heplots (version 1.8.1)

text_usr: Add Text to a Plot at Normalized Device Coordinates

Description

text_usr() draws the strings given in the vector labels at the coordinates given by x and y, but using normalized device coordinates (0, 1) to position text at absolute locations in a plot. This is useful when you know where in a plot you want to add some text annotation, but don't want to figure out what the data coordinates are.

Usage

text_usr(x, y, labels, ...)

Arguments

x, y

numeric vectors of coordinates in (0, 1) where the text labels should be written. If the length of x and y differs, the shorter one is recycled. Alternatively, a single argument x can be provided.

labels

a character vector or expression specifying the text to be written

...

other arguments passed to text, such as pos, cex, col, ...

Details

y may be missing since xy.coords is used for construction of the coordinates.

The function also works with par(xlog) == TRUE and par(ylog) == TRUE when either of these is set for log scales.

Examples

library(heplots)
x = c(0.5, rep(c(0.05, 0.95), 2))
y = c(0.5, rep(c(0.05, 0.95), each=2))
plot(x, y, pch = 16,
     xlim = c(0,1),
     ylim = c(0,1))
text_usr(0.05, 0.95, "topleft",    pos = 4)
text_usr(0.95, 0.95, "topright",   pos = 2)
text_usr(0.05, 0.05, "bottomleft", pos = 4)
text_usr(0.95, 0.05, "bottomright",pos = 2)