surface buffer cardinality and outputs

[Jason Ekstrand]

I'm not sure exactly what I think of all this surface transform
passing.  I'll get back to that once I get a chance to think about it.
 Part of the problem is that you don't want to try and make your
animations subpixel-perfect because that would require a lot of
round-trips to make it right.

One thing I did want to point out though regards the details of
subpixel rendering.  Right now the window has no knowledge at all of
where it sits on the screen.  While I think this is a great idea it
throws subpixel rendering off on some displays.  I was reading up on
it last night and, on some panels, the client would need to know its
position at least modulo 2 or 4 in order to render correctly.  For
completely uniform subpixel layouts, it doesn't need to know this.
However, some of the more clever pixel layouts are not uniform but
rather have a pattern and where the buffer sits in that pattern is
essential for proper subpixel rendering.

See also: http://en.wikipedia.org/wiki/Subpixel_rendering#Checkered_RG-BW_layout

--Jason Ekstrand