DECLARE_SCHEME_CALLBACK (stencil_height, (SCM smob));
DECLARE_SCHEME_CALLBACK (stencil_width, (SCM smob));
DECLARE_SCHEME_CALLBACK (pure_simple_vertical_skylines_from_extents, (SCM smob, SCM, SCM));
DECLARE_SCHEME_CALLBACK (simple_vertical_skylines_from_extents, (SCM smob));
DECLARE_SCHEME_CALLBACK (vertical_skylines_from_stencil, (SCM smob));
DECLARE_SCHEME_CALLBACK (stencil_height, (SCM smob));
DECLARE_SCHEME_CALLBACK (stencil_width, (SCM smob));
DECLARE_SCHEME_CALLBACK (pure_simple_vertical_skylines_from_extents, (SCM smob, SCM, SCM));
DECLARE_SCHEME_CALLBACK (simple_vertical_skylines_from_extents, (SCM smob));
DECLARE_SCHEME_CALLBACK (vertical_skylines_from_stencil, (SCM smob));