QPoint QwtPicker::trackerPosition() const
QPointF QwtPlotPicker::invTransform (const QPoint & pos) const
d_picker->invTransform( d_picker->trackerPosition() );
d:\qwt-6.0.1\src/qwt_plot_picker.h: In member function 'void Plot::sl_newScale1(double)':d:\qwt-6.0.1\src/qwt_plot_picker.h:98: error: 'QPointF QwtPlotPicker::invTransform(const QPoint&) const' is protected
class PlotPicker:: public QwtPlotPicker{ ...piublic: double invT_x() const { return invTransform(trackerPosition() ).x(); }};