Microsoft KB Archive/70968

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Support for Compound Document Architecture (CDA)

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Q70968

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The information in this article applies to:


 * Microsoft Word for Windows, versions 2.0, 2.0a, 2.0a-CD, 2.0b, 2.0c

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SUMMARY
CDA is a document description standard developed by Digital Equipment Corporation (DEC). It is very similar to an international standard known as Office Document Architecture (ODA).

Like ODA, CDA separates the logical structure of a document from the layout applied to the elements in the structure. Microsoft does not currently supply a CDA converter, but future support for both reading and writing of CDA format is planned. We will post new information here as it becomes available. For possible third-party workarounds, query on the following words in the Microsoft Knowledge Base:

"conv: and cda"

MORE INFORMATION
DEC CDA is a data interchange technology for representing a compound document. A compound document may be defined as a unified collection of data including text, graphics, embedded objects, and/or video that may be edited, formatted, or otherwise processed as a single document.

DEC promotes CDA as a means for moving compound documents (CDs) across dissimilar document-processing systems without traditional information loss. Solving the problem of converting valuable data locked within proprietary formats is an extremely high priority for large system manufacturers such as DEC and IBM. The CDA standard is designed to eventually eliminate the need for creating individual custom conversion utilities for every different application by creating a standard interchange format.

As stated above, a compound document is a unified collection of data that may be edited, formatted, or otherwise processed as a single document. A compound document contains a number of integrated components that may include proportionally spaced text in various forms and styles, graphics (including raster and vector), and embedded data from applications that process data other than text, such as spreadsheets and forms applications.

In the world of large, standardized compound document architectures (for example, ODA, CDA, and CALS), there are two distinct forms of data comprising a document: revisable and final. A compound document expressed in a revisable form contains abstract rather than concrete component relationships. This is analogous to the manner in which Word for Windows does not define specifically where each line of a document ends. Instead, the actual determination of a line end is a function of margins, font size, and so on.

A final (presentation) form representation of a document is analogous to a snapshot of a document as displayed on an output device at a given time (as on the printed page or on the screen). A final form of a document is produced by a formatter (that is, printer engine) with the capacity to layout a revisable form in accordance with the capabilities of the target device. Flexible relationships between document objects do not exist in final form; therefore, a final form cannot be taken to a revisable form.

A Rich Text Format (RTF) representation of a Word document can be viewed as something between revisable and final form. RTF contains some application calculated information (final form) such as field contents. However, running heads and footers (revisable form) are not actually formatted for an entire document, and are only specified and left to the application reading the RTF to layout.

CDA can maintain either revisable or final form data, or both in a single compound document. The format of either of these data forms is most commonly expressed in terms of Digital Document Interchange Format (DDIF) or Digital Table Interchange Format (DTIF).

DDIF documents are conceived as a hierarchy of objects that consist of one or more content elements, which include characters, polylines, frames, and galleys. There are two classes of objects in a document: logical and layout objects.

Logical objects (such as a paragraph) group content elements (characters and words) by logical relatedness (a topic).

Layout objects (such as text and page frames) group content elements (enclosed text within a frame and frames within a page) using spatial relationships (text and frame positioning relative to text frame and page frame margins). The hierarchies of logical and layout groupings may differ greatly. For instance, the characters that make up a paragraph may be split across columns or pages.

Additional query words: 2.00a 2.00a-CD 2.00b 2.00c textconv

Keywords : kbconversion

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