[gme-users] Controlling the order in which children are returned, decorators

[Krishnakumar B]

On Wednesday, 7 July 2004, Aditya Agrawal wrote:
> Kitty wrote:
> > I would like to know if there is a way in GME to control the order in
> > which children of a Model are returned. Specifically, I have a Model
> > which represents a IDL interface's method. I would like to preserve the
> > order in which the children of this model, i.e., the parameters of the
> > method, are stored and retrieved. I need this so that the parameters in
> > the generated IDL always appear in the same order. Is this possible?
> > 
> > Assume that the above is not possible, and I add an attribute to every
> > child that governs the order of the children. Is there a way that I can
> > automatically assign a value to this attribute everytime a child is
> > created in the model? I would like to keep track of the count and
> > increment/decrement the count on child creation/deletion. Is this
> > achieved with a decorator?
>  
> [Adi] 
> Usually the visual information is used to give a deterministic order to
> the object. The most common approach is to sort the children based on
> the y co-ordinate.

When you say that the most common approach, do you imply that the functions
in BON2/UDM already return children of a Model sorted by their ordinates,
or is this something that the interpreter should do, for example, using the
*_sorted functions in UDM?

> This allows the user to control the order and not have to worry about the
> unique numbering.

OK. But this brings one more question. When I have huge models i.e about 50
to 60 Models in a single sheet each with atleast 8 ports with heavy
connections between them, export them and then re-import them, GME doesn't
preserve the location information, and it is a big mess. It takes about an
hour or so to bring back the original layout by moving it again manually
(Will auto-layout help here?). Even then it seems that it wouldn't take a
lot of changes to store the co-ordinates in the XML export and use them
when re-importing back into GME. I wonder why this is not done. If I rely
on the ordinate to control the order, I would assume that just exporting to
XML and re-importing will break the order. No?


> If you still want to add an attribute and provide automatic numbering you
> will have to do so with the help of an add-on that will be triggered on
> the object created/deleted event and then manage the numbers.

OK.

> > Essentially we have a Component Assembly (a Model) which shows the
> > components in the assembly and the connections between them. But
> > currently there is no support for composition, i.e, one cannot create
> > an assembly of Component assemblies. But experience with using the tool
> > to make models which have many instances of the same grouping of
> > components i.e, an assembly, shows that the current view where one has
> > to scroll the sheet to view the bigger assembly is not very intuitive.
> > Hence my queries.
> > 
> > Any suggestions/pointers/ideas are very welcome.
> 
> [Adi] 
> I spoke to Peter about this a long time ago and it seems that this
> project would require a lot of effort and would probably have to be a
> part of GME. This is because the decorator should be able to call GME's
> internal draw method, scale it and the return the image.

Judging from Peter's silence, I guess he agrees with you. If I understand
what you say correctly, this doesn't involve big architectural changes to
GME.

Akos, is there any way that support for this feature can be added in the
near future? Please let me know if I should file an enhancement request in
JIRA. There is a lot of interest for such a capability from some of our
sponsors.

Thanks,
kitty.