7. The computer storage medium of claim 6 , wherein the application programming interface further comprises an XPS document class that provides access to XPS digital signatures, XPS document properties, and from which the document sequence may be accessed.
6. A computer storage medium containing instructions that when executed perform acts comprising: accessing a collection of resources specified for the creation of an XPS document, the XPS document based upon an extensible markup language; establishing individual pages from the collection of resources according to an XPS specification for a page; establishing at least one sub-document as a collection of the individual pages; establishing the XPS document as a collection of at least one sub-document, providing access to the document sequence via a document sequence writer interface and the method further comprising rendering the XPS document by providing access to the document sequence via a document sequence reader interface; defining global properties for the XPS document including accepting digital signatures for the XPS document; and providing an application programming interface that performs the acts of accessing the collection, establishing the individual pages, establishing the at least one sub-document, establishing the XPS document, and defining the global properties, the application programming interface comprises: providing a resource class that comprises the XPS resources; providing a page class that comprises the page reader interface and the page writer interface; providing a document class that comprises the document reader interface and the document writer interface; and providing a document sequence class that comprises the document sequence reader interface and the document sequence writer interface.