Re: [css3-multicol] overflow inside multicol elements

On Wed, Mar 6, 2013 at 9:12 AM, David Hyatt <hyatt@apple.com> wrote:

> Note that if the multicolumn block has overflow:hidden (which again will
> be common when you're paginating an entire document, you'll see a
> bad-looking slice with your approach as well), or you won't see the content
> at all if it is fully out of view.
>

True, but if the relative positioning isn't too large, authors can work
around that by adding padding to the multicolumn element.

(3) Vertical offsets are in the flow, relative positioned object paginates
> at its final position.
>     (a) Pros - Content is never lost, even when the column block is
> clipped. No bad slices ever occur.
>     (b) Cons - Relative positioning is being taken into account prior to
> layout, which does not match the current spec.
>

Also, this is likely to be insanely hard to implement IMHO.

So your use-cases revolve around situations where an author wants to render
content they don't control with vertical breaks, there's a real risk it
contains transforms or rel-pos that would extend outside any reasonable
margins/padding, and scrolling to view such transformed/rel-pos content is
not acceptable for some reason, so they're willing to visually slice and
accept poor vertical breaks in other situations.

If we're going to support those cases I think we should put this under
author control instead of forcing authors to accept a tradeoff that doesn't
make sense for them. Also, I think we should study your cases in more
detail. For one thing, if authors want to handle HTML they don't control,
they may well want to load it in a (possibly sandboxed) iframe, so we'd
really need a way to do visual-slicing pagination of <iframe> content,
which IE10 regions supports but CSS multicol doesn't.

Rob
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