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Re: [csswg-drafts] [css-multicol] How do elements between column-span and its multicol ancestor appear around the span

From: Morten Stenshorne via GitHub <sysbot+gh@w3.org>
Date: Mon, 06 Mar 2017 20:49:54 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-284527787-1488833393-sysbot+gh@w3.org>
In Blink, column content is completely interrupted by a column spanner (which is non-column content). It's similar to how blocks inside inlines behave, i.e. by interrupting them. Column content (whether it's block or inline doesn't really matter, I think?) and spanners don't interact (apart from a spanner finishing and balancing the preceding column row). No column content border/background is painted in the area occupied by the spanner. Also, the containing block width of the parent of the spanner doesn't matter. What matters is the size of the content box area established by the multicol container (measured before it's divided into columns, obviously).

For this to work sensibly, we cannot just allow any kind of ancestry between the spanner and the multicol container. The spec requires that parents do not establish new formatting contexts (I think we should disallow establishing *any* kind of formatting context, such as tables or flexbox - and this is what Blink does.). Then, how about relative-positioning and transforms? The most sensible thing would be to let spanners be affected by such parents, right? Or, alternatively, disallow spanners inside such ancestry. Blink ignores offsets caused by relatively positioned parents, FWIW, but I'm inclined to consider that to be a bug, seeing that this is not how blocks inside relatively positioned inlines work.

In Blink, column rows and column spanners are effectively siblings. The containing block of a spanner (and of a column row, really, but they don't have a DOM node, so kind of irrelevant perhaps) is always the multicol container.

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Received on Monday, 6 March 2017 20:50:00 UTC

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