Thomas Fuchs
Hi, I'm Thomas Fuchs. I'm the author of Zepto.js, of script.aculo.us, and I'm a Ruby on Rails core alumnus. With Amy Hoy I'm building cheerful software, like Noko Time Tracking and Every Time Zone and write books like Retinafy.me.
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So, what’s the status of hardware acceleration, really?

August 28th, 2010

It seems that Google Chrome is getting all the developer luv these days, but there are some facts that people get confused.

Here’s the deal: Google Chrome uses Apple’s WebKit HTML/CSS rendering engine that powers Safari. Google is not the creator of Webkit, Apple is.* What Chrome does is basically adding two components to the mix, Chrome’s user interface and a replacement JavaScript engine (V8, also used by node.js).

But, there are some parts of the Webkit engine that are either proprietary or are not easily ported to operating systems other than Mac OS X (or iOS). First and foremost among those parts is Safari’s ability to hardware-accelerate the compositing of web pages, including 3D CSS transformations.

These transformations and the added speed of the compositing are not available in Google Chrome (but they are on the way by means of a reimplementation). Neither are they available on Android.

Actually, regardless of what Google states in its design document about GPU accelerated compositing in Chrome (a good read otherwise, but they say hardware-acceleration is only available on Safari for Mac), there are several browsers “in the wild” that do support hardware-accelerated compositing (including 3D CSS), some of them cross-platform:

Here is the blurb from Safari’s features page:

Safari supports hardware acceleration on Mac and PC. With hardware acceleration, Safari can tap into graphics processing units to display computing-intensive graphics and animations, so standards like HTML5 and CSS3 can deliver rich, interactive media smoothly in the browser. Safari on Snow Leopard has improved hardware acceleration for plug-ins.

Tweet-sized conclusion: Hardware acceleration in (non-beta) browsers is only available on Safari (all platforms). There’s no hardware-accceleration (yet) for Chrome (or for Android).

(Other browsers will add support for hard-acceleration too, but it seems that all will be Windows-only for now, with both Firefox 4 and Internet Explorer 9 only supporting that platform.)

*WebKit was orginally created as a fork of the KTHML rendering engine. While the main development effort is done by Apple, patches come in from a lot of sources, and companies like Nokia, Google, RIM and Palm are all contributing, mainly to support their specific branches and platforms. Some of the ideas found in Google Chrome, namely the sandboxing of individual tabs, will make their way into WebKit2, a refactoring and reimplementation that is currently underway.