X Version 11
Release 6.4
X Print Attributes
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3
X Print Attributes
Printing-specific attributes play a key role in the X Print Service. They provide a general-purpose mecha-
nism for storing information associated with printing. This information includes user print setup options,
printer capabilities, and spooler subsystem options.
The X Print Service selects attributes in a way that is consistent with the X Windows System, ISO/IEC
10175 (ISO DPA), and POSIX 1387.4 print standards. The ISO DPA defines a number of abstract objects
that are managed and manipulated during the printing process. These are known as DPA-Objects. Each
DPA-Object is represented by a set of attributes which characterize that object. Each attribute in turn is com-
posed of an attribute-type (attribute name) and zero or more attribute-values.
The X Print Service utilizes selected DPA-Objects, and for each of these, a subset of the associated
attributes. The DPA-Objects used are:
Server Object
Specifies attributes defined for the X print server.
Job Object
Specifies attributes for a single print request as sent to the spooler.
Document Object
Specifies attributes used to define a single document within a job. If supported by
the implementation, multiple documents may be submitted within a given job.
Printer Object
Specifies attributes that identify printer capabilities.
The X Print Service also provides for changing certain attributes on a page-by-page basis. This is a
capability for which the ISO DPA does not define a separate DPA-Object. This set of attributes is known
within the X Print Service as Page Attributes.
The X Print Service requires some additional attributes that are not defined by the ISO DPA. The attribute
names for these attributes are prefixed with "xp-".
A server implementation can define additional attributes.
This section defines the following sets of attributes for the X Print Service:
·
Server Attributes
·
Printer Attributes
·
Job Attributes
·
Document Attributes
·
Page Attributes
3.1
Attribute Value Defaults And Validation
This section provides an overview of the handling of default attribute values and the procedure for the vali-
dation of attribute values within the X Print Service. Details for individual attributes can be found in the rest
of this chapter.
3.1.1
Assigning Attribute Value Defaults
An attribute specification with an empty value indicates that the attribute has no value. Within X Print Ser-
vice configuration files and attribute pools, an attribute specification that omits the value is effectively
treated as if there were no attribute specification. An empty valued attribute specification that has precedence
over a non-empty attribute specification (for instance, an empty printer qualified attribute over a non-empty