public void setCircleOval(RectF orginCircleOval) {
        pieChartRenderer.setCircleOval(orginCircleOval);
        ViewCompat.postInvalidateOnAnimation(this);
    }
Use this to change pie chart area. Because by default CircleOval is calculated onSizeChanged() you must call this
method after size of PieChartView is calculated. In most cases it will probably be easier to use
{@link #setCircleFillRatio(float)} to change chart area or just use view padding.
hellocharts-library/src/lecho/lib/hellocharts/view/PieChartView.java