path.closestPointLength(point [, opt])

Return the length of the path up to the point that lies closest to point.

Invisible segments (e.g. Moveto segments) have no length and are therefore skipped by the algorithm; if the path contains no visible segments, 0 is returned. If the path has no segments at all, 0 is returned.

The function finds a visible segment whose identified closest point lies at the lowest distance from point. It then determines the length of the path up to the identified closest point.

The opt argument is optional. Two properties may be specified, opt.precision and opt.segmentSubdivisions, which determine maximum error allowed in segment closestPoint calculations for curved segments (default precision is 3; this corresponds to maximum observed error of 0.1%). The opt.segmentSubdivisions property is an array of individual segments' subdivision arrays. The path.getSegmentSubdivisions() function may be used to obtain the segmentSubdivisions array. The opt.precision property is still necessary, however; it determines the precision of the point search algorithm in curved segments.