ANSI INCITS ISO IEC 9636-1-1991 Information Technology - Computer Graphics - Intefacing Techniques for Dialogues with Graphical Devices (CGI) - Functional Specification - Part 1 Ov.pdf

1、INCITS/ISO/IEC 9636-1-1991 (R1997)(formerly ANSI/ISO/IEC 9636-1-1991 (R1997)for Information Technology -Computer Graphics -Intefacing Techniques forDialogues with Graphical Devices (CGI) -Functional Specification -Part 1: Overview, Profiles, and ConformanceANSIIISOIIEC 9636-l -1991 Redesignation of

2、ANSI X3.161 (never published) American National Standard for Information Technology - Computer Graphics - Interfacing Techniques for Dialogues with Graphical Devices (CGI)- Functional Specification - Part 1: Overview, Profiles, and Conformance Secretariat Computer and Business Equipment Manufacturer

3、s Association Approved August 6, 1992 American National Standards Institute, Inc. AmericanNationalStandardApproval of an American National Standard requires review by ANSI that therequirements for due process, consensus, and other criteria for approval havebeen met by the standards developer.Consens

4、us is established when, in the judgment of the ANSI Board of StandardsReview, substantial agreement has been reached by directly and materiallyaffected interests. Substantial agreement means much more than a simplemajority, but not necessarily unanimity. Consensus requires that all views andobjectio

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6、ts, processes,or procedures not conforming to the standards.The American National Standards Institute does not develop standards and will inno circumstances give an interpretation of any American National Standard.Moreover, no person shall have the right or authority to issue an interpretation ofan

7、American National Standard in the name of the American National StandardsInstitute. Requests for interpretations should be addressed to the secretariat orsponsor whose name appears on the title page of this standard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any ti

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9、tute.Published byAmerican National Standards Institute11 West 42nd Street, New York, New York 10036Copyright 1991 by Information Technology Industry Council (ITI)All rights reserved.These materials are subject to copyright claims of International Standardization Organization (ISO),International Elec

10、trotechnical Commission (IEC), American National Standards Institute (ANSI), andInformation Technology Industry Council (ITI). Not for resale. No part of this publication may bereproduced in any form, including an electronic retrieval system, without the prior written permission of ITI.All requests

11、pertaining to this standard should be submitted to ITI, 1250 Eye Street NW, Washington, DC20005.Printed in the United States of America4 Contents Page Foreword 1” Introduction ” 1 Scope . 1 1.1 Relationship of CC1 to a computing environment 1 1.2 Position of CGI in a managed environment 2 2 Normativ

12、e references . 3 3 Definitions and abbreviations .:. . 4 3.1 Organization of the definitions 4 3.2 Definitions . 4 3.3 Abbreviations 16 Reference models 18 4.1 Introduction 18 4.2 Model for CC1 client/target relationships 18 4.2.1 CC1 configurations diagram 18 4.2.2 Types of clients 20 4.23 Types of

13、 targets . 20 4.3 Example configurations . 21 43.1 CC1 Virtual Devices as GKS workstations . 21 4.3.2 CGM interpretation using CC1 22 4.33 CC1 Virtual Devices as 3D workstations 22 4.3.4 Input/output workstations as combinations of CC1 Virtual Devices 22 4.4 Relationship to other standards . 24 4.4.

14、1 Introduction . 24 4.4.2 CC1 data encodings standards . 24 4.43 CC1 language bindings standards 24 4.4.4 Relation to GKS (IS0 7942 1985) 24 4.45 Relation to GKS3D (IS0 8805 1989) and PHIGS (ISO/IEC 9592 1989). 24 4.4.6 Relation to CGM (IS0 8632 1987) . 25 4.4.7 Relation to Procedures for Registrati

15、on of Graphical Items (ISOAEC TR 9973 1988) . 25 Concepts 26 5.1 Introduction 26 5.2 Global CC1 concepts . 26 5.2.1 CC1 Graphic Object Pipeline 26 5.23 CC1 state model . 32 5.23 Description tables 32 5.2.4 State lists . 32 5.25 Static and dynamic state lists . 33 5.2.6 The structure of description t

