Need help finding what I need to learn to be able to do an idea I had (I have no better way to word)

Basically i'm somewhat new, and don't know what I even need to research to be able to do this. It will be for mobile and basically I want to be able draw a simple shape ie. a circle, or like a diagonal line. Each one would correspond to the character doing something. Not only does it need to be able to recognise what it should do based on the shape drawn, but work out how accurate it is? I don't need someone to tell me exactly what to do, just tell me a sort of method i guess. Thank you for any pointers you can give.

 

Sounds like you're looking for a gesture recognition algorithm?

 

yes exactly that, idk why I couldn't think of what to call it