Rich Application Platforms

Well, there's been a bit of a kerfuffle about whether or not Silverlight (nee WPF/E) supports binding, widgets and XMLHttpRequest gubbins. And Adobe has open sourced Flex, as well as having had its Apollo platform out for a bit now. XULRunner is still going, being used for SongBird and Joost, and freshly the DVD version of Wikipedia, though whether or not Mozilla is promoting it well as a platform is under discussion.

Having done an awful lot of XULRunner programming in the last few months, there's still a lot to be done before its an easy to use platform. Quite a lot of undocumented interactions cause crashes - particularly race conditions between XBL bindings being attached and scripts in the body of the document being run, and any manipulation of the tree in script during an XBL constructor. But I don't have any idea how well Silverlight or Apollo handle such things, or even if they support anything as flexible as XBL. There needs to be an XULRunner 2.0 that is a lot more predictable in its behaviour, and less arcane in its invocations.

There's also a big question for the sort of system's I'm interested in - can a platform do something like the ClusterBall WikiPedia visualisation? XULRunner SVG grinds to a halt at a thousand or so arcs, and rotated font anti-aliasing is a bit off. Flash, using Haxe, can render ten thousand arcs, but getting text to rotate is a hassle - it requires embedded fonts, and that means more tools, you can't just set the rotation property. There's quite a lot of weirdness in Flash, half of it is object view graph based, the rest procedural, not everything works and it doesn't play nicely with the browser, for example capturing keyboard input and not being part of selections. As far as I know, there isn't an open high-quality 2D graphics library other than anti-grain 2.4 which will scale and isn't, well, a bit weird. But anti-grain has moved to GPL, and isn't hardware accelerated at 2.4, so what will become of it I don't know. I'd really like a good, object oriented language, with a mix of dynamic and static typing, support for mesh tuple spaces, event queues, first class functions and relations, orthogonal persistence, which runs fast enough, and generates portable, high quality visualisations and information displays. None of the options are quite there yet, but XULRunner's JavaScript and SVG seem to be the most sane.


Pete