Because overlap and concavity don't exist, the simple "nearest object center" policy used in virtual keyboards is all that's needed. When object dimensions aren't very uniform, some simple edge heuristics can be applied to penalize wide/tall objects, and reward thin/short objects. The dark classic theme of this site is a good example: Very small image links right next to large text links. Zooming and popups wouldn't be necessary, and users would quickly be trained to aim for the center of all links.