textPath = text.text(null).append("textPath") // Add a textPath element
.attr("startOffset", '50%')
.style("text-anchor", "middle")
.attr("xlink:href", function(d,i) { return "#SuperCategory" + i; }),
tspan = textPath.append('tspan'), // Inslide textPath, add a tspan element, for offset feature later.
path = d3.select(text.select('textPath').attr('xlink:href')); // Get the path to compute width of text later.
var startLoc = /M(.*?)A/;
var newStart = path.attr('d').match(startLoc)[1];
var newEnd = path.attr('d').indexOf(' 0 0 0 ') > -1
? path.attr('d').split(' 0 0 0 ')[1]
: path.attr('d').split(' 0 0 1 ')[1] ;
// Compute the start/end coordinate points of the arc that the text will follow.
var x1 = parseFloat(newStart.split(' ')[0]),
y1 = parseFloat(newStart.split(' ')[1]),
x2 = parseFloat(newEnd.split(' ')[0]),
y2 = parseFloat(newEnd.split(' ')[1]);