@property<EOL><INDENT>def null(self):<DEDENT>
if not self.option.axis:<EOL><INDENT>return -<NUM_LIT:1><EOL><DEDENT>else:<EOL><INDENT>return self.screen.height - (<EOL>-self.minimum * <NUM_LIT> / self.extents * self.size.y<EOL>)<EOL><DEDENT>
Zero crossing value.