RE: [DiaCanvas] using groupable_remove/add (crash)

[<arj...@he...>]

> Hi All,

Hi,

>  Maybe someone can clarify this for me, I might be doing something
> wrong:
>=20
>  * I have a DiaCanvas with a few DiaCanvasItem's that I added to it
>    using canvas->root and dia_canvas_groupable_add.
>  * This works fine, but then I want to detach these items from the
>    canvas, but *not* delete them. I am using =
dia_canvas_groupable_remove
>    to do this (and I am detaching all of them).

Do you own a reference to the detached item? If you created the item =
with dia_canvas_item_create() you should own one, if you use =
dia_canvas_group_create_item() you do *not* own a reference by default =
(you should do a g_object_ref() first).

>  * And after that I want to add some of these elements again, but not
>    all of them, and not in the same order they were added before.
>    I try to do this using dia_canvas_groupable_add again, but it
>    crashes in dia_canvas_group_groupable_add, because it is trying to
>    use some undo information stored as a Quark in the DiaCanvasItem,
>    which leads the code to think (I believe) that I am trying to undo
>    something, and re-add the Item to a list that does not exist=20
>    anymore.

Hmm... This sounds weird...

Could you please answer these quiestions in order to clarify this a bit =
for me...

- What version of DiaCanvas2 are you using?

- If you set the allow_undo property to FALSE (g_object_set(canvas, =
"allow_undo", FALSE, NULL);) does it still happen then? I can't think of =
any reason the canvas should think you're undoing something...=20

- The second time you add the canvas item, is it still a valid object =
(do you own a reference)? You can check that easely by printing the =
value of G_OBJECT(item)->ref_count.

- Did you create the items you added yourself, or are these the items =
from the library (e.g. DiaCancasLine, DiaCanvasBox)?

- I would be very interested in a test case that exposes this possible =
bug. Could you create a simple example?

Thanks in advance,

Arjan


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