def null(self):
        """Zero crossing value."""
        if not self.option.axis:
            return -1
        else:
            return self.screen.height - (
                -self.minimum * 4.0 / self.extents * self.size.y
            )
def null(self):
        """Zero crossing value."""
        if not self.option.axis:
            return -1
        else:
            return self.screen.height - (
                -self.minimum * 4.0 / self.extents * self.size.y
            )
def null ( self ) : if not self . option . axis : return - 1 else : return self . screen . height - ( - self . minimum * 4.0 / self . extents * self . size . y )
Zero crossing value.
Zero crossing value .