The bottom edge is the most pleasurable edge to use. Grab a phone, any phone, and slide your thumb up over the bottom edge, then back. Go on, do it a few times. Feel good? Yeah, our extensive research suggests this feels pretty amazing to pretty much everyone.

That’s why we’ve given the bottom edge to you, the developer, for your app. It’s the best one and we thought you could make the best use of it. If you want to create a truly “Ubuntu!” experience for your app you’ll want to invest in thoughtful but also creative interpretations of this edge in your app.

In fact, getting THIS ONE THING perfect is the most important thing you do when you bring your app to Ubuntu. Pretty much everything else is just… you know, obvious. But creating a bottom edge experience that is exactly perfect for your app and consistent with our values is where the magic happens.

Be perfect, be yourself, be exciting

There is no one answer for “the bottom edge”. There are definitely some values we can apply to judge if it’s a GREAT bottom edge, and there are several patterns that you’ll see, but you should start with a blank canvas and set yourself the goal of making your bottom edge experience YOURS.

Just to get the creative juices flowing, here are three great examples:

Think phases. Go beyond “one thing” in the gesture

The bottom edge swipe very naturally lends itself to what we call a “ranged gesture”. This is a gesture where going further does more. In other words, a great bottom edge will often be more than a simple transition. For example, you are unlikely to be great if you just reveal a toolbar, or pause a movie. You’ve got the opportunity to take several (well, two, at most three) logical “steps” on the way from the bottom edge up to the full stretch of the thumb.

When we design ranged gestures, though, we have to do a couple of things right to make them feel slick.

1. Make them connect smoothly

If your bottom edge gesture is going to have two phases, make sure that you pick two things which are related, so that the second one feels like a natural extension of the first.

A good example is the way we use the left edge: a little bit of left edge shows your *favourite* apps, a lot shows you ALL the apps. Seeing “all the apps” is a natural place to go if seeing your favourite apps wasn’t enough… it’s “more apps”. That makes a really good ranged gesture.

If the second phase was totaly unrelated to the first, it would feel jarring. Don’t do that!

Some examples of great ranged gestures:

1. In a movie player, start with the player controls, then go further to reveal the chapter selection, and maybe even further to pop out of the movie to show other movies available on the device.

2. In a map, use the bottom edge to zoom out. This is very sexy because the further you go the further you zoom, and zooming back is very naturally a tap where you want to zoom in.

3. In a calendar, use the bottom edge to go from day to week to month to year view, like zooming out in time.

4. In a turn-based game, use the bottom edge to pause the game and present game options.

5. Go radial – present a radial menu of 5 top actions. Make it fade in beautifully so people want to use the bottom edge just to see those things show up. Make it fast so you just have to slide to one of them and release to invoke the action. Slick. Fast. Yum.

2. Be reversible. Let people change their mind easily.

Your user might not have intended to invoke the bottom edge, so it should always be possible for them to change their mind before they let go and slide back down, at which point their app is unchanged, they haven’t switched mode or done anything that they have to undo. Sliding back down is like saying “Oops, not down this corridor!” and you should respect that perfectly.

So, don’t pause or commit to any change until the finger is lifted off the screen – make sure that someone can unwind the use of the edge just by changing direction.

Actually… I don’t need to create a new note

3. Make it visually sexy

This is a FANTASTIC opportunity to show off some really beautiful visual design and motion graphics skills. A really beautiful set of transitions or effects will make people say “ooooh!”. If you get this really right, you’ll see people showing their friends that experience. “Check this out!”. “Ooooooh”. “Do it again!”. “Aaaaah.”, “Can I try?”…. that’s what you want to get when you show it to friends and family before you reveal it to the world.

Trust us, there are a million options for you, but to make it really work well will take a lot of thought and testing…. but it’s definitely worth it! Remember the “desktop cube” and how much fun it was to show people that? Now imagine getting the same reaction to your bottom edge… that’s what you’re shooting for.

The very best bottom edge experience will have movement associated with every tiny move of your finger. It will feel “on rails”, as you move your finger up it feels like you are totally in control of the scene that is unfolding, all the way up to the point where the final phase of your experience “clicks” into place, the final commit.

