ISO/IEC 9592-2:1997

INTERNATIONAL
STANDARD
Second edition
1997-1 I-15
Information technology - Computer
graphics and image processing -
Programmer’s Hierarchical Interactive
Graphics System (PHIGS) -
Part 2:
Archive file format
lnfographie et fraitement de /‘image -
Technologies de 1 ‘information -
Interface de programmation du systeme graphique hikrarchisk (PHIGS) -
Partie 2: Format de fichier d’archive
Reference number
ISO/I EC 9592-2: 1997(E)

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ISOLIEC 9592-2: 1997(E)
Contents
1
1 Scope .
2
2 Normative references .
3
3 Definitions . .
4
4 Concepts .
4
4.1 Introduction .
.................................................................................... 5
4.2 Notational conventions
5
4.3 Archive file structure .
6
5 Conformance . .
6
5.1 Forms of conformance .
......................................................... 6
5.2 Functional conformance of archive files
6
5.3 Full conformance of archive files .
6
5.4 Conformance of other encodings .
6
5.5 Profiles . .
0 ISO/IEC 1997
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ii

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ISO/IEC 9592-2: 1997(E)
OISO/IEC
Foreword
IS0 (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form
the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC participate in the
development of International Standards through technical committees established by the respective organization to deal
with particular fields of technical activity. IS0 and IEC technical committees collaborate in fields of mutual interest.
Other international organizations, governmental and non-governmental, in liaison with IS0 and IEC, also take part in
the work.
In the field of information technology, IS0 and IEC have established a joint technical committee, ISO/IEC JTC 1. Draft
International Standards adopted by the joint technical committee are circulated to national bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote.
International Standard ISO/IEC 9592-2 was prepared by Joint Technical Committee ISO/IEC JTC 1, hformatio~z
.
technology, Subcommittee SC 24, Computer graphics and image processing.
This second edition cancels and replaces the first edition (ISO/IEC 9592-2: 1989), which has been technically revised. It
also incorporates Amendment 1: 1992.
ISO/IEC 9592 consists of the following parts, under the general title Information technology - Computer graphics arld
image processiflg - Programmer’s Hierarchical Interactive Graphics System (PHIGS):
- Part I: Fuwtiorlal description
- Part 2: Archive file fbrmut
- Part 3: Specificatiorl for clear-text encoding of archive file
.
. . .
111

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OISO/IEC
ISO/IEC 9592-2: 1997(E)
Introduction
This part of ISO/IEC 9592 defines an archive file format suitable for the storage and retrieval of PHIGS structure and
structure network definitions. The file format consists of a set of elements that represent structure elements in a way
that is compatible between systems of different architectures and devices of differing capabilities and design.
The main reasons for producing a standard PHIGS archive file are:
a) to allow structure definitions to be stored in an organized way on a graphical software system;
b) to facilitate transfer of structure definitions between different graphical software systems;
c) to enable structure definitions to be transferred between different computer graphics installations.
To reach these objectives, a number of design principles were adopted:
d) The archive file should provide a suitable set of elements for the storage of structure definitions.
e) The archive file should support all elements required by ISO/IEC 9592- 1.
f) The design of the archive file should not preclude extensions at a later stage to cover further facilities provided in
future revisions of ISOKIEC 9592- 1.
g) The archive file design should allow formats which address the needs of different application programs that have
conflicting requirements for size of archive file, speed of archival and retrieval, readability, editability and ease of
transfer through different transport mechanisms.
The following design criteria have been adopted in order to meet the design requirements listed above.
h) Completeness: The functionality specified by the archive file design should be capable of storing PHIGS struc-
ture definitions without recourse to other mechanisms.
i) Consistency: The elements of the archive file should match the elements of the PHIGS structure one for one.
j) Extensibility: The ability to add new elements and generality to the archive file design should not be precluded.
k) Orthogonality: No element in the archive file should depend on other elements to define the functionality being
represented.
The PHIGS archive file functionality has been designed so that, although its main usage is anticipated as being com-
pletely within a single implementation, it is possible to support multiple archive file formats some of which may be
standard formats and some of which may be private formats. It is intended that conversion between formats should be
readily possible and may occur off-line from any PHIGS application program. This will allow private formats to be
used on-line for greater efficiency with conversion to standard formats off-line for portability. Support for standard for-
mats on-line is not precluded.
The specific mechanisms of archive file generation and retrieval are not described in this part of ISO/IEC 9592,
although it does describe the intended result of such processing. The basic set of archive file elements includes the
PHIGS capability for the addition of application-dependent data.
The functionality provided by the archive file is separated from the specification of any particular encoding format. This
part of part of ISO/IEC 9592 provides for both standard and private encodings of the structure elements described in
ISO/IEC 9592-l and this part of ISO/IEC 9592. The rules for conformance of private encodings are also specified in
this part of ISO/IEC 9592. ISO/IEC 9592-3 (clear text encoding of archive file) defines a standard encoding of the
PHIGS archive file format: a clear-text encoding. Other standard encodings may be defined. These encodings are in
different forms to support differing requirements for readability, storage efficiency, and processing efficiency.
This part of ISO/IEC 9592 draws extensively for its model of a file format on IS0 8632.

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INTERNATIONAL STANDARD OISO/IEC ISO/IEC 9592-2: 1997(E)
Computer graphics and image processing -
Information technology -
Pro rammerSs Hierarchical Interactive Graphics System (PHIGS) - Part 2:
Arc P ive file format
1 Scope
This part of ISO/IEC 9592 specifies a file format suitable for the storage and retrieval of PHIGS structure definitions.
The file format consists of an ordered set of elements that can be used to describe structures in a way that is compatible
between systems of different architectures and implementations supporting different programming languages.
The archive file is defined in such a way that, in addition to sequential access to the whole archive file, random access to
individual structure definitions is well-defined; whether this is available in any system that uses this part of ISO/IEC
9592 depends on the medium, the encoding and the implementation.
Clause 4 describes the organization of an archive file.
ISO/IEC 9592-3 specifies a clear-text encoding of the archive file format.

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ISO/IEC 9592-2: 1997(E) OISO/IEC
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this p
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