'Return a point in local coordinates for `height` (in cluster
height scale).'

def pos_at_height(self, height):

    if (not self._root):
        return QPointF()
    if (self.orientation in [self.Left, self.Bottom]):
        base = self._root.value.height
        height = (base - height)
    if (self.orientation in [self.Left, self.Right]):
        p = QPointF(height, 0)
    else:
        p = QPointF(0, height)
    return self._transform.map(p)
