In a more practical way, you may also consider SVN Time-Lapse View
SVN Time-Lapse View is a cross-platform viewer that downloads all revisions of a file and lets you scroll through them by dragging a slider.
As you scroll, you are shown a visual diff of the current revision and the previous revision.
Thus you can see how a file evolved, and you can easily find the revision at which lines appeared, disappeared, or changed.
(not big on "animation", but still, can be useful)
