if (y) {
        y0 = z[0], y1 = z[1];
        if (x) y0 = y0[1], y1 = y1[1];
        extentDomain[0][1] = y0, extentDomain[1][1] = y1;
        if (y.invert) y0 = y(y0), y1 = y(y1);