Physical meaning of sharpness in ios corehaptics

Question

According to the developer documentation, the parameter hapticsharpness is not explained very clearly to me because there are only descriptions about haptic feedback, and no physical meaning.

I tried to figure it out from the vibration waveforms I tested in the lab, but it turns out that sharpness will affect both vibration acceleration and frequency. So, it comes to my second question: what is the point of creating another parameter hapticintensity if sharpness can already control acceleration? Any idea will be much appreciated.

Answer 1

I think the documentation is pretty clear about the fact that hapticIntensity refers to the amplitude (strength) of the vibration, whereas hapticSharpness controls the nature / feel of it.

Imagine a scenario where you want to simulate a knee-jerk reaction like an error, you might want to use a haptic feedback with a high sharpness, whereas imagine a scenario where you want to convey a soothing haptic feedback like maybe a calm loading indicator (nothing more useful comes to my mind right now ☺️).

You may want to still vary the intensity of these haptic which feedback while still maintaining the same 'feel'. If you had a single API then this would not be feasible.