Centering Objects (was: Re: help wanted, trying out a few ideas for post 0.94)

[Hans Breuer <Hans Breuer org>]

At 19:57 16.07.04, anthonym overture com wrote:
[...]
> One question for the group, is it possible to access alignment operations
> via the python scripting?  I'd love to have a keybinding which would do
> the equivalent of aligning 2 objects middle and center.  I often do this
> in order to get boxes of text, I'll draw the object, draw the text centered,
> then align center and middle (via many menu dives), finally group them.
>
> If the scripting would allow me to automate this sort of action, or if
> I've completely missed something and there's some easier way to do it
> I'd love to find out.

See the attached script. Implementing some alignment is pretty easy (I think).
There is no need to implement some some "alignment ops" in the bindings 
[what ever this means ;]. Everything to accomplish the task was already there.
Only it is lacking the ability to undo at the moment ...

        Hans

import sys, dia

def center_objects (objs) :
	r = objs[0].bounding_box
	cx = (r.right + r.left) / 2
	cy = (r.bottom + r.top) / 2
	for o in objs[1:] :
		r = o.bounding_box
		(x, y) = o.properties["obj_pos"].value
		dx = (r.right + r.left) / 2 - cx
		dy = (r.bottom + r.top) / 2 - cy
		o.move (x - dx, y - dy)

def dia_objects_center_cb (data, flags) :
	grp = data.get_sorted_selected()
	if (len(grp) > 1) :
		center_objects (grp)
		data.update_extents ()
	dia.active_display().diagram.add_update_all()
	
dia.register_callback ("Center Objects", 
                       "<Display>/Objects/Center", 
                       dia_objects_center_cb)

-------- Hans "at" Breuer "dot" Org -----------
Tell me what you need, and I'll tell you how to
get along without it.                -- Dilbert