Apple iPhone

Raycomm are a UK based, custom software and electronics design and development service company creating bespoke electronic products, mobile device software applications, backend web server software and e-commerce database software.

Apple's iPhone is a global success story.  Where as its initial appeal lay in its attractive design, intuitive interface and well-considered features, it is now its capability as a platform that is driving adoption.  The iPhone’s OS is based on Mac OS X, leveraging Apple’s massive development experience and utilising the rich, object-oriented frameworks that underpin the desktop OS.  For the first time, a mobile device is offering comparable developmental possibilities to a PC.

At the iPhone’s core is a highly customised BSD Unix environment.  Although stripped down and optimised, it nevertheless has many of the system libraries and facilities like the standard C libraries, POSIX threads and BSD sockets found in the typical UNIX implementation.  On top of this (and providing an abstraction layer to it) are the core services.  These include:

• Core Foundation, providing a range of vital services to applications including file handling, low-level data types, basic networking, memory management (although it does not support garbage collection for performance reasons), localisation support and control of the application run loop.
• CFNetwork, which provides a range of networking services and protocols (e.g. sockets, HTTP, FTP, bonjour, DNS). The iPhone now features both Wi-Fi and 3G connectivity.
• Database and XML support.
• Security framework, which provides certificate and key management , as well as encryption services

Next is the media layer. Until quite recently, the presentation and manipulation of content was limited with mobile devices, but this is not the case with the iPhone. It offers a wide range of services for dealing with media:

• Core Graphics (aka Quartz 2D) is the main 2D drawing and vector engine. As the name implies, it is used whenever 2D rendering is required.
• Core Animation is a 2D compositing engine that allows for implicit animation. Many of the standard user interface controls have integrated animation behaviours (e.g. cover flow). The application is developed by specifying start and end states, while the framework takes care of the animated transition between them.
• OpenGL|ES is the mobile version of the high performance 3D graphics framework. It allows extremely fine grained control of the iPhone’s frame buffer.
• Core audio is the basic sound engine, used for playing and recording audio streams.
• Audio Toolbox provides basic system level audio support, like the triggering of short sounds in response to events, as well as the iPhone’s vibration capabilities.
• OpenAL is the 3D spatial audio framework that allows for the positioning of sounds during playback.
• MediaPlayer is the framework that governs video playback and provides the numerous compression codecs required for such.

Additional graphics support in the form of the user interface controls and drawing functions is also built into the final layer: the Cocoa Touch application environment.

The defining feature of the iPhone’s user interface is, of course, the fact that it is touch based and that it will respond to multiple simultaneous touches and events based on the multi-touch model (both position and direction).  Cocoa Touch permits a series of touches to be recognized as a single group (or gesture).

The iPhone also features three sensitive accelerometers (one for each primary axis) that allow the iPhone’s orientation and movement to be detected and therefore used as part of the user interface to an application. 

Cocoa Touch also provides access to Core Location, the framework governing location-based services, including GPS. Apple places great store on the consistency of both appearance and functionality of applications and by providing common controls and uniform access to system-wide services (like the camera and the accelerometer, as well as contacts, photos and web content)

One important distinction about iPhone development that needs to be mentioned is that much of it (the entire Cocoa Touch API, in fact) is based on a language called Objective C. While this is a superset of C and can therefore call low level C-based frameworks directly, it features a number of key additional language facilities and paradigms (based on proven design patterns like model-view-controller and delegation).

Project examples coming soon...