[phenixbb] app which can calculate the number of reflections for a given unit cell, spacegroup, resolution?

Dear Scientific community, I am looking for an app which can calculate the number of reflections for a given unit cell, spacegroup, resolution. Preferred would be a graphical output too. The program XRayView http://www.phillipslab.org/downloads comes very close what I imagine but it is not possible to select a spacegroup. It would like to use it for teaching parts of practical part during lockdown. Many thanks, br Georg.