Arrange brain atlas views — position

Controls how an atlas's hemispheres and views are arranged in the plot – side by side, stacked, or in a grid – and can zoom each view in on the regions you care about. Pass the result to the `position` argument of [geom_brain()] (or [annotate_brain()]).

Usage

position_brain(
  position = "horizontal",
  nrow = NULL,
  ncol = NULL,
  views = NULL,
  zoom = NULL,
  zoom_pad = 0.05
)

Arguments

position: Formula describing the rows ~ columns organisation for cortical atlases (e.g., `hemi ~ view`). For subcortical/tract atlases, can be "horizontal", "vertical", or a formula with `type ~ .` where type is extracted from view names like "axial_1" -> "axial".
nrow: Number of rows for grid layout. If NULL (default), calculated automatically. Only used for subcortical/tract atlases when position is not a formula.
ncol: Number of columns for grid layout. If NULL (default), calculated automatically. Only used for subcortical/tract atlases when position is not a formula.
views: Character vector specifying which views to include and their order. If NULL (default), all views are included in their original order. Only applies to subcortical/tract atlases.
zoom: Controls per-view zoom. `NULL`/`FALSE` (default) draws each view at full extent. `TRUE` zooms each view onto its focus regions; a character vector names the focus regions explicitly.
zoom_pad: Fractional padding added around the focus window when `zoom` is active. Defaults to `0.05` (5%).

Value

A layout specification to hand to [geom_brain()]'s `position` argument.

Examples

library(ggplot2)

# Cortical atlas with formula
ggplot() +
  geom_brain(
    atlas = dk(), aes(fill = region),
    position = position_brain(. ~ view + hemi),
    show.legend = FALSE
  )


ggplot() +
  geom_brain(
    atlas = dk(), aes(fill = region),
    position = position_brain(view ~ hemi),
    show.legend = FALSE
  )


ggplot() +
  geom_brain(
    atlas = aseg(), aes(fill = region),
    position = position_brain(nrow = 2)
  )


ggplot() +
  geom_brain(
    atlas = aseg(), aes(fill = region),
    position = position_brain(
      views = c("sagittal", "axial_3", "coronal_2"),
      nrow = 1
    )
  )


ggplot() +
  geom_brain(
    atlas = aseg(), aes(fill = region),
    position = position_brain(type ~ .)
  )