CAN CSA-ISO IEC 8632-4-2001 Information Technology - Computer Graphics - Metafile for the Storage and Transfer of Picture Description Information - Part 4 Clear Text Encoding.pdf

1、National Standard of CanadaCAN/CSA-ISO/IEC 8632-4-01(ISO/IEC 8632-4:1999)International Standard ISO/IEC 8632-4:1999 (second edition, 1999-12-01), has been adopted withoutmodification as CSA Standard CAN/CSA-ISO/IEC 8632-4-01, which has been approved as a NationalStandard of Canada by the Standards C

2、ouncil of Canada.ISBN 1-55324-424-9 March 2001Reference numberISO/IEC 8632-4:1999(E)ISO/IEC1999The Canadian Standards Association, which The Standards Council of Canada is theoperates under the name CSA International coordinating body of the National Standards system, (CSA), under whose auspices thi

3、s National Standard has a federation of independent, autonomousbeen produced, was chartered in 1919 and accredited by organizations working towards the furtherthe Standards Council of Canada to the National development and improvement of voluntaryStandards system in 1973. It is a not-for-profit, sta

4、ndardization in the national interest.nonstatutory, voluntary membership association The principal objects of the Council are to foster engaged in standards development and certification and promote voluntary standardization as a means activities. of advancing the national economy, benefiting theCSA

5、 standards reflect a national consensus of producers health, safety, and welfare of the public, assisting and users including manufacturers, consumers, and protecting the consumer, facilitating domestic retailers, unions and professional organizations, and and international trade, and furthering int

6、ernationalgovernmental agencies. The standards are used widely cooperation in the field of standards.by industry and commerce and often adopted by A National Standard of Canada is a standard whichmunicipal, provincial, and federal governments in their has been approved by the Standards Council ofreg

7、ulations, particularly in the fields of health, safety, Canada and one which reflects a reasonablebuilding and construction, and the environment. agreement among the views of a number of capableIndividuals, companies, and associations across Canada individuals whose collective interests provide to t

8、heindicate their support for CSAs standards development greatest practicable extent a balance ofby volunteering their time and skills to CSA Committee representation of producers, users, consumers, andwork and supporting the Associations objectives others with relevant interests, as may be appropria

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10、irectors are chosen. Sustaining Approval of a standard as a National Standard ofmemberships represent a major source of income for Canada indicates that a standard conforms to theCSAs standards development activities. criteria and procedures established by the StandardsThe Association offers certifi

11、cation and testing services Council of Canada. Approval does not refer to thein support of and as an extension to its standards technical content of the standard; this remains thedevelopment activities. To ensure the integrity of its continuing responsibility of the accreditedcertification process,

12、the Association regularly and standards-development organization.continually audits and inspects products that bear the Those who have a need to apply standards areCSA Mark. encouraged to use National Standards of CanadaIn addition to its head office and laboratory complex in whenever practicable. T

13、hese standards are subject Toronto, CSA has regional branch offices in major centres to periodic review; therefore, users are cautioned across Canada and inspection and testing agencies in to obtain the latest edition from the organizationeight countries. Since 1919, the Association has preparing th

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15、ating the exchange of goods and 270 Albert Street, Suite 200services through the use of standards, certification and Ottawa, Ontario, K1P 6N7related services to meet national and international needs. CanadaFor further information on CSA services, write toCSA International178 Rexdale BoulevardToronto

16、, Ontario, M9W 1R3CanadaAlthough the intended primary application of this Standard is stated in its Scope, it is importantto note that it remains the responsibility of the users to judge its suitability for their particular purpose.Registered trade-mark of Canadian Standards AssociationInformation t

17、echnology Computer graphics Metafile for the storage andCAN/CSA-ISO/IEC 8632-4-01 transfer of picture description information Part 4: Clear text encodingMarch 2001 CSA/1CAN/CSA-ISO/IEC 8632-4-01Information technology Computergraphics Metafile for the storageand transfer of picture descriptioninforma

