[css-text-decor-3] are underline positions per-line or across lines?

http://www.w3.org/TR/CSS21/text.html#decoration says:
  # In determining the position of and thickness of text decoration
  # lines, user agents may consider the font sizes of and dominant
  # baselines of descendants, but must use the same baseline and
  # thickness on each line.

On the other hand,
http://dev.w3.org/csswg/css-text-decor-3/#line-position says "user
agents must consider, per line box, ..."

If this change was an intentional change from CSS 2.1, the
specification should say so.

However, I prefer the CSS 2.1 behavior.  Having the
underline calculated per-line-box means the behavior can differ
depending on where line breaks happen.  This, I think, means that
authors are more likely to produce content that works at some line
widths and doesn't work at others.  It also seems inconsistent to
me, although I'm not aware of common practice in other systems.

What was the rationale for this change?

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂

Received on Monday, 25 March 2013 04:18:24 UTC