Re: [Gegl-developer] bump-map operation

[Michael Natterer <mitch gimp org>]

On Wed, 2013-06-26 at 12:05 +0300, Dov Grobgeld wrote:
> The filter certainly is local as it is only using a 3×3 neighborhood.
> What example op can I look at in order to see exactly what
> requirements I need to fulfill to make the op into an "area filter"
> and make it work with Gimp's GEGL tool? Is this documented anywhere?

I'm not the über-expert myself, but look at the last two functions in
gegl-operation-area-filter.c, I think that's all you need to implement
in bump-map.

> I thought about looking at the NewsPrint plugin next. Or is there some
> other plugin that is more urgent?

That plug-in has a very complex GUI and we have no way just yet to
easily do that with the GEGL tool (with on-canvas preview), also
it's rather esoteric so it probably falls in the category "port
the GIMP plug-in to the new GeglBuffer API in libgimp and done".

My personal favorite is the mosaic plugin because I really like
the effect. That doesn't make it "urgent" tho ;) (If you really
want to do that, there is a patch in bugzilla that adds a configurable
random seed to the GIMP plugin, maybe the port should be done from
a version that includes that patch).

IMO dilate and erode are in the "must have" section for commonly
known generic operations that are missing.

Opinions from anyone?

Regards,
--Mitch

> Regards,
> Dov
>
>
> On Wed, Jun 26, 2013 at 1:30 AM, Michael Natterer <mitch gimp org> wrote:
> > On Tue, 2013-06-25 at 23:05 +0300, Dov Grobgeld wrote:
> > > I just added a bump-map operation. It is heavily based on the
> > > corresponding gimp code, but modified according to my understanding of
> > > gegl. The fact that the bumpmap is in floating point makes the
> > > resulting "surface" much smoother than the original gimp operation, as
> > > 8-bit is too little to get accurate surface normals.
> > >
> > > Please let me know your comments about the code and update wiki
> > > "Hacking:Porting filters to GEGL" page. (I would have done it myself
> > > if the maintainer of the wiki would have answered my email requesting
> > > write access.)
> >
> > Thanks Dov, that's cool :)
> >
> > I pushed a small whitespace cleanup to bump-map.c, and the last
> > parameter of the chanted properties is supposed to be a human readable
> > blurb that appears as tooltip in GIMP, so should be human readable :)
> >
> > Also, does the op really need the entire input? Can't it be done
> > like an area filter? Requiring the entire input makes it impossible to
> > adjust parameters interactively in GIMP's GEGL tool.
> >
> > Regards,
> > --Mitch