highlight: Highlight areas on a plot

In nicholasdavies/shmanipulate: Easily manipulate a plot using controls like sliders, drop-down lists and date pickers

Highlight areas on a plot

Description

Draws a series of highlights (translucent rectangles) onto a base R plot.

Usage

highlight(
  x = NULL,
  y = NULL,
  col = "#ffff00",
  label = NA,
  alpha = 0.2,
  shrink = TRUE,
  border = NA,
  ...
)

Arguments

x	x coordinates for highlight areas.
y	y coordinates for highlight areas (usually leave NULL).
col	fill colours for rectangles.
label	text labels for each rectangle.
alpha	opacity level (0 to 1) for rectangles.
shrink	if TRUE or numeric and y is NULL, lowers the top of each subsequent rectangle by the specified number of user plotting units so that the labels don't overlap; TRUE uses the line height times 2, which is a decent default. Set to zero for no shrinking.
border	colour for rectangle borders; NA (default) to omit.
...	other arguments to pass on to rect().

Details

x and y can either be: NULL, in which case the extent of the plotted area is used; a numeric vector, interleaved such that the elements are interpreted as e.g. c(x1_start, x1_end, x2_start, x2_end, ...); a list with two elements, e.g. list(c(x1_start, x2_start, ...), c(x1_end, x2_end, ...)); or a matrix with two columns (first column "starts", second column "ends").

Arguments are recycled as needed.

Examples

## Not run: 
curve(dnorm(x), 0, 4)
highlight(x = c(0, 0, 1, 3, 2, 4), label = letters[1:3], col = c("red", "blue", "purple"))

## End(Not run)

nicholasdavies/shmanipulate documentation built on July 16, 2025, 5:39 p.m.