Over the last few months, our browser team at Nuanti Ltd. has been developing Meta, a brand new WebKit port suited to embedding in OpenGL and 3D applications. The work is being driven by Linden Lab, who are eagerly investigating WebKit for use in Second Life.

While producing Meta we’ve paid great attention to resolving the technical and practical limitations encountered with other web content engines.

uBrowser running with the WebKit Meta engine

High performance, low resource usage

Meta is built around WebKit, the same engine used in web browsers like Safari and Epiphany, and features some of the fastest content rendering around as well as nippy JavaScript execution with the state of the art SquirrelFish VM. The JavaScript SDK is available independently of the web renderer for sandboxed client-side game scripting and automation.

It’s also highly scalable. Some applications may need only a single browser context but virtual worlds often need to support hundreds of web views or more, each with active content. To optimize for this use case, we’ve cut down resource usage to an absolute minimum and tuned performance across the board.

Stable, easy to use cross-platform SDK

Meta features a single, rock-solid API that works identically on all supported platforms including Windows, OS X and Linux. The SDK is tailored specifically to embedding and allows tight integration (shared main loop or operation in a separate rendering thread, for example) and hooks to permit seamless visual integration and extension. There is no global setup or initialization and the number of views can be adjusted dynamically to meet resource constraints.

Minimal dependencies

Meta doesn’t need to use a conventional UI toolkit and doesn’t need any access to the underlying windowing system or the user’s filesystem to do its job, so we’ve done away with these concepts almost entirely. It adds only a few megabytes to the overall redistributable application’s installed footprint and won’t interfere with any pre-installed web browsers on the user’s machine.

Open Source, no licensing fees

In the short term, we’ll be maintaining Meta in a public branch and putting out SDK builds, demo applications and developer documentation. Nuanti will be offering commercial and community support and is anticipating involvement from the gaming industry and homebrew programmers.

In the mid term, we’ll submit Meta as an official component of the WebKit Open Source project, where our developers are already actively involved in maintaining various subsystems.

Find out more

Today we’re launching meta.nuanti.com and two mailing lists to get developers talking. We’re looking to make this site a focal point for embedders, choc-full of technical details, code samples and other resources.

Epiphany using WebKit r32284

We also recently announced our plans to align more closely with the GNOME desktop and mobile platform. To this end we’re making a few technology and organisational changes that I hope to discuss in an upcoming post.

• GNOME ideas
  • Epiphany
    • Desktop integration
    • Bookmark and history integration
    • JavaScript debugger based on Drosera / Web Inspector
  • Evolution
    • Bug tracking aid
  • Empathy
    • WebKit Adium theme support
  • Desktop widgets
  • Integrated web app launcher
• WebKit ideas
  • Cairo SVG backend completion
  • GTK+ port test suite completion
• Mono ideas
  • WebKit-based HTML editor

If in doubt, now’s the time to submit proposals. Already-listed ideas are the most likely to get mentored but students are free to propose their own ideas as well. Proposals for incremental improvements will tend to be favoured over ideas for completely new applications, but a proof of concept and/or roadmap can help when submitting plans for larger projects.

Update: There’s no need to keep asking about the status of an application on IRC/private mail etc. It’s a busy time for the upstream developers but they’ll get back in touch as soon as possible.

Epiphany using WebKit r31371

There is actually still a little work to be done before we can claim a flawless Acid3 pass. Two of the most visible remaining issues in the GTK+ port are :visited (causing the “LINKTEST FAILED” notice in the screenshot) and the lack of CSS text shadow support in the Cairo/text backend which is needed to match the reference rendering.

It’s amazing to see how far we’ve come in the last few months, and great to see the WebKit GTK+ team now playing an active role in the direction of WebCore as WebKit continues to build momentum amongst developers.

Update: We now also match the reference rendering.

If you happen to be going, drop by on my WebKit Mobile presentation, 14:00 Room 01 this Monday. We have a small surprise waiting for Maemo developers.

View slides (PDF format)

Demo sources

• Hosting a Dashboard widget
  • Simple example without JS integration

(Will update this post with more demo code over the next few days.)

Citations

• Slide 20:  All the cool kids are doing it (February 3rd, 2008) — donscorgie.livejournal.com
  
• Slide 30: WebKit and XULRunner (Mozilla) side by side on the XO (August 2nd, 2007) — j5live.com
• Slide 32: WebKit testing methodology for reproducible mobile benchmark performance results
• WebKit/GTK+ build instructions

“WebKit/GTK+ is a brand new port of the WebKit content engine providing standards compliance, high performance and seamless integration with the GTK+ stack. I’ll be demonstrating some of the latest features and taking a look at the ways developers can adopt the WebView API and apply HTML5, CSS, SVG, canvas and AJAX to create location-aware hybrid Web/GTK+ rich internet applications.”

