     labels.exit().remove()
     labelLayout = d3.geom.quadtree().extent([
       [
-        -that.width
-        -that.height
+        -@width
+        -@height
       ]
       [
-        that.width
-        that.height
+        @width
+        @height
       ]
     ]).x((d) ->
       d.x

            i = d3.interpolate({startAngle: 0, endAngle: 0}, {startAngle: d.startAngle, endAngle: d.endAngle})
            return (t) -> 
                b = i(t)
                return arc(b)
        )
    #@path.exit().transition().duration(300).attrTween('d', that.removePieTween).remove()
    path.exit()

      #trig functions adjusted to use the angle relative
      #to the "12 o'clock" vector:
      #console.log 'ts: a', a
      d.cx = Math.sin(a) * (@radius - 75)
      d.cy = -Math.cos(a) * (@radius - 75)
      ### calculate the default position for the label,
         so that the middle of the label is centered in the arc
      ###
      bbox = @getBBox()
      #bbox.width and bbox.height will 
      #describe the size of the label text
      labelRadius = @radius - 20
      d.x = Math.sin(a) * labelRadius
      d.l = d.x - bbox.width / 2 - 2
      d.r = d.x + bbox.width / 2 + 2
      d.y = -Math.cos(a) * (@radius - 20)
      d.b = d.oy = d.y + 5
      d.t = d.y - bbox.height - 5
      #console.log 'ts: d', d
