displayIfNeeded()
Displays the view and all its subviews if any part of the view has been marked as needing display.
Declaration
func displayIfNeeded()Discussion
This method invokes the NSView methods lockFocus(), draw(_:), and unlockFocus() as necessary. If the view isn’t opaque, this method backs up the view hierarchy to the first opaque ancestor, calculates the portion of the opaque ancestor covered by the view, and begins displaying from there.