Note that the current vertex shape implementation is experimental and
it might change in the future. Currently vertex shapes are implemented
only for plot.igraph.
In igraph a vertex shape is defined by a function that 1) provides
information about the size of the shape for clipping the edges and 2)
plots the shape if requested. These functions are called shape
functions in the rest of this manual page. Shape functions have a mode argument that decides in
which mode they should operate. clip selects clipping
mode and plot selects plotting mode.
In clipping mode a shape function has the following arguments:
[object Object],[object Object],[object Object],[object Object],[object Object]
In clipping mode, a shape function should return a matrix
with the same number of rows as the el arguments.
If end is both then the matrix must have four
columns, otherwise two. The matrix contains the modified coordinates,
with the clipping applied.
In plotting mode the following arguments are supplied to the shape
function:
[object Object],[object Object],[object Object],[object Object]
In plotting mode the return value of the shape function is
not used.