[Xr] Dealing with groups in Xr

[David Lazaro]

Hello,

> BUT, beyond all of this, Keith has an interesting suggestion for the 
> problem of the default unit. He proposed taking some nominal unit 
> size, (some "point"), and rounding it up to the nearest device pixel 
> size. That should meet help address the need for device independent 
> metrics while still allowing alignment with the pixel grid, (which 
> will remain important for some number of years).
> 
> If I remember correctly, Keith got this idea from CSS. I haven't read 
> that specification yet myself.

This is a possible reference:
http://www.w3.org/TR/REC-CSS2/syndata.html#length-units. It comes from
the CSS2 specification.

In this model the definition of a pixel is a relative unit that depends
on the viewers distance.  It is a very good model for maintaining
relative sizes for web page elements.

I'm not defending the idea, though, because I feel that this abstraction
only makes sense in a limited context as web page rendering.  I'll
develop an explanation when I find a little bit more of time.

Best regards,

David.