Add a vector field overlay

Usage

add_vector_layer(
  x,
  vectors,
  vertices = NULL,
  scale = NULL,
  color = "red",
  alpha = 0.8,
  lwd = 1.5,
  hemi = c("both", "left", "right")
)

Arguments

x: A "neurosurf_plot" object.
vectors: Matrix (n x 3) of XYZ vectors or a list with left/right matrices. When supplying a single matrix for both hemispheres, rows are split left-to-right to match the vertex ordering.
vertices: Optional vector or list of vertex ids matching the rows of vectors when defined on a subset of vertices. For both hemispheres, supply a list to avoid ambiguity.
scale: Optional numeric scalar. If NULL, a heuristic scale is derived from the mesh extent and vector magnitudes.
color: Colour for the vectors (single value or vector).
alpha: Numeric in \([0,1]\) for vector opacity.
lwd: Numeric line width for the glyphs.
hemi: One of "both", "left", or "right" when a single vectors matrix is provided.

Value

A modified "neurosurf_plot" object.

Examples

# \donttest{
# Requires FreeSurfer-like surface files
# sp <- surface_plot(left = "lh.pial", right = "rh.pial")
# vectors <- matrix(rnorm(163842 * 3), ncol = 3)
# sp <- add_vector_layer(sp, vectors = vectors)
# }