ISO/IEC 7942-4:1998

INTERNATIONAL
STANDARD
First edition
1998-09-01
Information technology - Computer
graphics and image processing -
Graphical Kernel System (GKS) -
Part 4:
Picture part archive
- lnfographie et traitement d ’image -
Technologies de /‘information
Syst&me graphique Kernel (GKS) -
Partie 4: Archive de partie d ’image
Reference number
ISO/I EC 7942-4: 1998(E)

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ISO/IEC 7942-4: 1998(E)
Contents
...
111
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Foreword
iv
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Introduction
1
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1 Scope
2
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2 Normative references
3
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3 Definitions.
4
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4 Concepts .
4
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4.1 The structure of a GKS-94 picture part archive
4
. .
4.2 Metafile elements
4
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4.3 Delimiter elements
4
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4.4 Functional capability
4
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4.4.1 Introduction
5
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4.4.2 PPA-SET
. 5
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4.5 Representation of picture parts in the picture part archive
7
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5 Abstract specification of new element
7
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5.1 Data type definitions and abbreviations
7
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5.2 Delimiter element
8
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6 Encodings of the GKS-94 Picture Part Archive
8
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6.1 Introduction
8
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6.2 Character encoding
8
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6.3 Binary encoding
8
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6.4 Clear text encoding
9
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A Formal grammar.
10
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B New element list
10
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B.l Introduction
10
B.2 Delimiter elements .
0 ISO/IEC 1998
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ISO/IEC 7942-4: 1998(E)
0 ISO/IEC
Foreword
IS0 (the International Organization for Standardization) and IEC (the International Electrotechnical Commis-
sion) 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, ISOLIEC
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 7942-4 was prepared by Joint Technical Committee ISO/IEC JTC 1, Informa-
tion technology, Subcommittee SC 24, Computer graphics and image processing.
ISO/IEC 7942 consists of the following parts, under the general title Information technology - Computer
graphics and image processing - Graphical Kernel System (GKS).
Part I: Functional description
Part 2: NDC metaBle
Part 3: Audit trail
Part 4: Picture part archive
Annexes A and B form an integral part of this part of ISO/IEC 7942.
. . .
111

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0 ISO/IEC
ISO/IEC 7942-4: 1998(E)
Introduction
The GKS-94 picture part archive provides a file format and encodings suitable for the storage and retrieval of
GKS-94 picture parts. The file format consists of a set of elements that can be used to describe the contents of
picture parts. This part of ISO/IEC 7942 extends the provisions of ISO/IEC 8632: 1992/Amd.2: 1995.
iv

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ISO/IEC 7942-4: 1998(E)
INTERNATIONAL STANDARD @ ISOAEC
Information technology - Computer graphics and image processing -
Graphical Kernel System (GKS) - Part 4: Picture part archive
1 Scope
This part of ISO/IEC 7942 provides a file format and encodings for the storage and retrieval of GKS-94 picture
parts. It is based on Part 2 of ISO/IEC 7942, the NDC metafile, which is itself an extension of the Computer
Graphics Metafile, Version 4 defined by ISO/IEC 8632:1992/Amd.2: 1995 (all parts).
1

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ISO/IEC 7942-4: 1998(E) @ ISO/IEC
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this
part of ISO/IEC 7942. At the time of publication, the editions indicated were valid. All standards are subject to
revision, and parties to agreements based on this part of ISO/IEC 7942 are encouraged to investigate the possi-
bility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain
registers of currently valid International Standards.
ISO/IEC 7942- 1: 1994, Information technology - Computer graphics and image processing - Graphical Kernel
System (GKS) - Part I: Functional description
ISO/IEC 7942-2: 1997, Information technology - Computer graphics and image processing - Graphical Kernel
System (GKS) - Part 2: NDC metafile
ISO/IEC 8632: 1992/Amd.2: 1995, Information technology - Computer graphics - Meta$le for the storage and
transfer of picture description information (all parts). AMENDMENT 2: Application Structuring extensions.

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ISO/IEC 7942-4: 1998(E)
0 ISOfIEC
3 Definitions
For the purposes of this part of ISO/IEC 7942, the definitions given in ISO/IEC 7942-l and ISO/IEC 8632-
1 /Amd.2 apply.

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ISO/IEC 7942-4: 1998(E)
0 ISO/IEC
4 Concepts
4.1 The structure of a GKS-94 picture part archive
The structure of a GKS-94 picture part archive follows the GKS-94 NDC metafile described in Part 2 of this
International Standard. This in turn follows the structure of the Computer Graphics Metafile (CGM) standard
(ISO/IEC 8632-l : 1992). The structure of a picture part archive is shown in figure 1. PPA is used as an abbre-
viation for PICTURE PART ARCHIVE and MF for metafile
BEGIN PPA MF MD . . . END MF
f- ,
Figure 1: General form of a picture part archive
A Computer Graphics Metafile is a collection of eleme
...