php 16进制颜色代码转换为rgba,rgb格式

<?php
   $rgb = hex2rgba('#FFFFFF', false, true);
   echo 'rgb: '.$rgb[0].',';
   echo $rgb[1].',';
   echo $rgb[2].'<br>';

   $rgba = hex2rgba("FFFFFF");
   echo 'rgba: '.$rgba;

   function hex2rgba($color, $opacity = false, $raw = 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);

        if($raw){
            if($opacity){
                if(abs($opacity) > 1) $opacity = 1.0;
                array_push($rgb, $opacity);
            }
            $output = $rgb;
        }else{
            //Check if opacity is set(rgba or rgb)
            if($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;
    }