Label Centroids in Scatter Plots — label_centroids • bixverse.plots

Adds boxed text labels at the centroid position of each group in a scatter plot. Computes group centroids with data.table for efficient summarisation. Useful for labelling cluster centres in embedding or dimensionality reduction plots (UMAP, t-SNE, PCA).

Usage

label_centroids(
  data = NULL,
  label_by,
  colour = "black",
  fill = "white",
  alpha = 0.5,
  label.size = 0,
  size = 4,
  fontface = "bold",
  ...
)

Arguments

data: A data.frame or data.table containing the scatter plot points. If NULL, the data from the parent ggplot is used. Must contain the columns referenced by the parent plot's x/y aesthetics and by label_by.
label_by: Character. Name of the (discrete) column to group and label by.
colour: Text colour. Default: "black".
fill: Box fill colour. Default: "white".
alpha: Box fill transparency in [0, 1]. Default: 0.5.
label.size: Box border line width in mm. Set to 0 to hide the border. Default: 0.
size: Text size in mm. Default: 4.
fontface: Font face. Default: "bold".
...: Additional arguments passed to geom_label.

Value

A ggplot layer.

Examples

if (FALSE) { # \dontrun{
embedding_plot_sc(
  object = sc_object,
  embedding = "umap",
  colour_by = "donor_id"
) +
  label_centroids(label_by = "donor_id")
} # }