After writing my previous article: “Subscripting Shortcuts” I tried to come up with a good usage of string subscripts in iOS, and decided a good example was to boost the power of UIColor by adding a couple of initializers that catered for two more widespread colour notations that are more common in the design and web industries: 255-RGB and HEX.
In this tutorial we will make use of our favourite tool, categories, to extend the base power of the framework’s UIColor class and allow for new ways of creating colours. Bear in mind that these initializers are geared towards speeding up development processes in sacrifice of performance, specially when it comes to communications between developers and the design team. They will inherently produce a very small performance overhead on any app that adopts them (specially the hex conversion, as we will be doing string parsing and string parsing is ALWAYS expensive). Having said that, unless we iterate though a huge amount of colour objects, we can safely consider the knock-on effect as dismissible.