QwtPlot cursor (like Audacity)

Hi all,

I need cursor conception on a QwtPlot. The cursor is not a mouse cursor, but a part of plotted area across one axis. Looks like this Attachment 10733.

The cursor consists from marker on a scale (green triangle) and vertical rectangle on plotting area.

For instance, plotting data have ranve [0, 10] on X-axis, and the cursor has position 1 and width 2, i.e. [1,2). There will be vertical rectangle orthogonal X-axis and marker (green triangle) on X-axis scale located at 1.

How is the best way to implement this?

Thanks.

Drawing the marker on the scale could be done by deriving from QwtScaleDraw.

For the rectangle over the plot area you could implement it as QwtWidgetOverlay or as QwtPlotItem - depends on the use case of your application. Using an overlay is often the better solution for interactive elements like cursors or rubber bands. F.e QwtPlotPicker or QwtPlotZoomer use a widget overlay.

Uwe