Re: Objects & Layers relationships

["Dolores Alia de Saravia" <loli unsa edu ar>]

On 13 Aug 2003, Lars Clausen write:
> On 12 Aug 2003, Matthew J. Smith wrote:
> > Hello all-
> > As a Dia user, I just wanted to throw out one of my own 
observations. 
> > Currently, an object seems to reside in a single layer, and can 
have no
> > interaction (for example, connecting lines) with objects in another
> > layer.
> > I use layers all the time to show/hide the different components of 
my
> > drawing.  For example, an IT Environment diagram may have a 
physical
> > network layer, a logical routing layer, a server layer, an 
application
> > layer, etc.
> > It would be very useful to me to have an object that can belong in
> > multiple layers.  In the above example, it would be great to have 
the
> > firewall in all my layers, so that all objects can be connected.  
As
> > well, I'd like to hide all layers except for the one I am 
interested in,
> > and still have the firewall show up.
> > I think the easiest solution would be to make layer membership a
> > multi-value attribute of an object.  A layer view would then 
abstractly
> > be a query to find all the objects with the selected layer(s) 
listed as
> > an attribute.  This would also allow all objects to connect with 
all
> > others, regardless of layer, since all objects could belong to some
> > common "primary" layer.
> > Would this type of functionality be useful to anyone else?  Or, 
should
> > I just re-evaluate my use of layers in diagrams?
> 
> Your suggestion seems rather slow -- remember that when moving 
line-ends,
> we have to search for nearby objects to connect with, and that would 
make
> us search through a list of layers on each object in the whole 
diagram,
> rather than just the current layer.
> 
> What I've considered is to allow connections between layers.  Just 
like
> Gimp allows several layers to be marked as moveable together, we 
could allow
> layers to be marked for connectivity as well as visibility.  In your 
case,
> you'd make one layer that has the firewall, always have that visible 
and
> connectable, but turn visibility and connectibility on and of on the 
other
> layers (by switching current, i.e. selectable, layer).  I think 
that'd be
> fairly easy to do.


Perhaps it would be nice to have just  one more object: a very spetial 
one: one which would belong to every layer at exactly same position 
and with a "spetial connection point" for each layer (and user could 
bring to the diagram any number of them). 

For each layer, the connection point of these "transversal objects" 
could be connected of disconnected ( user's will) with the ojects 
"covering" its position: if the user  moves an object connected to a 
transversal object, all the object connected would move ...
 
While working with the diagram,  these "transversal objects" would be 
visible in every layer, but they would be invisible in printed 
diagrams;   

If this were the case, 
1) We could wark with several layers to show different aspects but it 
would be easy to mantain position relationships. For example, Mathew 
would have one firewall in each layer, but all of them connected to a 
transversal object, so they will always occuppy same position in every 
diagram (these positions could change but keeping them equal)
2) (I am not very sure about this): When we "configure" for printing 
with the "fitting",  all layers have an influence, so it would be 
convenient being able to use four no connected "transversal objects" 
just to mark what would be  the region to print, this way one can work 
independently in each layer witout moving outside the region, knowing 
that all layers would be well positioned for printing.
·

By the way: Is there a way to print a selected part  of a layer?  


Loli
email:  loli@unsa.edu.ar
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