RE: [DiaCanvas] ANNOUNCE : GraphTool is born :)

[Arjan J. M. <arj...@he...>]

On Tue, 2003-04-22 at 17:11, Aurélien Campéas wrote:
> Le mar 22/04/2003 à 16:27, arj...@he... a écrit :
> > > To Arjan : I see two possibilities here. 1) when DiaCanvasEdge/Node are
> > > ready (monthes from now), you include them... 2) you include them in
> > > their current state but they are marked EXPERIMENTAL and they will only
> > > help GraphTool work without too much pain.
> > 
> > 3) Include them in your own source tree ;-). 
> 
> It's 1) really. Currently those classes barely build in my own tree,
> since after each 'make clean' && ./configure I have to manually add two
> includes to the autogenerated python/diacanvas.c
> 
> Any idea why ?

You should edit diacanvas.override, that's where the includes are
defined.

> > 
> > I'd like to see the code as soon as it's available. Providing an alternative
> >  for the current line/element is a good thing.
> 
> CanvasNode is a ripoff of CanvasElement, with only 1 central node,
> CanvasEdge is CanvasLine really with much less code (I had to cut all
> the hard work you put in to understand what to do next...), and just one
> segment.
> 
> So... not very interesting.
> 
> For the node, the ONE HANDLE solution may not be good enough. In fact,
> the RIGHT THING would be :
> - edges connect to the border of the shape
> - when objects are moved, constraints help the connexion point move
> accordingly :
> 
> a)    (X)<----------(Y)     then we move Y around
> b)    (Y)----------->(X), not (-)----------(->) where Y and X are hidden
> due to the Edge/Node's braindead stickyness
> 
> So connection contraints ought to be set on shapes, not only on an
> object's bounding box. Maybe this is just a matter of putting in the
> right constraint. I'll have to do some basic planar maths...

I still haven't figured out the most feasable solution for this. At
least we need constaints other than "equals 0". But that's not enough,
though... Maybe a hook should be added for custom constraints solved
using a function.

> 
> For the Edge, I would be pleased with a multishape one :
> - viewable as straight segment (makes sense in a lot of cases)
> - ...as a bezier too (nice to look at, helps implementing loops...)
> -... as a multipath (quite like the current Line class)
> and the ability to switch at runtime.
> 
> 
> So, well, I can send code right now but of little interest (to you). 

Okay, keep me informed!

Regards,

Arjan