Version details: And 2.8.x
Distribution/Version: Debian sid

GnomeCanvasItem does not allow for the use of GObject construction properties
with gnome_canvas_item_new() due to the two-phase mechanism of object
construction.  The object properties are set in the second phase, after the
initial construction.  All properties must therefore be writable post-construction.

The attached patch reworks things to use a GObject constructor to replace
item_post_create_setup() and removes the need for gnome_canvas_item_construct()
by making the parent item and canvas into construction properties.

For backwards-compatibility and convenience, gnome_canvas_item_new() sets the
"canvas" and "parent" properties automatically, and puts them and the
user-supplied properties into a GParameter list to pass to g_object_newv() (the
va_list handling is taken from g_object_new_valist()).  However, it's now
possible to fully-construct canvas items using g_object_new alone, so it's far
less crufty than before.

For ABI compatibility, it might be necessary to retain
gnome_canvas_item_construct(), but stub it out so it simply wraps
g_object_set_valist (ignoring the parent argument, since this is construct-only).


If you apply this, it should subsequently be possible to make the derived
GnomeCanvasItem properties into construction parameters, and (if required) make
them construct only.


Regards,
Roger