ISO/IEC 8632-3:1992/Amd 1:1994

ISO/IEC
INTERNATIONAL
8632-3
STANDARD
Second edition
1992-10-01
AMENDMENT 1
1994-12-15
Information technology - Computer graphics -
Metafile for the storage and transfer of picture
description information -
Part 3:
Binary encoding
AMENDMENT 1: Rules for profiles
Technologies de /‘information - lnfographie - Mktafichier de stockage et de
transfefl des informations de description d’images -
Partie 3: Codage binaire
AMENDEMENT 7: R&g/es pour profils
Reference number
lSO/IEC 8632-3:1992/Amd.l:1994(E)

---------------------- Page: 1 ----------------------
ISO/IEC 8632-3: 1992/Amd.l: 1994(E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the Inter-
national 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.
Amendment 1 to International Standard ISO/IEC 8632-3:1992 was prepared by
Joint Technical Committee ISO/IEC JTC 1, Information technology, Sub-
committee 24, Computer graphics and image processing.
0 ISODEC 1994
All rights reserved. Unless otherwise specified, no part of this publication may be
reproduced or utilized in any form or by any means, electronic or mechanical, including
photocopying and microfilm, without permission in writing from the publisher.
ISO/IEC Copyright Office l Case postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii

---------------------- Page: 2 ----------------------
ISO/IEC 863203:1992/Amd.l:1994 (E)
@1s0/lEc
Metafile for the storage and transfer
Information technology - Computer graphics -
of picture description information -
Part 3:
Binary encoding
AMENDMENT 1: Rules for profiles
Page iii
Add to Contents:
” 10 Encoding rules, proforma, and Model Profile
.............................................
10.1 General principles
10.1.1 Encodings .
10.1.2 Metafile defaults .
”
10.2 Profile Proforma tables .
Clause 9, page 59
Add a new sentence before the first sentence:
“Conformance of metafiles to ISO/IEC 8632 is defined in terms of profiles.”
Change the first sentence to read:
“A metafile conforms to this binary encoding if it conforms to a profile and meets the following
requirements. ”
Change the first bullet item to read:
I’
- Each metafile element described in this part is coded in the manner described in this International
Standard and a profile.”
Add a new clause 10 aper page 59
“10 Encoding rules, proforma, and Model Profile
10.1 General principles
10.1.1 Encodings
Precisions are defined consistently with the principles of the encodings, not necessarily for inter-encoding
translation. Where both considerations might apply, compatibility with the principles of the encoding
are considered first and inter-encoding translation second.
1

---------------------- Page: 3 ----------------------
ISO/lEC 863203:1992/Amd.l:1994 (E)
@ISO/IEC
10.1.2 Metafile defaults
Clause 8 addresses all elements which have default values. While no profile can change these values,
an equivalent effect may be achieved by use of the METAFILE DEFAULTS REPLACEMENT element.
Profiles may require that a metafile contain a METAFILE DEFAULTS REPLACEMENT element with
well-defined content.
10.1.3 Floating point values
Profiles shall prohibit the values NaN, positive infinity, and negative infinity for ANSI/IEEE 754 floating
point numbers (see 5.5). For 32-bit floating point, NaN corresponds to e=255 and f # 0. For 64-bit
floating point, N&N corresponds to e=2047 and f # 0. For 32-bit floating point, positive and negative
infinity are defined respectively by s =0 and s = 1, with e=255 and f=O. For 64-bit floating point,
positive and negative infinity are defined respectively by s =0 and s = 1, with e =2047 and f =O.
10.2 Profile Poforma tables
The Profile Proforma is contained in table 12 and table 13. These tables, when completed by the author
of the profile, contain the normative specifications of the profile.
The PPF tables have 3 columns:
- The first identifies the element to be addressed.
- The second is the template for the profile writer to complete.
- The third is the completed specification for the Model Profile.
Each element to be addressed comprises a “row” of the table.
The first column of each row contains:
1) A unique identifier for that row, T.n.m, indicating that this is row “m” of table “n”. For
example, row T. 12.2 is the second row of table 12 (for the REAL PRECISION element).
2) The name of the element for that row, for example, REAL PRECISION.
3) The lowest metafile version (vl, v2, or v3) for which each element is defined.
4) References to other sections of this clause, for additional normative or informative material.
A second column is the PPF template for profile authors. Each row contains:
5) A check box indicating that all specifications for this row for this profile are exactly the same
as those for this row in the Model Profile.

---------------------- Page: 4 ----------------------
@1s0/IEc ISO/IEC 863203:1992/Amd.l:1994 (E)
6) Check boxes to indicate whether the element is required, permitted, or prohibited in metafiles
conforming to the pro
...