Re: QwtPlotMarker + Events

[Uwe R. <Uwe...@ti...>]

> i gave a QwtPlot a QwtPlotMarker to realize a curve-description on the
> plot. now i want to make the QwtPlotMarker "mouse-sensitive". its position
> on the qwtplot shall change if i click on it (or i want to move the
> QwtPlotMarker by dragged mouse).

Check the event_filter example. 

If you want to implement someting like drag&drop don't try to move the marker 
while dragging ( replot will be too slow for non trivial plots ). Instead 
remove the marker, when it has been selected and reinsert it when you have 
dropped it. While you are dragging use an overlay widget.

A simple way to implement this is to use the rubberband of a QwtPlotPicker, 
what is an overlay widget. All you have to do is to reimplement 
YourPicker::drawRubberband() displaying something that represents your marker 
at the current mouse position. 

Uwe