[CREATE] Blur Benchmarking: Synfig, Inkscape, Gimp, Anime Studio

[Carlos López González]

>
> > Hi!
> > I've been playing a bit with Blurs on some 2D raster and vector
> > applications and I would like to share some results with you.
> > After the tests I wonder if it is interesting to Gimp and Inkscape
> > people to improve the blurs methods to get closer to Synfig's methods.
> Short answer: no. Inkscape is bound by what SVG specifies, and we
> currently follow the specification, so changing our blur significantly
> would be a regression. I'm not entirely sure what synfig does (I've had
> a look at the code and I'm not entirely sure why it's so visibly
> different), but I'm afraid that we cannot adopt it (entirely), even if
> we would agree that it's better in a subjective sense.
>
> One of the differences might be the color space used for the filter (and
> blending), and this you can change in SVG using the color-interpolation
> attributes. These are unfortunately not supported in Inkscape, but I
> think most browsers do support it (not 100% sure).
>

I don't want to cause a regression on any application. I'm just sharing with
you those facts I've seen during blur comparison. In any case regressions
can be always handled given the user to add one option to render as old
version or as new version.

I'm not expert on the blur materia but intuitively I think that when you see
something blurred you shouldn't get color deviation of it and only alpha
channel should reflect that blur effect.

The thing is that when you get the blurred result of a single color shape on
a transparent background (like the example) and use it as source for other
operations like color saturate multiplication or similar,  (which is very
used for drawing compositions), the fact that it has color deviation may
cause further degradation of the result.

Similar happens to the antialiasing effect. See this antialiasing comparison
[1]<https://docs.google.com/document/d/17pNfb7TKw_wzAt6fGcDzQ5L5-Ms8iQka1VrLwMnKkNw/edit>.
It shows how Inkscape and Anime Studio create color biased pixels when
exporting a single color shape to png. This will cause antialiasing problems
when further processed.

On the example, Gimp and Synfig does exaclty the same job but Inkscape and
Anime Studio produce color biased pixels. I'm not aware on what other
applications do and might be interesting to know it.

IMHO it should be corrected.

-- 
Carlos
http://synfig.org

[1]
https://docs.google.com/document/d/17pNfb7TKw_wzAt6fGcDzQ5L5-Ms8iQka1VrLwMnKkNw/edit
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/create/attachments/20111026/80af9e9b/attachment.html>