since: 4.14

Declaration [src]

gsk_path_point_get_curvature (
  const GskPathPoint* point,
  GskPath* path,
  GskPathDirection direction,
  graphene_point_t* center

Description [src]

Calculates the curvature of the path at the point.

Optionally, returns the center of the osculating circle as well. The curvature is the inverse of the radius of the osculating circle.

Lines have a curvature of zero (indicating an osculating circle of infinite radius. In this case, the center is not modified.

Circles with a radius of zero have INFINITY as curvature

Note that certain points on a path may not have a single curvature, such as sharp turns. At such points, there are two curvatures — the (limit of) the curvature of the path going into the point, and the (limit of) the curvature of the path coming out of it. The direction argument lets you choose which one to get.

Osculating circle .

Available since: 4.14



Type: GskPath

The path that point is on.

The data is owned by the caller of the method.

Type: GskPathDirection

The direction for which to return the curvature.


Type: graphene_point_t

Return location for the center of the osculating circle.

The argument will be set by the function.
The argument can be set to NULL by the method.
The returned data is owned by the instance.

Return value

Type: float

The curvature of the path at the given point.