title: Find area inside closed object in ios
body: <p>I want to calculate the <code>area</code> inside an object which is any closed object like <code>rectangle</code> ,<code>square</code> ,<code>polygon</code> etc. </p>
  
  <p><a href="https://i.stack.imgur.com/xqwYn.gif" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xqwYn.gif" alt="enter image description here"></a></p>
  
  <p>I can not get exact solution to do this.Please help to find it.</p>
  
  <p>Thanks.</p>