ANSI INCITS ISO IEC 9592-2-1997 Information technology - Computer graphics and image processing - Programmer s Hierarchical Interactive Graphics System (PHIGS) - Part 2 Archive fil.pdf

1、INTERNATIONAL STANDARD ISOAEC 9592-2 Second edition 1997-11-15 Information technology - Computer graphics and image processing - Programmers Hierarchical Interactive Graphics System (PHIGS) - Part 2: Archive file format Technologies de /information - lnfographie et traitement de /image - Interface d

2、e programmation du systkme graphique hikrarchisb (PHIGS) - Par-tie 2: Format de fichier darchive Reference number ISOAEC 9592-2: 1997(E) Adopted by INCITS (InterNational Committee for Information Technology Standards) as an American National Standard.Date of ANSI Approval: 2/5/98Published by America

3、n National Standards Institute,25 West 43rd Street, New York, New York 10036Copyright 2002 by Information Technology Industry Council (ITI).All rights reserved.These materials are subject to copyright claims of International Standardization Organization (ISO), InternationalElectrotechnical Commissio

4、n (IEC), American National Standards Institute (ANSI), and Information Technology Industry Council(ITI). Not for resale. No part of this publication may be reproduced in any form, including an electronic retrieval system, withoutthe prior written permission of ITI. All requests pertaining to this st

5、andard should be submitted to ITI, 1250 Eye Street NW,Washington, DC 20005.Printed in the United States of AmericaISO/IEC 9592-2:1997(E) Contents 1 Scope . .l 2 Normative references 2 3 Definitions . .3 4 Concepts . 4 4.1 Introduction. . .4 4.2 Notational conventions . .5 4.3 Archive file structure

6、.5 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 . .6 0 ISWIEC 1997 All rights reserved. Unless otherwise specified. no part of this publication may he repro

7、duced or utilized in any form or by any means. electronic or mechanical. Including photocopying and microfdm. without permission m writing from the publisher. ISO/IEC Copyright Office - Case postale S6 l CH- I2 I I Genkve 20 l Switxrland Printed m Switzerland ii OISO/IEC LSO/IEC 9592-2:1997(E) Forew

8、ord 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 c

9、ommittees 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 t

10、he work. In the field of information technology, IS0 and IEC have established a joint technical committee, ISO/IEC JTC I. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by

11、 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 I, Irfiwmarior technology, Subcommittee SC 24. Computer graphics and imuge processing. This second edition cancels and replaces the first edition (ISO/IEC

12、 9592-2: 19X9), which has been technically revised. It also incorporates Amendment 1: 1992. ISO/IEC 9592 consists of the following parts, under the general title ltformatiorz techtlology - Computer graphics arid imrrge processitq - ProgrcrmmerS Hierarchical Itlteructive Graphics System (PHIGS): - Pa

13、rt I: Fuwtiorlrrl descriltiotl - Part 2: Archive,file fbrmut - Part 3: Specificatiotl for clear-te.u etlcodiq of archive file . . . II1 ISO/IEC 9592-2:1997(E) Introduction OISO/IEC This part of ISO/IEC 9592 defines an archive file format suitable for the storage and retrieval of PHIGS structure and

14、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)

15、 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

16、 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 preclu

17、de extensions at a later stage to cover further facilities provided in future revisions of ISO/IEC 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 ret

18、rieval, 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 PH

19、IGS 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) Ort

20、hogonality: 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 sup

21、port 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 f

22、or 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

23、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 fo

24、r both standard and private encodings of the structure elements described in ISO/IEC 9592-l and this part of ISOAEC 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 o

25、f 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 fil

26、e format on IS0 8632. iv INTERNATIONAL STANDARD OISOAEC ISO/IEC 9592-2:1997(E) Information technology - Computer graphics and image processing - Pro rammers Hierarchical Interactive Graphics System (PHIGS) - Part 2: Arc a ive file format 1 Scope This part of ISO/IEC 9592 specifies a file format suit

27、able 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

28、 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 implemen

29、tation. Clause 4 describes the organization of an archive file. ISO/IEC 9592-3 specifies a clear-text encoding of the archive file format. ISOLIEC 9592-2:1997(E) 2 Normative references OISO/IEC The following standards contain provisions which, through reference in this text, constitute provisions of

30、 this part of ISO/IEC 9592. 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 9592 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated

31、 below. Members of IEC and IS0 maintain registers of currently valid International Standards. ISO/IEC 8632:1992, Information technology - Computer graphics - MetaJile for the storage and transfer of picture description information - Part I : Functional description - Part 2 : Character encoding - Par

32、t 3 : Binary encoding - Part 4 : Clear text encoding OISO/IEC 3 Definitions ISO/IEC 9592-2:1997(E) For the purposes of this part of ISO/IEC 9592 the following definitions apply. NOTE As far as possible, graphics terminology which is commonly accepted and consistent with other graphics Standards is u

