[Gimp-developer] implement save handler troubles

[Pavel <pavel pamsoft cz>]

Hi team,

I somehow could not reach the author of the original mpo load file
handler, so I am trying to write my own.

My new load handler is working fine, however, I have quite big problems
with the save handler.

First of all, Gimp writes this message when starting from console:

> > GIMP-Error: load handler "save-mpo-file" does not take the standard
load handler args<<

but of course, the "save-mpo-file" function is passed to
"gimp_register_save_handler" function, not to
"gimp_register_load_handler" as the error message might suggest. But
anyway, it works OK afterward.

What is the bigger problem is that when the save function is called, I
get the image ID of an image with name "Untitled". This image has only
one layer. If I iterate through all the images available at the time of
saving, there are two - "Untitled", and "test01.jpg". The latter one has
been created by opening of two images "as layers" - test01.jpg and
test02.jpg. This image contains two layers - "Background" and
"test02.jpg".

So it looks like the export command of Gimp creates a temporary image
with one layer only (either the active one, or whatever). Which is quite
useless. Is this by design? Or how is it possible to export images with
multiple layers?

(I am testing it on Gimp 2.6, perhaps it has been improved since then?)

Thanks, Pavel