By Graham K. Rogers
In macOS, Sierra, some panels have seen changes in System Preferences, while some panels remain unchanged. Extensions was a new panel in Yosemite. This manages the way additional control files are used by the Mac, including those from 3rd-party developers. The use of this has expanded considerably in the last year or so.
Extensions for Apple operating systems have existed since long before OS X: indeed, the name of this site and the column I write for the Bangkok Post came from this and the new emphasis (then) on the X of OS X (OS Ten, not X). These files add functions to applications: extending their normal capabilities. Some other functions are already available by using the Services menu for each application.
When demonstrated at the World Wide Developers Conference in June 2014, an image captured from Safari was added to an email and then Markup was used to add information and comments to the photograph. Markup was one of the first extensions available and works in apps that already mix text and images, such as TextEdit and Stickies. It has recently been added to Photos. Not all apps have such extensibility. Preview incorporates similar functions as part of its tool-set.
As more developers (or Apple) increase the availability of extensions, functions will be added to those apps that are able to use such new features. Links to articles written on the feature are available below.
The single panel has two parts: to the left the types of extensions: All, Actions, Finder, Photos, Share Menu, Today. Below each extension type, is a summary (in grey) of what is available. When one of the types is highlighted, any extensions installed are shown in the main panel to the right.
- All - All third-party extensions. On my Mac, this shows several Photos extensions, Twitter, Dropbox and others each with a checkbox. Alongside each checkbox is the service (e.g. Finder, Photos) that the extension works with.
- Actions - Only two extensions are installed: Pixelmator Repair Tool and Markup. A checkbox alongside each indicates that they are active. If the Markup checkbox is deselected, it is immediately unavailable in apps. When the box is checked again, it is available right away. Markup has a number of ways to make comments or annotations on an image used in an application that allows this, including the use of a signature.
- Finder - currently my installation only has Dropbox shown (see All, above) with a checkbox. As future applications are developed to provide such interoperability, we should expect to see more, although two years since the arrival of Extensions, this still remains the only app I have in this section.
- Photos - This was not in the original implementation of the Extensions preferences, but its arrival allowed several third party developers to produce creative extensions that provided useful additions for the Photos app, expanding the value of that application significantly.
- Share Menu - this includes a list of several applications from which it is already possible to export or otherwise share data. These include Apple developed applications (including Mail, Messages and AirDrop) as well as a number of 3rd party ones, such as Facebook, Twitter and Flickr. Those that are currently in use, have their boxes checked. A number of other extensions that are installed, but are not used, are unchecked. These include certain Asian services, including Weibo and Tudou that I never use.
- Today is the other half of the Notifications Center panel in which a user may display icons that access specific functions or display certain information. The Notifications half is controlled in System Preferences > Notifications.
In my "Today" display I have Stocks, Weather, World Clock, and several other such data displays, including Social (allowing links to sites like Facebook and Twitter if wanted). Extensions that are installed, but not used, are unchecked.
The extensions here are installed for system-wide use, so those installed specifically for Safari (for example) are not shown here. It is expected that more extensions will appear, but will be part of new applications (or updates to already-installed applications).
As more information becomes available, or if changes are made, this page will be updated.
Graham K. Rogers teaches at the Faculty of Engineering, Mahidol University in Thailand. He wrote in the Bangkok Post, Database supplement on IT subjects. For the last seven years of Database he wrote a column on Apple and Macs. He is now continuing that in the Bangkok Post supplement, Life. He can be followed on Twitter (@extensions_th)