If you are a Print Driver developer using the XPS Filter Pipeline, you can now use unmanaged XPS functions that were previously only available as .NET managed code. Because these functions were originally written for .NET, they could not be called from a Print driver until now.
These XPS functions will enable driver developers to modify XPS documents in greater detail when they are in the filter pipeline. This will make it possible to make custom changes to the documents before they get to the printer. In addition, this API allows you to have access to the document metadata and content.
This API was previously unavailable to Print Driver developers, but has been recently converted to unmanaged code and is now documented in the Windows SDK. The new documentation includes overviews of the XPS Object Model and complete coverage of all interfaces, methods, structures, and enumerators that are implemented by the XPS API.
For more information, see the XPS Document Programming Guide and Reference at http://msdn.microsoft.com/en-us/library/dd316976(VS.85).aspx.
－Seth McEvoy [MSFT], WDK Senior Programming Writer