121     programming_error ("cannot align on self: empty element");
 122   else
 123     x -= ext.linear_combination (align);
 124
 125   if (!he.is_empty ())
 126     x += he.linear_combination (align);
 127
 128   return scm_from_double (x);
 129 }
 130
 131 void
 132 Self_alignment_interface::set_center_parent (Grob *me, Axis a)
 133 {
 134   add_offset_callback (me,
 135                        (a==X_AXIS) ? centered_on_x_parent_proc : centered_on_y_parent_proc,
 136                        a);
 137 }
 138
 139 void
 140 Self_alignment_interface::set_align_self (Grob *me, Axis a)
 141 {
 142   add_offset_callback (me,
 143                        (a==X_AXIS) ? x_aligned_on_self_proc : y_aligned_on_self_proc,
 144                        a);
 145 }
 146
 147 ADD_INTERFACE (Self_alignment_interface,
 148                "Position this object on itself and/or on its parent.  To this"
 149                " end, the following functions are provided:\n"
 150                "\n"
 151                "@table @code\n"
 152                "@item Self_alignment_interface::[xy]_aligned_on_self\n"
 153                "Align self on reference point, using"
 154                " @code{self-alignment-X} and @code{self-alignment-Y}."
 155                "@item Self_alignment_interface::aligned_on_[xy]_parent\n"
 156                "@item Self_alignment_interface::centered_on_[xy]_parent\n"
 157                "Shift the object so its own reference point is centered on"
 158                " the extent of the parent\n"
 159                "@end table\n",
 160
 161                /* properties */
 162                "self-alignment-X "
 163                "self-alignment-Y "
 164                );
 165