[Pixman] [PATCH v13 10/14] pixman-filter: Gaussian fixes

Bill Spitzak spitzak at gmail.com
Sat Mar 5 02:51:39 UTC 2016

On Fri, Mar 4, 2016 at 3:39 PM, Søren Sandmann <soren.sandmann at gmail.com>

> On Wed, Feb 10, 2016 at 1:25 AM, <spitzak at gmail.com> wrote:
>> From: Bill Spitzak <spitzak at gmail.com>
>> The SIGMA term drops out on simplification.
> But SIGMA has a meaning here: it's the standard deviation for the normal
> distribution corresponding to the Gaussian in question, so unless there is
> some good argument for reducing the formula, I think it should stay the way
> it is.

The simplification does not happen due to inexact math.

> Expanding the size is fine with me

This is based on checking other software for the widths it uses for such

There is a bit of hf at the cutoffs, enlarging the size reduces this. It is
very common for "gaussian" to actually be this function multiplied by a
sinc window to avoid this, but I did not think that change was a good idea.
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