Re: Properties of Custom Layout

On Wed, Jun 3, 2015 at 1:14 PM François REMY <francois.remy.dev@outlook.com>
wrote:

> >> - What if we want to emulate something like scrollbars or carousels?
> >> Should custom layout be allowed to layout out boxes that are not in
> >> the DOM for their own purposes, and get some basic events on them
> >> and on the layouted element itself if it's focusable (I was thinking
> >> about: pointer-over, pointer-click, focus, enter-key, space-key,
> >> left-key, right-key, up-key, down-key)?
> >
> > Custom Layout will need to know about boxes not in the DOM for layout
> > purposes (I.e. the fragment tree). I'm not sure what form this will take
> > yet.
> >
> > As an example, a text node which is a child of a flexbox, can be wrapped
> > in an anonymous box which isn't in the DOM.
>
> Okay, so a custom layout can create anonymous boxes. It may be able to
> display a scrollbar, for instance.
>

Custom layout might need to know about boxes not in the DOM. I don't think
we should allow it to *create* them during the layout though. It's very
hard to reason about the tree you're iterating over being modified.

Maybe we want to say that the style computation phase can create them, e.g.
for the case Ian pointed out. Or, maybe we want to say you need to modify
the actual DOM to get what you want. That'll be something we figure out as
we work out the details of how something like the flexbox example Ian gave
should work.