On Mon, 14 Jun 1999, [EMAIL PROTECTED] wrote:
> If objects in the active layer are connected to objects in another layer
> (which in turn may be connected to objects in yet other layers), and the
> object is moved, resized or otherwise changed this might trigger a change
> of the position, size and orientation of the connected objects (and
> therefore *any* object in *any* layer).
>
> And then when you need to recalculate the extents after having moved one
> object you can't do as usual, recalculate the extents for the active
> layer by looping over all objects in it and doing rectangle_union and
> then merge it with the extents of the other layers. Because the extents
> of the other layers may have changed too.
Oh, but you could do the transitive closure of the extents of the objects
that have changed. It would require any layer where any object has changed
to be recalculated, though. Or if we're keeping track of which objects
have changed, we just need to update those layers.
-Lars
--
Lars R. Clausen (http://shasta.cs.uiuc.edu/~lrclause) H�rdgrim of Westfield
"I do not agree with a word that you say, but I will defend to the death your
right to say it." -- Voltaire (?)
