Editor's Draft 28 May 2014
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http://www.idpf.org/epub/do/epub-do-20140528.html
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Copyright © 2014 International Digital Publishing Forum™
All rights reserved. This work is protected under Title 17 of the United States Code. Reproduction and dissemination of this work with changes is prohibited except with the written permission of the International Digital Publishing Forum (IDPF).
EPUB® is a registered trademark of the International Digital Publishing Forum.
Editors
Bill Kasdorf (Apex CoVantage)
Markus Gylling (IDPF)
Darryl Lehmann (Imagineeringart.com)
Matt Garrish (Invited Expert)
Status of this Document
This document is an Draft Specification, produced by the IDPF EPUB 3 Working Group. This document may be updated, replaced, or rendered obsolete by other documents at any time.
Open issues in this draft
This section will be removed when this document leaves draft status. Open issues in this draft include the following:
Table of Contents
2.2 The distributable-object collection
2.3.4 Publication Type Conformance
This section is informative
This specification, EPUB Distributable Objects, defines how individual discrete entities in a source EPUB® Publication that comprise a Distributable Object are identified and tagged through the use of the Package Document collection element [Publications301].
Distributable Objects can exist in three distinct states:
This version of this specification only addresses the first and third states, where the Distributable Object exists as a collection. A future update will address the transport state.
Refer to the EPUB Specifications for definitions of EPUB-specific terminology used in this document.
Distributable Object (or Object)
A collection of discrete content entities and associated resources that comprise a single logical unit of content, usable in other contexts.
The following typographic conventions are used in this specification:
markup
All markup (elements, attributes, properties), code (JavaScript, pseudo-code), machine processable values (string, characters, media types) and file names are in red-orange monospace font.
markup
Links to markup and code definitions are underlined and in red-orange monospace font. Only the first instance in each section is linked.
http://www.idpf.org/
URIs are in navy blue monospace font.
hyperlink
Hyperlinks are underlined and in blue.
[reference]
Normative and informative references are enclosed in square brackets.
Term
Terms defined in the Terminology are in capital case.
Informative markup examples are in monospace font.
NOTE
Informative notes are preceded by a "Note" header.
The keywords must, must not, required, shall, shall not, should, should not, recommended, may, and optional in this document are to be interpreted as described in [RFC2119].
All sections of this specification are normative except for examples, or except for sections identified by the informative status label "This section is informative". The application of informative status to sections and appendices applies to all child content and subsections they may contain.
A conformant Embedded Distributable Object must meet all of the following criteria:
› It must conform to all requirements for collections in 2.2 The distributable-object collection definition.
› It must include all required metadata as defined in 2.3 Metadata.
› It must reference one or more discrete content entities as defined in 2.4 Discrete Entities.
The Package Document collection element [Publications301] is used to identify the presence of Distributable Objects embedded within an EPUB Publication.
Each collection that contains a Distributable Object must have its role attribute set to the value "distributable-object".
The Distributable Object collection must include a child metadata element containing all required metadata and any optional metadata.
The collection also must include a child manifest collection [Manifest] that identifies the supplementary resources necessary to render the Object, such as style sheets, scripts and multimedia resources.
Finally, the collection must contain one or more child link elements, referencing the discrete entities that compose the object.
Each Distributable Object must include the required Dublin Core metadata properties defined in [Publications301].
All metadata is repeatable except for the dc:identifier element and the primary expression of the dcterms:modified property. The value of each Distributable Object's dc:identifier element must be unique.
In addition to the required metadata, the following [DCMES] elements are recommended for describing the Object:
Other metadata may be used to describe the Object.
Conformance with specific EPUB Publication types [Publications301] may introduce other metadata requirements.
The accessible nature of a Distributable Object is identified using the accessibility metadata properties [A11YProperties] from the [schema.org] CreativeWork type.
Each Distributable Object must identify all applicable accessibility features using the accessibilityFeature property. The property must be repeated for each applicable value.
If the given Rendition contains no accessible features, or the Author is unable to state which apply, a single accessibilityFeature declaration specifying the value "none" must be included.
It is recommended that the other properties be specified whenever applicable.
The vocabulary of recommended terms to use with these properties is maintained at the W3C Web Schemas Wiki [A11YProperties].
For more information on using these properties in the Package Document, refer to the Schema.org Integration Guide [SchemaGuide].
The dc:identifier element and dcterms:modified property serve as the release identifier [Publications301] for the Distributable Object.
The dcterms:modified value must not be updated when only a change in the state of the collection occurs (i.e., whether it is repackaged as a new EPUB Publication or integrated into a destination EPUB Publication). In order to identify the object as it moves around, changes to the identifier and last modified time only occur when making changes to the object content and metadata. For example:
A Distributable Object may conform to a particular type of EPUB Publication [Publications301], in which case it must include a dc:type element declaration for each.
A distributable object is composed of one or more discrete content entities, each of which must be identified in a child link element of the collection.
Each link element must point to an EPUB Content Document, or element fragment thereof. The sequence of child link elements represents the linear reading order of the the object (i.e., its spine).
If the IRI [RFC3987] in a link element href attribute includes a fragment identifier, only the referenced element is part of the object. The link element href attribute must not include EPUB canonical fragment identifiers [EPUBCFI].
EPUB Content Documents, including fragments, that are identified in the child link elements of the collection must not also be listed in the collection's manifest.
This specification places no requirements on the content of Distributable Objects beyond that it be conformant to the core suite of EPUB 3 specifications.
Conformance with specific EPUB Publication types may introduce other requirements.
NOTE
The Author of the distributable object has to ensure that all resources necessary to render the object are identified in the manifest and child link elements, including all linked entities that belong to the object (e.g., via [HTML5] a elements).
The following example shows a distributable object declaration for a learning object that contains MathML markup, a fallback image and two style sheets.
<collection role="distributable-object">
<metadata>
<dc:title>Learning Object 1</dc:title>
<dc:identifier>urn:uuid:5856b480-e1be-11e3-8b68-0800200c9a66
</dc:identifier>
<dc:creator>Object Author</dc:creator>
<dc:language>en</dc:language>
<meta property="schema:typicalAgeRange">9-11</meta>
<meta property="schema:accessibilityFeature">mathml</meta>
…
</metadata>
<collection role="manifest">
<link href="images/mathml01.gif" media-type="image/gif"/>
<link href="css/epub.css" media-type="text/stylesheet"/>
<link href="css/mathml.css" media-type="text/stylesheet"/>
</collection>
<link href="xhtml/chapter01.xhtml#learningobject01"/>
</collection>
The presence of a Distributable Object in an EPUB Publication does not, in itself, confer any rights to reuse the Object in any other context.
Usage is only permitted according to the terms of an included rights statement, or a link to where such information can be found. In the absence of such a statement, no rights can be inferred.
[A11YProperties] Schema.org Accessibility Metadata Properties.
[DCMES] Dublin Core Metadata Element Set, Version 1.1.
[DCMI] DCMI Metadata Terms.
[EPUBCFI] EPUB Canonical Fragment Identifier (epubcfi) Specification.
[HTML5] HTML5: A vocabulary and associated APIs for HTML and XHTML.
[Manifest] EPUB Manifest Role.
[Publications301] EPUB Publications 3.0.1.
[RFC2119] Key words for use in RFCs to Indicate Requirement Levels (RFC 2119) . March 1997.
[RFC3987] Internationalized Resource Identifiers (IRIs) (RFC 3987). M Duerst, et al. January 2005.
[schema.org] schema.org.
[SchemaGuide] Schema.org Metadata Integration Guide for EPUB 3.