Re: [Gimp-developer] Python-fu GIMP Layer "parent" property error

["Joao S. O. Bueno" <gwidion gmail com>]

Issue fixed in master and 2.8 branch.  (It will be generally
available as of gimp 2.8.12)

Thanks for spotting that.

  js
 -><-

On 19 June 2014 00:31, Joao S. O. Bueno <gwidion gmail com> wrote:
> yes - this is a bug - and it can be open in the bugtracker.
>
> On 18 June 2014 22:41, Seldom Needy <needthistool gmail com> wrote:
> > As stated at http://www.gimp.org/bugs/ I'm supposed to mention issues
> > here before throwing them into the tracker so here goes.
> >
> > Working on a plugin that does some layer manipulation and kept
> > encountering the error:
> > AttributeError: 'gimp.Layer' object has no attribute 'layers'
> > when trying to access the layer structure in a tree-like fashion to
> > find "sibling" layers in the same grouplayer/layergroup. After being
> > puzzled, I found the issue, which seems to essentially be that the
> > "parent" attribute of a layer automatically "upcasts" to gimp.Layer,
> > rather than yielding a gimp.GroupLayer, as I think should be expected.
> >
> > The behavior can be reproduced as follows from Python console in GIMP 2.8.8:
> > > > > image = gimp.image_list()[0]
> > > > > image.layers[0].layers[0].parent.layers # again with the result:
> > AttributeError: 'gimp.Layer' object has no attribute 'layers'
> >
> > Assuming an image's layer-structure is similar to:
> > [root image]
> > +--------GROUPLAYER ZERO
> > +--------+--------LAYER ZERO OF ZERO
> > +--------GROUPLAYER ONE
> > +--------+--------LAYER ZERO OF ONE
> > +--------+--------LAYER ONE OF ONE
> > +--------LAYER BACKGROUND
> >
> > From the console we have a hint as to why this is.
> > > > > image.layers[0]
> > <gimp.GroupLayer "GROUPLAYER ZERO">
> > > > > image.layers[0].layers[0].parent # should return the same layer as above but gives
> > <gimp.Layer "GROUPLAYER ZERO">
> >
> > I haven't seen this on the bugtracker nor was I able to find
> > discussion about it on the listserv archive. I assume it is a
> > platform-independent bug. Can anyone confirm that? I develop on
> > Windows XP at present.
> >
> > Workarounds for this bug exist I'm not in love with them (inelegant).
> > Regardless, a sketch of what might work without using globals:
> >
> > def get_all_layers(parent):
> >     """-> list. recursively get all layers from either an image, or a GroupLayer
> >     Proceeds depth-first.
> >     """
> >     container=[]
> >     for layer in parent.layers:
> >         container.append(layer)
> >         if hasattr(layer,"layers"):
> >             container.extend( get_all_layers(layer) )
> >     return container
> >
> > def get_parent(child):
> >     if hasattr(child,"parent"):
> >         for layer in get_all_layers(child.image):
> >             if layer.name==child.parent.name: return layer
> >             #^ layer will have the proper data-type of
> > gimp.GroupLayer, so return it.
> >             #^.. We do this because child.parent yields a gimp.Layer,
> > which is undesired.
> >     else:
> >         return child.image # if we're already top-level, parent must
> > just be the image.
> >
> > Cheers
> > - Seldom
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