title: "Distance" between colours in PHP
body: <p>I'm looking for a function that can accurately represent the distance between two colours as a number or something.</p>
  
  <p>For example I am looking to have an array of HEX values or RGB arrays and I want to find the most similar colour in the array for a given colour</p>
  
  <p>eg. I pass a function a RGB value and the 'closest' colour in the array is returned</p>