The Properties Object
Each Link Object may contain a Properties Object, containing a number of relevant information.
This document is meant to provide an exhaustive list of properties that can be associated to a Link Object, along with their semantics and usage.
Core properties
| Key | Semantics | Type | Values |
|---|---|---|---|
page |
Indicates how the linked resource should be displayed in a reading environment that displays synthetic spreads. | String | left, right or center |
page
The page property is meant to provide a hint to reading systems that rely on synthetic spreads to display more than a single resource at once.
In this example, the first page should be displayed of the left of a synthetic spread, the second page on the right.
"readingOrder": [
{
"href": "page1.jpg",
"type": "image/jpeg",
"properties": {
"page": "left"
}
},
{
"href": "page2.jpg",
"type": "image/jpeg",
"properties": {
"page": "right"
}
}
]
Extensions
| Key | Semantics | Type | Values | Reference |
|---|---|---|---|---|
contains |
Indentifies content contained in the linked resource, that cannot be strictly identified using a media type. | Array | mathml, onix, remote-resources, js, svg or xmp |
EPUB Profile |
layout |
Hint about the nature of the layout for the linked resources. | String | fixed or reflowable |
EPUB Profile |
encrypted |
Indicates how a given resource has been encrypted or obfuscated. | Encryption Object | See the definition of the Encryption Object | Encryption Module |
OPDS 2.0
While OPDS 2.0 itself is not an extension of the Readium Web Publication Manifest, it shares the same abstract model and syntax.
For this reason, it feels relevant to list the properties introduced by OPDS as well.
| Key | Semantics | Reference |
|---|---|---|
indirectAcquisition |
Provides the expected download format for a publication, after an acquisition through an intermediate resource. | OPDS 2.0 |
numberOfItems |
Hint about the number of items that are expected to be returned by the linked resource. | OPDS 2.0 |
price |
Provides the acquisition price in a given currency. | OPDS 2.0 |