opaque
A Boolean value that indicates whether the underlying Core Graphics context has an alpha channel.
Declaration
var opaque: Bool { get set }Discussion
Setting the value of this property to false specifies that the underlying Core Graphics context has an alpha channel, whereas true indicates it does not. The default value is false.
A Core Graphics context requires an alpha channel to express transparency. Without an alpha channel a Core Graphics context is said to be opaque, i.e. without transparency.