// x: where label could be put
    // y: where label could be put
    // value: value to show
    // total: total number to count %
    chart.each = function (f) {

        var that = this;

        for (var i = 0; i < len; i++)
        {
            (function (sector, cover, j)
            {
                var o =
                {
                    sector: sector,
                    cover: cover,
                    cx: cx,
                    cy: cy,
                    x: sector.middle.x,
                    y: sector.middle.y,
                    mangle: sector.mangle,
                    r: r,
                    value: values[j],
                    total: total,
                    label: that.labels && that.labels[j]
                };

                f.call(o);

            })(series[i], covers[i], i);
        }

        return this;
    };