in considering Qwt, how to put a marker on a diagram with the possibility that the marker can slip with the mouse. Morever, how to obtain a SIGNAL for the movement of the marker where i can connect it with a slot in my widget class.
In fact, i want to do as it is done on the diagram of rootlocus in sisotool of Matlab, where we can slip a pole or a zero on the diagram of rootlocus.