Focus and Parallax
On Apple TV, an icon, image, button, or other interface element is considered to be in focus when it’s the currently highlighted element. As an element comes into focus, it’s gently elevated to the foreground and sways playfully in response to subtle movements of a finger on the touch surface of the remote. As this occurs, illumination is applied to the item, making its surface appear to shine. After a period of inactivity, out-of-focus content dims while the focused element grows even larger. These effects work together to maintain a connection with people sitting on the couch. They provide a sense of clarity and context, reinforcing what’s in focus.
Parallax is a subtle visual effect used throughout the system to convey depth and dynamism when an element is in focus. Through image layering, transparency, scaling, and motion, parallax produces a 3D effect with a sense of realism and vitality. Image layering to support the parallax effect is a requirement for your app icon and is supported for dynamic top shelf content on the Home screen. Image layering is strongly encouraged anywhere that focusable, image-based content resides in your app.