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OASIS CGM Open specification - WebCGM 2.0 - Introduction to WebCGM
This section's subsections are informative, unless otherwise
indicated.
This subsection is normative.
The key words words “MUST”, “MUST NOT”,
“REQUIRED”, “SHALL”, “SHALL NOT”,
“SHOULD”, “SHOULD NOT”,
“RECOMMENDED”, “MAY”, and
“OPTIONAL” are to be interpreted as described in [RFC2119].
This subsection is normative.
- ISO/IEC 8632:1999(E)
- Information technology - Computer graphics - Metafile for the storage
and transfer of picture description information
- Part 1: Functional description
- Part 3: Binary encoding
- Part 4: Clear text encoding
Available at the ISO page of Publicly
Available Standards. CGM:1999 was reaffirmed by ISO, without
changes, at its 5-year review in 2004. The WebCGM profile is defined by
reference to the ISO standard.
- RFC 3986
- Uniform Resource
Identifiers (URI): Generic Syntax, available at
http://www.ietf.org/rfc/rfc3986.txt .
- RFC 3987
- Internationalized
Resource Identifiers (IRIs), available at
http://www.ietf.org/rfc/rfc3987.txt .
- RFC 1951
- Deutsch, P., "DEFLATE Compressed Data Format Specification version
1.3", RFC1951, Aladdin Enterprises, May 1996,
URL: http://www.w3.org/Graphics/PNG/RFC-1951
- ISO/IEC 10646-1:1993, AM2:1996
- Information technology - Universal multiple-octet coded character set
(UCS)
- Part 1: Architecture and Basic Multilingual Plane
AMENDMENT 2: UCS Transformation Format 8 (UTF-8)
- REC-png
- PNG (Portable Network Graphics) Specification, Version 1.0, URL:
http://www.w3.org/TR/REC-png-multi
- RFC 2119
- IETF RFC 2119:
Key words for use in RFCs to Indicate Requirement Levels, S.
Bradner, March 1997. Available at http://www.ietf.org/rfc/rfc2119.txt
.
- XML 1.0
- XML 1.0, third
edition, http://www.w3.org/TR/2004/REC-xml-20040204/ .
- Namespaces in XML
- http://www.w3.org/TR/REC-xml-names
- SVG 1.1
- http://www.w3.org/TR/SVG11/
- DOM Level 3 Core
- Document
Object Model (DOM) Level 3 Core Specification, available at
http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/.
- DOM Level 3 Events
- Document
Object Model Level 3 Events Specification, available at
http://www.w3.org/TR/2003/NOTE-DOM-Level-3-Events-20031107.
- HTML 4.01
- HTML 4.01 Specification, available at
http://www.w3.org/TR/html401/.
- CSS 2.0
- http://www.w3.org/TR/CSS2/
- Xpointer Framework
- http://www.w3.org/TR/2003/REC-xptr-framework-20030325/
- Cascading Profiles
- Definition and description of how to write a profile based on WebCGM
as the starting point, for closely related technical application
sectors. At http://www.cgmopen.org/technical/cascading-profiles.html
- WebCGM 2.0 Requirements
- The requirements used to define the new functionality for WebCGM 2.0.
At http://www.oasis-open.org/committees/download.php/14243/WebCGM_20_Requirements.html
- SpecGL 1.0
- The W3C QA
Framework: Specification Guidelines, has guided the
inclusion of the normative Conformance clause, and other
conformance-related details of WebCGM. At http://www.w3.org/TR/qaframe-spec/.
The scope of this WebCGMTM 2.0 specification includes three
components:
- an intelligent graphics profile of the ISO Computer Graphics Metafile
(CGM) standard (ISO/IEC 8632:1999), tailored to the requirements for
scalable 2D vector graphics in electronic documents on the World Wide
Web;
- a WebCGM Document Object Model (DOM), which provides an application
programming interface to WebCGM objects in WebCGM-supporting
applications;
- definition of a standard WebCGM XML Companion File (XCF), which allows
applications to externalize some non-graphical metadata from WebCGM
instances, yet maintain a tight binding of the metadata to WebCGM
objects.
WebCGM is a set of specifications targeted especially at the effective
application of the ISO CGM:1999 standard to representation of 2D graphical
content within Web documents.
CGM has been an ISO standard since 1987, and CGM has been a registered
media type (image/cgm) for the Internet and the World Wide Web since December
1995. WebCGM 1.0, comprising the original intelligent graphics profile of ISO
CGM, was first published in 1999, was re-released in 2001 with error
corrections, and forms the basis for the WebCGM 2.0 intelligent graphics
profile of this WebCGM 2.0 specification.
For much more information about WebCGM, please see the WebCGM
FAQ, as well as other numerous other references and reading materials, on
the OASIS CGM Open Web site.
