PHP RGB颜色和十六进制颜色互转，实现#FFFFFF 与rgb(255,255,255)自动转换！

/**

     * RGB转 十六进制

     * @param $rgb RGB颜色的字符串 如：rgb(255,255,255);

     * @return string 十六进制颜色值 如：#FFFFFF

     */

    function RGBToHex($rgb){

        $regexp = "/^rgb\(([0-9]{0,3})\,\s*([0-9]{0,3})\,\s*([0-9]{0,3})\)/";

        $re = preg_match($regexp, $rgb, $match);

        $re = array_shift($match);

        $hexColor = "#";

        $hex = array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F');

        for ($i = 0; $i < 3; $i++) {

            $r = null;

            $c = $match[$i];

            $hexAr = array();

            while ($c > 16) {

                $r = $c % 16;

                $c = ($c / 16) >> 0;

                array_push($hexAr, $hex[$r]);

            }

            array_push($hexAr, $hex[$c]);

            $ret = array_reverse($hexAr);

            $item = implode('', $ret);

            $item = str_pad($item, 2, '0', STR_PAD_LEFT);

            $hexColor .= $item;

        }

        return $hexColor;

    }

    /**

     * 十六进制 转 RGB

     */

    function hex2rgb($hexColor) {

        $color = str_replace('#', '', $hexColor);

        if (strlen($color) > 3) {

            $rgb = array(

                'r' => hexdec(substr($color, 0, 2)),

                'g' => hexdec(substr($color, 2, 2)),

                'b' => hexdec(substr($color, 4, 2))

            );

        } else {

            $color = $hexColor;

            $r = substr($color, 0, 1) . substr($color, 0, 1);

            $g = substr($color, 1, 1) . substr($color, 1, 1);

            $b = substr($color, 2, 1) . substr($color, 2, 1);

            $rgb = array(

                'r' => hexdec($r),

                'g' => hexdec($g),

                'b' => hexdec($b)

            );

        }

        return $rgb;

    }