Publication Structure 1.0.1 Publication Structure 1.0.1 Publication Structure 1.0.1Copyright © 2001 by Open eBook 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 Open eBook Forum.
The purpose of the Open eBook Publication Structure is to provide a specification for representing the content of electronic books. Specifically:
This specification is based on the premise that in order for electronic-book technology to achieve widespread success in the marketplace, reading systems must have convenient access to a large number and variety of titles.
This specification has been developed through a cooperative effort, bringing together publishers, reading system vendors, software developers, and experts in the relevant standards. The “Open eBook Authoring Group” was composed of the following people (affiliations given are those at the time of publishing version 1.0, September 16, 1999):
Version 1.0.1 of this specification was prepared by the Open eBook Forum Publication Structure Working Group. Active members of the working group at the time of publication of this revision (1.0.1) were:
This specification combines subsets and applications of other specifications. Together, these facilitate the construction, organization, presentation, and unambiguous interchange of electronic documents:
OEB is based on XML because of its generality and simplicity, and because this increases the likelihood that documents will survive longer. XML also provides well-defined rules for the syntax of documents, which decreases the cost to implementers and reduces incompatibility across systems. Further, XML enables extensibility because it is not tied to any particular set of element types, it supports internationalization, and it encourages document markup that can represent a document’s internal parts more directly, making them amenable to formatting and other types of computer processing.
OEB reading systems must be XML processors as defined in XML 1.0. All OEB documents must be well-formed XML documents, although they need not be valid XML documents. However, this specification ensures that for any basic OEB document, there is a syntax form that:
The last point above does not claim full HTML 4.0 conformance for one primary reason: HTML 4.0 supports the XML empty element syntax in practice (i.e., it works in browsers) but not in formal HTML 4.0 specifications prior to XHTML 1.0.
XML well-formedness requires characteristics beyond what HTML browsers typically require, such as:
Empty elements are those (such as the HTML br and hr elements) that permit no content. The XML and formal HTML syntaxes for these are incompatible, though the XML form with whitespace before the trailing slash is accepted by most HTML browsers (and is strictly conformant XML, as XML ignores whitespace within tags. For this reason, this specification requires this (conforming) variation of the XML form (for example, “<br />”); this is the most portable syntax and it contributes the most to document longevity, even though, strictly speaking, it is not valid in HTML.
Syntactic transformation from valid HTML to well-formed XML is trivial (though semantic transformations that also add brand-new structure and information value may not be). Transformation from invalid but moderately clean HTML is also usually an easy process and easily automated: several free tools already exist for this, such as “Tidy” (see http://www.w3.org/People/Raggett/tidy/). Transformation from extremely dirty HTML to XML, however, is of unpredictable complexity.
Not all well-formed XML 1.0 documents are conformant OEB documents. This is because this specification imposes further constraints in order to improve interoperability. These constraints are the “OEB Common Requirements,” defined below.
This specification defines two XML DTDs—the package DTD and the basic OEB document DTD. The package forms the “root” of a complete publication, and reading systems should use it to find and organize publication components. The basic OEB document DTD formally defines the HTML subset described in this specification.
This version of the specification does not demand that reading systems process XML namespace prefixes according to the XML Namespaces Recommendation at http://www.w3.org/TR/REC-xml-names.
Namespace prefixes are a method for prefixing element and attribute names to distinguish identical names that are drawn from different definition sets. A prefix is associated with a unique URI by an XML namespace declaration. Alternatively, a namespace declaration may identify a URI as the default namespace, applicable to elements lacking a namespace prefix. The XML namespace prefix is separated from the suffix element by a colon.
This specification forbids the use of an oeb: namespace prefix within OEB documents. The use of the dc: prefix, however, is required for Dublin Core metadata element attributes in the OEB package. An element within the OEB document that contains a namespace prefix is treated as an extended element, with the colon acting as a normal XML name character. Reading systems must recognize the colon as a valid name character within an OEB document.
For upwards compatibility, the element dc-metadata in an OEB package is required to have an attribute of xmlns:dc="http://purl.org/dc/elements/1.0/" and xmlns:oebpackage="http://openebook.org/namespaces/oeb-package/1.0/". In addition, the Dublin Core elements will be declared in the OEB package DTD with an explicit prefix of dc:.
This specification recognizes the importance of current software tools, legacy data, publication practices, and market conditions, and so is based on HTML. This approach allows content providers to exploit current HTML content, tools, and expertise.
To minimize the implementation burden on reading system implementers (who may be working with devices that have power and display constraints), the publication structure does not include all HTML elements and attributes. The elements and attributes were selected from the HTML 4.0 specification and were chosen to be consistent with current directions in HTML and XHTML development and the emergence of XML. See Appendix A for a complete table of the element types in HTML 3.2, HTML 4.0, and OEB documents.
Any HTML construct deprecated in HTML 4.0 is either omitted from this specification or is deprecated; CSS-based equivalents are provided in most such cases. Stylesheet constructs are also used for new functionality beyond that provided in HTML 4.0.
To achieve predictable results and to support upwards compatibility with future versions of this specification, it is strongly recommended that basic OEB documents be valid XML documents with respect to the OEB document DTD.
This specification defines a style language based on CSS 1 and CSS 2, with a media type of “text/x-oeb1-css”. The Publication Structure Working Group is aware that this definition of a media type goes against the recommendation of the CSS Working Group (see http://www.w3.org/TR/REC-CSS1), but has chosen to do so due to practical considerations.
The CSS-based stylesheet constructs in this specification have been included to define baseline rendering functionality. To minimize the burden on reading system developers and device manufacturers, not all CSS 1 or CSS 2 properties are included. A few additional properties and values have been added for supporting page layout, headers, and footers.
In a number of cases, this specification does not require reading systems to provide the full range of rendering that a standard CSS stylesheet might request. For example, some reading systems will use monochrome displays. It would neither be acceptable to limit all reading systems to monochrome, nor to declare color use a non-standardized extension beyond OEB. In such cases, the CSS settings are allowed, and keep their meanings; but a conforming reading system may gracefully degrade to a simpler rendering.
