This function provides a simple way to modify the panel border in ggplot2. It
doesn't do anything that can't be done just the same with ggplot2::theme(). However, it
saves some typing.
panel_border(color = "grey85", size = 1, linetype = 1, remove = FALSE, colour)The color of the border.
Size. Needs to be twice as large as desired outcome when panel clipping is on (the default).
Line type.
If TRUE, removes the current panel border.