4. Hint, reveal, commit

We have a pattern we call “hint, reveal, commit”. For any substantial change that a gesture might drive, we want first to hint that it will happen, then we want a stretch of the gesture which reveals the first part of the change without actually making it happen, and finally we want a “click” which is the commit.

Now, here’s the fun part. With a ranged gesture, you want to think about hint, reveal, commit for EACH PHASE of the gesture. It’s OK for the commit of one phase to immediately give you a hint of the next – you are, after all, in mid-gesture. In fact, that’s what we usually do ourselves, we show the second phase hint at the same time as the first phase commit.

The reveal is usually the place where  you want to make it feel like the user is in total control: have something that tracks the movement of the finger up the screen; it could be fading something in, or moving something in response to that movement. The important thing is that every tiny movement of the finger should reveal more, or less, until the commit.

Prioritise. Really, PRIORITISE

You have one bottom edge. Only one. It’s the sexiest thing for a user to do. They can even do it without looking where they are pressing – it’s an instinctive thing, pure muscle memory.

So you should think carefully about what’s REALLY IMPORTANT and CENTRAL in your app. Maybe there is something that the user will do all the time and you want to make it easy for them to do it fast, no hunting and pecking for buttons. Maybe there’s a natural “zoom out” expression in your app (those are usually good if you can make them beautifully visual). There is only one first phase to your bottom edge, it’s the first thing people will try – make it great, choose wisely!

Provide a visual cue

Having a magical bottom edge that nobody discovers is no fun at all!

We can’t guarantee that every app will use the bottom edge. Some apps will be so straightforward that a bottom edge experience would be superfluous – just for show. And we don’t want that.

So users can’t be CERTAIN there is a bottom edge worth trying. That’s risky, because if they try  it a few times and get no result, they’ll stop trying it for apps which DO have a great bottom edge. So, you want to provide some sort of cue that it’s worth their while to give it a go.

Sometimes you can provide that cue as part of a transition into the app. You could show the stuff that’s in there, and animate it away into the edge after a few seconds during the app launch, so people know its there. That might be enough.

You might also want to leave a visual cue on the screen all the time. If you do, though, keep it REALLY small. Just a hint, just a clue, just a taste. For example, you might have a teeny little tab with a (+) on it if that edge holds the magic for adding something. Or you might have a teeny tab with the word “London” on it, if the bottom edge will reveal more cities, starting with London. Or just a highlighted line might do the trick.

Be creative on the cue. Make it fit with the story you are telling. There are a million possibilities and only one is best for your particular design. Have fun, but don’t forget the cue!

Common patterns

Yes, if you’re stuck for inspiration, there are a few common patterns you might want to consider. We put this LAST because we really think you want to be inspired by the essence of YOUR APP, not just following a pattern that works elsewhere, in case you miss a chance to invent something really great for yourself and for others.

Zooming out

Many apps have the idea of an “outer” layer, or levels. Maps are an obvious case, calendars also have the idea of a “wider view” (days, weeks, months, years). But the concept of “taking a step back from the coal face” is very common. For example, in a word processor, you might step back to switch between files. In a browser, you might step back to switch between tabs. In a game, you might step back to change settings or invite a friend to play. In Evernote, stepping back from the current note might show you other notes in the same album, or other albums altogether.

By scaling down the content (objects, time, space) we offer a quicker way to navigate across large amounts of content. Step back, go HERE is a great way to get around.

Toggle

If your app has two, and only two, main faces, then the bottom edge is a fast, controlled way to switch between them. You can do a nice cross-fade, or a page-over effect that makes the user feel in control.

Controls

If your app has a set of controls – for example, a music player – then the bottom edge might be a great way to bring those smoothly onto the screen.

A great idea is to think carefully about the various controls, and have a ranged gesture which reveals steadily more. For example, first just play, pause, back and forward, then things like chapter selection which provide a broader view of the content.

Quick draw

Your app may have a particular thing that you want people to be able to do instantly, with nothing but a reflex reaction. For example, a note-taking app might use the bottom edge as a quick-draw “new note” facility.

Make it great!

This is bottom edge is something unique to Ubuntu – we’ve given it to you because it really is the prime edge from a user perspective, and the app has all the user’s attention. It’s worth taking time to think carefully, try a range of options, test them on your friends, and craft it beautifully.