setAxisScale become invalid to xTop Axis？

[MickyJhon]

thank you very much,that's the answer!

The coordinate systems spanned by the 4 axes are always present - independent from the visibility of an axis. A plot item is always related to one x/y combination, different plot items on the same plot might be related to different combinations ( see the bode example, where you have 2 y axes ). In your code the curve is related to the invisible xBottom scale - because xBottom/yleft is the default setting.

The following line is missing:

curve->setXAxis( QwtPlot::xTop ):

curve->setXAxis( QwtPlot::xTop ):

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Uwe

[Cah]

Yes

Thanks