Javascript function for converting the parameters that come with an SVG elliptic arc, namely the starting point ps, the end point pe, the horizontal radius rh, the vertical radius rv, the rotation in degree rot, the large arc flag fa, the sweep flag fs. These are converted to the ellipse center point pc and a point containing the elliptic arc start and end rotations in degrees, phi1 and phi2. Thus the function returns an array with two points. The term point always refers to a JS object of the type {x:number1, y:number2}.
More precisely this code is the rough (some input checking rules are ignored) implementation of this standard.