16、ables and state lists 33 5.2.7 The principles of inquiry . 33 5.28 Error philosophy 34 5.2.9 Method of describing functions . 36 5.2.10 Data types employed . 37 5 5.2.11 Formal grammar . . , Overview of ISO/IEC 9636-2 Overview of ISO/IEC 9636-3 Overview of ISO/IEC 9636-4 Overview of ISO/IEC 9636-5 O

17、verview of ISOAEC 9636-6 5.3 5.4 5.5 5.6 5.7 39 Control 40 outplt . 40 Segments . 40 Input and echoing 41 Raster 41 . . . III . ;. _ 6 7 A B C D E F Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 6.1 6.2 6.3 6.4 6S 6.6 6.7 Profile definition 42 6.1.1 Constituency Profile registration . 43 Foundation Profiles 43 Constituency Profiles 44 6.3.1 GKS Constituency Profiles . 44 63.2 CGM Constituenc

19、y Profile 44 6.33 Advanced l-Way Output Constituency Profile 44 Foundation Profile definition 44 6.4.1 2-WAY OUTPUT Foundation Profile 44 6.4.2 1 -WAY OUTPUT Foundation Profile 45 6.4.3 - It protects the large software investment made by both users and vendors because the software will not be render

20、ed obsolete by the introduction of new devices; - It allows developers of new software to focus on higher-level graphics functions and applications instead of device-level functions; - It reduces maintenance of software systems because the standard encourages modularity; - It increases vendor indepe

21、ndence for the user because any system designed to use a particular device can more easily be changed to use some other device; - It allows vendors to develop and market devices that will easily interface to the customers system; - It enables users, manufacturers and vendors to take advantage of new

22、, lower-cost graphics hardware designs. The total systems hardware cost may be reduced because system redesign may not be necessary. vii Design requirements To realize the benefits described above, a number of design principles have been adopted: a) The Computer Graphics Interface should provide a s

23、uitable set of functions for the description of a wide range of pictorial information; b) The Computer Graphics Interface should provide a suitable set of functions for the necessary CGI session control of a wide range of graphics devices; c) The Computer Graphics Interface should address the more u

24、sual and essential features found on graphical devices directly and should provide access to less common facilities; d) The design of the Computer Graphics Interface should not preclude extension of ISO/IEC 9636 at a later stage to cover facilities currently not standardized; e) The Computer Graphic

25、s Interface should be usable from GKS (Graphical Kernel System - IS0 7942). In particular, the CGI should include functional capability to support the various levels of a GKS workstation in an efficient and concise manner, without compromising the ability of the interface to support non-GKS systems

26、in an efficient and concise manneq f) The Computer Graphics Interface should be compatible with the Computer Graphics Metafile - IS0 8632. In particular, those CGM elements not associated with the file-oriented aspects of the CGM shall have corresponding CGI functions which have identical abstract n

27、ames and parameterization; g) ISO/IEC 9636 should address the needs of different applications that have conflicting reements for - allocation of processing burden between host and device; - speed of generation and interpretation of functions; - ease of transfer through different transport mechanisms

28、. Design criteria The above requirements were used to formulate the following design criteria: a) b) d a) 0) 0 it does not contain functional descriptions. The functional capability provided by the CGI is separate from the specification of any particular encoding format or language binding. ix . .,

29、_-.- c. / _. - _d.- b) provide an interface standard for computer graphics device manufacturers and suppliers; c) provide an inquiry and response mechanism for graphics device capabilities, characteristics, and states; d) provide a standard graphics escape mechanism to access non-standard graphics d

30、evice capabilities; e) allow for future functional extension of the CGI. In addition to the CGI functionality, device classes, and Foundation and Constituency Profiles are defined. The device classes included in the CGI arc output (OUTPUT), input (INPUT), and output/input (OUTIN). Profiles allow sub

31、sets of the CGI functions and features to be defined to suit particular well identified groups of users. There is also provision for Constituency hofiles to be registered after ISO/lEC 9636 is published. The Computer Graphics Interface (CGI) is a standard functional and syntactical specification of

32、the control and data exchange between device-independent graphics software and an implementation of a CGI Virtual Device. The syntax of the CGI, presented in ISO/lEC 9636, is an encoding-independent and binding-independent specification. Any similarity of the examples or function specifications to a

