AFP architecture

AFP's MO:DCA architecture is a device-independent data stream that governs the interchange of documents. Without such an architecture, information exchange is difficult and unpredictable. A subset of MO:DCA is Mixed Object Document Content Architecture for Presentation (MO:DCA-P), which defines presentation documents.

A mixed object document is the collection of data objects that comprise the document's content and the resources and formatting specifications that dictate the processing functions performed on the content. The term mixed in the MO:DCA-P architecture refers both to the mixture of data objects and the mixture of document constructs that comprise the document's components.

A MO:DCA-P document can contain a mixture of presentation data objects. Each data object type has unique processing requirements. An Object Content Architecture (OCA) is established for each IBM® data object to define its respective syntax and semantics. MO:DCA-P documents can contain data and data objects that are governed by these OCAs:

• Bar Code Object Content Architecture (BCOCA): Describes and generates bar code symbols.
• Color Management Object Content Architecture (CMOCA): Supports the color management information that is required to render presentation data.
• Font Object Content Architecture (FOCA): Supports the digital presentation of character shapes by defining their attributes, such as shape definitions, shape dimensions, and positioning information.¹
• Graphics Object Content Architecture (GOCA): Represents pictures that are generated by a computer, commonly referred to as computer graphics.
• Image Object Content Architecture (IOCA): Represents image information such as scanned pictures.
• Presentation Text Object Content Architecture (PTOCA): Defines text information.

MO:DCA-P documents can also contain or reference some non-OCA data objects that are registered in the MO:DCA-P architecture. Such data objects can be carried in a generic MO:DCA-P object envelope that is called an object container. Some examples of data objects that can be carried in an object container are image objects in Encapsulated PostScript (EPS) format, Portable Document Format (PDF) single-page and multiple-page objects, TrueType and OpenType fonts, and color mapping tables (CMT).

MO:DCA-P data is composed into pages before it is sent to the printer and includes data placement and presentation information (such as which font to use), along with the data to be printed. The data to be printed consists of embedded OCA objects and object containers, and included resources. An embedded object must be physically embedded every time that it is used and you need a separate object for each size and rotation you use. A resource is included in the MO:DCA-P data stream through a reference to the object, so it is not physically embedded in the data stream. You can save BCOCA, GOCA, IOCA, and PTOCA objects as resources. For information about BCOCA, GOCA, IOCA, and PTOCA resources, see Using resources.

To generate MO:DCA-P output from an application program, you can use any of these methods:

• Use a text-formatting program that generates page data, such as Document Composition Facility (DCF).
• Use AFP Toolbox (Program Number 5655-A25) to generate MO:DCA-P data in your application program. You can use this licensed program to generate MO:DCA-P output from an application without having detailed knowledge of the MO:DCA-P data stream and syntax.
• Use one of many products from IBM Business Partners to generate MO:DCA-P output and, with the provided design tools that are both flexible and easy to use, create personalized, customer-oriented documents.

For more information, see AFP Application Programming Interface: Programming Guide and Reference, S544-3872, Mixed Object Document Content Architecture Reference, AFPC-0004, or PSF for z/OS: Introduction.