Re: drawing graphs with dia [PATCH]

[Lars Clausen <lars raeder dk>]

On Mon, 2005-03-14 at 15:21 +0100, Grégoire Dooms wrote:
> Hello,
> Here is a context diff against CVS HEAD.
> I implemented auto gap + absolute gap for lines and beziers.
> It works like a charm (AFAIK :-).
> I added the properties GUI (could be prettier).

Works nicely, indeed.  Thank you very much for working on this!  There's
a few things I'd like to see changed, though.

Most importantly, the autogap feature should be dependent on which
connectionpoint you connect to -- it doesn't make a lot of sense unless
you're connected to a central connection point (a bit of sense, though,
but it looks weird).  Making it depend on the CP will also remove those
options from the properties dialog, always a good thing.

We'll then need a flag on CPs to say that they autogap (are interior).
I'm thinking the Element class should automatically add this.  For now,
we can just set it explicitly on the objects that have an interior CP.
Hmmm... CPs don't have flags as such yet, but they have the directions
4-bit which is kinda flaglike.  Nah, it's gotta be a new field flags.

For submitting patches, it'd be nice if you use the -u (unified) flag
and did not compress it (unless it's >40K large).

> The only thing missing for a very nice way to output a graph from 
> graphviz is the central connection point on the text object.
>
> I also attach an example dia file.

The bezier autogap is significantly different from the line autogap, in
that it doesn't move the head around the object.

I'd like to see the other simple lines (polyline, zigzagline in
particular) have gaps too.  And if the gap stuff is moved to the
Connection/Orthconn classes, it'll suddenly apply to a whole lot of
other objects.  See how autorouting is handled in OrthConn for examples
on how to do this.  But this is second priority, first is proper gap
defs for simple lines.

> There could be some additional work to do on the save/load front to 
> guarantee forward compatibility.

Setting the PROP_FLAG_OPTIONAL flag on the new attributes would help on
that.

-Lars

-- 
Lars Clausen <lars raeder dk>