art with code

2011-08-19

Ken Burns effect using CSS


The Ken Burns effect is a special effect used in documentaries when you only have a static photograph of an interesting item. To add some movement and life to the photograph, you zoom into the photo and pan towards a point of interest. It's named the Ken Burns effect because it was used a lot by a documentary film maker named Ken Burns.

Anyhow.

You can achieve the Ken Burns effect using CSS animations. It's not even particularly difficult. Just create a div with overflow:hidden to hold the image, then change the image's CSS transform property. Or if you want to be totally retro and backwards-compatible, you could also achieve the effect by changing the image's top, left, width and height using a JS setInterval.

So, CSS:

.kenburns {
overflow: hidden;
display: inline-block;
}
.kenburns img {
transition-duration: 5s;
transform: scale(1.0);
transform-origin: 50% 50%;
}
.kenburns img:hover {
transform: scale(1.2);
transform-origin: 50% 0%; /* pan towards top of image */
}


And the corresponding HTML:

<div class="kenburns" style="width:640px; height:480px;">
<img src="image.jpg" width="640" height="480">
</div>


If you hover over the image, it will slowly zoom in and pan towards its top edge.

You can see the effect in action here. And a more complex version with a JS-driven lightbox here.

The (quick, hacky) code is on GitHub.
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