On 19 June 2014 20:38, Ed . <ej_zg@xxxxxxxxxxx> wrote: > My understanding is that libgimp is for C plugins. Many libgimp functions > are in fact calls to PDB functions - see libgimp/gimppainttools_pdb.c for > example. The distinction between "high" and "low" level is not the one used > to determine what is in the PDB and what is not - despite what you say, > there are gimp-drawable-set-pixel and gimp-drawable-get-pixel procs in the > PDB. > > It seems you are knowledgeable in writing interface code for Python. Why not > add gimp_export_image to the available python functions? Because it is not there. One problem with the current implementation of Pygimp is exactly that it uses C to wrap around calls do libgimp. The problem with this approach is that one loses all the dynamic aspects from Python for these objects: The GIMP Python objects,as exposed in pygimp are "native" objects - as such they can not be modified by pure Python code. For writing Python plug-ins one does either use the objects ofered in Pygimp, with the functions enabled there in C code that requires a ton of boiler-plate for eachmethod made available, or use the Python PDB module, which allows one to call GIMP via the PDB. So, if it is not clear yet, the "gimp_file_export" function just is _not_ there. It can be made available by a C patch in pygimp - but that is adding functionality to a stable series. Or it could be made available through the PDB - which would also make it work from script-fu, and whatever other bindings happen to work. That is also adding new functionality. The correct thing to do is to add it both ways - as an "export" method for image objects, and as a PDB call - in the 2.9 branch. Now, talking about new features, you where the one experiencing with GIMP and GIO - that, on the contrary of this simple call, is something that matters: I'd very much like to rewrite GIMP Python using GIO - (so this kind of stuff would be a non issue in the future: everything available in C is ready without needing explicit wrappers with boiler plate code) - how far did you get with the GIO stuff? > > > -----Original Message----- From: Vladimir Rutsky > Sent: Thursday, June 19, 2014 11:52 PM > To: Ed . > Cc: gimp-developer > > Subject: Re: How to call gimp_export_image() from > Pythonplugin > > On 19.06.2014 22:09, Ed . wrote: >> >> It is not a PDB function, but a libgimp (C) function. Since pygimp can do >> gimpui stuff (also C functions), there is no conceptual reason why pygimp >> shouldn't also handle gimpexport (which is where gimp_export_image lives). > > > Which functions in GIMP goes to PDB, and which stays only in libgimp? > > As I understand, libgimp should contain _all_ functionality, that may be > needed for external C plugins. So it's "low-level" library. > > PDB functions are designed to be called from scripts for automation and > easer writing custom plugins in Scheme/Python/Perl scripts. > So there mostly should be "high-level" functions, since there is no > point in calling "low-level" operations, like set_pixel(), due to > performance overhead of PDB. > > gimp_export_image() is "high-level" function: it does several operations > on image as whole and optionally asks user for some input. > If gimp_export_image() would be available though PDB, it could be called > from any "fu"-script, that can call PDB functions, and there would be no > need to export it specifically in Python, Perl, Ruby, C#... > > Correct me if I'm wrong, since I'm new to PDB and GIMP development. > >> >> I thought that in Python it was straightforward to access C functions? >> This is simply a function that returns an integer, albeit one that uses the >> GIMP UI - which pygimp already can initialise. > > > Best way to use C functions from Python is to write wrapper module in C > that will export methods as Python functions/classes (just as > GIMP-Python does). > Also you can load shared object and call C-function directly using > libffi library (presented as ctypes module in Python), but this > error-prone and really hackish way. > > _______________________________________________ > gimp-developer-list mailing list > List address: gimp-developer-list@xxxxxxxxx > List membership: https://mail.gnome.org/mailman/listinfo/gimp-developer-list > List archives: https://mail.gnome.org/archives/gimp-developer-list _______________________________________________ gimp-developer-list mailing list List address: gimp-developer-list@xxxxxxxxx List membership: https://mail.gnome.org/mailman/listinfo/gimp-developer-list List archives: https://mail.gnome.org/archives/gimp-developer-list