This specification supports the inline style attribute, the style element, and externally linked stylesheets. This specification does not require that any handling of XML namespaces be performed by the reading system in the processing of stylesheets.
Stylesheets can be associated with an OEB document in several ways:
The relative priority of the first three cases is as defined for HTML 4.0 and CSS 2. Stylesheets linked via a processing instruction are treated as if they had been linked via HTML link elements preceding any actual HTML link elements. As defined in the Conformance section, if no stylesheet is defined or no applicable style is found for a given element, HTML rendering is the default as defined elsewhere in this specification and the HTML4.0 specification.
Styles attached via the first two methods listed above may use only those CSS constructs defined as supported in Section 4 of this specification. External stylesheets linked via the HTML link element or by the processing instruction xml-stylesheet, however, may use this or any other style language, such as XSL (see http://www.w3.org/TR/WD-xsl).
Only those CSS constructs defined as supported in Section 4 of this specification may be included in stylesheets of type “text/x-oeb1-css”. Stylesheets of other MIME media types may be substituted for the text/x-oeb1-css stylesheets at the discretion of the reading system.
The HTML 4.0 specification groups externally linked stylesheets into sets by their titles (including a “persistent” set for which the title is the null string). This specification requires that at least one stylesheet in each such set must be of MIME media type “text/x-oeb1-css”.
Reading systems that implement only the OEB CSS subset may ignore any stylesheets using other style languages. Reading systems that support extended stylesheet functionality may choose among any of the other external stylesheets. It is strongly recommended that unique MIME media types be defined for any novel stylesheet languages supported, and that stylesheets in those languages be detected by examining the MIME media type.
The Dublin Core is designed to minimize the burden of cataloging on authors and publishers, while providing enough data to be useful. This specification supports the entire current set of Dublin Core metadata elements, supplemented with a small set of additional attributes addressing areas where more specific information may be useful. For example, the role attribute added to the dc:Contributor element allows for much more detailed specification of contributors to a publication, including their roles expressed via relator codes.
Content providers must include a minimum set of a metadata elements, defined in section 2.2, and should incorporate additional metadata to enable readers to discover publications of interest.
Publications may use the entire Unicode character set, in UTF-8 or UTF-16 encodings, as defined by Internet RFC 2279 (see http://www.ietf.org/rfc/rfc2279.txt). The use of Unicode facilitates internationalization and multilingual documents. However, reading systems are not required to provide glyphs for all Unicode characters.
Reading systems are required to parse all UTF-8 and UTF-16 characters properly (as required by XML). Reading systems may decline to display some characters, but must be capable of signaling in some fashion that undisplayable characters are present. They must not display Unicode characters merely as if they were 8-bit characters. For example, the biohazard symbol (0x2623) need not be supported by including the correct glyph, but must not be parsed or displayed as if its component bytes were the two characters “&#” (0x0026 0x0023).
This specification defines a list of “core” MIME media types that all reading systems must support and publications may include. Publications may include resources of other media types, but for each such resource must include an alternative resource of a core MIME media type (using methods defined in this specification).
The core OEB MIME media types are:
| Media Type | Reference | Description |
|---|---|---|
| image/jpeg | RFC 2046 | Used for raster graphics |
| image/png | RFC 2083 | Used for raster graphics |
| text/x-oeb1-document | this specification | Used for basic or extended OEB documents |
| text/x-oeb1-css | this specification | Used for OEB CSS-subset stylesheets |
This section defines conformance for OEB documents, publications, and reading systems.
This specification defines two named levels of conformance for OEB documents–basic and extended, and one conformance level for OEB publications.
Conformant OEB documents (both basic and extended) and conformant OEB package files must meet these necessary conditions, referred to in this specification as the “common requirements:”
A document is a basic OEB document if and only if:
A document is an extended OEB document if and only if
OEB documents, basic or extended, may or may not be valid (as defined in XML 1.0) with respect to an associated DTD. However, all OEB documents must be well-formed XML 1.0 documents.
A collection of files is a conforming OEB publication if and only if
This specification defines only one level of conformance for a reading system. A reading system is conformant if and only if it processes documents as follows:
A) When presented with a basic OEB document the reading system
B) When presented with an extended OEB document the reading system
C) When presented with an OEB package the reading system
D) When providing navigation via the OEB spine, the reading system
E) When presented with one or more style sheets via the HTML link mechanism or the XML-stylesheet processing instruction, described in http://www.w3.org/TR/xml-stylesheet, the reading system
Note: Reading systems are not required to support XML entity and attribute declarations (beyond parsing past them as XML requires), because such constructs are not permitted in conforming OEB documents.
It is the intent of the contributors to this specification that subsequent generations of this specification continue in the directions established by the 1.0 release. Specifically:
Version 1.0.1 of the OEB Publication Structure is not meant to be a “new” specification. It does not add additional features to the specification, but rather removes some ambiguities and corrects errors. The changes made fall into one of three broad categories: clarifications of ambiguities; correction of typographical errors; and correction of other errors or inconsistencies.
It was a goal of version 1.0.1 that all documents conformant according to version 1.0 would remain conformant under 1.0.1. While several inconsistencies rendered full compatibility with version 1.0 impossible, these incompatibilities are unlikely to have appeared in real-world documents. These include:
OEB was developed in parallel with and in reference to XHTML 1.0, which requires the use of the alt attribute for img and area elements. It was intended that the OEB Publication Structure version 1.0 contain a similar requirement, which is reflected by the requirement of img and area alt in the Publication Structure version 1.0 XML DTD. Version 1.0.1 now reflects this intention in the text. While technically the prose specification of version 1.0 is authoritative over the DTD, the contributors felt that it was best to modify the specification to reflect original intention, because any version 1.0 Basic OEB Documents, if validated against the version 1.0 DTD, would have already contained the alt attribute for these elements.
