QWT plot with autoscaling shows negative values in y-axis

[Uwe]

Autoscaling means, that you want to calculate the scales from a given interval ( the bounding interval of all plot items having the QwtPlotItem::AutoScale flag enabled ). The algorithm for this calculation is implemented in the scale engine - usually QwtLinearScaleEngine::autoScale().

If you are not happy with the result of the algorithm you have 2 options:

• overload QwtLinearScaleEngine::autoScale
• not using autoscaling and doing setAxisScale instead

The code you would have to write is more or less the same.

Uwe