[css-display-viewport] Enabling fast layout for web apps via isolation

Hi,

This week, I had some time to write about a proposal I discussed during TPAC 
with Tab Atkins called ‘display: viewport’ aiming at making CSS layouts more 
efficient by reducing the intrication level (aka: downplaying the impact of 
large and dynamic DOM trees on rendering performance), and I did so mainly 
because I talked about it at least two times on the mailing list during the 
past month without even making it official. Let's consider this as my 
Christmas gift to the WG ;-)

The use cases I’m trying to solve are multiple, but here are the most 
important ones:

    - Fast relayout experience when elements are added in the DOM on complex 
web pages (infinite scrolling, non-canvas html games, animated layouts...) 
[1]

    - Better layout isolation for web components (aka ‘sandboxing’), and a 
first step toward enabling new use cases like “local MQ” (element-size-based 
layouts) [2]

I won’t repeat in this mail everything I already said previously in the 
different specialized threads referenced at the bottom of this mail, but you 
can find a nicely written introduction (1.0) and prior art discussion (1.3) 
as well as some open issues in the ‘specification’ itself, which I invite 
you to have a look at.

        http://fremycompany.com/TR/2012/ED-css-viewport/

Best regards and best wishes for the end of year,
François

[1] http://www.sencha.com/blog/the-making-of-fastbook-an-html5-love-story 
(look for ‘iframe’)
[1] http://lists.w3.org/Archives/Public/www-style/2012Nov/0527.html
[2] http://lists.w3.org/Archives/Public/www-style/2012Dec/0230.html