title: iOS voice recorder visualization on swift
body: <p>I want to make visualization on the record like on the original Voice Memo app:</p>
  
  <p><img src="https://i.stack.imgur.com/ISs5y.png" alt="enter image description here"></p>
  
  <p>I know I can get the levels
  - updateMeters
  - peakPowerForChannel:
  - averagePowerForChannel:</p>
  
  <p>but how to draw the graphic, should I do it custom?  Is there free/paid source I can use?</p>