---- "Øyvind Kolås" <pip...@gimp.org> wrote: > On Thu, Mar 29, 2012 at 4:12 PM, <boo...@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 compression. > > There is no such op at the moment, but it does sound like something > that would be a useful building block for other things. >
!? Nevermind: I think the gegl:scale with filter=cubic might be the same as reduce. I will study more. > > 2. A few weeks ago I posted to GIMP-dev list about > > https://github.com/bootchk/pluginGEGLpluginGIMP 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 > file: > > http://git.gnome.org/browse/gimp/tree/plug-ins/common/goat-exercise.c?h=goat-invasion > OK. It is not clear to me that the new API using GeglBuffers will let Python plugins use GEGL, only C-language plugins, unless there are more changes to, for example, the GIMP PDB or to Pygimp. But I understand it is not high priority, since few GIMP plugin developers, using Python and Scheme, need direct access to GEGL? I suppose the guiding principle is that fundamental filter operations should be GEGL plugins written in C. But why should non-fundamental Python GIMP plugins need to go through the PDB to get to GEGL? I suppose the architecture of GIMP plugins is of no concern to GEGL, and I am not an expert. Anyway, I will defer until after 2.10. > /Øyvind K. > -- > «The future is already here. It's just not very evenly distributed» > -- William Gibson _______________________________________________ gegl-developer-list mailing list gegl-developer-list@gnome.org http://mail.gnome.org/mailman/listinfo/gegl-developer-list
