Skip to contents

Transform vector of values into color specification

as.color.Rd

Convenience function to convert a vector of values into a color specification.

Usage

as.color(x, opacity = 1)

is.color(x)

Arguments

x

vector of numeric, character or factor values to be transformed

opacity

optional numeric value in the range 0.0 to 1.0 used to specify the opacity/transparency (alpha) of the colors to be returned. 0 means fully opaque, 1 means fully transparent.

Behavior of as.color is as follows:

  • integer numeric values: unchanged, (assumed to corespond to values of R's active palette)

  • integer real values: will be translated to into grayscale values ranging between the max and min

  • factor: integer values corresponding to factor levels will be used

  • character: if values are valid colors (as determined by is.color) they will be returned as is. Otherwise converted to factor and numeric value of factor returned.

The optional opacity parameter can be used to make colors partially transparent (as a shortcut for adjustcolor. If used, colors will be returned as hex rgb color string (i.e. "#00FF0080")

The is.color function checks if each character element of x appears to be a color name by comparing it to colors and checking if it is an HTML-style hex color code. Note that it will return FALSE for integer values.

These functions are used for the color parameters of plot.network.

Value

For as.color, a vector integer values (corresponding to color palette values) or character color name. For is.color, a logical vector indicating if each element of x appears to be a color

as.color() returns TRUE if x is a character in a known color format.

Examples



as.color(1:3)
#> [1] 1 2 3
as.color(c('a','b','c'))
#> [1] 1 2 3

# add some transparency
as.color(c('red','green','blue'),0.5) # gives "#FF000080", "#00FF0080", "#0000FF80"
#> [1] "#FF000080" "#00FF0080" "#0000FF80"

is.color(c('red',1,'foo',NA,'#FFFFFF55'))
#> [1]  TRUE FALSE FALSE    NA  TRUE