An open or closed path, composed of Bézier curves and segments. Uses
struct geom_path as data representation, which may be external
or internal.
It supports the object interface, the node interface and the shape interface.
struct vcl_path * vcl_path_new (struct geom_path * p)
Creates a path. The p argument is a pointer to external
path-representing data (which are not freed during the destroying of the obj). If
it is NULL, then the internal path-representing data are used (accessible as
the path -> embedded data item).
void vcl_path_source_changed (struct vcl_path * obj)
The user can freely modify the struct geom_path path representation,
but after that he must call vcl_path_source_changed() to
update the path node.