Arrows with direction -1 look weird when zooming in

[lndb]

The same live example that I gave before (wait a few seconds for the page to finish initializing):
http://lndb.info/light_novel/diagram/Hidan_no_Aria

This time I'm using JsPlumb 1.4.1 with the fix to the "out of place" arrows. Now these arrows are in the right place, but if you zoom on them you'll sometimes find the arrow drawn wrong.

Please zoom on the arrow that's pointing at the "Gouki Mutou" character. You can notice that the arrow even looks a little off even without zooming, but after zooming it will be even more noticeable.

[sporritt]

i think in fact it might be the connector at fault, not the arrow - this is what the arrow looks like with the connector line deleted:

this is the connector without the arrow - you can see that where the arrow is situated, the gradient of the connector changes suddenly. this is what causes the arrow to be painted the way it is.

i can't change the gradient of the connector at that point, of course. it might be possible to average the gradient over a few points, but that would take a lot more computation.