Calculating a new selection from the current selection would be faster (I think): def create_border(image, selection_type='rectangle', size=1): is_selection, x1, y1, x2, y2 = pdb.gimp_selection_bounds(image) if is_selection: if size < 1: size = 1 if selection_type =='rectangle': pdb.gimp_rect_select(image, x1+size, y1+size, (x2-x1)-(size*2), (y2-y1)-(size*2), CHANNEL_OP_SUBTRACT, False, 0) elif selection_type == 'ellipse': pdb.gimp_ellipse_select(image, x1+size, y1+size, (x2-x1)-(size*2), (y2-y1)-(size*2), CHANNEL_OP_SUBTRACT, True, False, 0) else: gimp.message("Please make a selection...") def test_plugin(image, drawable): image.undo_group_start() create_border(image) # A rectangular selecion with default settings... #create_border(image, selection_type='ellipse', size=3) # Or Ellipse with custom settings... # Fill pdb.gimp_edit_fill(drawable, 0) pdb.gimp_selection_none(image) image.undo_group_end() On 09/24/2010 10:19 AM, Ofnuts wrote: > Hi, > > My code needs to do a one-pixel-wide selection, at distance "x" from the > current selection. This looks a lot like a border selection except that > the border selection creates at best a two-pixel wide ribbon and I only > want one (but if I'm wrong, please tell me how to :-) > > So far my code goes like this: > > # Selects pixels that are between x and x+1 pixels from > # the original selection. Bumping the selection by one > # each time doesn't work, a small circle degenerates into > # a square with rounded corners instead of a big circle. > def select_ribbon(self,image,selection,dist): > pdb.gimp_selection_load(selection) > pdb.gimp_selection_grow(image,dist+1) > outer=pdb.gimp_selection_save(image) > pdb.gimp_selection_load(selection) > pdb.gimp_selection_grow(image,dist) > inner=pdb.gimp_selection_save(image) > pdb.gimp_channel_combine_masks(outer,inner,CHANNEL_OP_SUBTRACT,0,0) > pdb.gimp_selection_load(outer) > image.remove_channel(outer) > image.remove_channel(inner) > > That works, but can be slow (especially since it's at the core of a > loop). Is there any better way? Or useless code to jettison? > > Next improvement is to create a 3-pixels selection and feather it one > pixel. Anything to be wary of? > > -- > Ofnuts > > _______________________________________________ > Gimp-developer mailing list > Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx > https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer _______________________________________________ Gimp-developer mailing list Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer