c3_chart_internal_fn.regionX = function (d) {
    var $$ = this, config = $$.config,
        xPos, yScale = d.axis === 'y' ? $$.y : $$.y2;
    if (d.axis === 'y' || d.axis === 'y2') {
        xPos = config[__axis_rotated] ? ('start' in d ? yScale(d.start) : 0) : 0;
    } else {
        xPos = config[__axis_rotated] ? 0 : ('start' in d ? $$.x($$.isTimeSeries() ? $$.parseDate(d.start) : d.start) : 0);
    }
    return xPos;
};
c3_chart_internal_fn.regionY = function (d) {
    var $$ = this, config = $$.config,
        yPos, yScale = d.axis === 'y' ? $$.y : $$.y2;
    if (d.axis === 'y' || d.axis === 'y2') {
        yPos = config[__axis_rotated] ? 0 : ('end' in d ? yScale(d.end) : 0);
    } else {
        yPos = config[__axis_rotated] ? ('start' in d ? $$.x($$.isTimeSeries() ? $$.parseDate(d.start) : d.start) : 0) : 0;
    }
    return yPos;
};
c3_chart_internal_fn.regionWidth = function (d) {
    var $$ = this, config = $$.config,
        start = $$.regionX(d), end, yScale = d.axis === 'y' ? $$.y : $$.y2;
    if (d.axis === 'y' || d.axis === 'y2') {
        end = config[__axis_rotated] ? ('end' in d ? yScale(d.end) : $$.width) : $$.width;
    } else {
        end = config[__axis_rotated] ? $$.width : ('end' in d ? $$.x($$.isTimeSeries() ? $$.parseDate(d.end) : d.end) : $$.width);
    }
    return end < start ? 0 : end - start;
};
c3_chart_internal_fn.regionHeight = function (d) {
    var $$ = this, config = $$.config,
        start = this.regionY(d), end, yScale = d.axis === 'y' ? $$.y : $$.y2;
    if (d.axis === 'y' || d.axis === 'y2') {
        end = config[__axis_rotated] ? $$.height : ('start' in d ? yScale(d.start) : $$.height);
    } else {
        end = config[__axis_rotated] ? ('end' in d ? $$.x($$.isTimeSeries() ? $$.parseDate(d.end) : d.end) : $$.height) : $$.height;
    }
    return end < start ? 0 : end - start;
};
c3_chart_internal_fn.isRegionOnX = function (d) {
    return !d.axis || d.axis === 'x';
};