Certain information in the version 1.0 DTD relating to the XLink specification, which was still under development when the OEB Publication Structure 1.0 was released, was incorrect in light of later XLink modifications. It was thought best that XLink-related information not be included in the current specification, which makes no reference to XLink in its prose. Removing the XLink namespace identification attribute xmlns:xlink from the html element in the XML DTD, however, means that any document that conforms to OEB 1.0 and includes this attribute explicitly will now be non-conforming under version 1.0.1. Since the xmlns:xlink attribute was not mentioned in the version 1.0 prose, and since the version 1.0 DTD provided a fixed default value, it is again unlikely that many documents explicitly include that attribute.
Use of extended OEB documents is the recommended mechanism for adding information and structure beyond that provided by the HTML subset defined in this specification, for example, to associate further semantics with content. Arbitrary non-OEB elements may be added as long as such elements are provided with style definitions in accompanying stylesheets.
For example, the following document would be an extended OEB document excerpt:
<chapter> <milestone n="257" /> <chapterhead>Chapter one</chapterhead> <p>Now is the time… </p> </chapter>
if associated with a style sheet that contains the following excerpt:
chapter {page-break-before: always}
milestone { }
chapterhead {
font-weight: bold;
font-family: sans-serif;
text-align: center;
display: block;
margin-top: 4ex
}
This specification incorporates features that ensure content can be made accessible and usable by persons with disabilities. Existing accessibility features developed by the World Wide Web Consortium (W3C) for HTML 4.0 for content accessibility are incorporated into the OEB specification.
OEB publications should be authored in accordance with the W3C Web Content Accessibility Guidelines 1.0 (http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/) to ensure that the broadest possible set of users will have access to books delivered in this format.
In addition, recommendations from the W3C HTML 4.0 Guidelines for Mobile Access (http://www.w3.org/TR/NOTE-html40-mobile/) and the W3C Web Accessibility Initiative's proposed User Agent Guidelines (http://www.w3.org/TR/WD-WAI-USERAGENT/) should be reviewed and applied by OEB implementers to ensure that reading systems will be in conformance with accessibility requirements.
This specification is designed to take advantage of current practices while preparing for future developments. Although the nature of subsequent versions of this specification remain to be determined, it is the expectation of the contributors to this specification that these releases will continue in the same directions, including: increasing functionality, accessibility, internationalization, extensibility, and more rigorous separation of content and presentation, while maintaining alignment with relevant standards. Further, maintaining backward compatibility with this version of this specification is a high priority. Future directions can be tracked at http://www.openebook.org.
A publication conforming to this specification must include exactly one OEB package file, which specifies the OEB documents, images, and other objects that make up the OEB publication and how they relate to each other.
It is recommended that all package files use extension “.opf”, in order to make them readily identifiable within the group of files making up a publication. Package files are of MIME media type “text/xml”. This specification does not define means for physically bundling files together to make one data transfer object (such as using zip or tar).
It is not required that the OEB package DTD be physically included in every publication. If included, it should be referenced from the manifest (as described below for other files).
The major parts of the OEB package file are:
An OEB package must be a valid XML document conforming to the OEB package DTD. An informal outline of the package is as follows:
<?xml version="1.0"?> <!DOCTYPE package PUBLIC "+//ISBN 0-9673008-1-9//DTD OEB 1.0.1 Package//EN" "http://openebook.org/dtds/oeb-1.0.1/oebpkg101.dtd"> <package>
metadata
manifest
spine
guide
</package>
The following sections describe the parts of the OEB package.
The package element is the outermost element in a package file; all other elements are nested within it.
The package must specify a value for its unique-identifier attribute. The unique-identifier attribute’s value specifies which dc:Identifier element, described in section 2.2.10, provides the package’s preferred, or primary, identifier. The package file’s author is responsible for choosing a primary identifier that is unique to one and only one particular package (i.e., the set of files referenced from the package file’s manifest).
Notwithstanding the requirement for uniqueness, reading systems must not fail catastrophically should they encounter two distinct packages with the same purportedly unique primary identifier.
The required metadata element is used to provide information about the publication as a whole. It contains a Dublin Core metadata record within a dc-metadata element, and supplemental metadata in an x-metadata element.
The dc-metadata element contains specific publication-level metadata as defined by the Dublin Core initiative (http://purl.org/dc/). The descriptions below are included for convenience, and the Dublin Core's own definitions take precedence (see http://www.ietf.org/rfc/rfc2413.txt).
The x-metadata element must contain one or more instances of a meta element, analogous to the HTML 4.0 meta element, but applicable to the publication as a whole. The x-metadata element allows content providers to express arbitrary metadata beyond the data described by the Dublin Core language. Individual OEB documents may include the meta element directly (as in HTML 4.0) for document-specific metadata. This specification uses the OEB package file alone as the basis for expressing publication-level Dublin Core metadata.
For example:
<metadata>
<dc-metadata>
…
</dc-metadata>
<x-metadata>
<meta name="price" content="USD 19.99"/>
</x-metadata>
</metadata>
The XML namespace mechanism (see http://www.w3.org/TR/REC-xml-names/) is used to identify the elements used for Dublin Core metadata without conflict. Note that there is no requirement on reading systems to process namespaces. This syntax is used to provide for upwards-compatibility.
The dc-metadata element can contain any number of instances of any Dublin Core elements. Dublin Core element names begin with the “dc:” prefix followed by a leading uppercase letter. Dublin Core metadata elements may occur in any order; in fact, multiple instances of the same element type (multiple dc:Creator elements, for example) can be interspersed with other metadata elements without change of meaning.
For upwards-compatibility, the element dc-metadata in an OEB package is required to have an attribute of xmlns:dc="http://purl.org/dc/elements/1.0/" and xmlns:oebpackage="http://openebook.org/namespaces/oeb-package/1.0/".
