[cairo] [PATCH] Revert "image: Use convolution filters for sample reconstruction when downscaling"

[Bryce W. Harrington]

On Fri, May 16, 2014 at 06:59:53AM +0000, Bryce W. Harrington wrote:
> On Wed, May 14, 2014 at 02:54:35AM +0200, Krzysztof Kosiński wrote:
> > 2014-05-13 10:15 GMT+02:00 Uli Schlachter <psychon at znc.in>:
> > > This reverts commit fb57ea13e04d82866cbc8e86c83261148bb3e231.
> > >
> > > When running cairo-test-suite with the parameter "-a", it also runs each test
> > > with a non-zero device-offset and device-scaling. The above commit influenced
> > > the device-scaling results badly. E.g. some test results ended up with a black
> > > border at the top-most and left-most row that looked like there was an offset of
> > > "0.5" in drawing the image and thus pixels outside of the image were sampled.
> > >
> > > This can be seen by the influence that this revert has on the results from
> > > running CAIRO_TEST_TARGET=image ./cairo-test-suite -a:
> > >
> > > Before: 31 Passed, 489 Failed [1 crashed, 8 expected], 31 Skipped
> > > After: 225 Passed, 295 Failed [1 crashed, 8 expected], 31 Skipped
> > >
> > > Most of the failures that disappeared are from the device-scaling tests.
> > >
> > > With such disastrous results on the test suite, this cannot really be usable for
> > > real-world applications.
> 
> Krzysztof, in the previous thread there were several compromises
> suggested.  Can you re-review those and see if there is a plan that
> everyone can get on board with and agree to?  If so, then let's make a
> priority in getting that implemented for this release.  Otherwise, if
> there's no consensus position possible, then we should revert the patch
> from Cairo trunk and give the discussion more time to percolate.

As it's been a few weeks with no forward progress, I think we have no
choice but to proceed with plan B and revert the current patch from
trunk in hopes that will stimulate discussions towards a consensus plan.

Bryce