Generate ColumnDataSource dictionary for segment separation lines.

def _get_xmarks_data(self, order_seg, bins_seg):
        """Generate ColumnDataSource dictionary for segment separation lines.

        """

        if not self.xmarks:
            return dict(xs=[], ys=[])

        angles = self._get_markers(self.xmarks, order_seg, bins_seg)

        inner = self.max_radius * self.radius_inner
        outer = self.max_radius

        y_start = np.sin(angles) * inner + self.max_radius
        y_end = np.sin(angles) * outer + self.max_radius

        x_start = np.cos(angles) * inner + self.max_radius
        x_end = np.cos(angles) * outer + self.max_radius

        xs = zip(x_start, x_end)
        ys = zip(y_start, y_end)

        return dict(xs=list(xs), ys=list(ys))