Re: stability of root em unit spec

Also sprach Keith Rarick:

 > Aside from the naming question, David's review of my patch brought up
 > a possible need for clarification in the spec. From his comment:
 > 
 > > Another issue where the spec could use some clarification
 > > (although where I tend to think what you implemented is
 > > the correct behavior) is the question of which document's
 > > root element should be used.  For example, in SVG, things
 > > can be pulled in from other resource documents; in those
 > > cases, the root element doesn't even necessarily have a
 > > font size, or it could have more than one if it's used in
 > > different places.  So I think we really do want the root of
 > > the root document in that case (which is what you've done),
 > > although I think the spec could be clearer.  (This is different
 > > from frames, where we should, and your code does, use
 > > the root of the document inside the frame/iframe, not the
 > > root of the root document.  I think, anyway.)
 > 
 > So to be totally safe I need to know two things:
 > 
 > 1. Is this interpretation of the spec correct? (And perhaps the spec
 > should be clarified in this regard.)

I'm confused. The CSS model is quite simple: the root element inherits
from the initial value, and other elements inherit from their parent
element. This is expressed here:

  http://dev.w3.org/csswg/css3-cascade/#inheritance

Is this close to your own understanding? If the model needs to be
amended in any way, I would appreciate a suggested text.

 > 2. Do we expect any other (unrelated) changes to the spec for rem
 > in the future?

Not that I can see. The most likely source of changes would be if
implementors find issues. So, do let us know how it goes.

Cheers,

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

Received on Thursday, 8 January 2009 21:14:28 UTC