The Message UI framework provides specialized view controllers for presenting standard composition interfaces for email and SMS (Short Messaging Service) text messages. Use these interfaces to add message delivery capabilities without requiring the user to leave your app.

Render advanced 3D graphics and perform data-parallel computations. Get fine-grained access to the GPU while minimizing CPU overhead. The Metal Framework provides extremely low-overhead access to the GPU, enabling incredibly high performance for your sophisticated graphics rendering and computational tasks. Metal eliminates many performance bottlenecks—such as costly state validation—that are found in traditional graphics APIs. Metal moves all expensive state translation and compilation operations out of the critical path of your most performance sensitive rendering code. It provides precompiled shaders, state objects, and explicit command scheduling to ensure that your application achieves the highest possible performance and efficiency. Graphics, compute, and blit commands can be used together seamlessly and efficiently. Metal is specifically designed to exploit modern architectural considerations, such as multiprocessing and shared memory, to make it easy to parallelize the creation of GPU commands.

This collection of documents provides the API reference for the Quartz Core framework, which supports image processing and video image manipulation.

The Contacts framework provides Swift and Objective-C API to access the user’s contact information. Because most apps read contact information without making any changes, this framework is optimized for thread-safe, read-only usage.

Core Foundation is a framework that provides fundamental software services useful to application services, application environments, and to applications themselves. Core Foundation also provides abstractions for common data types, facilitates internationalization with Unicode string storage, and offers a suite of utilities such as plug-in support, XML property lists, URL resource access, and preferences.

The Core Graphics framework is based on the Quartz advanced drawing engine. It provides low-level, lightweight 2D rendering with unmatched output fidelity. You use this framework to handle path-based drawing, transformations, color management, offscreen rendering, patterns, gradients and shadings, image data management, image creation, and image masking, as well as PDF document creation, display, and parsing.

Core Image is an image processing and analysis technology designed to provide near real-time processing for still and video images.

The Core Location framework lets you determine the current location or heading associated with a device. The framework uses the available hardware to determine the user’s position and heading. You use the classes and protocols in this framework to configure and schedule the delivery of location and heading events. You can also use it to define geographic regions and monitor when the user crosses the boundaries of those regions. In iOS, you can also define a region around a Bluetooth beacon.