Check Color Argument

Checks whether an argument is a valid color. arg_color() additionally requires that a single color is supplied. British spellings are supported.

Usage

arg_color(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_colors(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_colour(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

arg_colours(x, .arg = rlang::caller_arg(x), .msg = NULL, .call)

Arguments

x

the argument to be checked

.arg

the name of the argument supplied to x to appear in error messages. The default is to extract the argument's name using rlang::caller_arg(). Ignored if .msg is supplied.

.msg

an optional alternative message to display if an error is thrown instead of the default message.

.call

the execution environment of a currently running function, e.g. .call = rlang::current_env(). The corresponding function call is retrieved and mentioned in error messages as the source of the error. Passed to err(). Set to NULL to omit call information. The default is to search along the call stack for the first user-facing function in another package, if any.

Value

Returns NULL invisibly if an error is not thrown.

Details

A color specification is considered valid if grDevices::col2rgb() returns a matrix when applied to it.

See also

grDevices::col2rgb()

Examples

f <- function(z) {
  arg_colors(z)
}

try(f("red"))       # No error
try(f("redhehehe")) # Error: not a valid color name
#> Error : Each element of `z` must be a valid color.

try(f("#A4A473")) # No error
try(f("~A4A473")) # Error: not a valid hex code
#> Error : Each element of `z` must be a valid color.

try(f(15))  # No error
try(f(-15)) # Error: not a valid color number
#> Error : Each element of `z` must be a valid color.

try(f(list("red", 15)))  # No error
try(f(list("red", -15))) # Error
#> Error : Each element of `z` must be a valid color.