Re: [g-a-devel]gnome-mag IDL

[Bill Haneman <bill haneman sun com>]

On Mon, 2002-09-16 at 15:04, Michael Meeks wrote:
> Hi Bill,

> 	Fair enough; I'd also be in favour of adding a 'property_bag_widget' or
> somesuch to libbonoboui that would list the contents of the
> PropertyBag's properties, and let them be manipulated, since this could
> be easily shared between glade, and various other projects.

OK, though time constraints may bite us here.  Probably we need to put
something together in the meantime, inside gnome-mag.
 
> > 	public interface ZoomRegion : Bonobo::PropertyBag
> > 
> > 		setMagFactor ()
> ...
> > 		setValue ("contrast", some-contrast-value-as-CORBA-any)
> 
> 	It sucks to inherit from PropertyBag; badly, for all the reasons
> discussed before.

Yep.  I suggest (and wrote in my recent IDL) a 

PropertyBag getProperties ();

API which would be a convenience wrapper around an aggregated
PropertyBag interface.

> > We would prefer, I suppose, not to have to call the Bonobo::PropertyBag
> > API via a getInterface() call on the ZoomRegion (for both convenience
> > anc code clarity).  However, making ZoomRegion derive from PropertyBag
> > directly seems a little unusual; 
> >
> > Michael, what is your suggestion here?
> 
> 	Consider if you can use a simple PropertyBag interface instead of
> ZoomRegion altogether ?

Probably not, since there are some ZoomRegion calls that are not
conveniently expressed via propertybag (though they could be,
theoretically).  Also the ZoomRegions do have a conceptual feeling of
being more than just a collection of properties.

> 	Can you have 'magFactor' as a property instead of a 'setMagFactor'
> method ?

Perhaps, but there are independent x and y factors, so we'd need either
a struct or x-mag-factor and y-mag-factor properties.  It's nicer I
think to have a single API call here, since this will be one of the most
used settings.  Similarly for the ROI bounds... though we could have a
Bounds structure.

But I don't see an advantage to making "everything" in gnome-mag into a
PropertyBag property, and I see some disadvantages with regard to
convenience and clarity. 

thanks,

Bill

 
> > suggestions welcome; I'll post complete draft IDL a little later today,
> 
> 	Look forward to seeing it.
> 
> 	Regards,
> 
> 		Michael.
> 
> -- 
>  mmeeks gnu org  <><, Pseudo Engineer, itinerant idiot
>