August 13, 2003
Copyright 2003 Printer Working Group, All Rights Reserved.
In traditional printing environments, clients rely on font downloads when they are not sure a given character is embedded in a chosen printer. As printing moves to small clients, downloading may not be an option and clients have a need to know what characters are available in a given device.
In discussing this problem, we use the term charset as defined in [RFC2978], which says in part:
The term "charset" is used here to refer to a method of converting a sequence of octets into a sequence of characters.
We define the term character repertoire as a named subset of the characters defined in a given charset standard (e.g., Unicode/4.0) that are supported for output rendering of document data. A repertoire, while defined in terms of one charset, may be used in the context of another charset (e.g., the value of "document-charset" in the the IPP Document object) through suitable mapping. For example, the repertoire "ISO 8859-7" may be used in a Unicode context, in which case it names the set of Unicode characters mapping to the underlying characters in ISO 8859-7.
The tasks of this group include:
Define a normative mechanism ("Repertoire Supported") by which a printing device (especially an XML-oriented one) can advertise which groups of characters it is able to render.
Produce a technical specification for that mechanism, and support incorporation of that mechanism in the PWG Semantic Model.
Produce Best Practice material recommending usage techniques for that mechanism to improve interoperability.
Consult with other groups (e.g. UPnP) on character repertoire issues.
Study issues of country and language, as they relate to character repertoires.
Study related topics, such as font download and application to non-XML (legacy) PDLs.
Summer/Fall 2003: Specification: The Printer Working Group Standard for Character Repertoire Interoperability
Summer/Fall 2003: Best Practices for use of Character Repertoires