Update: You can now get the slides from the talk.

What?

The talk will be short and light (only a 1/2 hour session) but I’ll be around all weekend so feel free to touch base if you have more questions or ideas. This session will target:

• GTK+ developers
• Web designers
• Anyone looking to deploy online and offline Web applications
  • on the desktop
  • on mobile devices

When?

11:15 - 12:15, Sunday, February 24, 2008

Where?

FOSDEM GNOME/Cross-desktop Developer Room, H.1301

This is the “native Windows port” a lot of people have been waiting for (though it’s technically no more or less native than Safari’s WebKit).

The taxonomy of the new port places it very close to Apple’s WebKit for Windows, which will remain the default build configuration. Both share the same foundation libraries, networking stack and build system.

The only difference is that the proprietary, non-redistributable CoreGraphics has been conditionally replaced (#16979) with the Cairo-based graphics backend developed and maintained by the WebKit GTK+ team. This conveniently lets us maintain the new code as an officially supported sub-port of WebKit without much additional infrastructure.

The result will be a WebKit Windows build that’s open and freely re-distributable for use in Open Source and proprietary/commercial applications (as long as any modifications to WebKit are made available), not just Safari.

This serves as validation of WebKit’s new porting layer, the modularity of the Windows port (Adam Roben and the Win team, you rock!) and the Cairo graphics backend.

Some technical details:

• Provides C++ and COM APIs including a full COM DOM binding. The interfaces aren’t yet final and are expected change.
• The Cairo backend will be used for on-screen rendering as well as printing, including native PDF output.
• Cairo is used for rendering all content including HTML, canvas and SVG.
• Will continue to use Apple’s Open Source CF and CFNetwork libraries for other functionality.
• The CF/CFNetwork libraries will need to be re-built from the available APSL 2.0 source releases. There may be small differences from the Safari binaries that need to be taken into account.
• Still needs work on basics like text rendering and build system integration. Patches welcome. Nothing available for end users yet.

For WebKit/GTK+ fans, the good news is that this work should help bring more developers and testers to the shared Cairo graphics backend. Everyone wins!

At first the colours were a bit off and performance was nothing to write home about. But Øyvind promptly pushed a fix and cooked up a patch to prevent static images being re-uploaded, and things started to fly.

The performance boost is most noticable for SVG and Web pages with large, animated graphics and dynamic content. We’re looking at full repainting is in the hundreds-of-FPS range.

I then turned my attentions to accelerating the canvas element. WebKit/GTK+’s canvas is already the fastest free implementation around, but traditional approaches to rendering the canvas will only get you so far.

Sure enough, with a little more work I had Ilmari Heikkinen’s Canvas Animation Kit Experiment (CAKE) running faster:

(The screenshot was caught during a GL buffer swap, it’s all very smooth in reality.)

Accelerating the canvas was slightly tricky since canvas makes some assumptions about image data, but as we see here it’s quite possible to make it go fast.

Patches should start to appear on #16885. There’s work to be done to improve rendering quality, get text smoothing back etc., but it’s a start.

This feature can be used both to acelerate WebKit/GTK+ and in a standalone configuration with only a GLib dependency, as requested by Linden Lab who are looking at integrating WebKit into their virtual 3D environment.

It should also be usable with the brand new Cairo-based WebKit Windows port (#16979) that’s on its way.

CSS2 ‘WebFonts’

With WebFonts you can define custom font faces by passing a URL to the font file:

@font-face {
  font-family: 'Bitstream Vera Sans';
  src: url('http://www.freedesktop.org/~alp/tmp/Vera.ttf') format(truetype);
}
 
h1 {
  font-family: 'Bitstream Vera Sans', sans-serif;
}

The font gets downloaded and used without installation. A List Apart has some fancy CSS Zen Garden examples showing off the feature:

Now that the WIP Acid3 test requires TrueType/@font-face support, I expect other browser engines will be quick to join Opera and WebKit in implementing this.

SVG fonts

Then there’s the recently added support for SVG fonts.

When #16880 lands, it’ll be possible to use SVG fonts not only in SVG content, but also as a standard WebFont format with @font-face:

@font-face {
  font-family: 'SVGraffiti';
  font-weight: normal;
  font-style: italic;
  src: url("SVGraffiti.svg") format(svg);
}

This is still under development but works remarkably well. Nice work, Nikolas!

SVG font backend for Cairo

SVG fonts aren’t just for the Web — work is under way to make it possible to use them throughout the desktop with the experimental SVG font backend for Cairo. More on this coming very soon.

Checking it out

Building WebKit/GTK+ is now easier with the newly introduced autotools build system. Try the build instructions on GNOME Live! or just use jhbuild (module ‘WebKit’).