UIColor

UIColor is a class in the UIKit framework that represents colors used in Apple platform user interfaces, including iOS and tvOS. It provides the color value applied to views, text, layers, and other UI elements. A UIColor object encapsulates color information in various color spaces and can be created from component values, grayscale, patterns, or asset catalogs. It can also be resolved from named assets.

Colors are commonly defined in the sRGB color space with four components: red, green, blue, and alpha (opacity). Each component is a value between 0.0 and 1.0. Component values can be retrieved or examined using methods such as getRed:green:blue:alpha:. In addition to RGB, UIColor supports grayscale via a white component plus alpha and tiling with a pattern image.

Creation options include UIColor(red:green:blue:alpha:) and UIColor(white:alpha:), as well as UIColor(displayP3Red:green:blue:alpha:) for a wider color gamut. Colors can also be loaded from asset catalogs using UIColor(named:), and there are many predefined system colors such as UIColor.systemBlue or UIColor.label. Since iOS 13, dynamic colors allow colors to adapt to light and dark appearances, using system colors or dynamic providers.

When using colors in code, it is common to store them in asset catalogs or use color literals. In macOS development, the analogous class is NSColor, and UIColor can interoperate with NSColor in cross-platform Swift code.