title: How is Windows 10 Night Light implemented?
body: <p>Windows 10 has a feature to change the screen's color temperature named Night Light. This is a blue light reduction feature.</p>
  
  <p>I would like to implement a clone of this feature in C++, using windows API. But have no idea how to do so.</p>
  
  <ul>
  <li>How do I access the screen and change what it displays system wide using win api? It must be resources efficient.</li>
  <li>And can we apply it only on a given window, not the whole screen?</li>
  </ul>