[PATCHv2] dix: add 3x3 transformation matrix xinput property for multi-head handling

[Simon Thum]

Am 24.05.2010 08:20, schrieb Peter Korsgaard:
> Ahh, the actual matrix elements? I don't right away see any need for
> values over 1, but you do need negative values when using rotation.
> 
> Perhaps >1 values are interesting if you want an absolue input device to
> span multiple screens for some kind of video wall with touchscreen
> setup?
> 
> All in all, I would prefer to not hardcode any policy here in the
> server. Strange values doesn't really harm us.
I tend to agree. Some people really want to scale up, even if it means
(some likelyhood of) skipping pixels. However, NaN or Inf should really
be checked for.

AFAIK in X it's ok to use isfinite
(http://www.kernel.org/doc/man-pages/online/pages/man3/isnan.3.html)
since X assumes Posix 2001.1 conformance.

Cheers,

Simon