18、tion Part 4: Clear textencodingCSA PrefaceStandards development within the Information Technology sector is harmonized with internationalstandards development. Through the CSA Technical Committee on Information Technology (TCIT),Canadians serve as the Canadian Advisory Committee (CAC) on ISO/IEC Joi

19、nt Technical Committee 1 onInformation Technology (ISO/IEC JTC1) for the Standards Council of Canada (SCC), the ISO memberbody for Canada and sponsor of the Canadian National Committee of the IEC. Also, as a member of theInternational Telecommunication Union (ITU), Canada participates in the Interna

20、tional Telegraph andTelephone Consultative Committee (ITU-T).This International Standard was reviewed by the CSA TCIT under the jurisdiction of the StrategicSteering Committee on Information Technology and deemed acceptable for use in Canada. (Acommittee membership list is available on request from

21、the CSA Project Manager.) From time to time,ISO/IEC may publish addenda, corrigenda, etc. The CSA TCIT will review these documents for approvaland publication. For a listing, refer to the CSA Information Products catalogue or CSA Info Update orcontact a CSA Sales representative. This Standard has be

22、en formally approved, without modification, bythese Committees and has been approved as a National Standard of Canada by the Standards Council ofCanada.March 2001 CSA International 2001All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permiss

23、ion ofthe publisher. ISO/IEC material is reprinted with permission. Inquiries regarding this National Standard of Canada shouldbe addressed to CSA International, 178 Rexdale Boulevard, Toronto, Ontario, M9W 1R3.Reference numberISO/IEC 8632-4:1999(E)ISO/IEC 1999INTERNATIONALSTANDARDISO/IEC8632-4Secon

24、d edition1999-12-01Information technology Computergraphics Metafile for the storage andtransfer of picture descriptioninformation Part 4:Clear text encodingTechnologies de linformation Infographie Mtafichier de stockageet de transfert des informations de description dimages Partie 4: Codage en clair

25、 des textesISO/IEC 8632-4:1999(E)PDF disclaimerThis PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall notbe edited unless the typefaces which are embedded are licensed to and installed on the computer performing the edit

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28、dress given below. ISO/IEC 1999All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronicor mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

29、ISOs member bodyin the country of the requester.ISO copyright officeCase postale 56 Gb7 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 734 10 79E-mail copyrightiso.chWeb www.iso.chii ISO/IEC 1999 All rights reservedISO/IEC 8632-4:1999(E) ISO/IEC 1999 All rights reserved iiiContents Page1 Scope12

30、 Conformance.13 Normative references .24 Notational conventions 25 Entering and leaving the metafile environment.25.1 Generic clear text and instantiations25.2 Implicitly entering the metafile environment25.3 Designating and invoking the CGM coding environment from ISO 2022 .36 Metafile format.36.1

31、Character repertoire36.2 Separators46.2.1 Element separators.46.2.2 Parameter separators.56.2.3 Comments in the metafile 56.3 Encoding of parameter types.56.3.1 Integer-bound types56.3.2 Real-bound types66.3.3 String-bound types.76.3.4 Enumerated types.86.3.5 Derived types.86.3.6 Bitstream datatype9

32、6.3.7 Structured data record operands96.4 Forming names .96.4.1 Words deleted .96.4.2 Words added .106.4.3 Words used unabbreviated106.4.4 Abbreviations10ISO/IEC 8632-4:1999(E)iv ISO/IEC 1999 All rights reserved6.4.5 The derived element names.127 Encoding the CGM elements .177.1 Encoding delimiter e

33、lements.177.2 Encoding metafile descriptor elements187.3 Encoding picture descriptor elements257.4 Encoding control elements287.5 Encoding graphical primitive elements307.6 Encoding attribute elements367.7 Encoding escape elements427.8 Encoding external elements 437.9 Encoding segment control and se

34、gment attribute elements.437.10 Encoding application structure descriptor elements458 Clear text encoding defaults459 Profile encoding rules, proforma, and Model Profile 469.1 Encodings469.2 Metafile defaults469.3 Profile Proforma tables (PPF)46Annex A (normative) Clear text encoding dependent forma

35、t grammar.48Annex B (informative) Clear text encoding example .49ISO/IEC 8632-4:1999(E) ISO/IEC 1999 All rights reserved vForewordISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission)form the specialized system for worldwide standardization.

