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palette: Set or View the Graphics Palette

palette

R Documentation

Set or View the Graphics Palette

Description

View or manipulate the color palette which is used when col= has a numeric index and supporting functions.

Usage

palette(value)
palette.pals()
palette.colors(n = NULL, palette = "Okabe-Ito", alpha, recycle = FALSE)

Arguments

`value`	an optional character vector specifying a new palette (see Details).
`n`	the number of colors to select from a palette. The default `NULL` selects all colors of the given palette.
`palette`	a valid palette name (one of `palette.pals()`). The name is matched to the list of available palettes, ignoring upper vs. lower case, spaces, dashes, etc. in the matching.
`alpha`	an alpha-transparency level in the range [0,1] (0 means transparent and 1 means opaque).
`recycle`	logical indicating what happens in case `n > length(palette(.))`. By default (`recycle = FALSE`), the result is as for `n = NULL`, but with a warning.

Details

The palette() function gets or sets the current palette, the palette.pals() function lists the available predefined palettes, and the palette.colors() function selects colors from the predefined palettes.

The color palette and referring to colors by number (see e.g. par) was provided for compatibility with S. R extends and improves on the available set of palettes.

If value has length 1, it is taken to be the name of a built-in color palette. The available palette names are returned by palette.pals(). It is also possible to specify "default".

If value has length greater than 1 it is assumed to contain a description of the colors which are to make up the new palette. The maximum size for a palette is 1024 entries.

If value is omitted, no change is made to the current palette.

There is only one palette setting for all devices in an R session. If the palette is changed, the new palette applies to all subsequent plotting.

The current palette also applies to re-plotting (for example if an on-screen device is resized or dev.copy or replayPlot is used). The palette is recorded on the displaylist at the start of each page and when it is changed.

Value

palette() returns a character vector giving the colors from the palette which was in effect. This is invisible unless the argument is omitted.

palette.pals() returns a character vector giving the names of predefined palettes.

palette.colors() returns a vector of R colors.

Examples

require(graphics)

palette()               # obtain the current palette
palette("R3");palette() # old default palette
palette("ggplot2")      # ggplot2-style palette
palette()

palette(hcl.colors(8, "viridis"))

(palette(gray(seq(0,.9,length.out = 25)))) # gray scales; print old palette
matplot(outer(1:100, 1:30), type = "l", lty = 1,lwd = 2, col = 1:30,
        main = "Gray Scales Palette",
        sub = "palette(gray(seq(0, .9, len=25)))")
palette("default")      # reset back to the default

## on a device where alpha transparency is supported,
##  use 'alpha = 0.3' transparency with the default palette :
mycols <- adjustcolor(palette(), alpha.f = 0.3)
opal <- palette(mycols)
x <- rnorm(1000); xy <- cbind(x, 3*x + rnorm(1000))
plot (xy, lwd = 2,
       main = "Alpha-Transparency Palette\n alpha = 0.3")
xy[,1] <- -xy[,1]
points(xy, col = 8, pch = 16, cex = 1.5)
palette("default")

## List available built-in palettes
palette.pals()

## Demonstrate the colors 1:8 in different palettes using a custom matplot()
sinplot <- function(main=NULL) {
    x <- outer(
	seq(-pi, pi, length.out = 50),
	seq(0, pi, length.out = 8),
	function(x, y) sin(x - y)
    )
    matplot(x, type = "l", lwd = 4, lty = 1, col = 1:8, ylab = "", main=main)
}
sinplot("default palette")

palette("R3");        sinplot("R3")
palette("Okabe-Ito"); sinplot("Okabe-Ito")
palette("Tableau")  ; sinplot("Tableau")
palette("default") # reset

## color swatches for palette.colors()
palette.swatch <- function(palette = palette.pals(), n = 8, nrow = 8,
                           border = "black", cex = 1, ...)
{
     cols <- sapply(palette, palette.colors, n = n, recycle = TRUE)
     ncol <- ncol(cols)
     nswatch <- min(ncol, nrow)
     op <- par(mar = rep(0.1, 4),
               mfrow = c(1, min(5, ceiling(ncol/nrow))),
     	       cex = cex, ...)
     on.exit(par(op))
     while (length(palette)) {
 	subset <- seq_len(min(nrow, ncol(cols)))
 	plot.new()
 	plot.window(c(0, n), c(0.25, nrow + 0.25))
 	y <- rev(subset)
 	text(0, y + 0.1, palette[subset], adj = c(0, 0))
 	y <- rep(y, each = n)
 	rect(rep(0:(n-1), n), y, rep(1:n, n), y - 0.5,
 	     col = cols[, subset], border = border)
 	palette <- palette[-subset]
 	cols    <- cols [, -subset, drop = FALSE]
     }
}

palette.swatch()

palette.swatch(n = 26) # show full "Alphabet"; recycle most others