title: Changing Label/Button Text colour dynamically based on the dynamically changing background
body: <p>I know it may sound a little bit of a drag to ask this question but I am curious if anything like this is available.</p>
  
  <p>I am building a app in which the background image (covers full view with a blur effect) of each view controller changes dynamically. This background image will be in all the view controllers, each one having a different set of UIControls (Labels, Buttons, Table Views, Collection Views, containers, tabs, etc). </p>
  
  <p>Sometimes when the background image is very light, the foreground texts (labels, buttons) with white text colour are not visible at all. Also the vice versa is a problem too.</p>
  
  <p>So I would like to know if there is any way to change the foreground text colour dynamically based on its background.</p>