During the keynote presentation at Apple’s 2014 Worldwide Developer’s Conference, they announced that they want to create better continuity between OS X and iOS.

‘We believe you should be able to use the right device for the moment’ (34:54 into Apple’s WWDC keynote presentation) – a task started on one Apple device should be able to be continued on another and perhaps concluded on a third. Apple group together OS X and iOS features that support this idea under the ‘Continuity’ heading.

The first kind of continuity Apple mentioned was AirDrop. Currently OS X users transfer files easily between nearby Macs using AirDrop. New in iOS 8 and OS X Yosemite is the ability to do the same between Macs and iOS devices and also between iOS devices.

The bigger news is ‘Handoff.’ Handoff allows users to use nearby Apple devices that are signed in using the same Apple ID to continue working in the same application. If you are browsing a page in Safari on a iOS device near your Mac, a separate Safari icon will appear past the end of your dock. Clicking that icon will open a Safari window on your Mac showing the web page that is on your iOS device. As well as the icon appearing in the dock, if you press Command-Tab you’ll also find the web page represented as an icon amongst the icons of applications running on your Mac.

Conversely, if you are writing an email in Apple Mail on your Mac and double-tap the home button on your iPad to bring up the multi-tasking switcher, you’ll see a pane to the left of the home screen that represents the email you are writing in Apple Mail on the Mac. If you tap that pane, you can continue working on your email in Apple Mail running on your iPad (if your iPad is asleep, you’ll see an Apple Mail icon on the lock screen, you can swipe up to go to Apple Mail).

Handoff uses Bluetooth LE to transfer information about the task; the information can include internet URLs and links to documents in iCloud.

More than email editing and web page viewing

How will complex Mac applications support Handoff? Mac apps are likely to be more complex that iOS apps. Opening a web page or editing an email is straightforward. On the Mac, applications will be able to specify a subset of what they can do as being able to be handed off to another device.

In practice a single Mac application will be able to Handoff activities to different iOS apps. One iOS app could be used to modify images, another could be used for editing text, another for audio waveform editing.

As well as being able to hand activities over so they can be completed on another device, applications can opt to stay connected between devices to work on an activity together. That means an iPhone and iPad can work together on the same data, or an iPad and a Mac can share information live. This is big news for post-production people who like to use iPads and iPhones to control applications on their Macs. All the information you need can be passed to the iOS device – such as current timecode or metadata associated with a piece of media, while tapping UI controls on the iOS device will be able to control the application on the Mac. Current remote control apps running on iOS are limited to simulating key presses on the controlled Mac’s keyboard – Handoff allows iOS apps to be able to directly manipulate the media being edited in your Mac application.

Currently Apple plan that only applications from the same developer will be able to collaborate using Handoff, perhaps if the wider Apple community comes up with enough exciting use cases, Apple will allow cross-developer handoffs.

Most editors don’t want to do complex timeline editing on their iPhone, but imagine group of people watching a Mac play out an edit in a screening room. With Handoff, an assistant could make text corrections on an Apple ‘Final Cut Pro X Inspector’ app running on an iPad, and the text being displayed over full screen video by Final Cut Pro X could change instantly.

Handoff is the current star of Apple’s Continuity plans – I’m looking forward to what developers and Apple will do with it, and I’m also excited by what Apple might do next to make Macs, iPads and iPhones work even better together.