Currently struggling with producing #SVG for labelling rivers. I need a #Bézier curve offset to place the label on an invisible path next to the river instead of on the river itself. So now I need to implement the heuristic approximation method proposed by Tiller and Hanson. This involves a lot of paper and ink.
https://math.stackexchange.com/a/467038
Image 1 shows the solution I am unhappy with. Image 2 shows the heuristic with simple control point translation. That's not good enough.