#page for ad hoc group to work on rendition metadata vocabulary.

Mission

The group is defining a specification for additional package document metadata called rendition metadata, which while primarily applicable to fixed layout content, can also be used for reflowable content. Rendition metadata provides reading systems information about the renditions in the epub so that the reading systems can select the appropriate rendition to display based upon device characteristics and user input.

Members

• Takeshi Kanai (Sony) - LEAD
• Peter Sorotokin (Adobe)
• Markus Gylling (IDPF)
• Roger Webster (Barnes & Noble)
• Jim Lester (Barnes & Noble)
• Brady Kroupa (Barnes & Noble)
• MURATA Makoto (JEPA)
• Dave Cramer (Hachette)
• Eric Freese (Aptara)
• PLEASE ADD YOUR NAME TO END

Action items

1. To review if the vocabulary is sufficient.
2. To choose one from the ways to set the vocabulary for each item.

General Principles

• The newly introduced items should follow ePub 3.0 schema as much as possible.

Vocabulary

• orientation

• page-spread

• fixed-layout

• overflow-scroll

• viewport

Anything else?

Syntax

For the spine item rendition, the most appropriate one should be selected from the candidates.

metadata in OPF

Publication base

• To use the vocabulary for meta@property.

Example:

<meta property="page-spread">double</meta>

Open questions:

1. A prefix for the vocabulary should be assigned?

Spine item base

• To use the vocabulary for meta@property for each item.

Example:

<metadata>
  :
 <meta refines="#page5" property="page-spread">double</meta>
  :
<metadata>
<manifest>
  :
 <item id="page5" href="page5.xhtml" media-type="application/xhtml+xml" />
  :
</manifest>

Open questions:

Manifest item Properties

Spine item base

• To use the vocabulary as Manifest item Properties.

Example:

<item properties="page-spread-double" id="page5" href="page5.xhtml" media-type="application/xhtml+xml" />

Open questions:

1. Should we introduce a new attribute for this purpose?

Spine itemref Properties

Spine item base

• To use the vocabulary as Spine itemref Properties.

Example:

<itemref idref="page5" properties="page-spread-double" />

Open questions:

XHTML metadata

• viewport

CSS viewport

viewport property See CSS Device Adaption viewport

Open questions:

1. The spec is a technical report. Should we support it at this stage?

Relation To Other Specifications

• Mapping|RenditionMappingAdHocGroup

Rendition Metadata helps in the process of selecting a rendition to view, while Rendition Mapping provides a way of expressing the relationship between content in the rendition. For instance in a document with 3 renditions - text, portrait-fixed, and landscape-fixed, the Rendition Metadata allows the Reading System to select the appropriate rendition - such as selecting between portrait and landscape as the user rotates the device. The Rendition Mapping allows the Reading system to synchronize the content while switching between those renditions.

• Others (TBD - Media Queries, CSS as the syntax for the metadata is agreed upon)

Use cases

1. A publication containing double-page spread as an image file. E.g.) Comics, Children books
• The publication will be set page-spread:full to indicate that each spine item is designed to display it on entire screen.
• The publication will be set viewport to indicate its aspect ratio, expecting the content will be fit to the screen size automatically.
• The publication will be set fixed-layout:true to indicate that the content does not need any adjustments, such as font-size change, font face change and margin adjustment.
• The publication might be set orientation:landscape to indicate that the content is designed for landscape.
2. A publication offering Web like user experience. E.g.) Magazines
• The publication will be set page-spread:full to indicate that each spine item is designed to display it on entire screen.
• The publication will be set overflow-scroll:true to indicate that the content requires scroll control, not pagination.
• The publication might be set fixed-layout:true to indicate that the content does not need any adjustments.
3. A publication which contains single page as an image file, and needs to be displayed with the previous or next page. E.g.) Comics, Children books
• The publication will be set page-spread:double to indicate that two spine item should be displayed simultaneously.
• The publication will be set fixed-layout:true to indicate that the content does not need any adjustments.
4. A publication containing a huge stuff, such as tables or maps, in a page. In most cases, the page has linear='no' attribute in the spine.
• The page will be set overflow-scroll:true to indicate that it requires scroll view to display the content.

Rendition Metadata Processing model

(To be updated)

1. Parse the rendition metadata written in the target OPF and calculate 'Viewport' width and height for each EPUB Content Document following the rules below.
1. orientation Calculate available Viewport dimension by using the direction of 'orientation' to render an EPUB Content Document. 'orientation:landscape' indicates that the content calls for vertical 'Viewport'. 'orientation:portrait' indicates that the content calls for horizontal 'Viewport'. 'orientation:auto' indicates that Reading Systems can display the content in anyways.
2. page-spread Update the caliculated Viewport dimension by using page-spread setting. When 'page-spread:double' is set, Reading Systems should split the Viewport into two and display both at the same time. If it is 'page-spread:full', Reading Systems should use entire the Viewport for rendering the content. 'page-spread:auto' indicates that Reading Systems can display the content in anyways.
3. overflow-scroll When 'overflow-scroll:true' is set, Reading Systems should display the content on scrollable view. If it is 'overflow-scroll:false' or Reading Systems have no capability to switch the view mode, Reading systems should ignore the setting and follow EPUB Content Document processing model.
4. fixed-layout When 'fixed-layout:true' is set, Reading Systems should render the EPUB Content Document as it is.
5. viewport Reading systems should apply the setting to each EPUB Content Document.
2. Render an EPUB Content Document into the 'Viewport' following EPUB Content Document processing model.

Proposals

(To be updated.)

• iBooksFixedLayout
• BNFixedFormat
• SonyFixedLayoutFormat
• AAPProposalForFixedLayout
• AzardiFixedLayoutMetadata