list of QwtCurves

[Uwe]

Whenever you change the scales behind the back of the zoomer you have to reinitialize the zoomer: see QwtPlotZoomer::setZoomBase().

Otherwise zooming out will return to the axes you had, when the zoomer was initialized the last time. In your case it is 1000x1000, what are the default axes ranges, because you created your zoomer before the first replot with data was done.

Uwe