On Wed, 23 Oct 2002, Mike Garnsey wrote:
> I have been experimenting with doing something
> like that, too. Why? I want to be able to have a set
> of "idiot-proof" objects for a Dia user to lay out a
> computer network diagram. For example, the user
> shouldnt be able to connect something like a PC object
> directly to something like a microwave transmitter
> object. Or, a USB printer object shouldnt be
> connectable to a 10BaseT repeater object.
I see. I suppose idiot-proofness is good, as long as it doesn't restrict
what people want to do.
> I had pretty good success with the following (crude!)
> 1. hack diagram_update_connections_object()
> to force a redraw of the connected object
> 2. for specific objects that you want restricted
> connection functionality, add code to the
> DrawFunc routine to analyze (and disconnect
> as appropriate) the objects that are
> Definitely not ideal (DrawFunc gets fired for a
> variety of reasons), but it worked.
The right place to add a checking call would be in
layer_find_closest_connectionpoint() in app/diagramdata.c. Problem is,
that loop goes over all objects in a layer, so we can't afford to spend a
lot of time there. Well, we can keep it within the if, that'll cut out
most of it. And instead of adding code to DrawFunc, a new object func
should be defined for it.
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| HŚrdgrim of Numenor
"I do not agree with a word that you say, but I |----------------------------
will defend to the death your right to say it." | Where are we going, and
--Evelyn Beatrice Hall paraphrasing Voltaire | what's with the handbasket?