36、 National bodies that are members of ISO or IECparticipate in the development of International Standards through technical committees established by therespective organization to deal with particular fields of technical activity. ISO and IEC technical committeescollaborate in fields of mutual intere

37、st. Other international organizations, governmental and non-governmental, inliaison with ISO and IEC, also take part in the work.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.In the field of information technology, ISO and IEC have establish

38、ed 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.Attention is drawn to th

39、e possibility that some of the elements of this part of ISO/IEC 8632 may be the subject ofpatent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.International Standard ISO/IEC 8632-4 was prepared by Joint Technical Committee ISO/IEC JTC 1, Informationt

40、echnology, Subcommittee SC 24, Computer graphics and image processing.This second edition cancels and replaces the first edition (ISO/IEC 8632-4:1992), which has been technicallyrevised. Note that the previous edition of ISO/IEC 8632-4, published in 1992, was a first edition but second editionwas in

41、dicated by error on its cover page and in the foreword.ISO/IEC 8632 consists of the following parts, under the general title Information technology Computer graphics Metafile for the storage and transfer of picture description information: Part 1: Functional specification Part 3: Binary encoding Par

42、t 4: Clear text encodingAnnex A forms a normative part of this part of ISO/IEC 8632. Annex B is for information only.NOTE In previous editions of ISO/IEC 8632, Part 2 defined a Character Encoding. Part 2 was withdrawn in 1998, due to its lackof implementation and use.ISO/IEC 8632-4:1999(E)vi ISO/IEC

43、 1999 All rights reservedIntroduction0.1 Purpose of the clear text encodingThe Clear Text Encoding of the Computer Graphics Metafile (CGM) provides a representation of the Metafilesyntax that is easy to type, edit and read. It allows a metafile to be edited with any standard text editor, using thein

44、ternal character code of the host computer system.0.2 Primary objectivesa) Human editable: The Clear Text Encoding should be able to be hand edited or, if desired, hand constructed.b) Human friendly: The Clear Text Encoding should be easy and natural for people to read and edit. Althoughwhat is easi

45、est and most natural is a subjective judgment that varies among users, contributing factors such asease of recognition, ease of remembering, avoidance of ambiguity, and prevention of mistyping have all beenconsidered.c) Machine readable: The Clear Text Encoding should be able to be parsed by softwar

46、e.d) Suitable for use in a wide variety of editors: The Clear Text Encoding should not have any features that makeit difficult to edit in normal text editors.e) Facilitate interchange between diverse systems: The Clear Text Encoding should be encoded in such a wayas to maximize the set of systems wh

47、ich can utilize it. No assumptions should be made as to word size orarithmetic modes used to interpret the metafile.f) Use standardized abbreviations as much as possible: Where language encoding of other graphics standardshave established standard abbreviations, or where common practice in the data

48、processing and graphicsindustries has established well known abbreviations, these abbreviations are used. In accordance with theprinciple of “least astonishment”, this approach should minimize the time needed to learn to use this encoding.0.3 Secondary objectivesBecause the other CGM encoding (the C

49、GM Binary Encoding) is targeted toward CPU efficiency and informationdensity, these objectives are considered of secondary importance for the CGM Clear Text Encoding.0.4 Relationship to other International StandardsThe set of characters required to implement the Clear Text Encoding is a subset of those included in nationalversions of ISO/IEC 646. Any character set that can be mapped to and from that subset may be used to implementthe encoding.For certain elements, the CGM defines value ranges as being reserved for registratio