Hello Sven and Oyvind:
> Have you already added the plug-ins to the
> GIMP plug-in registry?
I will when I have rewritten the code to my satisfaction.
The current versions are perfectly useable (and bug free),
but I'd rather release the final versions right of the bat.
> At this point we are concentrating on porting more and
> more of the GIMP core to GEGL.
It is unlikely that I will port EANBQH and IBFNBQH to GEGL,
because programming them so that they can be used analogously
to bilinear, bicubic and lanczos is a substancial programming
I have looked around the GEGL code, and it is very likely that
I will program a novel "co-convex resampling scheme" following
the lanczos model found there. This will take a while.
One good thing about the co-convex scheme is that the results
are not overly affected by what I understand is the current GEGL
"abyss" policy (set pixel values outside of the physical extent
of the image to 0): only if the sampling point is outside of the
rectangle defined by the boundary pixels will the value be
If the default GEGL abyss policy was "smear," this would have the
following general consequence:
Any linear method/filter (blur, resampling...) which is exact on
constant intensity data will still be exact on constant intensity data
without special handling within the filter. This does not mean that
the results are the same as if the filter carefully handles the boundary,
just that the dirty hack of using "ghost values" and then implementing
the filter in a boundary independent way will not give absurd results.
This has two consequences:
Implementing filters can be done in two passes: first, ignore boundary
build in boundary handling into the filter, using the x, y, width and height
information to determine the position relative to the boundary and perform
If speed/more compact code is desired, ignore boundary branching, confident
the results are still reasonable.
This being said, changing to "smear" will not make the results with
the co-monotone method any different, which is why I don't particularly care.
The co-monotone method is not linear.
I suspect that for some filters it is impossible to define an abyss policy which
is equivalent to careful handling of the boundary within the filter. The
trick of masking and normalizing the coefficients is another way of getting
reasonable results (and preserving the "exact on constants" property), but again
it only approximates careful boundary handling for most schemes. If I was to
I'd rather (approximately) fix things with a smear abyss policy (even though,
particular case of my next pet scheme, it makes no difference).
Thank you all for your comments,
Laurentian University/Universite Laurentienne
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