DECLARE_SCHEME_CALLBACK (pure_y_aligned_on_self, (SCM element, SCM start, SCM end));
- DECLARE_SCHEME_CALLBACK (centered_on_note_columns, (SCM element));
DECLARE_SCHEME_CALLBACK (centered_on_x_parent, (SCM element));
DECLARE_SCHEME_CALLBACK (centered_on_y_parent, (SCM element));
DECLARE_SCHEME_CALLBACK (aligned_on_x_parent, (SCM element));