https://www.w3.org/2016/03/17-svg-minutes.html#item03
RESOLUTION: Make the getTotalLength() and getPointAtLength(distance) methods, currently defined on the SVGPathElement interface, available for all elements that implement the SVGGeometryElement interface. The length calculation would be based on the equivalent path for each shape.
RESOLUTION: Make the pathLength attribute and IDL property available on all elements that implement the SVGGeometryElement interface.
Comment 1 by f...@opera.com
, Apr 12 2016