palette {grDevices}

R Documentation

Set or View the Graphics Palette

Description

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

Usage

palette(value)

Arguments

value

an optional character vector.

Details

The color palette and referring to colors by number (see e.g. par) was provided for compatibility with S: in R it is almost always better to specify colours by name.

If value has length 1, it is taken to be the name of a built-in color palette (only "default" is built-in currently). 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 (either by name or by RGB levels). 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 a R session. If the palette is changed, the new palette applies to all subsequent plotting.

Prior to R 3.0.0 the current palette also applies to re-plotting (for example if an on-screen device is resized or dev.copy or replayPlot is used). In current R, the palette is recorded on the displaylist at the start of each page and when it is changed.

Value

A character vector giving the palette which was in effect. This is invisible unless the argument is omitted.

See Also

colors for the vector of built-in named colors; hsv, gray, rainbow, terrain.colors, ... to construct colors.

adjustcolor, e.g., for tweaking existing palettes; colorRamp to interpolate colors, making custom palettes; col2rgb for translating colors to RGB 3-vectors.

Examples

require(graphics)

palette()               # obtain the current palette
palette(rainbow(6))     # six color rainbow

(palette(gray(seq(0,.9,len = 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")

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