Control of rendition properties in the navigator API

[JayPanoz]

Taking the liberty to open this issue as it’s been a TODO in the notes of the agenda of May, 22.

For reference, the navigator API ref: https://docs.google.com/document/d/1xqx_WJ28OAHAHODrMKZBj0wV1dcqM4420yBXVjZVx8w/edit#heading=h.fgulgr3ctcv5

So it’s part of the “What’s Missing?” section indeed.

I know @jccr wanted to discuss that in an issue since he had notes and remarks. Also cc’ing @danielweck, @HadrienGardeur and @mmenu-mantano

[HadrienGardeur]

Based on discussions in BDCoMa CG as well, I think that the following properties are good candidates for a navigator API:

• overflow (scrolled vs paginated resources), which doesn't apply to audio
• continuity (can I scroll across multiple resources?), which applies to all resources, even audio/video (continuous playback)
• reading progression (in which direction should I tap/swipe/scroll to continue reading the publication), which doesn't apply to audio
• fit (which dimensions should be contained in my viewport), which doesn't apply to audio

I think that we can mostly get rid of the concept of "layout" that we had in EPUB, since it can be expressed with a fit too (both dimensions should be contained in my viewport) where the overflow is disabled (none?).

While these navigator APIs should be initialized with a RWPM, the UA should be free to change these values to whatever makes sense for them.