15.5.424 pencolor

pencolor [, color]

Sets or displays the pen color. If color is specified, it must be a string containing a valid color name, or a numerical array with three elements specifying red, green, and blue components between 0 (absent) and 1 (full presence).

Which color names are valid depends on whether you are connected to an x server. If you are connected to an x server (for example, if you are plotting to a window, or if you have one or more LUX windows open already, or if you’ve executed xopen and not xclose), then all color names that x supports are valid, including names such as black and blue (Incidental Colors). If you are not connected to an x server and you are plotting to a PostScript file (i.e., !pdev is equal to 1), then only rgb and rgbi color names are valid (Incidental Colors).

See also: Incidental Colors, !pdev, pdev, xopen, xclose