Get Color Names from the Hex Code

Source: R/l_ColorList.R

Return the built-in color names by the given hex code.

l_colorName(color, error = TRUE, precise = FALSE)

Arguments

color

A vector of 12 digit (tcl) or 6 (8 with transparency) digit color hex code, e.g. "#FFFF00000000", "#FF0000"
error

Suppose the input is not a valid color, if TRUE, an error will be returned; else the input vector will be returned.
precise

Logical; When precise = FALSE, the name of the nearest built-in colour is returned. When precise = TRUE, the name is returned only if the minimum Euclidean distance is zero; otherwise the hex code of the colour is returned. See details.

Value

A vector of built-in color names

Details

Function colors returns the built-in color names which R knows about. To convert a hex code to a real color name, we first convert these built-in colours and the hex code to RGB (red/green/blue) values (e.g., "black" --> [0, 0, 0]). Then, using this RGB vector value, the closest (Euclidean distance) built-in colour is determined.

Matching is "precise" whenever the minimum distance is zero; otherwise it is "approximate", locating the nearest R colour.

See also

l_hexcolor, hex12tohex6, as_hex6color

Examples

l_colorName(c("#FFFF00000000", "#FF00FF", "blue"))

#> [1] "red"     "magenta" "blue"   

if(require(grid)) {
# redGradient is a matrix of 20 different colors
redGradient <- matrix(hcl(0, 80, seq(49, 68, 1)),
                      nrow=4, ncol=5, byrow = TRUE)
# a color plate
grid::grid.newpage()
grid::grid.raster(redGradient,
                  interpolate = FALSE)

# a "rough matching";
r <- l_colorName(redGradient)
# the color name of each row is identical...
r
grid::grid.newpage()
# very different from the first plate
grid::grid.raster(r, interpolate = FALSE)

# a "precise matching";
p <- l_colorName(redGradient, precise = TRUE)
# no built-in color names can be precisely matched...
p
}

#> Loading required package: grid
#>      [,1]      [,2]      [,3]      [,4]      [,5]     
#> [1,] "#C24C6A" "#C54E6D" "#C7516F" "#CA5472" "#CD5774"
#> [2,] "#D05A77" "#D35C79" "#D65F7C" "#D8627F" "#DB6581"
#> [3,] "#DE6884" "#E16A86" "#E46D89" "#E7708C" "#EA738E"
#> [4,] "#ED7591" "#F07894" "#F37B96" "#F57E99" "#F8809C"
if (FALSE) {
# an error will be returned
l_colorName(c("foo", "bar", "red"))

# c("foo", "bar", "red") will be returned
l_colorName(c("foo", "bar", "#FFFF00000000"), error = FALSE)
}