Windows Presentation Foundation, which provides the rich front end for Vista, will also eventually be available in compact form for other platforms, such as the Apple Macintosh, older versions of Windows, and smart devices such as phones or PDAs.

The portability is possible because the underlying technologies of Expression, including XAML, an XML-based user markup language for page layouts; and JavaScript, a scripting language for developing the controls on these pages, are not closely tied to any platform.

However, the impetus for Microsoft making parts of the rich Vista client available elsewhere are not simply because the technology makes it possible. Instead, the driver is that Microsoft and others are competing to deliver the de facto standard for the next-generation rich Internet client.

The cross-platform version, for now code named Windows Presentation Foundation Everywhere (WPF/E), would only get a subset of Vista richness.

According to Wayne Smith, UK-based Senior Product manager for Expression tools, WPF/E will likely support vector graphics, video, animation, text, and controls. However, 3D and hardware accelerators will probably not be part of the package. Right now we’re just scoping this out, he said, adding that WPF/E is mostly concept at this point.

It won’t be part of the Vista release, set for the second half of next year.

When WPF/E becomes available, it will be in the form of an Active X control that can be embedded in applications or as browser plug-in.