The Foundation Framework Provides Basic System Services for All Apps

Your apps, as well as AppKit and other frameworks, are built on the Foundation framework infrastructure. The Foundation framework provides many primitive object classes and data types, making it fundamental to app development. It also establishes conventions (for tasks such as deallocation) which makes your code more consistent and reusable.

Use Foundation to:

• Create and manage collections such as arrays and dictionaries

• Create and manage strings

• Access images and other resources stored in your app

• Post and observe notifications

• Create date and time objects

• Automatically discover devices on IP networks

• Manipulate URL streams

• Execute code asynchronously

The AppKit Framework Provides Classes to Create a Graphical, Event-Driven User Interface

All Mac apps are based on AppKit. You can’t ship an app without this framework. AppKit provides the infrastructure for drawing to the screen, handling events, and creating common user interface elements. AppKit also organizes a complex app by managing the content that is displayed onscreen.

Use AppKit to:

• Construct and manage your user interface

• Handle user events

• Present fonts, colors, and images

• Perform basic animation

• Support basic app features such as Spaces, Help Support, and multiple user accounts

• Create custom user interface elements

In Your First Mac App, you used AppKit. You implemented the NSApplicationDelegate protocol to call updateUserInterface. In fact, you used AppKit to create your entire interface with the NSTextField and NSSlider classes.

The Core Data Framework Manages the Data Model of an App

Core Data provides object-graph management. With Core Data, you create model objects, known as managed objects. You manage relationships between those objects and make changes to the data through the framework. Core Data takes advantage of the built-in SQLite technology to store and manage data efficiently.

Use Core Data to:

• Save and retrieve objects from storage

• Support basic undo/redo

• Validate property values automatically

• Filter, group, and organize data in memory

• Manage results in a table view with NSFetchedResultsController

• Support document-based apps

The Core Graphics Framework Helps You Create Graphics

High-quality graphics are an important part of all OS X apps. The simplest and most efficient way to create graphics in OS X is to use prerendered images with the standard views and controls of the AppKit framework and let OS X do the drawing. AppKit also provides classes for custom drawing—including paths, colors, patterns, gradients, images, text, and transformations. Use AppKit, a higher-level framework, instead of Core Graphics, a lower-level framework, whenever possible.

Use Core Graphics when you want to write drawing code that you share directly between iOS and OS X. The Core Graphics framework, also known as Quartz, is nearly identical on both platforms.

Use Core Graphics to:

• Make path-based drawings

• Use antialiased rendering

• Add gradients, images, and colors

• Use coordinate-space transformations

Core Animation Allows You to Make Advanced Animations and Visual Effects

AppKit provides animations that are built on top of the Core Animation technology. If you need advanced animations beyond the capabilities of AppKit, you can use Core Animation directly. The Core Animation interfaces are contained in the Quartz Core framework. With Core Animation, you create a hierarchy of layer objects that you manipulate, rotate, scale, transform, and so forth. By using Core Animation’s familiar viewlike abstraction, you can create dynamic user interfaces without having to use low-level graphics APIs such as OpenGL.

Use Core Animation to:

• Create custom animations

• Add timing functions to graphics

• Support key frame animation

• Specify graphical layout constraints

• Group multiple-layer changes into an atomic update

The OpenGL Framework Provides Tools for 2D and 3D Drawing

Use OpenGL for developing advanced three-dimensional (3D) graphics apps. OpenGL is specifically designed for apps such as games that need a rich, robust framework for visualizing shapes in two and three dimensions. Apple’s implementation of the OpenGL standard works closely with the hardware to provide high frame rates for full-screen game-style apps.

Use OpenGL to:

• Create 2D and 3D graphics

• Make more complex graphics such as data visualization, flight simulation, or video games

• Use multiple threads to process graphics data

• Access underlying graphics hardware