Each Dublin Core field is represented by an element whose content is the field's value. The dc:Title and at least one dc:Identifier must be included in the dc-metadata element. Dublin Core elements, like any other elements in the OEB package file, may have an id attribute specified. At least one dc:Identifier, that which is referenced from the package unique-identifier attribute, must have an id specified.
Because the Dublin Core metadata fields for Creator and Contributor do not distinguish roles of specific contributors (such as author, editor, and illustrator), this specification adds an optional role attribute for this purpose. See section 2.2.6 for a discussion of role.
This specification also adds a scheme attribute to the dc:Identifier element to provide a structural mechanism to separate an identifier value from the system or authority that generated or defined that identifier-value. See section 2.2.10 for a discussion of scheme.
This specification also adds a event attribute to the dc:Date element to enable content providers to distinguish various publication specific dates (for example, creation, publication, modification). See section 2.2.7 for a discussion of event.
For example:
<package unique-identifier="xyz"> <metadata> <dc-metadata xmlns:dc="http://purl.org/dc/elements/1.0/" xmlns:oebpackage="http://openebook.org/namespaces/oeb-package/1.0/"> <dc:Title>Alice in Wonderland</dc:Title> <dc:Type>Novel</dc:Type> <dc:Identifier id="xyz" scheme="ISBN">123456789X</dc:Identifier> <dc:Creator role="aut">Lewis Carroll</dc:Creator> </dc-metadata> </metadata> … </package>
Attributes of elements within the dc-metadata element are not defined by the Dublin Core—only the elements’ contents are so defined.
The following subsections describe the individual Dublin Core metadata elements.
The title of the publication. Although an OEB package must include at least one instance of this element type, multiple instances are permitted. Any reading system that displays title metadata to the user should either use the first dc:Title only, or all dc:Title elements.
A primary creator or author of the publication. Additional contributors whose contributions are secondary to those listed in dc:Creator elements should be named in dc:Contributor elements.
Publications with multiple co-authors should provide multiple dc:Creator elements, each containing one author. The order of dc:Creator elements is presumed to define the order in which the creators’ names should be presented by the reading system.
This specification recommends that the content of the dc:Creator elements hold the text for a single name as it would be presented to the user.
The dc:Creator element has two optional attributes, role and file-as. The set of values for role are identical to those defined in section 2.2.6 for the dc:Contributor element. The file-as attribute should be used to specify a normalized form of the contents, suitable for machine processing. For example, one might find
<dc:Creator file-as="King, Martin Luther Jr." role="aut"> Rev. Dr. Martin Luther King Jr. </dc:Creator>
If a reading system displays creator information, the reading systems must display the contents of all dc:Creator elements, in the order provided, with appropriate separating spacing and/or punctuation.
Multiple instances of the dc:Subject element are supported, each including an arbitrary phrase or keyword. This specification makes no attempt to standardize subject naming schemes, such as the Library of Congress Subject Heading System.
Plain text describing the publication’s content.
The publisher as defined in RFC2413.
A party whose contribution to the publication is secondary to those named in dc:Creator elements.
Other than significance of contribution, the semantic of this element are identical to those of dc:Creator. Reading systems are free to choose to display dc:Creator information without accompanying dc:Contributor information.
The dc:Contributor element has two optional attributes, role and file-as. The file-as attribute is defined as for dc:Creator, and is documented in section 2.2.2.
The normative list of values used for the role attribute is defined by the USMARC relator code list (http://www.loc.gov/marc/relators/re0002r1.html). When roles are specified, the 3-character USMARC values must be used when applicable. Although that list is extensive, other values may be added if a required role is not covered by those predefined values. Such values must begin with “oth.”, and shall be considered subdivisions of the “other” relator code. Like other constructs in this specification, these values are case-sensitive and must be coded entirely in lower-case.
For convenience, some relator code values are listed here as examples. Consult the USMARC code list cited above for the complete list.
| Adapter [adp] | Use for a person who 1) reworks a musical composition, usually for a different medium, or 2) rewrites novels or stories for motion pictures or other audiovisual medium. |
| Annotator [ann] | Use for a person who writes manuscript annotations on a printed item. |
| Arranger [arr] | Use for a person who transcribes a musical composition, usually for a different medium from that of the original; in an arrangement the musical substance remains essentially unchanged. |
| Artist [art] | Use for a person (e.g., a painter) who conceives, and perhaps also implements, an original graphic design or work of art, if specific codes (e.g., [egr], [etr]) are not desired. For book illustrators, prefer Illustrator [ill]. |
| Associated name [asn] | Use as a general relator for a name associated with or found in an item or collection, or which cannot be determined to be that of a Former owner [fmo] or other designated relator indicative of provenance. |
| Author [aut] | Use for a person or corporate body chiefly responsible for the intellectual or artistic content of a work. This term may also be used when more than one person or body bears such responsibility. |
| Author in quotations or text extracts [aqt] | Use for a person whose work is largely quoted or extracted in a works to which he or she did not contribute directly. Such quotations are found particularly in exhibition catalogs, collections of photographs, etc. |
| Author of afterword, colophon, etc. [aft] | Use for a person or corporate body responsible for an afterword, postface, colophon, etc. but who is not the chief author of a work. |
| Author of introduction, etc. [aui] | Use for a person or corporate body responsible for an introduction, preface, foreword, or other critical matter, but who is not the chief author. |
| Bibliographic antecedent [ant] | Use for the author responsible for a work upon which the work represented by the catalog record is based. This may be appropriate for adaptations, sequels, continuations, indexes, etc. |
| Book producer [bkp] | Use for the person or firm responsible for the production of books and other print media, if specific codes (e.g., [bkd], [egr], [tyd], [prt]) are not desired. |
| Collaborator [clb] | Use for a person or corporate body that takes a limited part in the elaboration of a work of another author or that brings complements (e.g., appendices, notes) to the work of another author. |
| Commentator [cmm] | Use for a person who provides interpretation, analysis, or a discussion of the subject matter on a recording, motion picture, or other audiovisual medium. |
