ForceDiagram.face_vertex_ancestor

ForceDiagram.face_vertex_ancestor(fkey, key, n=1)[source]

Return the n-th vertex before the specified vertex in a specific face.

Parameters:

  • fkey (int) – Identifier of the face.

  • key (int) – The identifier of the vertex.

  • n (int, optional) – The index of the vertex ancestor. Default is 1, meaning the previous vertex.

Returns:

int – The identifier of the vertex before the given vertex in the face cycle.

Raises:

ValueError – If the vertex is not part of the face.