Add transparency to color

This functions add (or set) transparency to a vector of colors.

Usage

add_transparency(x, alpha = 0, maxColorValue = 255)

Arguments

x

vector of original color.

alpha

numeric between O and 1, desired transparency.

maxColorValue

integer, same as in rgb.

Value

vector of colors with alpha.

Details

Both 'x' and 'alpha' may be vectors. In case their length are not compatible, a vector of the maximum length will be generated without any warning.

Author

Frédéric Grelot

Examples

add_transparency("black", .5)
#> [1] "#00000080"
add_transparency(c("red", "black"), .5)
#> [1] "#FF000080" "#00000080"

# No warnings when length differs
add_transparency(c("#000000FF", "black", "red", "blue"), c(0, .5, 1))
#> [1] "#00000000" "#00000080" "#FF0000FF" "#0000FF00"