t points to display units.

        You need to override this function (unless your backend
        doesn't have a dpi, e.g., postscript or svg).  Some imaging
        systems assume some value for pixels per inch::

            points to pixels = points * pixels_per_inch/72 * dpi/72

        Parameters
        ----------
        points : float or array-like
            a float or a numpy array of float

        Returns
        -------
        Points converted to pixels
        rd