boxtext: Add text with background box to a plot From:...
In dco61/isteahMAT104: MAT104 Probabilité et Statistiques

Description Usage Arguments Value Author(s) Examples

boxtext places a text given in the vector labels onto a plot in the base graphics system and places a coloured box behind it to make it stand out from the background.

boxtext(
  x,
  y,
  labels = NA,
  col.text = NULL,
  col.bg = NA,
  border.bg = NA,
  adj = NULL,
  pos = NULL,
  offset = 0.5,
  padding = c(0.5, 0.5),
  cex = 1,
  font = graphics::par("font")
)

`x`	numeric vector of x-coordinates where the text labels should be written. If the length of `x` and `y` differs, the shorter one is recycled.
`y`	numeric vector of y-coordinates where the text labels should be written.
`labels`	a character vector specifying the text to be written.
`col.text`	the colour of the text
`col.bg`	color(s) to fill or shade the rectangle(s) with. The default `NA` means do not fill, i.e., draw transparent rectangles.
`border.bg`	color(s) for rectangle border(s). The default `NA` omits borders.
`adj`	one or two values in [0, 1] which specify the x (and optionally y) adjustment of the labels.
`pos`	a position specifier for the text. If specified this overrides any adj value given. Values of 1, 2, 3 and 4, respectively indicate positions below, to the left of, above and to the right of the specified coordinates.
`offset`	when `pos` is specified, this value gives the offset of the label from the specified coordinate in fractions of a character width.
`padding`	factor used for the padding of the box around the text. Padding is specified in fractions of a character width. If a vector of length two is specified then different factors are used for the padding in x- and y-direction.
`cex`	numeric character expansion factor; multiplied by codepar("cex") yields the final character size.
`font`	the font to be used

Returns the coordinates of the background rectangle(s). If multiple labels are placed in a vactor then the coordinates are returned as a matrix with columns corresponding to xleft, xright, ybottom, ytop. If just one label is placed, the coordinates are returned as a vector.

Ian Kopacka

## Create noisy background
plot(x = runif(1000), y = runif(1000), type = "p", pch = 16,
col = "#40404060")
boxtext(x = 0.5, y = 0.5, labels = "some Text", col.bg = "#b2f4f480",
    pos = 4, font = 2, cex = 1.3, padding = 1)
## Vector of labels, using argument 'pos' to position right of coordinates:
boxtext(x = c(0.3, 0.1), y = c(0.6, 0.1), labels = c("some Text", "something else"), col.bg = "#b2f4f4c0", pos = 4, padding = 0.3)
## Tweak cex, font and adj:
boxtext(x = 0.2, y = 0.4, labels = "some big and bold text", col.bg = "#b2f4f4c0", adj = c(0, 0.6), font = 2, cex = 1.8)