33、sed. 3.1 archive file descriptor: A group of elements that describe the functional capabilities needed to process the archive file. 3.2 archive file generation: The process that produces a PHIGS archive file. 3.3 archive file retrieval: The process that reads a PHIGS archive file, retrieves the cont

34、ents, and transfers the result to the PHIGS centralized structure store. ISOAEC 9592-2:1997(E) 4 Concepts OISO/IEC 4.1 Introduction The objective of the archive file is to provide for the description, storage, and communication of graphical information on (possibly off-line) storage media. To accomp

35、lish this, this part of ISO/IEC 9592 defines the form (syntax) and func- tional behaviour (semantics) of a set of elements that may occur in the archive file. There are seven classes of archive file elements: a) DELIMITER ELEMENTS: delimit significant entities within the archive file. b) ARCHIVE FIL

36、E DESCRIPTOR ELEMENTS: describe the functional content, default conditions, identification, and characteristics of the archive file. c) OUTPUT PRIMITIVE ELEMENTS: describe the visual components of a structure in the archive file. d) AlTRIBUTE ELEMENTS: describe the appearance of output primitive ele

37、ments. e) MODELLING TRANSFORMATION ELEMENTS: describe the geometric relationships between output primi- tive elements. f) MISCELLANEOUS ELEMENTS: describe elements which facilitate the usage of structures. These include label elements, the execute structure element, the view index element, the pick

38、identifier element, elements related to name sets, application data, and elements which describe device- or system-dependent structure elements (GSEs) (some of which may be defined in the IS0 International Register of Graphical Items which is maintained by the Registration Authority); however, the e

39、lements are not otherwise standardized). g) EXTERNAL ELEMENTS: communicate information not related to the contents of structures, An archive file is a collection of elements from this set of seven archive element types. The contents of an archive file are never directly displayed; instead, the struc

40、tures represented in the archive file are first retrieved by the archive file retrieval process and stored in the PHIGS centralized structure store. Any archive file contains certain delimiter elements. Archive file delimiters identify the beginning and end of an archive file. The BEGIN ARCHIVE FILE

41、 delimiter has parameters for a name by which the archive file can be identified. Structure delimiters identify the beginning and end of a structure definition within an archive file. BEGIN STRUCTURE has parameters specifying which structure is being defined. Once the archive file descriptor has bee

42、n read, access to individual structures, on a random as opposed to sequential basis, may be safely accomplished if the encoding, access mechanism and implementation permit. The version number of the archive file is: h) Version number 1: the archive file contains only structure elements defined in th

43、e PHIGS BASIC profile. i) Version number 2: the archive file contains only structure elements defined in the PHIGS PLUS profile. j) Version number 3: the archive file contains structure elements defined in the PHIGS FULL profile. Other parts of ISO/IEC 9592 may define standardized archive file encod

44、ings. Other encodings may be developed, either for private use or as additional parts of ISO/IEC 9592. All such encodings will conform to the functionality specified in this part of ISO/IEC 9592. 1) For the purpose of this part of ISO/IEC 9592 and according to the rules for the designation and opera

45、tion of registration authorities in the ISO/IEC Directives, the IS0 and IEC Councils have designated the following as the registration authority: National Institute of Standards and Technology (National Computer Systems Laboratory), The Registration Authority for Graphical Items, A-266 Technology Bu

46、ilding, Gaithersburg, MD 20899, USA, 4 OISO/IEC ISO/IEC 9592-2:1997(E) Concepts Notational conventions 4.2 Notational conventions The following notation is used in 4.3: a) Upper-case strings are terminals. b) Lower-case strings are nonterminals. c) The following metasymbols define productions, group

47、ing, and repetition - - + “becomes” or “is realized as” * + *star closure (0 or more occurrences) + exactly one of x or y 4.3 Archive file structure The archive file structure is defined below by a formal grammar over the following symbols: BEGIN ARCHIVE FILE END ARCHIVE FILE BEGIN STRUCTURE END STR

48、UCTURE ARCHIVE FILE VERSION ARCHIVE FILE DESCRIPTION STRUCTURE ELEMENT EXTERNAL ELEMENT Any standardized encoding of PHIGS archive files defines the further structuring of these terminal symbols. For exam- ple, subclause 4.3.1 of ISO/IEC 9592-3, defines the clear text encoding of BEGIN ARCHIVE FILE.

49、 The start symbol for the formal grammar is . - - * * - - := * * * I * * := * * * * ISO/IEC 9592-2:1997(E) OISO/IEC 5 Conformance 5.1 Forms of conformance This part of ISO/IEC 9592 specifies the format of PHIGS archive files; operations or required capabilities of archive file processors are specified in ISO/IEC 9592- 1. An archive file may conform to this part of ISO/IEC 9592 in one of two ways. Full conformance occurs when the archive file conforms to one of the encodings specified in one of the parts of ISO/IEC 9592 (e.g., ISO/IEC 9592-3). Functional conformance occurs when the