Core-Plot: How to keep axises are always at bottom-left side of screen

Currently, I can keep the axises at开发者_如何学Python bottom-left side of screen by using CPConstraints, isFloatingAxis and set a properly value for orthogonalCoordinateDecimal, but when I change the xRange and yRange value, the axises are moved, so is there anyway to keep them always at bottom-left side without re-calculate and change orthogonalCoordinateDecimal value?

I found an workaround solution that just set FloatingAxis = YES and rthogonalCoordinateDecimal is 0, do not use CPConstraints, then the axises are always stay at the bottom-left border.