text: var kityPie = kity.createClass({
      base: kity.Path,
      constructor: function(r, R, a1, a2, x, y) {
          this.callBase();
          this.draw(r, R, a1, a2, x, y);
          this.center = kity.Point.fromPolar((R + r) / 2, (a1 + a2) / 2);
      },
      draw: function(r, R, a1, a2, x, y) {
          var d = this.getDrawer();
          var p1 = kity.Point.fromPolar(r, a1),
              p2 = kity.Point.fromPolar(R, a1),
              p3 = kity.Point.fromPolar(R, a2),
              p4 = kity.Point.fromPolar(r, a2);
          d.moveTo(p1.x + x, p1.y + y);
          d.lineTo(p2.x + x, p2.y + y);
          var dir = Math.abs(a2 - a1) > 180 ? 1 : 0;
          d.carcTo(R, dir, 1, p3.x + x, p3.y + y);
          d.lineTo(p4.x + x, p4.y + y);
          d.carcTo(r, dir, 0, p1.x + x, p1.y + y);
          d.close();
      }
  });