[css3-background] should radii be capped?

I've run into an issue where the specification for border-radius seems
more limiting than necessary. Consider this test case and screenshot:

  http://people.opera.com/howcome/2009/tests/border-radius7.html
  http://people.opera.com/howcome/2009/tests/border-radius7.png

The top part of the screenshot shows how Opera's internal
implementation renders the test case, the bottom in Firefox 3.5.

I believe Firefox caps the radii as per the current specification [1]
which states:

  The sum of two adjacent radii may not be more than the width or
  height (whichever is relevant) of the box. If any sum exceeds that
  value, all radii are reduced according to the following formula

   <nasty formula deleted>

Opera, however, doesn't cap the radii but attempts to honor them. I
can see many uses for the elliptic expressions that this behavior
allows. The spec, instead, will leave us with many stadium-like
borders, as can be seen in the two leftmost Firefox renditions.

One added benefit of removing the cap is that the nasty formula can be
scrapped.

No?

[1] http://www.w3.org/TR/2008/WD-css3-background-20080910/

-h&kon
              Håkon Wium Lie                          CTO °þe®ª
howcome@opera.com                  http://people.opera.com/howcome

Received on Tuesday, 21 July 2009 20:24:14 UTC