View: Tracer is off
The tracer does not point exactly to the center of the tracking dot (or vice versa), but instead at the bottom right corner. This is particularly bad, because the trajectory id is rendered there as well and is black as well.
Please verify that it is not the tracking dot that is off.
I'm not 100% sure, but I think it is the tracer that is off. This is the line that sets the marker position:
https://github.com/BioroboticsLab/biotracker_core/blob/master/BioTracker/CoreApp/BioTracker/View/ComponentShape.cpp#L268
while this sets the tracer position:
https://github.com/BioroboticsLab/biotracker_core/blob/master/BioTracker/CoreApp/BioTracker/View/ComponentShape.cpp#L349
L268: getXpx() is the member that directly grabs the coordinates from the data structure. Hence getXpx() - m_w/2, where m_w is the width of the marker, should be correct.