Hello Erik,
You are correct: the command userdraw arc,color could/should be improved!
The ‘static’ way of using first 3 points (the second point is set to be the center point…) and then afterwards draw the arc is not very practical…and probably the way the ‘direction’ argument to the html5 canvas command arc(xc,yc,radius,start,end,direction) is determined, is not correct.
As this is all amateur driven opensource stuff, you could just upload any improvements to SVN.
(as long as the fly-like command syntax is unchanged)
kind regards,
Joke