Re: [Gimp-developer] GIMP_DEPRECATED - recipe for translation?

[Teo Mazars <mazarst ensimag grenoble-inp fr>]

Hi, 

Yes, nexts majors versions of GIMP will use GEGL to process images. I won't describe here what are advantages 
of using GEGL, but only how to get started using it instead of the <=2.8 api. 

0) There is no exact matches between the old and the new api, though, generally speaking, GEGL makes things 
simpler and cleaner. 
1) You may have a look at http://wiki.gimp.org/index.php/Hacking:Porting_filters_to_GEGL, which contains some 
informations on how to do that. 
2) I strongly encourage you to get in touch with us on IRC, irc.gimp.net channel #gimp and #gegl, for any 
question, or if you need help. 
3) Keep in mind that gegl.org is a bit outdated, so please use the documentation available after building 
sources from the git repository. (using --enable-gtk-doc) 
4) Also both GEGL' and GIMP's git trees contain good examples. 

There are basically two ways of porting a plug-in to GEGL : 

1) by creating a "GEGL operation" instead of a GIMP plug-in, you will find a lot of examples in the GEGL 
source tree /operations/common/*.c, depending on what your operation does, I can be more specific. 
2) for some plug-ins, using a GEGL operation is currently not possible (handling parasites, reodering layers, 
specific UI, ...), then a gimp plug-in is still needed. In that case, gimp_drawable_get_buffer() will provide 
the GeglBuffer containing all pixels of the drawable. 

In both cases, you have then to deal with GeglBuffer's accessors to do what you want with pixels. You can use 
either gegl_buffer_get() to get all pixels needed inside a contiguous array, or a GeglBufferIterator, or even 
a GeglSampler. I won't say more for now, these hints are not precises hint on how to go from 
gimp_pixel_rgn_init to something else since it depends on what you want to do. If you are more specific (you 
can show us what plug-in is this about), we will probably be more helpful to your specific use case. 

And again, most of things happen on IRC, so feel free to meet us there. 

Kind regards, 

Téo 

----- Mail original -----

De: "Helmut Jarausch" <jarausch skynet be> 
À: "gimp-developer" <gimp-developer-list gnome org> 
Envoyé: Mercredi 27 Novembre 2013 18:17:13 
Objet: [Gimp-developer] GIMP_DEPRECATED - recipe for translation? 

Hi, 

I have a plugin which uses lots of functions which are deprecated now. 
Since the macro GIMP_DEPRECATED_FOR suggests functions with totally 
different parameters 
GIMP_DEPRECATED_FOR(gimp_drawable_get_buffer) 
void gimp_pixel_rgn_init (GimpPixelRgn *pr, 
GimpDrawable *drawable, 
gint x, 
gint y, 
gint width, 
gint height, 
gint dirty, 
gint shadow); 

(gimp_drawable_get_buffer has a single drawable_ID parameter only) 

is there a recipe how to translate the old calls into the current 
function calls? 

Many thanks for a hint, 
Helmut. 
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