As promised, I refined the AntiGareth bookmarklet I introduced yesterday by making it aim precisely at those Unicode code points (mostly combining characters) which are found to bleed vertically by this canvas-based scanner.
Warning: I’m hosting the scanner on evil.hackademix.net because it amounts to a quite effective DOS attack against your CPU, especially on Firefox (which, on the other side, finds much more “overbleeders” than Chrome): you’ll probably want to click the “STOP” button after \u20d2. Could anybody explain the awful speed difference, by the way?
However, I’m sure the script can be improved, both accuracy and performanc wise, hence patches and forks are welcome. Enjoy :)