PK_SPCURVE_t

This type represents a Surface Parameter CURVE; that is, the curve resulting
from embedding a 2D curve in the parameter space of a surface.

Used in:

PK_CURVE_embed_in_surf
PK_CURVE_embed_in_surf_2
PK_CURVE_make_spcurves
PK_CURVE_make_spcurves_2
PK_SPCURVE_ask
PK_SPCURVE_create

An spcurve is a type of curve (PK_CLASS_spcurve is a subclass of
PK_CLASS_curve).

The spcurve is defined by data contained in a PK_SPCURVE_sf_t