title: How to detect "light" colors with PHP
body: <p>I am working on a dynamic store project and I use a loop to print all color options for a product as color boxes, however I really need to add a "border" to these colors which are light. I tried something like the following but It is very limited, it is actually limited to white color only, it won't catch something like #ddd, #eea... etc</p>
  
  <p>Here is my loop:</p>
  
  <pre><code>foreach($colors as $color) {
      $color = trim($color);
      if (!empty($color)) {
          if (in_array($color, array('white','White','#fff','#FFF','#FFFFFF','#ffffff'))) {
              $bordercolor = '#bbb';
          } else {
              $bordercolor = $color;
          }
      }
  }
  </code></pre>
  
  <p>Colors is an array from backend like: White, #000, #cc0000, etc. It is not practical to add all exceptions in the if/else condition too, any quick idea?</p>