I'm interesting in undo of plugin changes. I add before:
and after changes:
Undo-action is created, press Ctrl+Z, but image not come back.
I try use only "gimp_image_undo_group*" function is not worked too. Next download GIMP 2.6.11 source, browse file blur-selective.c and blur-gauss.c and not found above functions. And after run these filters undo is working.
How correctly change image, that may be undo it? "Changes" is calls "gimp_pixel_rgn_set_row".