Tom Arah looks at Microsoft’s upcoming Expression Studio and its underlying WPF and XAML-based strategy.

Key to understanding Microsoft's future plans is an appreciation of Windows Vista’s new presentation subsystem, Windows Presentation Foundation (WPF)...

This is a total rewrite and rethink of the operating system’s design duties offering resolution-independent, vector-based graphics and font handling, in-built multimedia support, native databinding, adaptive onscreen layouts, fixed print-based documents, animation, 3D, and so on. In short: whenever you want to move beyond the design limitations of today’s static HTML web pages, Microsoft wants you to turn to WPF. So how do you go about putting this design power to use?
Perhaps the most significant feature of WPF is its intrinsic and complete support for XAML (eXtensible Application Markup Language). XAML (pronounced zammel) lets the average designer take advantage of all WPF features through a comparatively straightforward markup language. Crucially XAML is declarative rather than procedural so that you only need to declare what you want to see – a title this big here, a user form here and so on – without worrying about how this will actually be achieved.

XAML is a markup language for describing WPF content

In this regard XAML is very like HTML whose declarative text markup is interpreted by the web browser. Look at a XAML file, for example and you will see a bunch of tags and attributes in angled brackets surrounding the actual textual content. In theory this means that you could write XAML code in a text editor but in practice that isn’t feasible – with dozens of tags and attributes, XAML is far more complicated than HTML and also far stricter and less forgiving – make an error and the whole project will fail.
To take advantage of WPF via XAML then you need dedicated tools. The potential here is enormous as XAML is an open standard so expect a flood of new authoring solutions to appear along with new XAML export capabilities for existing applications. In fact the first solutions are already out of the gate such as Mobiform’s Aurora XAML designer and Michael Swanson’s XAML exporter for Illustrator. Inevitably though Microsoft has a massive head start on third-party developers and a massive strength in terms of controlling where WPF and XAML go in the future and it is determined to press home its advantage. Alongside the launch of Vista and WPF then Microsoft is launching its new Expression suite of applications aimed directly at the designer.