Diferences with the SVG getPointAtLength method about bezierjs HOT 2 CLOSED

Created a JSbin with your code, and modified it so it doesn't pretend what you're doing with bezierjs is even remotely the same as what you're doing in SVG: http://jsbin.com/fiyiyivefa/edit?js,output

Note that because bezier.js does not have a "get point at some distance" function, this is not a perfect match: we would have to find the point at i-step/2 and at i, and then we would have to do a second check in side of that range to find the exact point T for which curve.get(T) yields the point at 20% distance along the curve.

from bezierjs.

yes, obviously those are different points: Bezier curves are non-linear, evaluated based on a parameter of time, not a parameter of distance, so we cannot assume that t=0.2 lies at 20% of the total length of the curve, or that t=0.75 lies at 75% of the total length of the curve (read the previous link for a much more detailed explanation on why).

As such, get(0.2) and getPointAtLength(0.2 * totalLength) are completely different things, and even if we make the curve looks like a straight line, it is still defined as a non-linear plot, and so it is trivial to prove that .get(n) and getAtLength(total * n) always differ except at n=0 and n=1 and a possible handful of singleton points (where the number of points for where this is true depends on the order of the curve and the number of inflections expressed on it)

from bezierjs.