PHP Hex to RGBA

hexToRgba.php

<?php

/**
 * Hex to RGBA
 * 
 * @param string            $hexColor
 * @param string|int|double $opacity
 * 
 * @return string
 */
function hexToRgba(string $hexColor, $opacity = 1): string
{
    // Remove # Chacter
    if ($hexColor[0] === '#'){
        $hexColor = substr($hexColor, 1);
    }

    // Convert to Array
    if (strlen($hexColor) === 3) {
        $hexColor = str_split($hexColor);
        foreach ($hexColor as $index => $color) {
            $hexColor[$index] = $color . $color;
        }
    } else if (strlen($hexColor) === 6){
        $hexColor = str_split($hexColor, 2);
    } else {
        throw new Exception('Invalid Hex Color');
    }

    // Result to RGBA 
    return sprintf('rgba(%s, %s)', implode(',', array_map('hexdec', $hexColor)), $opacity);
}

Example

hexToRgba('#AABBCC', 0.2)