[CSSWG][css-break][css21] Priority of widows/orphans vs. break-*

At dinner after the F2F, I asked Dave Cramer to look over the
last remaining issue in the Fragmentation spec:
   http://www.w3.org/TR/2015/WD-css3-break-20150129/#unforced-breaks
   "This means that widows and orphans restrictions are given
    priority over the break-* controls. Is this appropriate?"

Dave confirmed that this is indeed an issue, and in fact, the
spec has it completely backwards: widows and orphans restrictions
should be be dropped before page-break-* restrictions.

He drew up a quick testcase showing a large image followed by
a caption with a high widows value and that the entire caption
was pushed to the next page and separated from the image, to
demonstrate.

The general explanation was that widows and orphans limits are
"nice to have" for better continuity, but the break-* controls
usually reflect structural concerns, and are therefore more
important.

Since we had a quorum of the fragmentation-focused CSSWG members:
   Dave Cramer
   Liam Quin
   Peter Linss
   Johannes Wilm
   Alan Stearns
   and myself
plus a chair (Peter), and everyone agreed that this was clearly
backwards, we ended up with

RESOLVED: widow/orphan restrictions should be dropped before, not
           after, break-* restrictions

If anyone not present would like to reopen the issue, please
reply here. Otherwise I'll edit it in and republish as such.

For CSS2.1, I recommend we drop all the restrictions simultaneously
and leave it up to the UA, which means both behaviors are valid.
The edits for this are

   # If the above does not provide enough break points to keep
   # content from overflowing the page boxes, then rules A, B
   # and D are dropped in order to find additional breakpoints.
   # If that still does not lead to sufficient break points,
   # rule C is dropped as well, to find still more break points.

Remove the last sentence and add C to the list of rules dropped.
Bert, can you add an erratum?

Thanks~
~fantasai

Received on Wednesday, 2 September 2015 18:35:07 UTC