Re: [Gegl-developer] Converting Plug-ins from GIMP (despeckle)

On Mon, 2016-07-18 at 15:39 -0700, Gregg Hauser wrote:
I'm considering converting existing GIMP plug-ins to use GEGL,
initially at  despeckle.c

Hi Greg,

that's great news, new contributors are very welcome :)

The algorithm changes the source buffer if "Recursive" mode is

Question: Is changing the source buffer returned by gegl_buffer_get 

This plug-in falls in the "filter" category and you would get
rid of the GIMP plug-in alltogether and write a GEGL op, which
will then gets its GIMP GUI auto-generated. This is also the
much easier approach, you can simply port such filters to float,
drop the GUI and done.

Request for Comments: The basic algorithm in GIMP's despleckle
chooses a 
pixel randomly from those pixels closest to the median in luminance, 
avoiding pixels above and below user specified levels of luminance. 
Colors may change as long as the luminance of the pixel chosen is
to median around the pixel being calculated. This seems like a
to me. The 3 channel median-blur.c algorithm in gegl/workshop seems
lot closer to what this plug-in should be than the original code in 
GIMP. The literature is full of other despeckle algorithms, some of 
which preserve detail better than the median technique. Some
algorithms are appropriate for black and white images only.

I'm not the master of algorithms here, maybe somebody else can answer
that question...

Question: Does the 2.10 or 3.00 version of GIMP need to slavishly
the existing plug-ins?

It is preferred, unless the GIMP plug-in code is broken or otherwise
totally shitty. We'd like to auto-redirect scripts calling the
plug-in to the new GEGL op, and that works best if they do exactly
the same. It's not a strict rule tho and probably mostly depends on
you own judgement, because having looked into the issue makes you
the foremost expert on despeckle :) (GIMP plug-ins don't get a lot
of attention usually).


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