* @param y1 a corner of the enclosing rectangle
     * @param x2 a corner of the enclosing rectangle
     * @param y2 a corner of the enclosing rectangle
     * @param startAng starting angle in degrees
     * @param extent angle extent in degrees
     */
    public void arc(final float x1, final float y1, final float x2, final float y2, final float startAng, final float extent) {
        ArrayList<float[]> ar = bezierArc(x1, y1, x2, y2, startAng, extent);
        if (ar.isEmpty())
            return;
        float pt[] = ar.get(0);
        moveTo(pt[0], pt[1]);
        for (int k = 0; k < ar.size(); ++k) {
            pt = ar.get(k);
            curveTo(pt[2], pt[3], pt[4], pt[5], pt[6], pt[7]);
        }
    }