PHP function to Convert Hex Colors to RGBA

functions.php

<?php

//* Function to convert Hex colors to RGBA
function hex2rgba( $color, $opacity = false ) {

    $defaultColor = 'rgb(0,0,0)';

    // Return default color if no color provided
    if ( empty( $color ) ) {
        return $defaultColor;
    }

    // Ignore "#" if provided
    if ( $color[0] == '#' ) {
        $color = substr( $color, 1 );
    }

    // Check if color has 6 or 3 characters, 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 hex values to rgb values
    $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;

}

/*
 * Example Usage:
 * $mycolor = '#ff0000';
 * $rgb = hex2rgba($mycolor);
 * $rgba = hex2rgba($mycolor, 0.5);
 */