[GRASS-dev] Modules

[Moritz Lennert]

On 23/02/07 16:23, Wolf Bergenheim wrote:
> Glynn Clements wrote:
>  >
>  > IOW, a hybrid Tcl/Tk+C (or Python+C) program will work, but a
>  > combination of a pure Tcl/Tk (or Python) program with a pure C helper
>  > program won't work.
>  >
> 
> Not necessarily. When I first started writing v.edit my idea was that 
> the GUI wold have an internal undo / changes stack, where it would 
> record what the user has drawn. Then when the user chooses to save his 
> work, v.edit would be called to commit these changes to the vector file.
> That way v.edit the editor doesn't need to build partial topologies, 
> etc, and that way the GUI doesn't need direct access to the vector 
> library. The GUI would be mostly a visual drawing tool, and v.edit would 
> then make sure that everything is topologically correct. Perhaps it's 
> not a good idea, I don't know, but that was the original idea of how to 
> use v.edit as a back end. After the save the editor would clear its 
> change stack and read the vector file (using v.to.ascii, or some other 
> interface like SWIG).

My guess would be that the problem with this is the topology. If you 
want to have real-time response of v.digit concerning the status of an 
object you draw (i.e. is the polygon closed, have you snapped the line 
to the node, etc), you need some form of topological feedback 
immediately, not only when you push a save button.

Moritz