Convert Hex Color to RGBa to create Color Shades on the fly

functions.php

<?php
/* Convert hexdec color string to rgb(a) string */
 
function hex2rgba($color, $opacity = false) {
 
 $default = 'rgb(0,0,0)';
 
 //Return default if no color provided
 if(empty($color))
          return $default; 
 
 //Sanitize $color if "#" is provided 
        if ($color[0] == '#' ) {
         $color = substr( $color, 1 );
        }
 
        //Check if color has 6 or 3 characters and get values
        if (strlen($color) == 6) {
                $hex = array( $color[0] . $color[1], $color[2] . $color[3], $color[4] . $color[5] );
        } elseif ( strlen( $color ) == 3 ) {
                $hex = array( $color[0] . $color[0], $color[1] . $color[1], $color[2] . $color[2] );
        } else {
                return $default;
        }
 
        //Convert hexadec to rgb
        $rgb =  array_map('hexdec', $hex);
 
        //Check if opacity is set(rgba or rgb)
        if($opacity){
         if(abs($opacity) > 1)
         $opacity = 1.0;
         $output = 'rgba('.implode(",",$rgb).','.$opacity.')';
        } else {
         $output = 'rgb('.implode(",",$rgb).')';
        }
 
        //Return rgb(a) color string
        return $output;
}