Can you explain what CADisplayLink is and in what cases it is used in interface development?

CADisplayLink is a class from the iOS SDK that allows synchronization of interface updates with the screen refresh rate (usually 60 frames per second). It creates a timer that calls a specified method before each screen update, which is useful for smooth animations and graphics updates.

CADisplayLink is used when you need to update the UI or animations with the highest possible smoothness, such as in game development, custom animations, or visualizations, where it is important that updates occur in sync with the screen rendering.

Example of usage in Swift:

var displayLink: CADisplayLink?

func startAnimation() {
    displayLink = CADisplayLink(target: self, selector: #selector(updateFrame))
    displayLink?.add(to: .main, forMode: .default)
}

@objc func updateFrame() {
    // Update animation state
}

func stopAnimation() {
    displayLink?.invalidate()
    displayLink = nil
}