[Pixman] [PATCH v13 11/14] pixman-filter: Negative subsample values produces scaled result

Bill Spitzak spitzak at gmail.com
Sat Mar 5 02:54:12 UTC 2016

On Fri, Mar 4, 2016 at 3:49 PM, Søren Sandmann <soren.sandmann at gmail.com>

> On Tue, Feb 16, 2016 at 4:45 PM, Bill Spitzak <spitzak at gmail.com> wrote:
>> I have a new version of this patch, which fixes a math error that
>> caused it to produce too many samples at small sizes (large scales). I
>> am not clear if I can submit a v14 of just this patch or I should
>> instead submit a v14 of the entire patch series.
> I don't think this functionality belongs in pixman at all. Computing the
> number of subsamples is essentially a performance/quality tradeoff, which
> is something that cairo and other clients need to make for themselves. In
> general, pixman is not the place for heuristics; its API should be
> predictable and explicit.
> So, NACK from me on this patch.

The scale demo is almost useless without this as you have to adjust this
every time you change the scale.

Most software I am familiar with use a fixed number of samples for the
width of the filter, not per integer. This was an attempt to simulate that.

I guess the scale demo could do this math, though that makes it rather
difficult to use the scale demo to figure out the best settings.
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