isOpaque
A Boolean value indicating whether the view fills its frame rectangle with opaque content.
Declaration
var isOpaque: Bool { get }Discussion
The default value of this property is false to reflect the fact that views do no drawing by default. Subclasses can override this property and return true to indicate that the view completely covers its frame rectangle with opaque content. Doing so can improve performance during drawing operations by eliminating the need to render content behind the view.