I’m still new to this Google thing, so I’d like to stress that the stuff below is my personal view as a web developer.

Opera is ditching it’s Presto engine in favour of Chromium, which is WebKit + V8 + other bits (http://my.opera.com/ODIN/blog/300-million-users-and-move-to-webkit). I’m pretty split on how I feel about this.

I’m a fan of Chromium, I think it’s the best combination of engines we have, especially in terms of performance. IE is making strides in that area, but they support one OS, an OS they’re also in control of. Chromium is performing better across multiple platforms. As a Chromium fan, I’m delighted to hear Opera is joining.

At risk of getting a slap from my employer, I always felt that Opera “got” the web better than the other browser vendors. They saw the internet as a “web of sites”, not a “store of apps”. Even their articles on “Woo yey! New technology!” had a healthy dose of “Careful now! Progressive enhancement! Accessibility!”. I’m delighted those people are involved in the Chromium project.

As an Opera fan, I’m a bit gutted. Some great people have lost jobs. But I worry that we’ve lost a uniquely built engine that could innovate in different ways.

Opera was the first browser I used after IE6. It’s still the only browser I’ve paid for (excluding those I’ve indirectly paid for via OS bundling). I loved the tabs, I loved the mouse gestures. I loved the overall design of the UI.

On my TV, if I wanted to watch something on iPlayer, I’d use their browser on the Wii rather than the browser on PS3, despite the Wii being lower resolution and having an analogue connection to my TV. The PS3 browser was dire, some Netfront clusterfuck that I’m told had a lot of IE4 in it (a Sony engineer told me this, but I’ve never heard it before or since, but it did have a lot of IE-specific DOM APIs that no other engine had). The PS3 browser is now a much healthier WebKit, as are all Netfront browsers, but the UI still lags behind Opera’s efforts on the Wii. I thought it was a shame Opera didn’t do the DS browser.

Anyway, Opera will still innovate with devices and UI, but what of the engine - Presto?

Presto is full of surprises, and I’m only saying that half-sarcastically. In 2009 I was preparing a talk on JS performance and discovered that, in Opera, pages would continue to be responsive (scrolling, text selection) while JavaScript was stuck in a loop. No other browser did this, JavaScript blocks the UI thread. I believe JS is still on the same thread as the UI in Opera, but it’s chunked up in a way that allows it to return to UI processing regularly. In fact, I believe their initial implementation of Web Workers was all smoke and mirrors, since they had the non-blocking behaviour already. In 2013, you’ll be able to scroll the page while JavaScript is blocking in Chrome, although we’re doing it in a multi-threaded way.

I develop in Chrome, then check stuff in Safari & Firefox. Usually, this would be painless, everything would be as expected (usually). Testing in IE and Opera was often less fun. But here’s the difference, things would be wrong in IE because of bugs, whereas things would be wrong in Opera because they were adhering to the spec (I’m generalising, of course). When Opera did the wrong thing with appcache FALLBACK entries I poured over the spec for a couple of hours on the assumption they were doing it right and the others were doing it wrong. Turns out Opera had a bug, but if any other browser was behaving so differently I’d have instantly assumed it was that browser getting it wrong.

Opera’s text rendering has some nice surprises too. If you include a webfont as normal weight, but render it bold using CSS, some browsers will try to fake the effect of bold on the web font. This looks terrible in every browser except Opera, which is suspiciously accurate for most typefaces. You probably don’t want the browser “making fonts up”, but it was nice to see Opera doing a good job of it.

Not all of Presto’s surprises are pleasant of course, and with the current velocity of browser development there have been more nasty surprises than pleasant ones.

If I didn’t have a stupid £50 bet with my partner that I wouldn’t drink for a week, I’d be raising a glass to Presto. I really hope the Opera engineers and advocates bring the same innovation and attitude to Chromium.