What is this generation’s obsession with pinch to zoom?  It’s so often touted as “natural”, “intuitive”, and “cool” that it’s beginning to make me go insane!  Yes, it might be cool, but have the people who say these things even thought implications of both what they say and the use of such an interface?

Intuitive

First, let’s get the bit out of the way that always grates me.  Pinch to zoom isn’t “natural” or “intuitive”, contrary to what people say.  Do people even know what it means?  Let’s have a quick look at the Chambers UK dictionary, since it’s what I have to hand:

intuitive adj having, showing or based on intuition.
intuition **noun **1 the power of understanding or realizing something without conscious rational thought or analysis.

Cast your mind back to when you first experienced pinch-to-zoom.  Had you already heard about it from all the marketing and fanboyism?  Did you work it out for yourself?  Did you struggle?

I didn’t struggle, at least to find it, because I knew about it from the web and friends well before I ever used the gesture myself.  But I was always asking myself why–why is it like this?  I mean, I don’t know about you, but I’ve never bought a map or a picture printed on latex before, and I don’t think it would be a terribly good idea if someone were to do it.  Stretching a map just to be able to see to a larger scale sounds like too much work and ridiculously impractical.

At this point you’re probably thinking I’m taking it too seriously.  Damn right I’m taking it seriously–these are the interfaces that people all over the world use millions of times a day.  Shouldn’t something so prolific be polished to perfection?

A more “intuitive” interface would either be one that we can relate to in real life–such as a magnifying glass–or something that we are already used to–buttons, for example.  The latter is a bad example of intuition however, as the only reason most people can use buttons without any conscious rational thought now is because they have made the conscious ration thought a long time ago.  And as an added bonus, what do most zoom buttons look like?  That’s right: magnifying glasses.

Accessibility

I realise that I am a very fortunate person to be fully able to use my body and interact with the devices in my life easily such as computers or mobile phones.  But if I were ever do gain disabilities–specifically motor disabilities–then I want to damn well make sure that I’ll still be able to use my beloved electronics!

You can probably see where this is going.  Pinch to zoom requires a surprising amount of motor- and hand-to-eye coordination.  And this is coming from a very seasoned gamer!

Break down pinch to zoom into its most basic motions for zooming in:

  1. Locate two physical inputs on either side of the point of interest you want to zoom in on.
    • By “two physical inputs” I mean most commonly a thumb and an index finger or two thumbs.
  2. Move each input away from the point of interest.  If you want to keep the subject in the centre of the screen you need to make sure you move each input an equal distance.
  3. Remove both inputs from the screen without moving them across the screen.

Likewise, do the same for zooming out:

  1. Locate two physical inputs far away from the centre of the screen.  This is typically in the corners to maximise the distance that can be travelled by the inputs.
  2. Pull the inputs closer together, typically until they touch.
  3. Remove the inputs from the screen without moving them across the screen.

Now you might take this for granted, but this is actually quite a difficult operation.  After all, you need to line up your two chosen inputs in relation to the object on the screen that you want to zoom in or our with.  If anyone attempting to do this has any long-standing physical problems, they’ll probably find it hard and annoying.

And that’s before we even consider someone who only has the ability to work with one hand at once–i.e. they have very limited finger motion, but are able to use their arms otherwise okay.  They hold the phone in one hand, and then things become very awkward as soon as they decide they want to zoom.  Taps? Easy.  Swipes? Not too bad. Pinching?  Ah.

Usability

Heck, it can be difficult for fully able people to use the pinch to zoom gesture properly.

To use the iPhone as an example (though all other phones with pinch to zoom fall foul of this), you’ve gone on a walk on a hot summer’s day.  Needless to say the warmth is taking its toll on you, but you’re smart and have come prepared with a drink in hand.  You forget exactly which path it is you’re taking to get to your destination, so you pull out your iPhone in your other hand, fire up the Maps app and do a quick search.  There seem to be a lot of junctions ahead…  So you decide to zoom in to see which–ah.

If you’ve ever tried to pinch a phone’s screen whilst hold it in the same hand, you know it’s a challenge to try and hold a device as big as the iPhone and *lay two fingers on it *and move those fingers precisely.  Even the fact that I am trained in the Monster Hunter “claw"–named for the PSP game’s awkward controls featuring movement on the analogue stick and camera adjustment on the D-pad– didn’t help me at all.  Trying to use it with one hand is just plain awful.  And that’s a big shame, as being able to use a phone one-handed is a big feature for me.

The problem is only exacerbated by circumstances such as driving.  With Android 2.0 recently being announced to have full in-car GPS support, including a special mode which makes buttons larger and a voice speak directions, it’s becoming even more likely that devices with pinch to zoom being used in the car.  Now granted that having buttons to zoom won’t work great unless they’re quite large.  Pinching to zoom however is even worse in that it needs two fingers, both of them to be on and stay on the screen until you’ve hit the zoom level you want.  Now this is going to take concentration and attention.  Probably quite a lot of it.  And driving with your attention off the road isn’t exactly the best idea in the world.  Not the worst, but not the best.

One other thing I haven’t mentioned is multi-touch gestures being implemented on devices that aren’t phones, such as laptops.  I’ve been using 3-finger gestures on my Asus Eee PC 901 for over a year now (yes, there is space for three fingers on the trackpad–just), and there were new MacBooks released earlier this year with support for 4 points of contact!  That’s pretty cool, and I am very much keen on the idea of being able to do lots of different gestures with multiple fingers.  However, when you start to implement many that are similar to each other, people are bound to activate one when they meant to do another.  It’s just a shame sometimes that the people who make these devices know better than you, so much so that they don’t let you adjust anything to your preferences.

So just remember when you next think about pinch to zoom about what I said earlier: it is a gesture that people all over the world use millions of times a day–so long as you have good motor proficiency, hand-to-eye co-ordination, and two hands free.