Core Animation

that you use to animate the views and other visual elements of your app.

Core Animation is not a drawing system itself.

It is an infrastructure for compositing and manipulating your app’s content in hardware.

At the heart of this infrastructure are layer objects, which you use to manage and manipulate your content.

A layer captures your content into a bitmap that can be manipulated easily by the graphics hardware.

In most apps, layers are used as a way to manage the content of views but you can also create standalone layers depending on your needs.