+Self_alignment_interface::centered_on_object (Grob *him, Axis a)
+{
+ return scm_from_double (robust_relative_extent (him, him, a).center ());
+}
+
+
+MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_x_parent, 1);
+SCM
+Self_alignment_interface::centered_on_x_parent (SCM smob)
+{
+ return centered_on_object (unsmob_grob (smob)->get_parent (X_AXIS), X_AXIS);
+}
+
+
+MAKE_SCHEME_CALLBACK (Self_alignment_interface, centered_on_y_parent, 1);
+SCM
+Self_alignment_interface::centered_on_y_parent (SCM smob)
+{
+ return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), Y_AXIS);
+}
+
+
+MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_centered_on_y_parent, 1);
+SCM
+Self_alignment_interface::x_centered_on_y_parent (SCM smob)
+{
+ return centered_on_object (unsmob_grob (smob)->get_parent (Y_AXIS), X_AXIS);
+}
+
+MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_x_parent,1);
+SCM
+Self_alignment_interface::aligned_on_x_parent (SCM smob)
+{
+ return aligned_on_parent (unsmob_grob (smob), X_AXIS);
+}
+
+MAKE_SCHEME_CALLBACK (Self_alignment_interface, aligned_on_y_parent,1);
+SCM
+Self_alignment_interface::aligned_on_y_parent (SCM smob)
+{
+ return aligned_on_parent (unsmob_grob (smob), Y_AXIS);
+}
+
+SCM
+Self_alignment_interface::aligned_on_parent (Grob *me, Axis a)