That was one of the functions of the abandoned Nokia touchscreen project, maybe 2003. Instead of capacitance or resistance, it had pressure sensor on all 4 corn

That was one of the functions of the abandoned Nokia touchscreen project, maybe 2003. Instead of capacitance or resistance, it had pressure sensor on all 4 corners and rigid display panel. With those sensors the location and force of the finger could be accurately calculated. Likewise the panel could be moved up and down, giving the impression the finger is sliding on uneven surface. I say one day this touchscreen technique will rise again, because it does not rely on electric properties of the "finger". You can have gloves on or use fingernails or hand prosthesis.