Get the plot curve to which the mouse is pointing to

[Uwe]

A QwtPlotPicker gives you the current position of the mouse ( in screen and plot coordinates ). Then you need to find the closest points of your curves. You can use QwtPlotCurve::closestPoint(), but in most cases you can find a much faster implementation depending on the characteristics of your data.

When you need to compare the mouse position with the lines between the points you need the pixel position of these points ( use QwtPlot::canvasMap ).

Maybe looking at the CanvasPicker of the eventfilter example helps.

Uwe