The Rainbow Creator provides developers with easier methods to create custom colours. Apple provides a limited number of pre-defined colours such as UIColor.blackColor() and UIColor.greenColor(). The Rainbow UIColor library adds over 1500 more colours but not even that may have the exact colour that you require.
As of April 23, 2015 the library supports both NSColor and UIColor. If the OS is detected then the library creates the extension as UIColor otherwise the extension is created as one of NSColor. All of the examples below show UIColor but you can just substitute NSColor.
To use the library download the file and import it into your project.
Then you can change your code from
let backgroundColour = UIColor ( red: 94.0/255.0, green: 7.0/255.0, blue: 95.0/255.0, alpha: 1.0 )
to the following
let backgroundColour = UIColor ( redValue: 94, greenValue: 7, blueValue: 95, alphaValue: 1.0 )
Note that because the alpha value in this case was 1.0 it could have been left off because the function has it set to that value by default.
There are also functions that allow you to create UIColor objects using a hexadecimal integer or string.
let backgroundColour = UIColor ( hex: 0x42ac58, alpha: 0.75 )
let foregroundColour = UIColor ( hexString: "#0f23ec" )
The setting of the alpha is available in both but if you leave it out then it defaults to 1.0. When specifying a colour with a hexadecimal string the hash sign ('#') is optional. (Please note that I have no idea what those values for colors will produce. I just made them up as an example.)
An additional function allows you to create colors using RGB values but without specifying a value for the opacity (alpha). In this case it will default to 1.0.
let newColour = UIColor ( red: 0.8, green: 0.4, blue: 0.75 )
New in April 2016 is a function that lets you create colors by specifying HSB values. As usual with you can leave off the alpha and it will default to a value of 1.0.
let newColour = UIColor ( hueDegrees: 359, saturationPercent: 100, brightnessPercent: 100, alpha: 0.8 )
Currently the extension works in Swift as that is what I primarily develop with. If I get requests to port the extension over to Objective-C I will take the time to do so.
If there is some extra functionality that you would like see added please feel free to get in touch. I'd be happy to look into it. Or even say hi you can reach me on @NrthrnRealities on Twitter.
I am terribly sorry about mixing up the spellings of colour and color. I'm from Canada and we spell it with the 'u' and I can't get out of the habit. However when it comes to function names, parameters, and other cases when it really counts I've strived to go against my instincts and spelt it without the extra letter as per the Apple standard. In other cases I've allowed myself to spell it the proper way. :) Please forgive me my little indulgence.