3D Transformations in CSS

Source: http://coding.smashingmagazine.com/2012/01/06/adventures-in-the-third-dimension-css-3-d-transforms/

Back in 2009, the WebKit development team proposed a new extension to CSS that would allow Web page elements to be displayed and transformed on a three-dimensional plane. This proposal was called 3D Transforms, and it was soon implemented in Safari for Mac and iOS. About a year later, support followed for Chrome, and early in 2011, for Android. Outside of WebKit, however, none of the other browser makers seemed to show much enthusiasm for it, so it’s remained a fairly niche and underused feature.

That’s set to change, though, as the Firefox and Internet Explorer teams have decided to join the party by implementing 3D Transforms in pre-release versions of their browsers. So, if all goes according to plan, we’ll see them in IE 10 and a near-future version of Firefox (possibly 10 or 11, but that’s not confirmed yet), both of which are slated for release sometime this year.

That being the case, this is an ideal time to get ahead of the curve and start learning about the possibilities and potential of adding an extra dimension to your Web pages. This article aims to help you do just that, by taking you on a flying tour of the 3D Transforms syntax.

Please bear in mind that in order to see the examples in this article, you’ll need a browser that supports 3D Transforms; as I write this, that’s Safari, Chrome, IE 10 Platform Preview or Firefox Aurora.

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The Third Dimension

On the Web, we’re accustomed to working in two dimensions: all elements have width and height, and we move them around the screen horizontally (left to right) and vertically (top to bottom). The move to a third dimension can be thought of as adding depth to elements, and adding movement towards and away from you (the viewer). Think about 3D films in which objects are constantly thrust out of the screen towards you in an attempt to demonstrate the possibilities of the extra depth.

To use 3D Transforms in CSS, you’ll need to know about axes (that’s the plural of axis, not the plural of axe). If you already know about working in three dimensions or remember using axes in math class at school, you can skip the next section. For everyone else, here is…

A Quick Primer On Axes

I just mentioned that on the 2-D Web, we move elements around horizontally and vertically. Each of these directions is called an axis: the horizontal line is known as the x-axis, and the vertical line is the y-axis. If we think of the top-left corner of an element as our origin (i.e. the point from which movement is measured), a movement to the left is a negative movement along the x-axis, and a move to the right is a positive movement along the x-axis. The same goes for moving an element up (negative on the y-axis) and down (positive on the y-axis).

The third dimension is known as the z-axis and, as I said, can be thought of as towards or away from you; a negative movement along the z-axis is away from you, and a positive movement is towards you.

Showing the three axes: x (left-right), y (up-down) and z (away-towards).

If you’ve read all of this talk of axes and negative movements and you’re rubbing your eyes and blinking in disbelief and misunderstanding, don’t worry: it will all become clear when you get stuck in the code. Come back and read this again after a few examples and it should all be clear.

Transformation Functions

The various transformations are all applied with a single CSS property: transform — yes, the same property that’s used for 2-D CSS Transforms. At the moment, this property is still considered experimental, so remember to use all of the browser prefixes, like so:

Note that Opera doesn’t currently have an implementation of 3D Transforms, but I’m including it here because work is apparently underway. For the sake of clarity, in the examples throughout this article, I’ll use only non-prefixed properties, but remember to include all of the prefixed ones in your own code.

Anyway, the transform property accepts a range of functions as values, each of which applies a different transformation. If you’ve used 2-D CSS Transforms, then you’ll already know many of these functions because they are quite similar (or, in some cases, the same). Here are all of the 3D functions:

• matrix3d
• perspective
• rotateX, rotateY, rotateZ, rotate3d
• scaleX, scaleY, scaleZ, scale3d
• translateX, translateY, translateZ, translate3d

Now, matrix3d definitely sounds the coolest, but it’s so unbelievably complex (it takes 16 values!) that there’s no way I could cover it in this article. So, let’s put that aside and take a quick look at the others.

Rotation

To explain what this does, I’ll have to ask you to do a little mental exercise (which will come in useful later in the article, too). Imagine a sheet of card with a string running through the middle that fixes it in place. By taking the top corners in your fingers, you can move the card up and down, left and right, and forwards and backwards, pivoting around the string. This is what the rotate() function does. The individual functions rotateX(), rotateY() and rotateZ() take a deg (i.e. degree) value and move the element around its point of origin (where the string passes through it) by that much.

Have a look at our first example (a screenshot is shown below in case you don’t have access to a supported browser). Here we’ve rotated each of the elements 45° around a different axis (in order: x, y, z), so you can see the effect of each. The semi-translucent red box shows the original position of the element, and if you mouse over each, you’ll see the transformations removed (I’ve used this convention in all of the examples in this article).

Each element is rotated 45° around a different axis: x (left), y (center) and z (right).

There is a rotate3d() function as well, but it’s too complex to explain in a brief article like this one, so we’ll skip it.

Translation

This is really just a fancy way of saying “movement.” The functions translateX(), translateY() and translateZ() each take a length value, which moves the element by that distance along the given axis. So, translateX(2em) would move the element 2 ems to the right, and translateZ(-10px) would move the element 10 pixels away from the viewer. There’s also a shorthand function, translate3d(), which takes three values in order, one for each axis, like so: translate3d(x, y, z).