| Compiler [com] | Use for a person who produces a work or publication by selecting and putting together material from the works of various persons or bodies. |
| Designer [dsr] | Use for a person or organization responsible for design if specific codes (e.g., [bkd], [tyd]) are not desired. |
| Editor [edt] | Use for a person who prepares for publication a work not primarily his/her own, such as by elucidating text, adding introductory or other critical matter, or technically directing an editorial staff. |
| Illustrator [ill] | Use for the person who conceives, and perhaps also implements, a design or illustration, usually to accompany a written text. |
| Lyricist [lyr] | Use for the writer of the text of a song. |
| Metadata contact [mdc] | Use for the person or organization primarily responsible for compiling and maintaining the original description of a metadata set (e.g., geospatial metadata set). |
| Musician [mus] | Use for the person who performs music or contributes to the musical content of a work when it is not possible or desirable to identify the function more precisely. |
| Narrator [nrt] | Use for the speaker who relates the particulars of an act, occurrence, or course of events. |
| Other [oth] | Use for relator codes from other lists which have no equivalent in the USMARC list or for terms which have not been assigned a code. |
| Photographer [pht] | Use for the person or organization responsible for taking photographs, whether they are used in their original form or as reproductions. |
| Printer [prt] | Use for the person or organization who prints texts, whether from type or plates. |
| Redactor [red] | Use for a person who writes or develops the framework for an item without being intellectually responsible for its content. |
| Reviewer [rev] | Use for a person or corporate body responsible for the review of book, motion picture, performance, etc. |
| Sponsor [spn] | Use for the person or agency that issued a contract, or under whose auspices a work has been written, printed, published, etc. |
| Thesis advisor [ths] | Use for the person under whose supervision a degree candidate develops and presents a thesis, memoir, or text of a dissertation. |
| Transcriber [trc] | Use for a person who prepares a handwritten or typewritten copy from original material, including from dictated or orally recorded material. |
| Translator [trl] | Use for a person who renders a text from one language into another, or from an older form of a language into the modern form. |
Date of publication, in the format defined by “Date and Time Formats” at http://www.w3.org/TR/NOTE-datetime and by ISO 8601 on which it is based. In particular, dates without times are represented in the form YYYY[-MM[-DD]]: a mandatory 4-digit year, an optional 2-digit month, and if the month is given, an optional 2-digit day of month.
The dc:Date element has one optional attribute, event. The set of values for event are not defined by this specification; possible values may include: creation, publication, and modification.
Dublin Core provides examples of resource types “such as home page, novel, poem, working paper, technical report, essay, dictionary.” The Dublin Core is currently considering revisions to the usage of this field, and should be consulted for updated definitions.
An enumerated list of formats for this content is being developed by the Dublin Core.
A string or number used to uniquely identify the resource.
At least one dc:Identifier must have an id specified, so it can be referenced from the package unique-identifier attribute of Section 2.1.
The dc:Identifier element has an optional attribute, scheme. The scheme attribute names the system or authority that generated or assigned the text contained within the dc:Identifier element, for example “ISBN” or “DOI.” The values of the scheme attribute are case sensitive.
This specification does not standardize or endorse any particular publication identifier scheme. Specific use of URLs or ISBNs is not yet addressed by this specification. Identifier schemes are not currently defined by Dublin Core.
Information regarding a prior resource from which the publication was derived (see RFC 2413).
If specified, identifies the primary language of the content. The content of this element must comply with RFC 1766 (see http://www.ietf.org/rfc/rfc1766.txt), or its successor on the IETF Standards Track. US English (en-us) is the default. The Dublin Core permits other descriptions as well; this specification does not.
An identifier of an auxiliary resource and its relationship to the publication. An enumerated list of relationship types is currently under development by the Dublin Core.
The place or time which the publication’s content addresses.
A statement about rights, or a link to one. In this specification, the copyright notice and any further rights description should appear directly.
This specification does not address the manner in which a Content Provider specifies to a secure distributor any licensing terms under which readership rights or copies of the content may be sold.
The manifest provides a list of all the files that are parts of the publication. The manifest element must contain one or more item elements. Each item describes a document, an image file, a stylesheet, or other component that is considered part of the publication.
Each item element contained within a manifest element must have an id attribute. In addition, each item element in the manifest must have an href attribute, which is a URI (if relative, the URI is interpreted as relative to the package file itself). Additionally, each item element must have its MIME media type specified via the media-type attribute.
The order of item elements in the manifest is not significant.
For example,
<manifest> <item id="intro" href="introduction.html" media-type="text/x-oeb1-document" /> <item id="c1" href="chapter-1.html" media-type="text/x-oeb1-document" /> <item id="c2" href="chapter-2.html" media-type="text/x-oeb1-document" /> <item id="toc" href="contents.xml" media-type="text/x-oeb1-document" /> <item id="oview" href="arch.png" media-type="image/png" /> </manifest>
The URIs in href attributes of item elements in the manifest may not use fragment identifiers.
This specification defines a set of core MIME media types that all conforming reading systems must support. For a publication that uses only those media types, the manifest merely needs to list the publication's component files directly. However, content providers may construct publications that reference items of additional media types. In order that such publications can nevertheless be read by all conforming reading systems, content providers must always provide alternative “fallback” items for each such item. For every item that is not in a core media type, at least one of its associated fallback items must be of a type drawn from the set of core media types.
This specification defines two different mechanisms for specifying core media type fallbacks. For inline “replaced” elements, this specification relies on the HTML-based object element, described in section 3. For non-inline destinations, whether referenced from a document or a package, the fallback attribute of an item is used.
