Plotting around 1000 shape items in qwt polar/ qwt plot. Help needed.

[Uwe]

"most performant implementation" - is it best performance implementation?

No.

Actually, also, a unique number is to be displayed along with symbol;

A marker offers displaying symbol + text, but the text is not cached ( also QStaticText is not used ), so there will be room for optimizations. If you want to go with the one vehicle = one item approach customizing QwtPlotMarker is probably easier than implementing a new item from scratch ( also nothing difficult ).

So, I assume, the steps for movement of plot items on plot area would be: i. Create item. ii. Attach item to plot. iii. Detach/Delete and Attach it again at new position.

In case of a marker it would be:

marker->setValue( ... )
plot->replot();

Detaching/reattaching only because of an attribute change is not necessary.

Uwe