Trajectory snippet

It would be helpful to give the option in the PostVis to show only a snippet of the trajectory, e.g. only for the last 10 footsteps / timesteps. Maybe it is also helpful to show only the trajectories of the pedestrians who are in the current visible part of the scenario (if that is easily done). The goal is to see easier if pedestrians trajectories intersect.

Another idea is to give a higher linewidth to the latest positions in the trajectories and then fade out the trajectory.

Problem to solve

At the moment, all trajectories of all agents who are still in the simulation are shown. If that is a large number of agents, it is sometimes hard to see what recently happened.