Date: Fri, 17 Sep 2004 09:05:42 +0900 (JST)
Message-Id: <20040917.090542.59460509.garrigue at kurims.kyoto-u.ac.jp>
To: andrieu at ijm.jussieu.fr
Cc: lablgtk at kaba.or.jp
Subject: Re: (Q) How to store "pixbuf" into GTree.model?
From: Jacques Garrigue <garrigue at kurims.kyoto-u.ac.jp>
In-Reply-To: <20040914.160525.92586750.oandrieu at nerim.net>
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	<20040914151922.733e64d0@tintin.inria.fr>
	<20040914.160525.92586750.oandrieu@nerim.net>
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From: Olivier Andrieu <andrieu at ijm.jussieu.fr>

> let colpix = cols#add Gobject.Data.gobject in
> 
> would is more likely to work (pixbufs are gobjects)

Indeed, it works.

> Anyway, the GTree code needs some fixing : right now it converts the
> GTypes of the column list to fundamental types before creating the
> GtkListStore of GtkTreeStore. It's wrong, I don't know why it does
> this.

This is due to the fact columns are made from data_conv's, and
data_conv's only know fundamental types.
(It think I tried to make data_conv's more general once, but bumped into
problems with GTK. It's not always a good idea to tell too much about
types to GTK...)

GTK only checks the fundamental type of columns (accessing them with
g_value_get_{object,boxed,...}), so this information is sufficient, at
least for gobject's.

On the other hand, there seems to be a real problem with boxed values,
as you cannot create a GValue of a boxed type without knowing which
one:
# let v = Value.create (Type.of_fundamental `BOXED);;
(ocaml:692): GLib-GObject-WARNING **: gvalue.c:95: cannot initialize GValue with type `GBoxed', this type has no GTypeValueTable implementation

This should be solved at the gobject.ml level.
Fortunately, boxed values are not a requirement for tree models,
and this conversion problem does not apply to usual object properties
(in that case, the type field of the data_conv is ignored)

Jacques