drawing of degenerate shape computation crashes CindyJS

[montaga]

When I draw the (degenerate) shape, halfplane(join(A,B),A)~~circle(A,1) for two points A and B with fill or draw, CindyJS crashes. There should be some better error handling.

[strobelm]

It looks like only Firefox is affected.

[montaga]

Chromium is affected too. I guess some numerical sideeffects safe us from the bug. But if points are moved around in this applet, then the tab eventually crashes.

[strobelm]

evaluator.halfplane$2 needs some work. I'll look into it.

[montaga]

What wonders me is that an applet drawing halfplane(join(A,B),A) only does not crash. Maybe the bug is related to the clipper