Convert colors to semitransparent colors.
alphablend(col, alpha = NULL, bg = NULL)
a vector specifying colors.
a numeric vector containing the alpha values (between 0 and 1).
the background color to be used for alphablending. This can be used as a workaround for graphics devices that do not support semitransparent colors.
a vector containing the semitransparent colors.
alphablend("red", 0.6)
#> [1] "#FF000099"