An item identifies a fallback item using its fallback attribute, which must specify the ID of the item element that identifies the fallback. Items referenced from fallback attributes may each specify a fallback attribute in turn, forming a longer “fallback path.” For example,
<manifest> <item id="item1" href="FunDoc.txt" media-type="text/plain" fallback="fall1" /> <item id="fall1" fallback="fall2" href="FunDoc.html" media-type="text/html" /> <item id="fall2" href="FunDoc.oeb" media-type="text/x-oeb1-document" /> <item …> </manifest>
If a fallback attribute points to an item that also has a fallback attribute, a reading system must continue down the fallback path until it reaches a reference to an item of a media type it can display. A reading system may continue further, and may display any item from the chain. Every item in a publication that is not of one of the core MIME media types must, directly or indirectly, specify a fallback path to an item of one of the core MIME media types.
Fallback paths must terminate; circular references are not permitted. Nevertheless, reading systems should not fail catastrophically if they encounter such a cycle.
Following the manifest, there must be one spine element, which defines a primary linear reading order of the publication. It specifies an ordered list of one or more OEB documents drawn from the manifest, using itemref elements contained within the spine element.
A publication must specify exactly one spine. Reading systems must treat the file named in the first itemref element within the spine as the first file to be rendered in the reading of the book. The successive files named in its itemref elements are those that are to be rendered using “next-page”-type functionality that may be available in the reading system.
The spine may refer only to item elements of media type text/x-oeb1-document. Content of other media types may be referenced via OEB documents, which can (and should) provide text alternates and other information to enhance accessibility as appropriate.
The spine need not include references to every one of the manifest’s item elements that reference OEB documents, because there are means other than the spine for accessing documents in the publication. For example, hypertext links may provide access to documents not in the spine, as may tours and guides (see below).
For example,
<manifest> <item id="toc" href="contents.html" media-type="text/x-oeb1-document" /> <item id="c1” href="chap1.html" media-type="text/x-oeb1-document" /> <item id="c2” href="chap2.html" media-type="text/x-oeb1-document" /> <item id="c3” href="chap3.html" media-type="text/x-oeb1-document" /> <item id="footnotes" href="footnotes.html" media-type="text/x-oeb1-document" /> <item id="f1" href="fig1.jpg" media-type="image/jpeg" /> <item id="f2" href="fig2.jpg" media-type="image/jpeg" /> <item id="f3" href="fig3.jpg" media-type="image/jpeg" /> </manifest> <spine> <itemref idref="toc" /> <itemref idref="c1" /> <itemref idref="c2" /> <itemref idref="c3" /> </spine>
In the above example, suppose the document referenced by ID “c1” is being viewed by a reader. When the end of that document is reached, the next document in linear order would be that referenced by ID “c2”. Document “c1” might also have hypertext links to locations in another file such as the “footnotes”. Such a file must be listed in the manifest, but need not be named by any itemref of the spine. If a reader follows the hyperlink in “c1” to “footnotes”, and the end of that file is reached, then no successor in linear order is defined by this specification.
Much as a tour-guide might assemble points of interest into a set of sightseers’ tours, a content provider may assemble selected parts of a publication into a set of tours to enable convenient navigation.
An OEB package may, but need not, contain one tours element, which in turn contains one or more tour elements. Each tour must have a title attribute, intended for presentation to the user. Reading systems may use tours to provide various access sequences to parts of the publication, such as selective views for various reading purposes, reader expertise levels, etc. Because reading systems are not required to implement tour support, content providers should also provide other means of accessing content referenced from tours.
Each tour element contains one or more site elements, each of which must have an href attribute and a title attribute. The href attribute must refer to an OEB document included in the manifest, and may include a fragment identifier as defined in section 4.1 of RFC 2396 (see http://www.ietf.org/rfc/rfc2396.txt). Each site element specifies a starting point from which the reader may explore freely. Reading systems may use the bounds of the referenced element to determine the scope of the site. If a fragment identifier is not used, the scope is considered to be the entire document. This specification does not require Reading Systems to mark or otherwise identify the entire scope of a referenced element. The order of site elements is presumed to be significant, and should be used by reading systems to aid navigation.
Example:
<tours>
<tour id="tour1" title="Chicken Recipes">
<site title="Chicken Fingers"
href="appetizers.html#r3" />
<site title="Chicken a la King"
href="entrees.html#r5" />
</tour>
<tour id="tour2" title="Vegan Recipes">
<site title="Hummus" href ="appetizer.html#r6" />
<site title="Lentil Casserole" href="lentils.html" />
</tour>
</tours>
Within the package there may be one guide element, containing one or more reference elements. The guide element identifies fundamental structural components of the publication, to enable reading systems to provide convenient access to them.
Example:
<guide>
<reference type="toc" title="Table of Contents"
href="toc.html" />
<reference type="loi" title="List Of Illustrations"
href="toc.html#figures" />
<reference type="other.intro" title="Introduction"
href="intro.html" />
</guide>
The structural components of the books are listed in reference elements contained within the guide element. These components may refer to the table of contents, list of illustrations, foreword, bibliography, and many other standard parts of the book. Reading systems are not required to use the guide element in any way.
Each reference must have an href attribute referring to an OEB document included in the manifest, and which may include a fragment identifier as defined in section 4.1 of RFC 2396 (see http://www.ietf.org/rfc/rfc2396.txt). Reading systems may use the bounds of the referenced element to determine the scope of the reference. If a fragment identifier is not used, the scope is considered to be the entire document. This specification does not require Reading Systems to mark or otherwise identify the entire scope of a referenced element.
The required type attribute describes the publication component referenced by the href attribute. The values for the type attributes must be selected from the list defined below when applicable. Other types may be used when none of the predefined types are applicable; their names must begin with the string “other.”. The value for the type attribute is case-sensitive.
