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iOS Introduction to Auto Layout in iOS Visual Format Language Views Dictionary and Format Strings

Gavin Hobbs
Gavin Hobbs
5,205 Points
Posted by Gavin Hobbs
Gavin Hobbs
5,205 Points

Why the double in the RGBA color?

Hi there! Quick question. Why do we write the RGBA color denominator as a double?

orangeView.backgroundColor = UIColor(displayP3Red: 255/255.0, green: 148/255.0, blue: 0/255.0, alpha: 1.0)

Why is the 255.0 have the .0? Why doesn't the first number have a .0 on the end of it also? (148.0/255.0)

Thanks!

-Gavin

1 Answer

micram1001
micram1001
33,833 Points
micram1001
micram1001
33,833 Points

Copied from https://www.codingexplorer.com/create-uicolor-swift/

Each of the ones that take a CGFloat take a value between 0.0 and 1.0, referring to either the complete absence of, or the maximum amount of that color component respectively. So, this means that even if you have pure RGB values in decimal or hexadecimal format, you will have to divide them by decimal 255 to get the amount to input here.

orangeView.backgroundColor = UIColor(displayP3Red: 255/255.0, green: 148/255.0, blue: 0/255.0, alpha: 1.0) can be seen as: orangeView.backgroundColor = UIColor(displayP3Red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat)