CORE ANIMATION

Core Animation provides a way for developers to produce animated user interfaces via an implicit animation model as well as an "explicit" model. The developer specifies the original and final states of an object, and Core Animation handles interpolation. This allows animated interfaces to be created with relative ease, as no specific code for the animation is required by the developer.

Core Animation can animate any visual element, and it provides a unified way of accessing Core Image, Core Video, and the other Quartz technologies. Like the rest of the graphics model, Core Animation can be accelerated by a graphics processor (GPU).

Animated sequences execute in a thread independent from the main run loop, allowing application processing to occur while the animation is in progress. In this way, application performance is not affected, and animations can be stopped, reversed, or retargeted while in progress.

Updating an existing Cocoa application to use Core Animation should be a simple process. The standard GUI widgets and windows used by the application need be initially registered into a Core Animation setup function. Beyond that, core animation code can be largely segregated from standard GUI logic.

Mac OS X Leopard introduces a fantastic new technology that makes writing applications with animated and cinematic user interfaces much easier. Core Animation for Mac OS X and the iPhone: Creating Compelling Dynamic User Interfaces (Pragmatic Bookshelf, $34.95) will get you up to speed quickly and take you into the depths of this new technology.

Author Bill Dudney explains: "Consider how Apple integrates animation into its operating systems and applications. For example, when users start Front Row, the whole desktop changes to an animation-centric, three-dimensional look and feel with smooth animations and beautiful reflections. You�ll find animation even when you are working on something as simple as preparing a presentation in Keynote. When a slide in Keynote is moved to another spot in a presentation, the rest of the slides move around to get out of the moving slide�s way. Not only does this look great, but it also helps the user understand what their actions are doing. Subtly or dramatically, Keynote and Front Row are keeping their users informed with their use of animation."