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Although no prior knowledge of Core Animation is assumed, this is not merely a cursory
introduction to the framework. The aim of this book is to leave no stone unturned when it comes
to the Core Animation APIs. Even if you have already used Core Animation for many years in
an iOS-specific context, it would be surprising if you did not find things in here that you don’t
already know about or fully understand.
This book is specifically geared toward the iOS platform. Where appropriate, differences
between Core Animation on iOS and Mac OS are mentioned, but Mac-specific Core Animation
features such as
CALayoutManager
or Core Image integration or are not discussed in detail. If
you are already well versed in Core Animation on Mac OS, much of the material will already be
familiar to you, but this should serve as a useful conversion guide.
Core Animation has been a key part of iOS since the beginning, and the majority of its features
are available on older iOS versions. Any methods or classes that are new to iOS 6 are
highlighted as such, but the purpose of this book is to document the
current
feature set of Core
Animation; so with very few exceptions, the task of providing backward compatibility for
earlier iOS versions is left as an exercise for the reader.
Book Structure
This book is structured in a linear fashion, with each chapter building upon concepts introduced
in the previous ones. That said, wherever we refer back to a concept covered in an earlier
chapter, the chapter is referenced explicitly so that you can read the book in a nonlinear fashion
if you prefer.
The subject matter is split into three parts, dealing with static content, animation, and
performance optimization, respectively. These parts are self-contained, so (for example) if you
already know about animation and layout, you can dive straight into the part on performance.
Each chapter contains figures and example code to illustrate the topics discussed. The sample
code projects are available for download from www.informit.com/title/9780133440751 if you
prefer not to retype them by hand.
Before We Begin
The examples in this book were written and tested using Xcode 4.6 on Mac OS 10.8 (
Mountain
Lion
). The latest version of Xcode can be downloaded free of charge from the Mac App Store,
and most of the examples can be run in the iOS simulator. In addition, you need to sign up for a
free Apple developer account to access most of the tools and documentation for the classes
referenced in the book.
The code examples have all been tested with iOS 6.1, but most will either run unmodified on
iOS 5+, or can be trivially modified to do so by removing noncritical iOS 6 features such as
Autolayout. All examples make use of modern Objective-C practices such as ARC (Automatic
Reference Counting), automatic property synthesis, and object literals and so require Xcode 4.5
and iOS 4 as a minimum.