logical of whether to include alpha channel. NULL
to let the function decide by input.
use.names
logical of whether to preserve names of input vector.
na.rm
logical indicating whether to ignore missing values as x
is normalized. (defult is TRUE)
Value
a matrix with rgba columns in which each row corresponds to the rgba
value (0-255) of each element in input vector x. Use csscolor
to convert the matrix to css color strings compatible with web browsers.