The WebCGM profile is a conforming profile of ISO CGM under the
stipulations of CGM:1999 Clause 9, "Profiles and conformance", and it
utilizes the Profile Proforma (PPF) of CGM:1999 Annex I.1, Proforma tables,
for representation of the element-by-element content details.
The WebCGM profile is an "intelligent graphics" profile, which means that
in addition to graphical content based on CGM Versions 1-3, the profile
includes non-graphical content based on CGM Version 4, Application
Structures. The non-graphical content allows the definition of hierarchies of
application objects, as well as the association of metadata, such as link
specifications and layer definitions, with the objects.
The original WebCGM 1.0 profile resulted from a collaboration between the
CGM Open Consortium and W3C Graphics Activity. The requirements that
determined the content selection for CGM 1.0 were derived from:
The selection criteria for the WebCGM profile include:
- graphical content: it should have high expressive power; and, it should
be both widely implemented, and implementable with a reasonable level of
effort.
- intelligence content (structuring and metadata elements): criteria came
from the above-mentioned requirements document, [cgmreq], plus additional
requirements generated during the first 5 years of deployment and use of
the WebCGM 1.0 standard.
The upgraded content of the WebCGM 2.0 profile -- a set of additions,
deletions, and modifications applied to the 1.0 profile -- has been shaped
by:
- additional requirements generated during 5 years of deployment of
WebCGM 1.0 in industry;
- apparent non-use of certain 1.0 features;
- need for convergence with similar profiles in closely related
industries.
The DOM and XCF components of WebCGM 2.0 derive from requirements
generated during 5 years of deployment of WebCGM 1.0 in industry. The WebCGM
2.0 Requirements document summarizes these requirements.
The WebCGM 2.0 intelligent graphics profile, like its predecessor WebCGM
1.0, is a profile of the ISO CGM:1999 standard, designed for effective
application of CGM in technical Web applications. WebCGM is not aimed at or
optimized for any particular technical application sector, but is intended to
satisfy general requirements shared by different but closely related
technical Web applications.
Following five years of deployment and application of WebCGM and other
technical profiles (such as Air Transport Association's), some divergence
began to appear. WebCGM 2.0 represents a major effort towards convergence of
intelligent graphics profiles in closely related industries. In fact, it is
the intention of the authors and publishers of WebCGM 2.0 that it be used as
a basis for the definition of industry-specific profiles. The use of WebCGM
as a core profile from which specific-industry technical profiles are derived
and defined is defined in Cascading
Profiles.
CGM:1999 Clause 9, "Profiles and conformance", prescribes that profiles
shall maintain revision control by using a standard "ProfileEd" keyword.
Instances of a profile carry this edition information in their identification
section.
This release of WebCGM is Edition 2.0 ("ProfileEd:2.0"). Higher editions
may be defined in the future.
This release is the first release of WebCGM 2.0. There may be future
releases of WebCGM 2.0, for maintenance and defect correction.
WebCGM is written in these major sections:
- This section, containing introductory and overview material, which is
mostly informative, but does contain two normative
subsections.
- A WebCGM Concepts section,
informative but not normative.
- Detailed descriptive material on the V4
content of WebCGM, including Content Model which can be used for V4
content. This section is normative.
- The definition of a standard XML Companion
File (XCF) for use with WebCGM. This section is
normative.
- The definition of the WebCGM Document
Object Model (DOM). This section is normative (including
normative IDL definitions of the DOM interfaces).
- The Profile Proforma (PPF),
comprising an extensive table which addresses every element of the ISO
CGM standard, per CGM:1999 Annex I. This section is
normative.
- The normative Conformance section
describes the conformance targets and conformance details of WebCGM.
- The ECMAScript chapter give a
normative description of an ECMAScript binding for WebCGM DOM.
- Appendixes, including informative
sections such as revision history, comparison of WebCGM 1.0 and 2.0,
etc.
This subsection is informative (non-normative).
Copies of the ISO standards may be obtained from ISO:
ISO Central Secretariat
1, rue de Varembe
Case postale 56
CH-1211 Geneve 20
Switzerland
For the purpose of this Recommendation and according to the rules for the
designation and operation of registration authorities in the ISO/IEC
Directives, the ISO and IEC Councils have designated the following as the
registration authority:
National Imagery and Mapping Agency (NIMA)
(Joint Interoperability Test Command)
The Registration Authority for Graphical Items
Building 57305
Fort Huachuca
Arizona
85613-7020
USA
For more information on the CGM standard itself, the CGM Open Web site has both bibliographic
references, and short articles on CGM topics:
- CGM Open
- http://www.cgmopen.org/
The following World Wide Web sites have more information on CGM:
- ISO/JTC1/SC24
- http://www.cwi.nl/JTC1SC24/
- W3C WebCGM Overview
- http://www.w3.org/Graphics/WebCGM
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