The following list of type values is derived from the 13th edition of the Chicago Manual of Style:
| cover | the book cover(s), jacket information, etc. |
| title-page | page with possibly title, author, publisher, and other metadata |
| toc | table of contents |
| index | back-of-book style index |
| glossary | glossary |
| acknowledgements | |
| bibliography | |
| colophon | |
| copyright-page | |
| dedication | |
| epigraph | |
| foreword | |
| loi | list of illustrations |
| lot | list of tables |
| notes | |
| preface |
This section lists all element types included in the OEB document specification. They are drawn from the HTML 4.0 specification found at http://www.w3.org/TR/REC-html40. See also Appendix A, which includes an index of element types and their status in HTML 4.0 and this specification.
This section does not list HTML 4.0 element types that are not supported in OEB documents (the table in Appendix A, however, does show them explicitly and marks them as excluded). For elements that are supported, this section does, however, explicitly indicate attributes that are ruled out. Reading systems may accept the presence of additional attributes (except in valid OEB documents), but need not support their semantics.
The following typographic conventions are used to indicate the status of element types, attributes, and attribute values:
Attributes and attribute values whose names are struckthrough below are HTML 4.0 constructs that are explicitly not supported by this specification. Reading systems may, but need not provide default presentation for them. In some cases, the constructs are intended to be permanently obsolete; in other cases, future revisions of this specification may add support for these constructs.
Elements, attributes, and attribute values whose names are followed by “(meaning changed)” below have had their semantics altered from those of the HTML 4.0 specification.
Elements, attributes, and attribute values whose names are followed by “(deprecated)” below are deprecated (that is, permitted but not recommended) in OEB documents. The accompanying text indicates whether they are also deprecated in HTML 4.0. Although reading systems must recognize and support them, future releases of this specification are likely to prohibit them. Most but not all are deprecated in HTML 4.0. All elements, attributes, and attribute values that are deprecated in HTML 4.0 are either deprecated or prohibited by this specification.
Elements that cannot contain subelements or text content are shown with the required empty-element syntax, while others are shown as start- and end-tag pairs. Note the XML documents may not omit start- or end-tags. The supported HTML elements for which this restriction is relevant include: html, body, head, dt, li, p, caption, td, and th.
HTML 4.0 defines the following four attributes that may be applied to nearly all elements. These attributes are therefore not listed in the following element descriptions, except to note their absence from the few exceptional elements.
Similarly, XML 1.0 defines the attribute xml:lang, which may be applied to any element in a Basic OEB Document or an Extended OEB Document, and is therefore not listed in the following element descriptions.
This attribute is used to give a unique identifier to each element. Values for id must be unique across all elements in a single document, must begin with a letter, and may consist of the full range of XML name characters. For compatibility with HTML, restricting the id values to the HTML name characters (A-Za-z0-9.-_) is recommended.
This attribute applies to all elements in both Basic and Extended OEB Documents.
This attribute is included to allow for inline style specification. See the discussion of supported CSS properties elsewhere in this specification.
This attribute applies to all elements in both Basic and Extended OEB Documents.
This attribute is included to allow selector-based style specifications. Its value must be a space-separated list of class names. OEB class names are limited to valid HTML 4.0 names, although HTML 4.0 allows arbitrary CDATA.
This attribute applies to all elements in both Basic and Extended OEB Documents.
This attribute may be used to provide an “advisory title/amplification” for the element. Reading systems are not required to do anything in particular with its value.
This attribute may be inserted in documents to specify the language used in the contents and attribute values of any element in an XML document. The value of the xml:lang attribute must comply with RFC 1766 (see http://www.ietf.org/rfc/rfc1766.txt), or its successor on the IETF Standards Track.
A number of elements and attributes that are allowed below permit semantics that are not required of all OEB reading systems. For example, some devices may be monochrome, or provide mainly audio or tactile interfaces. In such cases this specification generally requires reading systems to accept all syntax (such as attribute values) permitted for the HTML construct, but does not require that they be honored. For example, a reading system must parse and recognize the border attribute on table elements, but may choose to treat all values other than 0 the same as 1.
Note that this specification does not mandate specific rendering behavior for HTML constructs. Some reading systems may choose to express the intent of elements in presentation by closely following web-browser usages—a blank line before a paragraph, but no first-line text-indent, for example. Other reading systems may gear their presentation towards sustained novel-like readability: for example, no extra whitespace between paragraphs, but text-indent on the first line of each. Still other systems, such as speech generators, may present particular elements or entire documents in completely different ways.
An OEB document must begin with the XML processing instruction
<?xml version="1.0" ?>
It is recommended that a character encoding be specified, for example:
<?xml version="1.0" encoding="UTF-16" ?>
A <!DOCTYPE> declaration in a basic OEB document must reference the OEB document DTD, by system and optionally the public identifier. For example:
<!DOCTYPE html PUBLIC "+//ISBN 0-9673008-1-9//DTD OEB 1.0.1 Document//EN" "http://openebook.org/dtds/oeb-1.0.1/oebdoc101.dtd">
Note that the <!DOCTYPE> declaration must not include a trailing slash, but may include “[ ]” preceding the closing “>”. “DOCTYPE” must be in upper case. Also, implementations should normalize whitespace in PUBLIC identifiers in accordance with the rules defined in XML, though the use of non-normalized whitespace in PUBLIC identifiers in OEB documents is prohibited.
Marks either the origin or destination for a hypertext link. Note that many browsers by default underline anchors with href attributes, to visually indicate links. Similarly, reading systems will use some sort of highlighting, perhaps some form of underline, to show links. The CSS-property setting text-decoration: none may be used to suppress such highlighting.
Used to provide an address to which hypertext links may refer.
Deprecated in XHTML 1.0 and in this specification, in favor of the id attribute. HTML 4.0 allows any string as the value of this attribute; this specification limits them to being XML names.
Provides a URI to be used as the destination when traversal from the a element is requested. If this URI references a destination that is not an OEB core media type, a fallback must be provided in the manifest to an OEB core media type. If a fallback is not provided in the manifest, content at the end of this link must not be rendered by the reading system.
May be used to indicate the relationship between the document or portion linked, and the current document or portion.
Omitted from this specification.