33、 particular encoding technique or language is coincidental unless explicitly stated otherwise. The functions specified provide for the representation of a wide range of two-dimensional pictures and for control over their display on a wide range of graphics devices. The functions are split into group

34、s that perform device and CGI session control, specify the data representations used, control the display of the picture, perform basic drawing actions, control the attributes of the basic drawing actions, acquire data from input devices, and provide access to non-standard device capabilities. This

35、part of ISO/IEC %36 gives an overview of ISO/IEC 9636, explains the relationship between its parts and their relation to other standards, describes a reference model for graphics systems, and defines certain Foundation and Constituency Profiles. ISO/IEC 9636-2, ISO/IEC 9636-3, ISO/IEC 96364, ISO/IEC

36、 9636-5, and ISO/lEC 9636-6 specify the CGI functions for different functional areas using an abstract notation. ISO/lEC 9637 and ISO/IEC 9638 define standard data stream encodings, procedural library bindings, and single entry point procedural bindings of the CGI. 1.1 Relationship of CGI to a compu

37、ting environment ISO/IEC %36 describes graphical services provided by a Virtual Graphics Device. The model for description of these services is expressed in terms of graphical capabilities of a single instance of a hypothetical graphics device. In all but the simplest of 1 ISO/IEC %36-l : 1991 (E) S

38、cope Relationship of CC1 to a computing environment computing environments, CGI functions alone will not be sufficient to provide complete control over a device. Additional functions, not included in ISO/IEC 9636, will likely be needed. Examples of such functions include - means to configure (sets o

39、f) physical devices to be accessed as CGI Virtual Devices; - means to control a device capable of offering CGI-defined services as well as other, non-CGI-defined services, such as those implied by IS0 2022 and IS0 6429; - means to differentiate among separate instances of CGI Virtual Devices in the

40、same computing environmenu - means of defming or determining communication paths from CGI clients to CGI Virtual Devices. In some cases, other standards exist that describe the functions required. For example, various communications standards address the needs of the last point above. In other cases

41、, no standards may exist, but the tasks indicated are outside the scope of ISO/IEC 9636. 1.2 Position of CGI in a managed environment There exists a large and growing family of computer controlled display systems that have the ability to act as if they are multiple individual display devices. Resour

42、ces, most notably the visible drawing surface resources, are coordinated by the display system so that multiple non-cooperating client programs can each access the services of a separate individual device while all are actually running in a single managed environment. The graphical capabilities of t

43、he CGI Virtual Device may suffice, in some instances, as the basis for implementing a complex, multiple-client display system. However, the complete needs of such a system are quite complex, include many non-graphical services, and (as current practice shows) are quite technology dependent. The CGI

44、does not, therefore, purport to be a generally sufficient interface on which a managed display environment may be built. Rather, within a managed environment, the CGI will be one of the managed interfaces in a way not visible to the CGI client without recourse to services not part of ISO/IEC 9636. T

45、he use of the CGI as a managed interface within a managed display environment is not limited to raster devices. ISO/IEC 9636-l : 1991 (E) 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISODEC 9636. At the

46、 time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO/TJX 9636 are encouraged to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and IS0 mainta

47、in registers of currently valid International Standards. IS0 646 : 1983 Information processing - IS0 7-bif co- _- .Ldz.-.- ISO/IEC 9636-l : 1991 (E) 3 Definitions and abbreviations 3.1 Organization of the definitions The following list of definitions describes the usage of words or phrases which hav

48、e been given special technical meaning in the context of ISO/IEC 9636. These meanings are not in conflict with dictionary meanings or usage in other IS0 and IEC standards. However, there are usually additional semantics associated with the words or phrases which are essential to understanding ISO/IE

49、C 9636. The list of definitions is arranged in alphabetical order of main entry. Occasionally a term will be used with or without optional qualification in the text: in such cases, the optional qualification appears in parentheses in the term. Under each main entry, certain derived terms may also be covered; all such derived terms are underlined. With a few exceptions, where the appropriate main heading may not be immediately obvious, derived terms do not have separate main entries. Where a phrase appears in italic text, its definition may be as another main entry or it may be a derive