The inside story of the iPhone’s ‘Slide to Unlock’ gesture

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slide to unlock lock screen
Slide-to-unlock is one of the iconic gestures of the iPhone. It looks simple, but it was tricky to get right.
Photo: Leander Kahney/Cult of Mac

iPhone turns 10 This an excerpt from Unsung Apple Hero, an e-book about UI designer Bas Ording’s career at Apple. Ording is responsible for a big chunk of today’s computing interfaces, but is little-known because of Apple’s super-strict privacy policies. Hit the link at the bottom of this post to get a free copy of the e-book.

One of the key design decisions that Apple’s Human Interface Team made early on while developing the iPhone was to go all in on big, simple gestures. They wanted to make a single, simple swipe accomplish as much as possible.

It’s a bit ironic. After investing so much in multitouch technology, which relies on multiple touch inputs, one of Apple’s key edicts was to make as many gestures as possible work with a single finger.

Bas Ording Apple interface designer
Former Apple UI designer Bas Ording was one of the key people behind the iPhone.
Photo: Jim Merithew/Cult of Mac

Former Apple UI-designer Bas Ording said the edict came from Steve Jobs, and was largely because it was difficult to execute any kind of multitouch gesture with one hand. It’s easy to swipe your thumb with one hand, but impossible to pinch or zoom.

“We worked super-hard on multitouch, but then we tried to make everything just work with one finger,” he said laughing.

Ording is one of those little-known Apple employees who produced an outsize influence on our digital lives. He is responsible for a big chunk of today’s computing interfaces. In the 15 years he worked at Apple, he was one of the leading designers of the iOS and Mac interfaces we use every day. He’s the brains behind the iPhone’s “rubber band” scrolling, OS X’s Dock magnification effect, Expose and many more. Yet practically nobody knows who Ording is because of Apple’s notorious secrecy.

Ording holds hundreds of patents and was a key witness in the Apple-Samsung trials, but he has not given many interviews. In this exclusive extract from Unsung Apple Hero, a Cult of Mac e-book detailing his career at Apple, Ording tells how the Human Interface team perfected Slide to Unlock — one of the most recognizable gestures on the original iPhone.

Making the iPhone’s Slide to Unlock feature

While Slide to Unlock is one of the iPhone’s simplest gestures, it proved tricky to design.

The iPhone’s built-in proximity sensor turned off the screen off when the device was held up to the user’s face. At first, the UI team thought the proximity sensor would be sufficient to turn the screen off when the phone was pocketed.

But they were worried about pocket dials or deleting emails when the iPhone was pulled out again. They decided the screen should be locked, and there needed to a big, simple gesture to activate the screen. This ultimately led to the invention of Slide to Unlock.

They initially tried several different things — a two-finger slide, like zooming, or a two-finger unlock gesture, like turning a virtual door handle. They tried pressing two different points on the screen at the same time.

The team liked the twisting door handle analogy, but discovered it was impossible to do with one hand. That’s around the time Jobs decided that as much as possible should be accomplished with a single swipe.

A long, simple swipe

For Slide to Unlock, the team knew it needed to utilize a big, long swipe. The gesture also needed to be horizontal rather than vertical, because otherwise it would be too easy to accidentally unlock the screen as it was pulled out of a pocket.

The mechanism included a button that slid across and the text “Slide to Unlock” appeared in the slider bar. But to make it crystal clear it was a slider, the team wanted to add some kind of animation that incited the user to slide the button across the screen.

Arrows were one possibility, but they would have junked up the box, which was already full with text. Ording thought of shining a spotlight on the text, which then moved along the slider box as though someone was shining a flashlight across it.

He was delighted with the effect — it was simple, elegant and fun.

Apple got awarded a patent for the effect in 2011, and it became a key point of contention in the Apple-Samsung trial. Credited are former head of iOS development Scott Forstall, as well as Ording and other members of the Human Interface Group: Imran Chaudhri, Freddy Allen Anzures, Marcel Van Os, Stephen O. Lemay and Greg Christie.

The gesture was retired in 2016 with the introduction of iOS 10. The iPhone’s Touch ID fingerprint sensor has taken over screen unlocking duties, using biometrics (or via the device’s Passcode).

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Sign up to get a free copy of Unsung Apple Hero, an e-book detailing Bas Ording’s career at Apple. We’ll email you a copy when the e-book is released in July. Unsung Apple Hero details Ording’s long career spent building key components of iPhone and Mac software. The book describes what it was like to work at Apple and to work closely with Steve Jobs; where Ording got his ideas from; and how he worked through problems like the rubber band effect. It takes a deep dive into his methodology with lessons for all designers. 

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