title: Draw a rectangle with an arc cut on one side
body: <p>I'm beginning to start to draw custom shapes using core graphics on iOS. Right now I am trying to draw a rectangle with a transparent arc cut on one side. </p>
  
  <p><img src="https://i.stack.imgur.com/QJIkH.png" alt="enter image description here"></p>
  
  <p>I'm trying to use the <code>CGContextAddArcToPoint</code> function to draw the arc but can't get the gist out of it. Also, is there other way to achieve this shape?</p>