Use gestures to control your Mac

If you’ve used one of the current-generation game consoles such as an Xbox One or PlayStation 4, you’ve probably discovered the sheer joy — and frustration — that comes with using a camera as a controller.

The principle is simple: the camera figures out where you are and what position your body and links are in, and uses changes in your position to influence specially-written software.

It doesn’t always work all that well, of course, for myriad reasons such as lighting, cluttered backgrounds and so forth. But it’s fun when it works.

Basic setupGiven the limitations of specially designed cameras and software engineered from the ground up to take advantage of gesture controls, you can imagine the experience with a general-purpose camera and software not written with gestures in mind is even more limited. It is, however, lots of fun.

Thankfully, it’s also free. ControlAir, a utility available on the Mac App Store, lets you use the iSight camera built in to your Mac as a gesture controller, so you can use media controls by literally waving a finger in the air.

First, download and install ControlAir from the App Store. When it runs for the first time, it will take you through a brief setup procedure involving calibrating the position of your camera and finding your finger.

Find a fingerUnlike the camera controllers for game consoles, your Mac’s iSight camera has only one lens, and therefore no real depth perception — so you have to help it find you.

Once it’s established where you are and what’s background, it’s time to set it up with a media program.

At this stage ControlAir only works with media apps such as iTunes, QuickTime Player and a variety of others.

It’s also limited to understanding the position of your finger and whether it’s pointing up or down — but it’s early days yet, and the developers are looking to do much more.

One feature we’d like to see added is support for multiple cameras — increasingly common, especially as many Mac users have multiple monitors, all with built-in cameras. Depth perception would massively increase the range of gestures the application could recognise and therefore the range of commands it could carry out.

In useOnce you’ve trained it to recognise what your finger is doing, the application disappears to the background and lets you get on with whatever you were doing. Raise a finger, though, and the on-screen controls appear to allow you to play, pause, skip tracks or change the volume.

It’s surprisingly useful once you’re doing it.

Speaking of gestures

Find the toolIn the past we’ve covered how you can use OS X’s inbuilt Preview application to sign electronic documents by holding a physical signature on paper in front of the iSight camera. If you happen to have a trackpad (either built in to a laptop or a Magic Trackpad) you can now do the same using gestures.

Yosemite includes a system-wide feature called Markup, which introduces a set of drawing tools to a wide range of applications, including Preview. It also works in Mail and even Stickies.

To create a signature using Markup, open a document you wish to sign, such as a PDF, in Preview. Navigate to Tools > Annotate > Signature and if you haven’t created a signature before, select Manage Signatures.

A window will open, allowing you to choose between the old (and still way nifty) camera method or the new Trackpad method of signing. Choose the latter, then click on the blue box in the middle to start signing.

Create a signatureUsing a finger to sign your name is a fairly awkward thing, but thankfully any stylus that works with an iPhone or iPad (such as those from Wacom or Kensington) will do nicely.

Don’t try using an ordinary piece of plastic — it won’t work. And for heaven’s sake don’t use a pen. If you’ve been signing things on an iPad screen for a while, you may already have the knack.

When you’re done, press any key on the keyboard. If you like the signature you’ve created, click Done and it will be added to your Signature menu. If you don’t like it, click Clear and try again.

Next time you choose Signature from the menu, you’ll have the choice of signatures you’ve created, and you simply add them to any document like a rubber stamp. Simple and clever.