Dynamic lines between two items during animation

[Tim Chen <ht timchen gmail com>]

Hi,

I am trying to create a small animation clip where two items are
connected by a polyline.

However, when I animated the items with goo_canvas_item_animate(),
which signal should I intercept *during* the item animation?

Currently I can only update the polyline *after* the animation
finished using the signal "animation-finished".

Thanks,
Tim