[whatwg] A question about portrait-secondary of screen orientation

[Chundong Wang]

Hello - Got a question of screen orientation on portrait/landscape.

Let's say we have a device doesn't support portrait-secondary, by spec<http://www.w3.org/TR/screen-orientation/> we should remove it from allow list which is fine. However if web developer specified "portrait" instead of "portrait-primary" for lockOrientation(), which I suppose is a common case, we'll have to expand it to "portrait-primary, portrait-secondary" according spec. In this case the lockOrientation() would fail because orientations isn't a supported orientation set. I don't think it'll satisfy the original purpose of "portrait".

IMHO, we should explain this more detailed.  We could either,

1.       Only expand "portrait"(or "landscape") into allowed orientations, or;

2.       Filter out disallowed orientations from orientation sequence and lock the screen with that list.

Thoughts?

CD