Various vertex shapes when plotting igraph graphs

add.vertex.shape() was renamed to add_shape() to create a more consistent API.

Usage

add.vertex.shape(
  shape,
  clip = shape_noclip,
  plot = shape_noplot,
  parameters = list()
)

shape: Character scalar, name of a vertex shape. If it is NULL for shapes(), then the names of all defined vertex shapes are returned.
clip: An R function object, the clipping function.
plot: An R function object, the plotting function.
parameters: Named list, additional plot/vertex/edge parameters. The element named define the new parameters, and the elements themselves define their default values. Vertex parameters should have a prefix ‘vertex.’, edge parameters a prefix ‘edge.’. Other general plotting parameters should have a prefix ‘plot.’. See Details below.