Re: Dia Python

[Lars Clausen <lrclause cs uiuc edu>]

On Thu, 16 Jan 2003, Hans Breuer wrote:
> At 06:48 16.01.03 -0600, Lars Clausen wrote:
>>On 15 Jan 2003, Lars Clausen wrote:
> [...]
>>> 2) If I do changes values that way, will it be undoable?  I don't see a
>>>     lot of undo-related stuff in the python plugin code, does that need
>>>     to be rewritten?  I'd like to avoid the situation in Gimp where
>>>     plugins can totally screw up undo.
>>
>>Well, I found the answer to this one:  Not only isn't it undoable, but
>>connections aren't moved with it and the display isn't updated.
> 
> I fail to see the relation between undoing and display update.

These are all things that need to be done around a move.

>>Unfortunately, the display update part is all in app, which we don't want
>>to link to from plug-ins.  
> What about calling:
> 
>  dia.active_display().add_update_all()
> 
> Though probably some bounding box object recalculation 
> would be needed before, not sure how to do it ...

That's one way to do it, though that puts it in the hands of the script
writer. 

> But it even is possible on win32 to link the Python plug-in
> against lib and app. Obviously this does mean there will be
> no stand alone python plug-in to use the same bindings.

Yeah, I noticed later there was stuff from app in use there.

>>If there's also a perl plugin coming up, we'll
>>need to encapsulate these things differently, so they behave the same
>>between main program and plugins.
>>
> There is nothing which can be done in Perl which can not be done
> in Python but readable. Not to start language wars but do we
> really need another language binding if we lack resources to 
> maintain one?

No, what I meant was that instead of having both Dia itself and every
single language plugin implement these things (undo, connection moves,
display update), we should have a function that's reasonable for them to
call.  In this case, a function that handles all that is necessary for an
object to move to a new place, including undo, connections etc.

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| Hårdgrim 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?