Currently, a user can get a clicked position from the plot arena by using

MouseArea {
            x: chartView.x + chartView.plotArea.x
            y: chartView.y + chartView.plotArea.y
            width: chartView.plotArea.width
            height: chartView.plotArea.height
...
}
 

However, the point from the MouseArea is in "render coordinates" and needs to be calculated in data point coordinates. Usually, the render coordinates are calculated from data point coordinates in the Point Renderer. The Point Renderer has a method for reversing render coordinates back data point coordinates. So, if the user wants to get a clicked position in data point coordinates, they need to be able to perform those reversing operations for the point.