R: Set or View the Graphics Palette

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.

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

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")

[Package grDevices version 3.5.1 Index]