Re: [Gegl-developer] gaussian reduce operator, and GIMPGEGL operator

On Thu, Mar 29, 2012 at 4:12 PM,  <bootch nc rr com> wrote:
This message has two subjects.
1. Is there a gaussian reduce operation in GEGL?  Refer to the paper by Burt and Adelson, 1983, where it is 
called REDUCE and apparently claims that it is faster than operation gaussian blur followed by down-sample 
(scale by 1/2).  Used in the production of a gaussian pyramid.  It seems to me to be a fundamental 
operation and should be in GEGL.  A search shows that the operation mantiuk06 for GSOC might have generated 
gaussian pyramids but AFAIK did not expose reduce() as a operation.  There is also a corresponding inverse 
operation EXPAND, which is useful in generating a Laplacian pyramid.  I have a use for a gaussian pyramid 
and might consider implementing gaussian reduce for GEGL (instead of the naive approach of using gaussian 
blur followed by scale.)  The gaussian and laplacian pyramids are used in texture synthesis and image 

There is no such op at the moment, but it does sound like something
that would be a useful building block for other things.

2. A few weeks ago I posted to GIMP-dev list about a GEGL 
operation that lets you used GEGL in GIMP plugins written in Python and using Pygegl binding.  Its not in 
the form of a proper patch to GEGL but I would make a patch if I thought it would help anyone to evaluate 
whether it should be part of GEGL.

The proper migration of GIMP to GEGL has ramped up significantly the
last month, in GIMP-2.10 the tile based drawable API will be marked as
deprecated and the official way for plug-ins to interact with the GIMP
core will be through GeglBuffers, for a very simple example see this

/Øyvind K.
«The future is already here. It's just not very evenly distributed»
                                                 -- William Gibson

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