Using the named colors will of course be restricted to the colors known by the library. If some other colors are needed then they must be specified manually.
The first variant uses the RGB values for the color, i.e. the Red, Green and Blue component of a color. Each component is specified as an integer in the range [0,255] and the triple is specified as an array.
As usual a value of
array(0,0,0) specifies black and a value of
array(255,255,255) specifies white.