You have content you would like to provide to the user to enrich the presentation or experience of the main content. It could be something to experience before the user chooses to start interacting with the main content and/or something additional to consider while interacting with the main content. You might want to have an image available while an audio-only Canvas is playing or, conversely, audio available while a user is navigating an image-only Manifest.
Across a Manifest and its properties, you may use more than one
accompanyingCanvas, allowing you to have an authentic
accompanyingCanvas for each appropriate resource (Collection, Manifest, Canvas, and Range).
target of the
Annotation of an
accompanyingCanvas should have as its value the
id of the
accompanyingCanvas, not the
id of the resource that has the
Always keep in mind the wide latitude given conforming clients: It is up to the client whether and in what sort of UI to display content you place in a
accompanyingCanvas property. Don’t use this property for content that must be displayed. On the other hand, placing content in a
accompanyingCanvas does tell a client that the content, if displayed, should be displayed at the same time as the resource to which it is attached.
Each instance of
accompanyingCanvas may only contain one Canvas, and as such may specifically not contain an additional
accompanyingCanvas or a
In the example, the main Canvas contains audio of a performance of Gustav Mahler’s Symphony No. 3 and the
accompanyingCanvas contains an image of a page from the score.
accompanyingCanvas property is not yet supported in viewers.
- Simplest Manifest - Video
- Load a Preview Image Before the Main Content, using
placeholderCanvasto present one resource ahead of another.