Seadragon AJAX and Deep Zoom
It's been a while since my last post, but that's because I've been also helping out with the Seadragon AJAX release. You have to check out what we did there. You can now browse single images in web browsers where Silverlight is either not supported or not installed.
Check out Seadragon AJAX in action:
The picture above is actually my own bike. I did this as an example of a sparse image, a technology I am saving for a later post. The above image is actually roughy 1 terra pixel in size. Of course it doesn't have that kind of resolution in every spot, in fact it's really only one terra pixel in the spot where the the image gallery spirals off into seemingly infinity.
Now look below at deep zoom:
So how does this all work, and what's the difference?
If you look at the AJAX version you'll notice a few things. For one, it's much slower (i.e. lower framerate than the deep zoom version). It's not as buttery smooth as deep zoom. The reason for that is the way browser renders images: it's just not that fast. Then, on top of it, there is a ton of blending between the various levels of detail, and all of that has to be done in the browser's DOM. It's not really what the browser was designed to do.
In Silverlight on the other hand, we've had the chance to improve the software rasterizer - the deep zoom rendering not only takes advantage of the ultra fast software rasterizer in Silverlight, we've also been able to speed up the blending significantly by optimizing the blending with direct bitmap manipulation. All of this shows that while AJAX is a great technology for some scenarios, but if you want the last bit of performance, you'll be better off with Silverlight.
Then the next obvious difference is the lack of collections in Seadragon AJAX. For the deep zoom app above I cobbled together all of the images in the Seadragon AJAX gallery and put them into a collection that I posted on Silverlight streaming. So you can see all of the images from the Seadragon AJAX gallery at once in Deep Zoom, and you could move the images independently. BTW - how I built this collection is another whole topic post for another day.
So why did we do Seadragon AJAX? It's quite simple. I've been in a number of meetings where people loved the zooming UIs that Deep Zoom enables, but advertisers usually back off when they hear it requires an ActiveX install. They don't even want to invest in cooler zooming UIs because of that, or they want to wait until Silverlight has a larger deployed base. Well, now there is no reason to wait. You can use Seadragon AJAX as the downlevel version when Silverlight is not installed, then graduate the user to a smoother, richer experience with Silverlight Deep Zoom if it is installed.
And then of course, Seadragon AJAX is so cool, we just had to do it!
