Convert Hex string to RGBA

hex-to-rgba.php

<?php 
/**
 * Take Accent color, and convert it to RGBA, and add an opacity of .75.
 */
$accent        = get_theme_mod( 'site_accent_color' );
$accent_string = ltrim( $accent, '#' );
$arr           = str_split( $accent_string, '2' );

foreach ( $arr as $value ) {
    $new_value = hexdec( $value ) . ', ';
    $rgb      .= $new_value;
}
$accent_opacity = 'rgba(' . $rgb . '.75)';
?>