Extensions Preferences
There are four different types of extensions available on the Mac – some of which are more widely used than others. You can see which extensions are installed on your Mac by taking a look at the Extensions preferences panel that was introduced as part of Yosemite.
The extensions shown in the preferences panel are organised into four categories – Actions, Finder, Share Menu and Today.
Today extensions – also known as ‘widgets’ – are perhaps the most popular form of extension at the moment, as they can be used to display messages and updates in the Notifications Centre on your Mac desktop.
The weather reports, stock prices and other notifications that are automatically shown in the Notifications Centre are all controlled by extensions that are built into Yosemite. If you don’t want to see some of this information then you can use the preferences panel to turn individual extensions on or off.
There are other extensions also included in Yosemite that aren’t used by default, but which can be turned on whenever you want.
Today Extensions
I use the Calculator app on my Mac quite a lot, and it turns out that the Calculator can be used as an extension too. I’m not that interested in stock prices, so I can turn off the Stocks extension in order to make room for the Calculator, and then I can do a few quick sums right in the Notifications Centre whenever I need to.
You can turn any of these extensions on or off in the Extensions preferences panel, and use the Edit option in Notification Centre to modify the layout of information and keep everything tidy.
There are plenty of third-party apps that use Today Notifications too, including the popular PCalc, which provides far more powerful calculator features than Apple’s basic Calculator app. One of my favourites is Wunderlist, which is one of the best To-Do apps available for the Mac. Wunderlist includes a Today extension that allows me to view reminders for my To-Do tasks without needing to open the Wunderlist app itself. I’ve also got a Today extension for Parallels Desktop that monitors the state of my Windows virtual machines. Philips has even demonstrated an extension that lets you control its Hue lighting systems directly from within Notification Centre. And if you press the Edit button at the bottom of Notification Centre you’ll see another button that takes you to the Mac App Store where there’s a whole collection of apps that provide extensions you can use here).
Share Extensions
Many of Apple’s own apps, such as Safari and iPhoto, now have a Share menu that allows you to send photos and files to your friends using Mail or Messages, or to upload them to social media sites such as Facebook and Twitter. There’s also a Share option built into the Finder too, allowing you to Command-Click on a file and share it right from your Mac desktop.
Yosemite extends the Share menu by using extensions to add other apps and social sites to the menu. Any social media service can provide a Share extension of its own, and it will then be added to the Share menu so that you can share files and information online. Look in the Extensions preferences panel and you’ll see the standard set of extensions for the likes of Twitter and Facebook, but – with an eye on the huge Chinese market – Apple has included its own extensions for Chinese video-sharing services such as Youku and Tudou.
There are also some great third-party apps that provide Share extensions, such as Pocket, which allows you to quickly copy web pages, photos and other files straight into Pocket and view them offline later on. The handy file-sharing service CloudApp has a sharing extension too, so you can upload and share files right from the desktop by Command-clicking on the file and using the Share menu in the Finder.
Read about Safari extensions here: The best Extensions for Safari on the Mac
Action Extensions
Action extensions allow you to edit or modify files in some way.
One of the big additions to Mail in Yosemite is the Markup option that allows you to annotate photos and PDF files, and even to add create a digital signature using your FaceTime camera. In fact, most of those Markup tools were already available in Preview, but Apple turned them into an extension for Yosemite so that they could be shared with Mail and other apps.
The Markup extension is also available within any other app that has been written to work with extensions, such as TextEdit. We’ve not come across any third-party apps that can use Markup at the moment, or which use Action extensions to add new features to apps, but this type of extension is starting to become popular with iOS apps, so maybe the Mac will catch up soon.
Finder Extensions
The last category is called Finder extensions, or sometimes ‘Finder Sync’. This is a specialised type of extension that can monitor the sync status of files on your Finder desktop.
The latest version of Dropbox includes a Finder extension that puts a green tick by the name of any file or folder so that you can instantly see when it has been fully uploaded to your Dropbox account without having to launch the Dropbox app itself.
Read: Super-advanced tips for Mac OS X Yosemite and Yosemite tips: learn to use OS X Yosemite