alphacol adds an alpha value to a colour specification and convert to
a hexadecimal colour string.
Usage
alphacol(col, alpha = FALSE)
Value
a character vector of color specifications.
Arguments
col
vector of any of the three kinds of R color specifications,
i.e., either a color name (as listed by colors()), a
hexadecimal string of the form "#rrggbb" or
"#rrggbbaa" (see rgb), or a positive integer
i meaning palette()[i].
alpha
logical value indicating whether the alpha channel (opacity)
values should be returned.