def _compute(self):
        """Compute x/y min and max and x/y scale and set labels"""
        if self.xvals:
            xmin = min(self.xvals)
            xmax = max(self.xvals)
            xrng = (xmax - xmin)
        else:
            xrng = None

        if self.yvals:
            ymin = min(min(self.yvals), self.zero)
            ymax = max(max(self.yvals), self.zero)
            yrng = (ymax - ymin)
        else:
            yrng = None

        for serie in self.all_series:
            serie.points = serie.values

        if xrng:
            self._box.xmin, self._box.xmax = xmin, xmax
        if yrng:
            self._box.ymin, self._box.ymax = ymin, ymax

        if self.range and self.range[0] is not None:
            self._box.ymin = self.range[0]

        if self.range and self.range[1] is not None:
            self._box.ymax = self.range[1]
Compute x/y min and max and x/y scale and set labels