Subclassing NSColor

Subclasses of NSColor need to implement the colorSpaceName and set methods, as well as the methods that return the components for that color space and the methods in the NSCoding protocol. Some other methods—such as colorWithAlphaComponent:, isEqual:, and colorUsingColorSpaceName:device:—may also be implemented if they make sense for the color space. Mutable subclasses (if any) should additionally implement copyWithZone: to provide a true copy.