[Pixman] [PATCH v3 1/2] Remove the 8e extra safety margin in COVER_CLIP analysis

[Pekka Paalanen]

On Fri, 25 Sep 2015 07:38:34 +0300
Siarhei Siamashka <siarhei.siamashka at gmail.com> wrote:

> On Wed, 23 Sep 2015 11:40:32 +0300
> Pekka Paalanen <ppaalanen at gmail.com> wrote:
> 
> > From: Ben Avison <bavison at riscosopen.org>
> > 
> > As discussed in
> > http://lists.freedesktop.org/archives/pixman/2015-August/003905.html
> > 
> > the 8 * pixman_fixed_e (8e) adjustment which was applied to the transformed
> > coordinates is a legacy of rounding errors which used to occur in old
> > versions of Pixman, but which no longer apply. For any affine transform,
> > you are now guaranteed to get the same result by transforming the upper
> > coordinate as though you transform the lower coordinate and add (size-1)
> > steps of the increment in source coordinate space. No projective
> > transform routines use the COVER_CLIP flags, so they cannot be affected.
> > 
> > Proof by Siarhei Siamashka:

> > Cc: Siarhei Siamashka <siarhei.siamashka at gmail.com>
> > Signed-off-by: Ben Avison <bavison at riscosopen.org>
> > [Pekka: adjusted commit message, left affine-bench changes for another patch]
> > [Pekka: add commit message parts from Siarhei]
> > Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> > 
> > ---
> > 
> > v2 is part 1/2 of the patch "Change conditions for setting
> > FAST_PATH_SAMPLES_COVER_CLIP flags".
> > 
> > This is v3 with a yet more bikeshedded commit message.
> > 
> > Ben, Siarhei,
> > 
> > for the record, gentlemen, please give your reviewed-by's
> > so I can just push these two out without any confusion. :-)
> 
> Yes, sure. Even the older commit message already included a
> link to the mailing list archive, so I did not have any
> problems with it. This final revision is also fine.
> 
> Reviewed-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>

With all the comments, well-actuallys and by-the-ways, it's sometimes
hard to tell. :-)

I wasn't sure if you meant to give R-b also for 2/2, so I put only
Ben's R-b there.

Pushed:
   23525b4..2876d8d  master -> master


Thanks,
pq
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