The possible values are:
| rect | The default. Coordinates are left, top, right, bottom values. |
| circle | Coordinates are center x, center y, and radius. |
| poly | Coordinates are x, y pairs for successive points. |
| default | The default type, rect, can also be set explicitly. |
Comma-separated list of lengths, as integer coordinates or percentages. The values are interpreted according to the specific shape value.
Provides a URI to be used as the destination when traversal from this area is requested (for example by clicking within a hotspot). If this URI references a destination that is not an OEB core media type, a fallback must be provided in the manifest to an OEB core media type. If a fallback is not provided in the manifest, the destination resource must not be rendered by the reading system.
If set to nohref="nohref", indicates that the area isn’t “hot,” effectively “punching a hole” in a larger hot region.
This required attribute must be used to provide an alternative textual representation for the hot-spot, accessible to print-disabled users.
Omitted from this specification.
The b tag is commonly used in HTML documents. Use of CSS font-weight:bold or the HTML strong tag is preferable.
Used in resolving links from OEB documents.
Provides a URI to be used as the basis for relative URIs elsewhere in the document.
HTML 4.0 and this specification exclude these general attributes from this element.
The big tag is sometimes used in HTML documents. Use of CSS font-size is preferable.
This optional attribute provides a URI for the source of the quoted material.
This element defines a container for OEB content. It is assumed, in formatting, that its default rendering is consistent with the CSS property page-break-before having been set to right (which behaves like always on one-page reading systems), but may be overridden by an appropriate stylesheet declaration.
Deprecated in HTML 4.0 and in this specification, in favor of CSS background-color equivalent. See section 4.1, the CSS color and background-color properties, for discussion of acceptable values.
Deprecated in HTML 4.0 and in this specification, in favor of CSS color equivalent. See section 4.1, the CSS color and background-color properties, for discussion of acceptable values.
This specification does not require reading systems to support color control of link anchors or background bitmaps. These attributes are deprecated in HTML 4.0 and omitted from this specification.
Omitted from this specification.
The possible values are:
| none (default) |
| left |
| right |
| all |
Deprecated in HTML 4.0, in favor of CSS clear property.
When present, the caption element's text should describe the nature of the table.
Deprecated in HTML 4.0 and omitted from this specification, in favor of CSS text-align property..
Equivalent to <div align="center">. Deprecated in HTML 4.0 and in this specification. See section 3.25.1 for additional discussion.
Citations of other sources.
Computer program fragments.
Definition description.
Inline definitions, such as the first instance of a definition.
See section 3.25.1 for additional discussion.
Definition list.
See section 3.58.2, ul, for additional discussion.
Definition term.
Emphasis, typically formatted like i.
The font element is deprecated in HTML 4.0 and this specification, with its functionality replaced by CSS equivalents.
Deprecated in HTML 4.0 and in this specification, in favor of CSS font-size property.
See section 3.12.1, the bgcolor and text attributes of the body element, for additional discussion.
Deprecated in HTML 4.0 and in this specification, in favor of CSS font-family property.
The possible values are:
| left |
| center |
| right |
| justify |
Deprecated in favor of the equivalent CSS construct, text-align.
Omitted from this specification.
HTML 4.0 excludes these general attributes from this element.
The possible values are:
| left |
| right |
| center |
Deprecated in favor of the equivalent CSS construct, text-align.
Deprecated in HTML 4.0, omitted from this specification.
Deprecated in HTML 4.0 and this specification, in favor of CSS height.
Deprecated in HTML 4.0 and this specification, in favor of CSS width. Value is specified in pixels or percentage.
This element is required in Basic OEB documents.
HTML 4.0 and this specification exclude these general attributes from this element.
The i tag is commonly used in HTML documents. Use of CSS font-style:italic or the HTML em tag is preferable.
A reference to an image to be displayed inline. This element may only be used to refer to images of OEB core media types (PNG and JFIF [JPEG]). Inline references to non-core media types require specification of alternate (fallback) rendering. The object element provides a general fallback mechanism by which all reading systems may locate an alternate of a core media type, and is the preferred mechanism for including non-core media types. However, a non-null value for the alt attribute, which must always be present, is also considered an adequate fallback.
Images must be of type PNG (see http://www.ietf.org/rfc/rfc2083.txt) or JFIF (see ISO/IEC 10918-1:1994(E) and http://www.w3.org/Graphics/JPEG).
This required attribute must be used to provide a non-graphical alternative to a graphic. This is crucial to accessibility of documents to print-disabled users, as well as for use on very low-resolution display devices. See http://www.w3.org/TR/1999/WAI-WEBCONTENT-19990505/#gl-provide-equivalents for further information on the use of this and related accessibility attributes.
Value should be a URI pointing to a long description, typically more detailed than, but complementary to, alt. Use of this attribute is strongly recommended because it can greatly enhance accessibility for print-disabled users.
Deprecated in HTML 4.0 and this specification, in favor of CSS float and vertical-align properties.
The possible values are:
| top |
| middle |
| bottom |
| left |
| right |
Deprecated in this specification, though not in HTML 4.0, in favor of CSS width property.
Deprecated in this specification, though not in HTML 4.0, in favor of CSS height property.
Deprecated in HTML 4.0 and this specification, in favor of CSS border property.
Pixel width for image border. The value 0 is particularly useful for img elements embedded in a elements, because typical HTML browsers apply a default border when rendering image-based hypertext links. This specification requires only that values of 0 and 1 be respected. Values greater than 1 may be mapped by the reading device to any smaller non-zero value.
Deprecated in HTML 4.0 and this specification, in favor of CSS margin mechanisms.
Reserves equal amount of whitespace to the left and right of an image.
Deprecated in HTML 4.0 and this specification, in favor of CSS margin mechanisms.
Reserves equal amount of whitespace above and below an image.
Points to a client-side map; the value of usemap refers to the map element’s name or id attribute (see map 3.34).
Omitted from this specification. In HTML 4.0, value is a reference to a server-side map for defining hotspots.